Bio


Lynn Hildemann's current research areas include the sources and dispersion of airborne particulate matter indoors, and assessment of human exposure to air pollutants.

Prof. Hildemann received BS, MS, and PhD degrees in environmental engineering science from the California Institute of Technology. She is an author on >100 peer-reviewed publications, including two with over 1000 citations each, and another 6 with over 500 citations each. She has been honored with Young Investigator Awards from NSF and ONR, the Kenneth T. Whitby Award from the AAAR (1998), and Stanford's Gores Award for Teaching Excellence (2013); she also was a co-recipient of Atmospheric Environment’s Haagen-Smit Outstanding Paper Award (2001).

She has served on advisory committees for the Bay Area Air Quality Management District and for the California Air Resources Board. She has been an Associate Editor for Environmental Science & Technology, and Aerosol Science and Technology, and has served on the advisory board for the journal Environmental Science & Technology.

At Stanford, Prof. Hildemann has been chair of the Department of Civil & Environmental Engineering, and served as an elected member of the Faculty Senate. She has chaired the School of Engineering Library Committee, the University Committee on Judicial Affairs, and the University Breadth Governance Board.

Academic Appointments


Administrative Appointments


  • Sr. Associate Vice Provost, for Undergraduate Education (2022 - Present)
  • Sr. Associate Dean of Education, Stanford Doerr School of Sustainability (2022 - Present)
  • Department Chair, Civil & Environmental Engineering (2016 - 2021)

Honors & Awards


  • Gerhard Casper University Fellow in Undergraduate Education, Stanford University (2021 - present)
  • Gores Award for Excellence in Teaching, Stanford University (2013)
  • Mentoring Excellence Award, Stanford Chapter, Society of Women Engineers (2010)
  • Haagen-Smit Outstanding Paper Award, Atmospheric Environment (2001)
  • Kenneth T. Whitby Award, American Association for Aerosol Research (1998)
  • Young Investigator Award, Office of Naval Research (1994)
  • Presidential Young Investigator, National Science Foundation (1991)

All Publications


  • PM2.5 exposure to marijuana smoke on golf courses and other public outdoor locations: A pilot observational study. The Science of the total environment Cheng, K., Huang, G., Hildemann, L. M. 2023: 165236

    Abstract

    Secondhand exposure to cannabis smoke occurs in public outdoor locations due to outdoor smoking or leakage of indoor smoking. Very little is known regarding the actual levels of exposure. This study examined PM2.5 exposure to marijuana smoke, focusing on one type of public outdoor location - golf courses where illegal marijuana consumption is increasingly common. Based on 24 visits to 10 courses over a 6-month period, >20 % visits encountered marijuana smoke, with peak PM2.5 exposures up to 149 mug/m3. The levels of exposure depended upon the source type (smoking versus vaping) and the proximity to the smoker/vaper. Ten additional investigations were performed to measure marijuana secondhand exposure in other public outdoor locations (near a smoker in a public park, near a parked car with in-car smoking/vaping, and near a residential garage with indoor smoking/vaping). 23 encounters of marijuana exposure events were documented in total. Average outdoor exposures to PM2.5 close to public outdoor smoking and vaping (on golf courses and a public park) were >3 times as high as those near a car or a building with indoor marijuana emissions. The average outdoor exposure caused by the leakage of in-car secondhand smoke was higher than that caused by in-building emissions.

    View details for DOI 10.1016/j.scitotenv.2023.165236

    View details for PubMedID 37392887

  • Measuring PM2.5 concentrations from secondhand tobacco vs. marijuana smoke in 9 rooms of a detached 2-story house. The Science of the total environment Ott, W. R., Wallace, L. A., Cheng, K., Hildemann, L. M. 2022: 158244

    Abstract

    The widespread legalization of recreational marijuana raises growing concerns about exposure to secondhand marijuana smoke. An important location for marijuana smoking is the home, but few measurements of air pollutant concentrations in the home are available for a marijuana joint fully smoked in one of its rooms. We used research grade calibrated real-time continuous PM2.5 air monitors in controlled 5-hour experiments to measure fine particle concentrations in the 9 rooms of a detached, two-story, 4-bedroom home with either a tobacco cigarette or a marijuana joint fully smoked in the home's living room. The master bedroom's door was closed, and the other bedroom doors were open, as was the custom of occupants of this residence. In two experiments with a Marlboro tobacco cigarette smoked by a machine in the living room, the 5-hour mean PM2.5 concentration in 9 rooms of the home were 15.2 mug/m3 (SD 5.6 mug/m3) and 15.0 mug/m3 (SD 3.7 mug/m3). In contrast, three experiments with pre-rolled marijuana joints smoked in the same manner in the living room produced 5-hour mean PM2.5 concentrations of 38.3 mug/m3 (SD 10.0 mug/m3), 79.8 mug/m3 (SD 25.7 mug/m3) and 80.7 mug/m3 (SD 28.8 mug/m3). In summary, the average secondhand PM2.5 concentrations from smoking a marijuana joint in the home were found to be 4.4 times as great as the secondhand PM2.5 concentrations from smoking a tobacco cigarette. Opening 3 windows by 12.7 cm reduced the high PM2.5 concentrations from marijuana smoking by 67 %, but the PM2.5 levels still exceeded those produced by tobacco smoking with the windows closed.

    View details for DOI 10.1016/j.scitotenv.2022.158244

    View details for PubMedID 36037897

  • Method for estimating the volatility of aerosols using the piezobalance: Examples from vaping e-cigarette and marijuana liquids ATMOSPHERIC ENVIRONMENT Wallace, L. A., Ott, W. R., Cheng, K., Zhao, T., Hildemann, L. 2021; 253
  • Measuring indoor fine particle concentrations, emission rates, and decay rates from cannabis use in a residence ATMOSPHERIC ENVIRONMENT-X Ott, W. R., Zhao, T., Cheng, K., Wallace, L. A., Hildemann, L. M. 2021; 10
  • PM2.5 exposure close to marijuana smoking and vaping: A case study in residential indoor and outdoor settings. The Science of the total environment Cheng, K. C., Ott, W., Wallace, L., Zhu, Y., Hildemann, L. 2021; 802: 149897

    Abstract

    We conducted 35 experiments for spatial measurement of marijuana aerosols in a current smoker's residential spaces. Fine particulate matter (PM2.5) concentrations were measured every second at 1, 2, and 3 m horizontal distances from the smoker who performed prescribed 5-min smoking and vaping activities. In each experiment, five SidePak monitors measured PM2.5 concentrations at five different angles facing the front of the smoker, representing the worst-case exposures. We studied the effect of distance from the smoker for two marijuana sources - smoking a marijuana cigarette, or joint, and vaping a liquid-cartridge vaping pen. Experiments were conducted in the family room indoors and in the backyard outdoors where the smoker normally consumes marijuana. Indoor marijuana vaping had higher average exposures (5-min PM2.5) at 1 m distance than indoor marijuana smoking, but the levels from indoor vaping decreased more rapidly with distance (e.g., 77% reduction for vaping versus 33% for smoking from 1 to 2 m). Smoking and vaping in the outdoor environment reduce the average exposures down to <5% of the indoor levels at each distance. Cumulative frequency distributions of the 1-s PM2.5 concentrations revealed the frequencies of exceeding any selected transient peak exposure limit at a given distance. The frequency of exceedance decreased more quickly with distance for vaping than for smoking. Smoking and vaping outdoors made the transient peak exposures close to the source much less frequent than smoking and vaping indoors (e.g., <1% exceeded 1000 μg/m3 outdoors versus >20% indoors at 1 m). Plotting the frequency of exceedance versus distance could offer additional guidance for a recommended minimum distance from a marijuana source.

    View details for DOI 10.1016/j.scitotenv.2021.149897

    View details for PubMedID 34464798

  • Characteristics of secondhand cannabis smoke from common smoking methods: Calibration factor, emission rate, and particle removal rate ATMOSPHERIC ENVIRONMENT Zhao, T., Cheng, K., Ott, W. R., Wallace, L., Hildemann, L. M. 2020; 242
  • Secondhand exposure from vaping marijuana: Concentrations, emissions, and exposures determined using both research-grade and low-cost monitors ATMOSPHERIC ENVIRONMENT-X Wallace, L., Ott, W., Zhao, T., Cheng, K., Hildemann, L. 2020; 8
  • Impact of fan mixing on air pollutant exposure near indoor sources: An analytical model to connect proximity effect with energy BUILDING AND ENVIRONMENT Cheng, K., Zheng, D., Hildemann, L. M. 2020; 183
  • Using Indoor Positioning and Mobile Sensing for Spatial Exposure and Environmental Characterizations: Pilot Demonstration of PM2.5 Mapping ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Cheng, K., Tseng, C., Hildemann, L. M. 2019; 6 (3): 153–58
  • Effectiveness of air purifier on health outcomes and indoor particles in homes of children with allergic diseases in Fresno, California: A pilot study JOURNAL OF ASTHMA Park, H., Cheng, K., Tetteh, A. O., Hildemann, L. M., Nadeau, K. C. 2017; 54 (4): 341-346

    Abstract

    Epidemiologic studies indicate that indoor air pollution is correlated with morbidity caused by allergic diseases. We evaluated the effectiveness of reducing the levels of indoor fine particulate matter <2.5 micrometer diameter (PM2.5) in Fresno, California using air purifiers on health outcomes in children with asthma and/or allergic rhinitis.The active group (with air purifiers) and the control group consisted of eight houses each. Air purifiers were installed in the living rooms and bedrooms of the subjects in the active group during the entire 12-week study duration. Childhood asthma control test, peak flow rate monitoring, and nasal symptom scores were evaluated at weeks 0, 6, and 12.At 12 weeks, the active group showed a trend toward an improvement of childhood asthma control test scores and mean evening peak flow rates, whereas the control group showed deterioration in the same measures. Total and daytime nasal symptoms scores significantly reduced in the active group (p = 0.001 and p = 0.011, respectively). The average indoor PM2.5 concentrations reduced by 43% (7.42 to 4.28 μg/m(3)) in the active group (p = 0.001).Intervention with air purifiers reduces indoor PM2.5 levels with significant improvements in nasal symptoms in children with allergic rhinitis in Fresno.

    View details for DOI 10.1080/02770903.2016.1218011

    View details for Web of Science ID 000400169700002

  • Fine and ultrafine particle exposures on 73 trips by car to 65 non-smoking restaurants in the San Francisco Bay Area INDOOR AIR Ott, W. R., Wallace, L. A., McAteer, J. M., Hildemann, L. M. 2017; 27 (1): 205-217

    Abstract

    A number of studies indicate cooking is a major source of exposure to particulate matter, but few studies have measured indoor air pollution in restaurants, where cooking predominates. We made 73 visits by car to 65 different non-smoking restaurants in 10 Northern California towns while carrying portable continuous monitors that unobtrusively measured ultrafine (down to 10 nm) and fine (PM2.5 ) particles to characterize indoor restaurant exposures, comparing them with exposures in the car. The mean ultrafine number concentrations in the restaurants on dinner visits averaging 1.4 h was 71 600 particles/cm(3) , or 4.3 times the mean concentration on car trips, and 12.3 times the mean background concentration in the residence. Restaurants that cooked dinner in the same room as the patrons had higher ultrafine concentrations than restaurants with separate kitchens. Restaurant PM2.5 mass concentrations averaged 36.3 μg/m(3) , ranging from 1.5 to 454 μg/m(3) , but were relatively low on most visits: 43% of the indoor means were below 10 μg/m(3) and 66% were below 20 μg/m(3) , with 5.5% above 100 μg/m(3) . Exposure to fine and ultrafine particles when visiting a restaurant exceeded the exposure a person received while traveling by car to and from the restaurant.

    View details for DOI 10.1111/ina.12292

    View details for Web of Science ID 000391032600019

    View details for PubMedID 26895613

  • Effectiveness of air purifier on health outcomes and indoor particles in homes of children with allergic diseases in Fresno, California: A pilot study. journal of asthma Park, H., Cheng, K., Tetteh, A. O., Hildemann, L. M., Nadeau, K. C. 2016: 1-6

    Abstract

    Epidemiologic studies indicate that indoor air pollution is correlated with morbidity caused by allergic diseases. We evaluated the effectiveness of reducing the levels of indoor fine particulate matter <2.5 micrometer diameter (PM2.5) in Fresno, California using air purifiers on health outcomes in children with asthma and/or allergic rhinitis.The active group (with air purifiers) and the control group consisted of eight houses each. Air purifiers were installed in the living rooms and bedrooms of the subjects in the active group during the entire 12-week study duration. Childhood asthma control test, peak flow rate monitoring, and nasal symptom scores were evaluated at weeks 0, 6, and 12.At 12 weeks, the active group showed a trend toward an improvement of childhood asthma control test scores and mean evening peak flow rates, whereas the control group showed deterioration in the same measures. Total and daytime nasal symptoms scores significantly reduced in the active group (p = 0.001 and p = 0.011, respectively). The average indoor PM2.5 concentrations reduced by 43% (7.42 to 4.28 μg/m(3)) in the active group (p = 0.001).Intervention with air purifiers reduces indoor PM2.5 levels with significant improvements in nasal symptoms in children with allergic rhinitis in Fresno.

    View details for PubMedID 27723364

  • Personal exposure to airborne particulate matter due to residential dryer lint cleaning BUILDING AND ENVIRONMENT Cheng, K., Zheng, D., Tetteh, A. O., Park, H., Nadeau, K. C., Hildemann, L. M. 2016; 98: 145-149
  • Mixing and sink effects of air purifiers on indoor PM2.5 concentrations: A pilot study of eight residential homes in Fresno, California AEROSOL SCIENCE AND TECHNOLOGY Cheng, K., Park, H., Tetteh, A. O., Zheng, D., Ouellette, N. T., Nadeau, K. C., Hildemann, L. M. 2016; 50 (8): 835-845
  • Measuring Indoor Air Quality and Engaging California Indian Stakeholders at the Win-River Resort and Casino: Collaborative Smoke-Free Policy Development. International journal of environmental research and public health Klepeis, N. E., Dhaliwal, N., Hayward, G., Acevedo-Bolton, V., Ott, W. R., Read, N., Layton, S., Jiang, R., Cheng, K., Hildemann, L. M., Repace, J. L., Taylor, S., Ong, S., Buchting, F. O., Lee, J. P., Moore, R. S. 2016; 13 (1)

    Abstract

    Most casinos owned by sovereign American Indian nations allow smoking, even in U.S. states such as California where state laws restrict workplace smoking. Collaborations between casinos and public health workers are needed to promote smoke-free policies that protect workers and patrons from secondhand tobacco smoke (SHS) exposure and risks. Over seven years, a coalition of public health professionals provided technical assistance to the Redding Rancheria tribe in Redding, California in establishing a smoke-free policy at the Win-River Resort and Casino. The coalition provided information to the casino general manager that included site-specific measurement of employee and visitor PM2.5 personal exposure, area concentrations of airborne nicotine and PM2.5, visitor urinary cotinine, and patron and staff opinions (surveys, focus groups, and a Town Hall meeting). The manager communicated results to tribal membership, including evidence of high SHS exposures and support for a smoke-free policy. Subsequently, in concert with hotel expansion, the Redding Rancheria Tribal Council voted to accept a 100% restriction of smoking inside the casino, whereupon PM2.5 exposure in main smoking areas dropped by 98%. A 70% partial-smoke-free policy was instituted ~1 year later in the face of revenue loss. The success of the collaboration in promoting a smoke-free policy, and the key element of air quality feedback, which appeared to be a central driver, may provide a model for similar efforts.

    View details for DOI 10.3390/ijerph13010143

    View details for PubMedID 26805860

    View details for PubMedCentralID PMC4730534

  • Determining PM2.5 calibration curves for a low-cost particle monitor: common indoor residential aerosols ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS Dacunto, P. J., Klepeis, N. E., Cheng, K., Acevedo-Bolton, V., Jiang, R., Repace, J. L., Otta, W. R., Hildemann, L. M. 2015; 17 (11): 1959-1966

    Abstract

    Real-time particle monitors are essential for accurately estimating exposure to fine particles indoors. However, many such monitors tend to be prohibitively expensive for some applications, such as a tenant or homeowner curious about the quality of the air in their home. A lower cost version (the Dylos Air Quality Monitor) has recently been introduced, but it requires appropriate calibration to reflect the mass concentration units required for exposure assessment. We conducted a total of 64 experiments with a suite of instruments including a Dylos DC1100, another real-time laser photometer (TSI SidePak™ Model AM-510 Personal Aerosol Monitor), and a gravimetric sampling apparatus to estimate Dylos calibration factors for emissions from 17 different common indoor sources including cigarettes, incense, fried bacon, chicken, and hamburger. Comparison of minute-by-minute data from the Dylos with the gravimetrically calibrated SidePak yielded relationships that enable the conversion of the raw Dylos particle counts less than 2.5 μm (in #/0.01 ft(3)) to estimated PM2.5 mass concentration (e.g. μg m(-3)). The relationship between the exponentially-decaying Dylos particle counts and PM2.5 mass concentration can be described by a theoretically-derived power law with source-specific empirical parameters. A linear relationship (calibration factor) is applicable to fresh or quickly decaying emissions (i.e., before the aerosol has aged and differential decay rates introduce curvature into the relationship). The empirical parameters for the power-law relationships vary greatly both between and within source types, although linear factors appear to have lower uncertainty. The Dylos Air Quality Monitor is likely most useful for providing instantaneous feedback and context on mass particle levels in home and work situations for field-survey or personal awareness applications.

    View details for DOI 10.1039/c5em00365b

    View details for Web of Science ID 000364146800010

    View details for PubMedID 26487426

  • Surface tensions of solutions containing dicarboxylic acid mixtures ATMOSPHERIC ENVIRONMENT Lee, J. Y., Hildemann, L. M. 2014; 89: 260-267
  • Stochastic modeling of short-term exposure close to an air pollution source in a naturally ventilated room: An autocorrelated random walk method JOURNAL OF EXPOSURE SCIENCE AND ENVIRONMENTAL EPIDEMIOLOGY Cheng, K., Acevedo-Bolton, V., Jiang, R., Klepeis, N. E., Ott, W. R., Kitanidis, P. K., Hildemann, L. M. 2014; 24 (3): 311-318

    Abstract

    For an actively emitting source such as cooking or smoking, indoor measurements have shown a strong "proximity effect" within 1 m. The significant increase in both the magnitude and variation of concentration near a source is attributable to transient high peaks that occur sporadically-and these "microplumes" cause great uncertainty in estimating personal exposure. Recent field studies in naturally ventilated rooms show that close-proximity concentrations are approximately lognormally distributed. We use the autocorrelated random walk method to represent the time-varying directionality of indoor emissions, thereby predicting the time series and frequency distributions of concentrations close to an actively emitting point source. The predicted 5-min concentrations show good agreement with measurements from a point source of CO in a naturally ventilated house-the measured and predicted frequency distributions at 0.5- and 1-m distances are similar and approximately lognormal over a concentration range spanning three orders of magnitude. By including the transient peak concentrations, this random airflow modeling method offers a way to more accurately assess acute exposure levels for cases where well-defined airflow patterns in an indoor space are not available.

    View details for DOI 10.1038/jes.2013.63

    View details for Web of Science ID 000334571000011

    View details for PubMedID 24064529

  • Controlled experiments measuring personal exposure to PM2.5 in close proximity to cigarette smoking. Indoor air Acevedo-Bolton, V., Ott, W. R., Cheng, K., Jiang, R., Klepeis, N. E., Hildemann, L. M. 2014; 24 (2): 199-212

    Abstract

    Few measurements of exposure to secondhand smoke (SHS) in close proximity to a smoker are available. Recent health studies have demonstrated an association between acute (< 2 h) exposures to high concentrations of SHS and increased risk for cardiovascular and respiratory disease. We performed 15 experiments inside naturally-ventilated homes and 16 in outdoor locations, each with 2-4 nonsmokers sitting near a cigarette smoker. The smoker's and nonsmokers' real-time exposures to PM2.5 from SHS were measured by using TSI SidePak monitors to sample their breathing zones. In 87% of the residential indoor experiments, the smoker received the highest average exposure to SHS, with PM2.5 concentrations ranging from 50-630 μg/m(3) . During the active smoking period, individual nonsmokers sitting within ~1 m of a smoker had average SHS exposures ranging from negligible up to >160 μg/m(3) of PM2.5 . The average incremental exposure of the nonsmokers was higher indoors (42 μg/m(3) , n = 35) than outdoors (29 μg/m(3) , n = 47), but the overall indoor and outdoor frequency distributions were similar. The 10-s PM2.5 averages during the smoking periods showed great variability, with multiple high concentrations of short duration (microplumes) both indoors and outdoors. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/ina.12057

    View details for PubMedID 23808850

  • Identifying and quantifying secondhand smoke in source and receptor rooms: logistic regression and chemical mass balance approaches. Indoor air Dacunto, P. J., Cheng, K., Acevedo-Bolton, V., Jiang, R., Klepeis, N. E., Repace, J. L., Ott, W. R., Hildemann, L. M. 2014; 24 (1): 59-70

    Abstract

    Identifying and quantifying secondhand tobacco smoke (SHS) that drifts between multiunit homes is critical to assessing exposure. Twenty-three different gaseous and particulate measurements were taken during controlled emissions from smoked cigarettes and six other common indoor source types in 60 single-room and 13 two-room experiments. We used measurements from the 60 single-room experiments for (i) the fitting of logistic regression models to predict the likelihood of SHS and (ii) the creation of source profiles for chemical mass balance (CMB) analysis to estimate source apportionment. We then applied these regression models and source profiles to the independent data set of 13 two-room experiments. Several logistic regression models correctly predicted the presence of cigarette smoke more than 80% of the time in both source and receptor rooms, with one model correct in 100% of applicable cases. CMB analysis of the source room provided significant PM2.5 concentration estimates of all true sources in 9 of 13 experiments and was half-correct (i.e., included an erroneous source or missed a true source) in the remaining four. In the receptor room, CMB provided significant estimates of all true sources in 9 of 13 experiments and was half-correct in another two.

    View details for DOI 10.1111/ina.12049

    View details for PubMedID 23631597

  • Outdoor fine and ultrafine particle measurements at six bus stops with smoking on two California arterial highways-Results of a pilot study JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION Ott, W. R., Acevedo-Bolton, V., Cheng, K., Jiang, R., Klepeis, N. E., Hildemann, L. M. 2014; 64 (1): 47-60

    Abstract

    As indoor smoking bans have become widely adopted, some U.S. communities are considering restricting smoking outdoors, creating a need for measurements of air pollution near smokers outdoors. Personal exposure experiments were conducted with four to five participants at six sidewalk bus stops located 1.5-3.3 m from the curb of two heavily traveled California arterial highways with 3300-5100 vehicles per hour. At each bus stop, a smoker in the group smoked a cigarette. Gravimetrically calibrated continuous monitors were used to measure fine particle concentrations (aerodynamic diameter < or = 2.5 microm; PM2.5) in the breathing zones (within 0.2 m from the nose and mouth) of each participant. At each bus stop, ultrafine particles (UFP), wind speed, temperature, relative humidity, and traffic counts were also measured. For 13 cigarette experiments, the mean PM2.5 personal exposure of the nonsmoker seated 0.5 m from the smoker during a 5-min cigarette ranged from 15 to 153 microg/m3. Of four persons seated on the bench, the smoker received the highest PM2.5 breathing-zone exposure of 192 microg/m3. There was a strong proximity effect: nonsmokers at distances 0.5, 1.0, and 1.5 m from the smoker received mean PM2.5 personal exposures of 59, 40, and 28 microg/m3, respectively, compared with a background level of 1.7 microg/m3. Like the PM2.5 concentrations, UFP concentrations measured 0.5 m from the smoker increased abruptly when a cigarette started and decreased when the cigarette ended, averaging 44,500 particles/cm3 compared with the background level of 7200 particles/cm3. During nonsmoking periods, the UFP background concentrations showed occasional peaks due to traffic, whereas PM2.5 background concentrations were extremely low. The results indicate that a single cigarette smoked outdoors at a bus stop can cause PM2.5 and UFP concentrations near the smoker that are 16-35 and 6.2 times, respectively, higher than the background concentrations due to cars and trucks on an adjacent arterial highway.Rules banning smoking indoors have been widely adopted in the United States and in many countries. Some communities are considering smoking bans that would apply to outdoor locations. Although many measurements are available of pollutant concentrations from secondhand smoke at indoor locations, few measurements are available of exposure to secondhand smoke outdoors. This study provides new data on exposure to fine and ultrafine particles from secondhand smoke near a smoker outdoors. The levels are compared with the exposure measured next to a highway. The findings are important for policies that might be developed for reducing exposure to secondhand smoke outdoors.

    View details for DOI 10.1080/10962247.2013.832712

    View details for Web of Science ID 000328535100006

  • Surface tension of solutions containing dicarboxylic acids with ammonium sulfate, D-glucose, or humic acid JOURNAL OF AEROSOL SCIENCE Lee, J. Y., Hildemann, L. M. 2013; 64: 94-102
  • Identifying and quantifying secondhand smoke in multiunit homes with tobacco smoke odor complaints ATMOSPHERIC ENVIRONMENT Dacunto, P. J., Cheng, K., Acevedo-Bolton, V., Klepeis, N. E., Repace, J. L., Ott, W. R., Hildemann, L. M. 2013; 71: 399-407
  • Experimental study on visible-light induced photocatalytic oxidation of gaseous formaldehyde by polyester fiber supported photocatalysts CHEMICAL ENGINEERING JOURNAL Han, Z., Chang, V., Wang, X., Lim, T., Hildemann, L. 2013; 218: 9-18
  • Real-time particle monitor calibration factors and PM2.5 emission factors for multiple indoor sources ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS Dacunto, P. J., Cheng, K., Acevedo-Bolton, V., Jiang, R., Klepeis, N. E., Repace, J. L., Ott, W. R., Hildemann, L. M. 2013; 15 (8): 1511-1519

    Abstract

    Indoor sources can greatly contribute to personal exposure to particulate matter less than 2.5 μm in diameter (PM2.5). To accurately assess PM2.5 mass emission factors and concentrations, real-time particle monitors must be calibrated for individual sources. Sixty-six experiments were conducted with a common, real-time laser photometer (TSI SidePak™ Model AM510 Personal Aerosol Monitor) and a filter-based PM2.5 gravimetric sampler to quantify the monitor calibration factors (CFs), and to estimate emission factors for common indoor sources including cigarettes, incense, cooking, candles, and fireplaces. Calibration factors for these indoor sources were all significantly less than the factory-set CF of 1.0, ranging from 0.32 (cigarette smoke) to 0.70 (hamburger). Stick incense had a CF of 0.35, while fireplace emissions ranged from 0.44-0.47. Cooking source CFs ranged from 0.41 (fried bacon) to 0.65-0.70 (fried pork chops, salmon, and hamburger). The CFs of combined sources (e.g., cooking and cigarette emissions mixed) were linear combinations of the CFs of the component sources. The highest PM2.5 emission factors per time period were from burned foods and fireplaces (15-16 mg min(-1)), and the lowest from cooking foods such as pizza and ground beef (0.1-0.2 mg min(-1)).

    View details for DOI 10.1039/c3em00209h

    View details for Web of Science ID 000322177300004

    View details for PubMedID 23784066

  • Comparisons between Hygroscopic Measurements and UNIFAC Model Predictions for Dicarboxylic Organic Aerosol Mixtures ADVANCES IN METEOROLOGY Lee, J. Y., Hildemann, L. M. 2013
  • Preparation of TiO2-Coated Polyester Fiber Filter by Spray-Coating and Its Photocatalytic Degradation of Gaseous Formaldehyde AEROSOL AND AIR QUALITY RESEARCH Han, Z., Chang, V. W., Zhang, L., Tse, M. S., Tan, O. K., Hildemann, L. M. 2012; 12 (6): 1327-1335
  • Low demand for nontraditional cookstove technologies PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Mobarak, A. M., Dwivedi, P., Bailis, R., Hildemann, L., Miller, G. 2012; 109 (27): 10815-10820

    Abstract

    Biomass combustion with traditional cookstoves causes substantial environmental and health harm. Nontraditional cookstove technologies can be efficacious in reducing this adverse impact, but they are adopted and used at puzzlingly low rates. This study analyzes the determinants of low demand for nontraditional cookstoves in rural Bangladesh by using both stated preference (from a nationally representative survey of rural women) and revealed preference (assessed by conducting a cluster-randomized trial of cookstove prices) approaches. We find consistent evidence across both analyses suggesting that the women in rural Bangladesh do not perceive indoor air pollution as a significant health hazard, prioritize other basic developmental needs over nontraditional cookstoves, and overwhelmingly rely on a free traditional cookstove technology and are therefore not willing to pay much for a new nontraditional cookstove. Efforts to improve health and abate environmental harm by promoting nontraditional cookstoves may be more successful by designing and disseminating nontraditional cookstoves with features valued more highly by users, such as reduction of operating costs, even when those features are not directly related to the cookstoves' health and environmental impacts.

    View details for DOI 10.1073/pnas.1115571109

    View details for Web of Science ID 000306641100027

    View details for PubMedID 22689941

    View details for PubMedCentralID PMC3390883

  • Measurement of the proximity effect for indoor air pollutant sources in two homes JOURNAL OF ENVIRONMENTAL MONITORING Acevedo-Bolton, V., Cheng, K., Jiang, R., Ott, W. R., Klepeis, N. E., Hildemann, L. M. 2012; 14 (1): 94-104

    Abstract

    Personal exposure to air pollutants can be substantially higher in close proximity to an active source due to non-instantaneous mixing of emissions. The research presented in this paper quantifies this proximity effect for a non-buoyant source in 2 naturally ventilated homes in Northern California (CA), assessing its spatial and temporal variation and the influence of factors such as ventilation rate on its magnitude. To quantify how proximity to residential sources of indoor air pollutants affects human exposure, we performed 16 separate monitoring experiments in the living rooms of two detached single-family homes. CO (as a tracer gas) was released from a point source in the center of the room at a controlled emission rate for 5-12 h per experiment, while an array of 30-37 real-time monitors simultaneously measured CO concentrations with 15 s time resolution at radial distances ranging from 0.25-5 m under a range of ventilation conditions. Concentrations measured in close proximity (within 1 m) to the source were highly variable, with 5 min averages that typically varied by >100-fold. This variability was due to short-duration (<1 min) pollutant concentration peaks ("microplumes") that were frequently recorded in close proximity to the source. We decomposed the random microplume component from the total concentrations by subtracting predicted concentrations that assumed uniform, instantaneous mixing within the room and found that these microplumes can be modeled using a 3-parameter lognormal distribution. Average concentrations measured within 0.25 m of the source were 6-20 times as high as the predicted well-mixed concentrations.

    View details for DOI 10.1039/c1em10521c

    View details for Web of Science ID 000298855800012

    View details for PubMedID 22068152

  • Determination of response of real-time SidePak AM510 monitor to secondhand smoke, other common indoor aerosols, and outdoor aerosol JOURNAL OF ENVIRONMENTAL MONITORING Jiang, R., Acevedo-Bolton, V., Cheng, K., Klepeis, N. E., Ott, W. R., Hildemann, L. M. 2011; 13 (6): 1695-1702

    Abstract

    The amount of light scattered by airborne particles inside an aerosol photometer will vary not only with the mass concentration, but also with particle properties such as size, shape, and composition. This study conducted controlled experiments to compare the measurements of a real-time photometer, the SidePak AM510 monitor (SidePak), with gravimetric mass. PM sources tested were outdoor aerosols, and four indoor combustion sources: cigarettes, incense, wood chips, and toasting bread. The calibration factor for rescaling the SidePak measurements to agree with gravimetric mass was similar for the cigarette and incense sources, but different for burning wood chips and toasting bread. The calibration factors for ambient urban aerosols differed substantially from day to day, due to variations in the sources and composition of outdoor PM. A field evaluation inside a casino with active smokers yielded calibration factors consistent with those obtained in the controlled experiments with cigarette smoke.

    View details for DOI 10.1039/c0em00732c

    View details for Web of Science ID 000291403300019

    View details for PubMedID 21589975

  • Fine particle air pollution and secondhand smoke exposures and risks inside 66 US casinos ENVIRONMENTAL RESEARCH Repace, J. L., Jiang, R., Acevedo-Bolton, V., Cheng, K., Klepeis, N. E., Ott, W. R., Hildemann, L. M. 2011; 111 (4): 473-484

    Abstract

    Smoking bans often exempt casinos, exposing occupants to fine particles (PM(2.5)) from secondhand smoke. We quantified the relative contributions to PM(2.5) from both secondhand smoke and infiltrating outdoor sources in US casinos. We measured real-time PM(2.5), particulate polycyclic aromatic hydrocarbons (PPAH), and carbon dioxide (CO(2)) (as an index of ventilation rate) inside and outside 8 casinos in Reno, Nevada. We combined these data with data from previous studies, yielding a total of 66 US casinos with smoking in California, Delaware, Nevada, New Jersey, and Pennsylvania, developing PM(2.5) frequency distributions, with 3 nonsmoking casinos for comparison. Geometric means for PM(2.5) were 53.8 μg/m(3) (range 18.5-205 μg/m(3)) inside smoking casinos, 4.3 μg/m(3) (range 0.26-29.7 μg/m(3)) outside those casinos, and 3.1 μg/m(3) (range 0.6-9 μg/m(3)) inside 3 nonsmoking casinos. In a subset of 21 Reno and Las Vegas smoking casinos, PM(2.5) in gaming areas averaged 45.2 μg/m(3) (95% CI, 37.7-52.7 μg/m(3)); adjacent nonsmoking casino restaurants averaged 27.2 μg/m(3) (95% CI, 17.5-36.9 μg/m(3)), while PM(2.5) outside the casinos averaged 3.9 μg/m(3) (95% CI, 2.5-5.3 μg/m(3)). For a subset of 10 Nevada and Pennsylvania smoking casinos, incremental (indoor-outdoor) PM(2.5) was correlated with incremental PPAH (R(2)=0.79), with ventilation rate-adjusted smoker density (R(2)=0.73), and with smoker density (R(2)=0.60), but not with ventilation rates (R(2)=0.15). PPAH levels in 8 smoking casinos in 3 states averaged 4 times outdoors. The nonsmoking casinos' PM(2.5) (n=3) did not differ from outdoor levels, nor did their PPAH (n=2). Incremental PM(2.5) from secondhand smoke in approximately half the smoking casinos exceeded a level known to produce cardiovascular morbidity in nonsmokers after less than 2h of exposure, posing acute health risks to patrons and workers. Casino ventilation and air cleaning practices failed to control secondhand smoke PM(2.5). Drifting PM(2.5) from secondhand smoke contaminated unseparated nonsmoking areas. Smoke-free casinos reduced PM(2.5) to the same low levels found outdoors.

    View details for DOI 10.1016/j.envres.2011.02.007

    View details for Web of Science ID 000290141600001

    View details for PubMedID 21440253

  • Modeling Exposure Close to Air Pollution Sources in Naturally Ventilated Residences: Association of Turbulent Diffusion Coefficient with Air Change Rate ENVIRONMENTAL SCIENCE & TECHNOLOGY Cheng, K., Acevedo-Bolton, V., Jiang, R., Klepeis, N. E., Ott, W. R., Fringer, O. B., Hildemann, L. M. 2011; 45 (9): 4016-4022

    Abstract

    For modeling exposure close to an indoor air pollution source, an isotropic turbulent diffusion coefficient is used to represent the average spread of emissions. However, its magnitude indoors has been difficult to assess experimentally due to limitations in the number of monitors available. We used 30-37 real-time monitors to simultaneously measure CO at different angles and distances from a continuous indoor point source. For 11 experiments involving two houses, with natural ventilation conditions ranging from <0.2 to >5 air changes per h, an eddy diffusion model was used to estimate the turbulent diffusion coefficients, which ranged from 0.001 to 0.013 m² s⁻¹. The model reproduced observed concentrations with reasonable accuracy over radial distances of 0.25-5.0 m. The air change rate, as measured using a SF₆ tracer gas release, showed a significant positive linear correlation with the air mixing rate, defined as the turbulent diffusion coefficient divided by a squared length scale representing the room size. The ability to estimate the indoor turbulent diffusion coefficient using two readily measurable parameters (air change rate and room dimensions) is useful for accurately modeling exposures in close proximity to an indoor pollution source.

    View details for DOI 10.1021/es103080p

    View details for Web of Science ID 000289819400033

    View details for PubMedID 21456572

  • Measurement of fine particles and smoking activity in a statewide survey of 36 California Indian casinos JOURNAL OF EXPOSURE SCIENCE AND ENVIRONMENTAL EPIDEMIOLOGY Jiang, R., Cheng, K., Acevedo-Bolton, V., Klepeis, N. E., Repace, J. L., Ott, W. R., Hildemann, L. M. 2011; 21 (1): 31-41

    Abstract

    Despite California's 1994 statewide smoking ban, exposure to secondhand smoke (SHS) continues in California's Indian casinos. Few data are available on exposure to airborne fine particles (PM₂.₅) in casinos, especially on a statewide basis. We sought to measure PM₂.₅ concentrations in Indian casinos widely distributed across California, exploring differences due to casino size, separation of smoking and non-smoking areas, and area smoker density. A selection of 36 out of the 58 Indian casinos throughout California were each visited for 1-3 h on weekend or holiday evenings, using two or more concealed monitors to measure PM₂.₅ concentrations every 10 s. For each casino, the physical dimensions and the number of patrons and smokers were estimated. As a preliminary assessment of representativeness, we also measured eight casinos in Reno, NV. The average PM₂.₅ concentration for the smoking slot machine areas (63 μg/m³) was nine times as high as outdoors (7 μg/m³), whereas casino non-smoking restaurants (29 μg/m³) were four times as high. Levels in non-smoking slot machine areas varied: complete physical separation reduced concentrations almost to outdoor levels, but two other separation types had mean levels that were 13 and 29 μg/m³, respectively, higher than outdoors. Elevated PM₂.₅ concentrations in casinos can be attributed primarily to SHS. Average PM₂.₅ concentrations during 0.5-1 h visits to smoking areas exceeded 35 μg/m³ for 90% of the casino visits.

    View details for DOI 10.1038/jes.2009.75

    View details for Web of Science ID 000285452900006

    View details for PubMedID 20160761

    View details for PubMedCentralID PMC3007589

  • Contributions of Foot Traffic and Outdoor Concentrations to Indoor Airborne Aspergillus AEROSOL SCIENCE AND TECHNOLOGY Goebes, M. D., Boehm, A. B., Hildemann, L. M. 2011; 45 (3): 352-363
  • Association of size-resolved airborne particles with foot traffic inside a carpeted hallway ATMOSPHERIC ENVIRONMENT Cheng, K., Goebes, M. D., Hildemann, L. M. 2010; 44 (16): 2062-2066
  • Measuring and modeling the composition and temperature-dependence of surface tension for organic solutions ATMOSPHERIC ENVIRONMENT Aumann, E., Hildemann, L. M., Tabazadeh, A. 2010; 44 (3): 329-337
  • Model-based reconstruction of the time response of electrochemical air pollutant monitors to rapidly varying concentrations JOURNAL OF ENVIRONMENTAL MONITORING Cheng, K., Acevedo-Bolton, V., Jiang, R., Klepeis, N. E., Ott, W. R., Hildemann, L. M. 2010; 12 (4): 846-853

    Abstract

    Electrochemical sensors are commonly used to measure concentrations of gaseous air pollutants in real time, especially for personal exposure investigations. The monitors are small, portable, and have suitable response times for estimating time-averaged concentrations. However, for transient exposures to air pollutants lasting only seconds to minutes, a non-instantaneous time response can cause measured values to diverge from actual input concentrations, especially when the pollutant fluctuations are pronounced and rapid. Using 38 Langan carbon monoxide (CO) monitors, which can be set to log data every 2 s, we found electrochemical sensor response times of 30-50 s. We derived a simple model based on Fick's Law to reconstruct a close to accurate time series from logged data. Starting with experimentally measured data for repetitive step input signals of alternating high and low CO concentrations, we were able to reconstruct a much improved 2-s concentration time series using the model. We also utilized the model to examine errors in monitor measurements for different averaging times. By selecting the averaging time based on the response time of the monitor, the error between actual and measured pollutant levels can be minimized. The methodology presented in this study is useful when aiming to accurately determine a time series of rapidly time-varying concentrations, such as for locations close to an active point source or near moving traffic.

    View details for DOI 10.1039/b921806h

    View details for Web of Science ID 000276532100007

    View details for PubMedID 20383365

  • The Effects of Human Activities on Exposure to Particulate Matter and Bioaerosols in Residential Homes ENVIRONMENTAL SCIENCE & TECHNOLOGY Chen, Q., Hildemann, L. M. 2009; 43 (13): 4641-4646

    Abstract

    Indoor and outdoor airborne particle mass, protein, endotoxin and (1 --> 3)-beta-D-glucan in three size fractions (PM2.5, PM10, and TSP) were measured in ten single-family homes, along with quantifying household activities in the sampling room. Correlations between human activity levels and elevations in the indoor concentrations of particles and biomarkers were evaluated using four approaches for distinguishing activity levels: diurnal differences, the number of occupants, self-estimated occupancy, and activity strength. The concentrations of particles, protein, endotoxin and (1 --> 3)-beta-D-glucan in all three size fractions (PM < 2.5 microm, PM10-2.5, and PM >10 microm) were found, in most cases, to be significantly elevated during the day, and with higher activity levels in the room. The coarser fractions of particle mass and bioaerosols were more strongly correlated with human activity levels. Activity strength was the most statistically robust measure for relating human activities to indoor bioaerosol levels. While self-estimated activity and analysis of diurnal differences both offer reasonable (but not perfect) alternatives to activity strength, the number of occupants appears to be a weaker indicator for homes.

    View details for DOI 10.1021/es802296j

    View details for Web of Science ID 000267435500007

    View details for PubMedID 19673245

  • Wind Tunnel Measurements of the Dilution of Tailpipe Emissions Downstream of a Car, a Light-Duty Truck, and a Heavy-Duty Truck Tractor Head JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION Chang, V. W., Hildemann, L. M., Chang, C. 2009; 59 (6): 704-714

    Abstract

    The particle and gaseous pollutants in vehicle exhaust emissions undergo rapid dilution with ambient air after exiting the tailpipe. The rate and extent of this dilution can greatly affect both the size evolution of primary exhaust particles and the potential for formation of ultrafine particles. Dilution ratios were measured inside of a wind tunnel in the region immediately downstream of the tailpipe using model vehicles (approximately one-fifth to one-seventh scale models) representing a light-duty truck, a passenger car, and a heavy-duty tractor head (without the trailer). A tracer gas (ethene) was released at a measured flow rate from the tailpipe, and 60 sampling probes placed downstream of the vehicle simultaneously sampled gas tracer concentrations in the near-wake (first few vehicle heights) and far-wake regions (beyond 10 vehicle heights). Tests using different tunnel wind speeds show the range of dilution ratios that can be expected as a function of vehicle type and downstream distance (i.e., time). The vehicle shape quite strongly influences dilution profiles in the near-wake region but is much less important in the far-wake region. The tractor generally produces higher dilution rates than the automobile and light-duty truck under comparable conditions.

    View details for DOI 10.3155/1047-3289.59.6.704

    View details for Web of Science ID 000266797400006

    View details for PubMedID 19603738

  • Dilution Rates for Tailpipe Emissions: Effects of Vehicle Shape, Tailpipe Position, and Exhaust Velocity JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION Chang, V. W., Hildemann, L. M., Chang, C. 2009; 59 (6): 715-724

    Abstract

    The rate at which motor vehicle exhaust undergoes dilution with ambient air will greatly affect the size distribution characteristics of the particulate emissions. Wind tunnel experiments were conducted to investigate the impacts of vehicle shape, tailpipe orientation, and exhaust exit velocity on the dilution profiles under steady driving conditions for three model vehicles: a light-duty truck, a passenger car, and a heavy-duty tractor head. A three dimensional array of 60 sensors provided simultaneous measurements of dilution ratios for the emissions in the near- and far-wake regions downstream of the vehicle. The processes underlying the observations were investigated via nondimensionalization. Many of the trends seen substantially downstream can be well generalized using a simple nondimensionalization technique; however, this is not true in the near-wake region (within a downstream distance equivalent to a few vehicle heights). In the near-wake region, using the vehicle width and length to normalize for the vehicle shape is not enough to fully account for the variations seen. Including the exhaust flow rate in the nondimensionalization process is effective further downwind but does not adequately capture the complexity in the near-wake region. Tailpipe orientation and location are also shown to be influential factors affecting the near-wake dilution characteristics.

    View details for DOI 10.3155/1047-3289.59.6.715

    View details for Web of Science ID 000266797400007

    View details for PubMedID 19603739

  • Effect of interior door position on room-to-room differences in residential pollutant concentrations after short-term releases ATMOSPHERIC ENVIRONMENT Ferro, A. R., Klepeis, N. E., Ott, W. R., Nazaroff, W. W., Hildemann, L. M., Switzer, P. 2009; 43 (3): 706-714
  • Size-Resolved Concentrations of Particulate Matter and Bioaerosols Inside versus Outside of Homes AEROSOL SCIENCE AND TECHNOLOGY Chen, Q., Hildemann, L. M. 2009; 43 (7): 699-713
  • Effect of building construction on Aspergillus concentrations in a hospital INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY Goebes, M. D., Baron, E. J., Mathews, K. L., Hildemann, L. M. 2008; 29 (5): 462-464

    Abstract

    Air samples taken in a hospital undergoing construction and analyzed with a quantitative polymerase chain reaction (qPCR) assay for the Aspergillus genus did not show elevated concentrations of Aspergillus or particulate matter with a diameter of 5 microm or less in patient areas. Air samples from the construction zone indicated the containment system, which used polyethylene film barrier and negative pressure, was effective.

    View details for DOI 10.1086/587189

    View details for Web of Science ID 000254898800016

    View details for PubMedID 18419373

  • ENHANCED ACUTE RESPONSES IN AN EXPERIMENTAL EXPOSURE MODEL TO BIOMASS SMOKE INHALATION IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE EXPERIMENTAL LUNG RESEARCH Mattson, J. D., Haus, B. M., Desai, B., Ott, W., Basham, B., Agrawal, M., Ding, W., Hildemann, L. M., Abitorabi, K. M., Canfield, J., Mak, G., Guvenc-Tuncturk, S., Malefyt, R. d., McClanahan, T. K., Fick, R. B., Kuschner, W. G. 2008; 34 (10): 631-662

    Abstract

    Chronic obstructive pulmonary diseases (COPD) may increase air pollution-related mortality. The relationship of immune mechanisms to mortality caused by fine particulates in healthy and COPD populations is incompletely understood. The objective of this study was to determine whether fine particulates from a single biomass fuel alter stress and inflammation biomarkers in people with COPD. Healthy and COPD subjects were exposed to smoke in a controlled indoor setting. Immune responses were quantified by measuring cell surface marker expression with flow-cytometric analysis and mRNA levels with quantitative reverse transcriptase-polymerase chain reactions in whole blood before and after exposure. Preexposure COPD subjects had more leukocytes, mainly CD14(+) monocytes and neutrophils, but fewer CD3(+) T cells. Fifty-seven of 186 genes were differentially expressed between healthy and COPD subjects' peripheral blood mononuclear cells (PBMCs). Of these, only nuclear factor (NF)-kappa B1, TIMP-1, TIMP-2, and Duffy genes were up-regulated in COPD subjects. At 4 hours post smoke exposure, monocyte levels decreased only in healthy subjects. Fifteen genes, particular to inflammation, immune response, and cell-to-cell signaling, were differentially expressed in COPD subjects, versus 4 genes in healthy subjects. The authors observed significant differences in subjects' PBMCs, which may elucidate the adverse effects of air pollution particulates on people with COPD.

    View details for DOI 10.1080/01902140802322256

    View details for Web of Science ID 000261737300001

    View details for PubMedID 19085563

  • Real-time PCR for detection of the Aspergillus genus JOURNAL OF ENVIRONMENTAL MONITORING Goebes, M. D., Hildemann, L. M., Kujundzic, E., Hernandez, M. 2007; 9 (6): 599-609

    Abstract

    Aspergillus is a genus of mold that has strong indoor sources, including several species capable of acting as opportunistic pathogens. Previous studies suggest that Aspergillus could serve as an indicator for abnormal mold growth or moisture, making it an important genus for environmental monitoring. Here, a quantitative polymerase chain reaction (qPCR, or real-time PCR) assay is presented for Aspergillus. The assay shows good specificity for the genus, detecting all Aspergillus species tested, although a few non-Aspergillus species are also amplified. Sensitivity testing demonstrates that DNA representing one conidium can be detected. A validation study compared qPCR results against direct microscopy counts using A. fumigatus conidia aerosolized into a laboratory chamber. The assay was then used to quantify Aspergillus in indoor air samples, demonstrating its utility for environmental monitoring. Analysis of a small number of clinical sputum samples showed complete agreement with culturing results.

    View details for DOI 10.1039/b618937g

    View details for Web of Science ID 000247103700031

    View details for PubMedID 17554432

  • Fine organic aerosols collected in a humid, rural location (Great Smoky Mountains, Tennessee, USA): Chemical and temporal characteristics ATMOSPHERIC ENVIRONMENT Yu, L. E., Shulman, M. L., Kopperud, R., Hildemann, L. M. 2005; 39 (33): 6037-6050
  • Size distributions and height variations of airborne particulate matter and cat allergen indoors immediately following dust-disturbing activities JOURNAL OF AEROSOL SCIENCE Montoya, L. D., Hildemann, L. M. 2005; 36 (5-6): 735-749
  • Characterization of organic compounds collected during Southeastern Aerosol and Visibility Study: Water-soluble organic species ENVIRONMENTAL SCIENCE & TECHNOLOGY Yu, L. E., Shulman, M. L., Kopperud, R., Hildemann, L. M. 2005; 39 (3): 707-715

    Abstract

    As part of the Southeastern Aerosol and Visibility Study (SEAVS), water-soluble organic species (WSOS) in fine aerosols collected from July 15 to August 25, 1995, at the Great Smoky Mountain National Park, Tennessee (USA), were chemically classified into seven groups, with concentrations ranging from around 1 to >200 ng/m3. Dicarboxylic acids represented the dominant identified compound class, and succinic acid was the most abundant dicarboxylic acid. The trends in data suggest that most WSOS collected in the SEAVS samples were mainly generated from secondary photochemical reactions, especially during the first (cleaner) half of the sampling campaign. High relative humidity at the sampling site resulted in substantial water uptake by the aerosols, which may have enhanced the levels of succinic acid by reducing its rate of photooxidation. Concurrent trends in malic and malonic acid concentrations suggest these were generated from the oxidation of succinic acid. Consistent with the conversion of 3-hydroxypropanoic acid to malonic acid, it appears that 4-hydroxybutanoic acid served as a major precursor contributing to high levels of succinic acid in the daytime. Nocturnal WSOS generally followed the trend of diurnal WSOS, but they exhibited different chemical compositions and lower concentrations, unlike what has been reported for an urban site. A nocturnal-to-diurnal ratio of succinic acid larger than 0.25 may indicate an atmosphere dominated by photochemical reactions, rather than by primary emissions.

    View details for DOI 10.1021/es0489700

    View details for Web of Science ID 000226712600015

    View details for PubMedID 15757330

  • Outdoor versus indoor contributions to indoor particulate matter (PM) determined by mass balance methods 4th Colloquium on PM and Human Health Kopperud, R. J., Ferro, A. R., Hildemann, L. M. AIR & WASTE MANAGEMENT ASSOC. 2004: 1188–96

    Abstract

    This study compares an indoor-outdoor air-exchange mass balance model (IO model) with a chemical mass balance (CMB) model. The models were used to determine the contribution of outdoor sources and indoor resuspension activities to indoor particulate matter (PM) concentrations. Simultaneous indoor and outdoor measurements of PM concentration, chemical composition, and air-exchange rate were made for five consecutive days at a single-family residence using particle counters, nephelometers, and filter samples of integrated PM with an aerodynamic diameter of less than or equal to 2.5 microm (PM2.5) and PM with an aerodynamic diameter of less than or equal to 5 microm (PM5). Chemical compositions were determined by inductively coupled plasma mass-spectrometry. During three high-activity days, prescribed activities, such as cleaning and walking, were conducted over a period of 4-6 hr. For the remaining two days, indoor activities were minimal. Indoor sources accounted for 60-89% of the PM2.5 and more than 90% of the PM5 for the high-activity days. For the minimal-activity days, indoor sources accounted for 27-47% of PM2.5 and 44-60% of the PM5. Good agreement was found between the two mass balance methods. Indoor PM2.5 originating outdoors averaged 53% of outdoor concentrations.

    View details for Web of Science ID 000223701500016

    View details for PubMedID 15468671

  • Elevated personal exposure to particulate matter from human activities in a residence 9th International Conference on Indoor Air Quality and Climate (Indoor Air 2002) Ferro, A. R., Kopperud, R. J., Hildemann, L. M. NATURE PUBLISHING GROUP. 2004: S34–S40

    Abstract

    Continuous laser particle counters collocated with time-integrated filter samplers were used to measure personal, indoor, and outdoor particulate matter (PM) concentrations for a variety of prescribed human activities during a 5-day experimental period in a home in Redwood City, CA, USA. The mean daytime personal exposures to PM(2.5) and PM(5) during prescribed activities were 6 and 17 times, respectively, as high as the pre-activity indoor background concentration. Activities that resulted in the highest exposures of PM(2.5), PM(5), and PM(10) were those that disturbed dust reservoirs on furniture and textiles, such as dry dusting, folding clothes and blankets, and making a bed. The vigor of activity and type of flooring were also important factors for dust resuspension. Personal exposures to PM(2.5) and PM(5) were 1.4 and 1.6 times, respectively, as high as the indoor concentration as measured by a stationary monitor. The ratio of personal exposure to the indoor concentration was a function of both particle size and the distance of the human activity from the stationary indoor monitor. The results demonstrate that a wide variety of indoor human resuspension activities increase human exposure to PM and contribute to the "personal cloud" effect.

    View details for DOI 10.1038/sj.jea.7500356

    View details for Web of Science ID 000221128900005

    View details for PubMedID 15118743

  • Source strengths for indoor human activities that resuspend particulate matter ENVIRONMENTAL SCIENCE & TECHNOLOGY Ferro, A. R., Kopperud, R. J., Hildemann, L. M. 2004; 38 (6): 1759-1764

    Abstract

    A mathematical model was applied to continuous indoor and outdoor particulate matter (PM) measurements to estimate source strengths for a variety of prescribed human activities that resuspend house dust in the home. Activities included folding blankets, folding clothes, dry dusting, making a bed, dancing on a rug, dancing on a wood floor, vacuuming, and walking around and sitting on upholstered furniture. Although most of the resuspended particle mass from these activities was larger than 5 microm in diameter, the resuspension of PM2.5 and PM5 was substantial, with source strengths ranging from 0.03 to 0.5 mg min(-1) for PM2.5 and from 0.1 to 1.4 mg min(-1) for PM5. Source strengths for PM > 5 microm could not be quantified due to instrument limitations. The source strengths were found to be a function of the number of persons performing the activity, the vigor of the activity, the type of activity, and the type of flooring.

    View details for DOI 10.1021/es0263893

    View details for Web of Science ID 000220193900025

    View details for PubMedID 15074686

  • Evolution of the mass distribution of resuspended cat allergen (Fel d 1) indoors following a disturbance ATMOSPHERIC ENVIRONMENT Montoya, L. D., Hildemann, L. M. 2001; 35 (5): 859-866
  • Concentration and composition of atmospheric aerosols from the 1995 SEAVS experiment and a review of the closure between chemical and gravimetric measurements Air-and-Waste-Management-Association Specialty Conference on Visual Air Quality, Aerosols, and Global Radiation Balance Andrews, E., Saxena, P., Musarra, S., Hildemann, L. M., Koutrakis, P., McMurry, P. H., Olmez, I., White, W. H. AIR & WASTE MANAGEMENT ASSOC. 2000: 648–64

    Abstract

    We summarize the results from the various measurements and the inter-sampler comparisons from Southeastern Aerosol and Visibility Study (SEAVS), a study with one of its objectives to test for closure among chemical, gravimetric and optical measurements of atmospheric aerosol particles. Sulfate and organics are the dominant components of the SEAVS fine particles (nominally, particles with aerodynamic diameter < or = 2.5 microns) but between 28 and 42% (range over various samplers) of the gravimetrically measured total fine particle concentration is unidentified by the chemical measurements. Estimates of water associated with inorganic components and measurement imprecision do not totally explain the observed difference between gravimetric and chemical measurements. We examine the theoretical and empirical basis for assumptions commonly made in the published literature to extrapolate total fine particle concentration on the basis of chemical measurements of ions, carbon and elements. We then explore the more general question of closure using the SEAVS data as well as data from other, similar studies reported in the literature. In so combining the SEAVS measurements with other similar studies, we find a strong association between organic carbon and the unidentified component, that is, the fraction of the total fine particle concentration not identified by chemical measurements. We offer several tenable hypotheses for the relationship between the organic and unidentified components that deserve to be tested in future work. Specifically, we hypothesize that (1) errors in the sampling and analysis of organic carbon; (2) estimates of organic mass from measurements of organic carbon; and/or (3) water absorption by organics may all contribute to the observed relationship.

    View details for Web of Science ID 000086986300002

    View details for PubMedID 10842930

  • Investigations of the proximity effect for pollutants in the indoor environment JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY McBride, S. J., Ferro, A. R., Ott, W. R., Switzer, P., Hildemann, L. M. 1999; 9 (6): 602-621

    Abstract

    More than a dozen indoor air quality studies have reported a large discrepancy between concentrations measured by stationary indoor monitors (SIMs) and personal exposure monitors (PEMs). One possible cause of this discrepancy is a source proximity effect, in which pollutant sources close to the respondent cause elevated and highly variable exposures. This paper describes three sets of experiments in a home using real-time measurements to characterize and quantify the proximity effect relative to a fixed distant location analogous to a SIM. In the first set of experiments, using sulfur hexafluoride (SF6) as a continuously emitting tracer pollutant from a point source, measurements of pollutant concentrations were made at different distances from the source under different air exchange rates and source strengths. A second set of experiments used a continuous point source of carbon monoxide (CO) tracer pollutant and an array of high time resolution monitors to collect simultaneous concentration readings at different locations in the room. A third set of experiments measured particle count density and particle-bound polycyclic aromatic hydrocarbon (PAH) concentrations emitted from a continuous particle point source (an incense stick) using two particle counters and two PAH monitors, and included human activity periods both before and during the source emission period. Results from the SF6 and CO experiments show that while the source is emitting, a source proximity effect can be seen in the increases in the mean and median and in the variability of concentrations closest to the source, even at a distance of 2.0 m from the source under certain settings of air exchange rate and source strength. CO concentrations at locations near the source were found to be higher and more variable than the predictions of the mass balance model. For particles emitted from the incense source, a source proximity effect was evident for the fine particle sizes (0.3 to 2.5 microm) and particle-bound PAH up to at least 1.0 m from the source. Analysis of spatial and temporal patterns in the data for the three tracer pollutants reveal marked transient elevations of concentrations as seen by the monitor, referred to as "microplumes," particularly at locations close to the source. Mixing patterns in the room show complex patterns and directional effects, as evidenced by the variable intensity of the microplume activity at different locations. By characterizing the spatial and temporal variability of pollutant concentrations in the home, the proximity effect can be quantified, leading to improved indoor monitoring designs and models of human exposure to air pollutants.

    View details for Web of Science ID 000086103600008

    View details for PubMedID 10638846

  • Characteristics of nitrogen-containing aromatic compounds in coal tars during secondary pyrolysis FUEL Yu, L. E., Hildemann, L. M., Niksa, S. 1999; 78 (3): 377-385
  • Human exposure to particles due to indoor cleaning activities 7th International Air Pollution Conference Ferro, A., Hildemann, L. M., McBride, S. J., Ott, W., Switzer, P. WIT PRESS. 1999: 487–496
  • Generation of polar organic aerosols from combustion processes 7th International Air Pollution Conference Hildemann, L. M., Yu, L. E. WIT PRESS. 1999: 935–942
  • Trends in aromatic ring number distributions of coal tars during secondary pyrolysis ENERGY & FUELS Yu, L. E., Hildemann, L. M., Niksa, S. 1998; 12 (3): 450-456
  • Characterization of coal tar organics via gravity flow column chromatography FUEL Yu, L. E., Hildemann, L. M., Dadamio, J., Niksa, S. 1998; 77 (5): 437-445
  • Sources of fine organic aerosol. 9. Pine, oak and synthetic log combustion in residential fireplaces ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1998; 32 (1): 13-22
  • Modeling vertical spread of airborne pollutants from sources near ground level - Comparison with field measurements JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE Lin, J. S., Hildemann, L. M. 1997; 123 (12): 1194-1202
  • Water absorption by organics: Survey of laboratory evidence and evaluation of UNIFAC for estimating water activity ENVIRONMENTAL SCIENCE & TECHNOLOGY Saxena, P., Hildemann, L. M. 1997; 31 (11): 3318-3324
  • Size-resolved quantification of nonviable indoor aeroallergens: A review JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE Montoya, L. D., Hildemann, L. M. 1997; 123 (10): 965-973
  • Sources of fine organic aerosol .8. Boilers burning No. 2 distillate fuel oil ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1997; 31 (10): 2731-2737
  • Sources of fine organic aerosol .7. Hot asphalt roofing tar pot fumes ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1997; 31 (10): 2726-2730
  • Characterization of the Southwestern Desert Aerosol, Meadview, AZ JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION Turpin, B. J., Saxena, P., Allen, G., Koutrakis, P., McMurry, P., Hildemann, L. 1997; 47 (3): 344-356

    Abstract

    Sulfate, organic carbon, and soil dust were the major components of the fine aerosol at Meadview, AZ, during the summer of 1992. Sulfate mass median diameters (typically 0.15-0.27 μm) were much smaller than mass median diameters for organic carbon (typically 0.43-0.83 μm). Organic carbon size distributions were broader and more varied. Intersampler comparisons show that sulfur and sulfate measurement technology provided precise and relatively accurate (within 2-22%) concentrations. However, large differences were observed between IMPROVE filter and MOUDI impactor carbon concentrations. This is indicative of the large uncertainties with which carbon concentrations are measured. The IMPROVE backup filter subtraction procedure was partially responsible for these differences. Meadview sulfate was not completely neutralized by ammonium; SO2 concentrations were comparable to sulfate concentrations; and virtually all of the nitrate was present as gas-phase nitric acid. Our estimates suggest that primary organic aerosol from urban areas accounts for no more than 24% on average of the organic aerosol found at Meadview, AZ. The remainder is most likely secondary and biogenic OC, as well as OC from local and regional anthropogenic sources.

    View details for Web of Science ID A1997WQ33500007

  • Characterization of the Southwestern Desert Aerosol, Meadview, AZ. Journal of the Air & Waste Management Association (1995) Turpin, B. J., Saxena, P., Koutrakis, G. A., McMurry, P., Hildemann, L. 1997; 47 (3): 344-356

    Abstract

    Sulfate, organic carbon, and soil dust were the major components of the fine aerosol at Meadview, AZ, during the summer of 1992. Sulfate mass median diameters (typically 0.15-0.27 μm) were much smaller than mass median diameters for organic carbon (typically 0.43-0.83 μm). Organic carbon size distributions were broader and more varied. Intersampler comparisons show that sulfur and sulfate measurement technology provided precise and relatively accurate (within 2-22%) concentrations. However, large differences were observed between IMPROVE filter and MOUDI impactor carbon concentrations. This is indicative of the large uncertainties with which carbon concentrations are measured. The IMPROVE backup filter subtraction procedure was partially responsible for these differences. Meadview sulfate was not completely neutralized by ammonium; SO2 concentrations were comparable to sulfate concentrations; and virtually all of the nitrate was present as gas-phase nitric acid. Our estimates suggest that primary organic aerosol from urban areas accounts for no more than 24% on average of the organic aerosol found at Meadview, AZ. The remainder is most likely secondary and biogenic OC, as well as OC from local and regional anthropogenic sources.

    View details for DOI 10.1080/10473289.1997.10464451

    View details for PubMedID 29081278

  • A generalized mathematical scheme to analytically solve the atmospheric diffusion equation with dry deposition ATMOSPHERIC ENVIRONMENT Lin, J. S., Hildemann, L. M. 1997; 31 (1): 59-71
  • Source apportionment of airborne particulate matter using organic compounds as tracers ATMOSPHERIC ENVIRONMENT Schauer, J. J., Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1996; 30 (22): 3837-3855
  • Contribution of primary aerosol emissions from vegetation-derived sources to fine particle concentrations in Los Angeles 5th International Conference on Carbonaceous Particles in the Atmosphere Hildemann, L. M., Rogge, W. F., Cass, G. R., Mazurek, M. A., SIMONEIT, B. R. AMER GEOPHYSICAL UNION. 1996: 19541–49
  • Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations 5th International Conference on Carbonaceous Particles in the Atmosphere Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. AMER GEOPHYSICAL UNION. 1996: 19379–94
  • A mathematical model for predicting trends in carbon monoxide emissions and exposures on urban arterial highways JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION Yu, L. E., Hildemann, L. M., Ott, W. R. 1996; 46 (5): 430-440

    Abstract

    The roadway is one of the most important microenvironments for human exposure to carbon monoxide (CO). To evaluate long-term changes in pollutant exposure due to in-transit activities, a mathematical model has been developed to predict average daily vehicular emissions on highways. By utilizing measurements that are specific for a given location and year (e.g., traffic counts, fleet composition), this model can predict emissions for a specific roadway during various time periods of interest, allowing examination of long-term trends in human exposure to CO. For an arterial highway in northern California, this model predicts that CO emissions should have declined by 58% between 1980 and 1991, which agrees fairly well with field measurements of human exposure taken along that roadway during those two years. An additional reduction of up to 60% in CO emissions is predicted to occur between 1991 and 2002, due solely to the continued replacement of older cars with newer, cleaner vehicles.

    View details for Web of Science ID A1996UJ64700005

    View details for PubMedID 8624785

  • Water-soluble organics in atmospheric particles: A critical review of the literature and application of thermodynamics to identify candidate compounds JOURNAL OF ATMOSPHERIC CHEMISTRY Saxena, P., Hildemann, L. M. 1996; 24 (1): 57-109
  • Analytical solutions of the atmospheric diffusion equation with multiple sources and height-dependent wind speed and eddy diffusivities ATMOSPHERIC ENVIRONMENT Lin, J. S., Hildemann, L. M. 1996; 30 (2): 239-254
  • ORGANICS ALTER HYGROSCOPIC BEHAVIOR OF ATMOSPHERIC PARTICLES JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Saxena, P., Hildemann, L. M., McMurry, P. H., Seinfeld, J. H. 1995; 100 (D9): 18755-18770
  • A NONSTEADY-STATE ANALYTICAL MODEL TO PREDICT GASEOUS EMISSIONS OF VOLATILE ORGANIC-COMPOUNDS FROM LANDFILLS JOURNAL OF HAZARDOUS MATERIALS Lin, J. S., Hildemann, L. M. 1995; 40 (3): 271-295
  • Polarities and ring size distributions of polycyclic aromatic compound emissions during secondary pyrolysis with various coals 8th International Conference on Coal Science Yu, L. E., Dadamio, J., Hildemann, L. E., Niksa, S. ELSEVIER SCIENCE BV. 1995: 1939–1942
  • A nonsteady-state analytical model to predict VOC emissions from hazardous waste sites National Conference on Innovative Technologies for Site Remediation and Hazardous Waste Management Lin, J. S., Hildemann, L. M. AMER SOC CIVIL ENGINEERS. 1995: 238–245
  • Mathematically modeling the transport of hazardous air pollutants from multiple sources National Conference on Innovative Technologies for Site Remediation and Hazardous Waste Management Lin, J. S., Hildemann, L. M. AMER SOC CIVIL ENGINEERS. 1995: 620–627
  • SOURCES OF URBAN CONTEMPORARY CARBON AEROSOL ENVIRONMENTAL SCIENCE & TECHNOLOGY Hildemann, L. M., Klinedinst, D. B., Klouda, G. A., Currie, L. A., Cass, G. R. 1994; 28 (9): 1565-1576

    View details for Web of Science ID A1994PE25800011

    View details for PubMedID 22176356

  • Sources of fine organic aerosol. 6. Cigaret smoke in the urban atmosphere. Environmental science & technology Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1994; 28 (7): 1375-1388

    View details for DOI 10.1021/es00056a030

    View details for PubMedID 22176334

  • SOURCES OF FINE ORGANIC AEROSOL .6. CIGARETTE-SMOKE IN THE URBAN ATMOSPHERE ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R. 1994; 28 (7): 1375-1388
  • SEASONAL TRENDS IN LOS-ANGELES AMBIENT ORGANIC AEROSOL OBSERVED BY HIGH-RESOLUTION GAS-CHROMATOGRAPHY AEROSOL SCIENCE AND TECHNOLOGY Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1994; 20 (4): 303-317
  • SOURCES OF FINE ORGANIC AEROSOL .5. NATURAL-GAS HOME APPLIANCES ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1993; 27 (13): 2736-2744
  • SOURCES OF FINE ORGANIC AEROSOL .4. PARTICULATE ABRASION PRODUCTS FROM LEAF SURFACES OF URBAN PLANTS ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1993; 27 (13): 2700-2711
  • LIGNIN PYROLYSIS PRODUCTS, LIGNANS, AND RESIN ACIDS AS SPECIFIC TRACERS OF PLANT CLASSES IN EMISSIONS FROM BIOMASS COMBUSTION ENVIRONMENTAL SCIENCE & TECHNOLOGY SIMONEIT, B. R., Rogge, W. F., Mazurek, M. A., Standley, L. J., Hildemann, L. M., Cass, G. R. 1993; 27 (12): 2533-2541
  • MATHEMATICAL-MODELING OF URBAN ORGANIC AEROSOL - PROPERTIES MEASURED BY HIGH-RESOLUTION GAS-CHROMATOGRAPHY ENVIRONMENTAL SCIENCE & TECHNOLOGY Hildemann, L. M., Cass, G. R., Mazurek, M. A., SIMONELT, B. R. 1993; 27 (10): 2045-2055
  • SOURCES OF FINE ORGANIC AEROSOL .3. ROAD DUST, TIRE DEBRIS, AND ORGANOMETALLIC BRAKE LINING DUST - ROADS AS SOURCES AND SINKS ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1993; 27 (9): 1892-1904
  • QUANTIFICATION OF URBAN ORGANIC AEROSOLS AT A MOLECULAR-LEVEL - IDENTIFICATION, ABUNDANCE AND SEASONAL-VARIATION 4TH INTERNATIONAL CONF ON CARBONACEOUS PARTICLES IN THE ATMOSPHERE Rogge, W. F., Mazurek, M. A., Hildemann, L. M., Cass, G. R., SIMONEIT, B. R. PERGAMON-ELSEVIER SCIENCE LTD. 1993: 1309–30
  • SOURCES OF FINE ORGANIC AEROSOL .2. NONCATALYST AND CATALYST-EQUIPPED AUTOMOBILES AND HEAVY-DUTY DIESEL TRUCKS ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1993; 27 (4): 636-651
  • MODELING THE EMISSION AND DISPERSION OF VOLATILE ORGANICS FROM SURFACE AERATION WASTE-WATER TREATMENT FACILITIES WATER RESEARCH Chrysikopoulos, C. V., Hildemann, L. M., Roberts, P. V. 1992; 26 (8): 1045-1052
  • A 3-DIMENSIONAL STEADY-STATE ATMOSPHERIC DISPERSION DEPOSITION MODEL FOR EMISSIONS FROM A GROUND-LEVEL AREA SOURCE ATMOSPHERIC ENVIRONMENT PART A-GENERAL TOPICS Chrysikopoulos, C. V., Hildemann, L. M., Roberts, P. V. 1992; 26 (5): 747-757
  • QUANTITATIVE CHARACTERIZATION OF URBAN SOURCES OF ORGANIC AEROSOL BY HIGH-RESOLUTION GAS-CHROMATOGRAPHY ENVIRONMENTAL SCIENCE & TECHNOLOGY Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONEIT, B. R. 1991; 25 (7): 1311-1325
  • SOURCES OF FINE ORGANIC AEROSOL .1. CHARBROILERS AND MEAT COOKING OPERATIONS ENVIRONMENTAL SCIENCE & TECHNOLOGY Rogge, W. F., Hildemann, L. M., Mazurek, M. A., Cass, G. R., SIMONELT, B. R. 1991; 25 (6): 1112-1125
  • CHEMICAL-COMPOSITION OF EMISSIONS FROM URBAN SOURCES OF FINE ORGANIC AEROSOL ENVIRONMENTAL SCIENCE & TECHNOLOGY Hildemann, L. M., Markowski, G. R., Cass, G. R. 1991; 25 (4): 744-759
  • SUBMICROMETER AEROSOL MASS DISTRIBUTIONS OF EMISSIONS FROM BOILERS, FIREPLACES, AUTOMOBILES, DIESEL TRUCKS, AND MEAT-COOKING OPERATIONS AEROSOL SCIENCE AND TECHNOLOGY Hildemann, L. M., Markowski, G. R., Jones, M. C., Cass, G. R. 1991; 14 (1): 138-152
  • A DILUTION STACK SAMPLER FOR COLLECTION OF ORGANIC AEROSOL EMISSIONS - DESIGN, CHARACTERIZATION AND FIELD-TESTS AEROSOL SCIENCE AND TECHNOLOGY Hildemann, L. M., Cass, G. R., Markowski, G. R. 1989; 10 (1): 193-204
  • AMMONIA AND NITRIC-ACID CONCENTRATIONS IN EQUILIBRIUM WITH ATMOSPHERIC AEROSOLS - EXPERIMENT VS THEORY ATMOSPHERIC ENVIRONMENT Hildemann, L. M., Russell, A. G., Cass, G. R. 1984; 18 (9): 1737-1750