2006 Progress Report: Relationship between Indoor, Outdoor and Personal Air (RIOPA). Part II: Analyses of Concentrations of Particulate Matter Species

EPA Grant Number: R828678C006
Subproject: this is subproject number 006 , established and managed by the Center Director under grant R824834
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Mickey Leland National Urban Air Toxics Research Center (NUATRC)
Center Director: Beskid, Craig
Title: Relationship between Indoor, Outdoor and Personal Air (RIOPA). Part II: Analyses of Concentrations of Particulate Matter Species
Investigators: Weisel, Clifford P. , Colome, Steven D. , Morandi, Maria T. , Turpin, Barbara , Spektor, Dalia , Zhang, Junfeng , Stock, Tom
Institution: Environmental and Occupational Health Sciences Institute , The University of Texas Health Science Center at Houston
EPA Project Officer: Chung, Serena
Project Period: January 1, 1997 through January 31, 2005
Project Period Covered by this Report: January 1, 2005 through January 31, 2006
RFA: Mickey Leland National Urban Air Toxics Research Center (NUATRC) (1997) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Targeted Research

Objective:

The RIOPA study was funded by the NUATRC in response to RFA 96-01. The project is comprised of three studies initially independently funded:

  • A study funded by NUATRC with Dr. Clifford Weisel at Environmental and Occupational Health Sciences Institute (EOHSI) as principal investigator;
  • A study funded by HEI with Dr. Jim Zhang of EOHSI as principal investigator; and
  • A study funded by HEI with Dr. Barbara Turpin of Rutgers University as principal investigator.

Because the two HEI studies complemented and added to the initial study funded by NUATRC, both organizations have treated the three studies as one so that the results can be reported in a coherent manner.

The RIOPA study measured personal exposures and outdoor and indoor air concentrations of PM2.5 and selected VOCs and carbonyls for adults and children. Sampling was conducted during two 48-hour sampling periods in different seasons between the summer of 1999 and the spring of 2001. The study was designed to address the hypothesis that outdoor sources contribute a significant proportion of the pollutant concentrations in the indoor and personal air for residents who live near those sources. The study included approximately 100 homes and 100 adult residents of those homes in each of three urban centers with different weather conditions and air pollution source profiles: Los Angeles CA, dominated by mobile sources; Houston TX, dominated by large industrial stationary and area sources (with a portion contributed from mobile sources); and Elizabeth NJ, with a mixture of mobile, point, and area sources. Samples of VOCs, carbonyls, and PM2.5 were collected inside and outside the homes and in subjects’ personal air (breathing zone). The subjects carried personal samplers during their daily activities. In a subset of homes, the personal exposures of one or more children were monitored; in-vehicle exposures to carbonyls were also measured for some residents.

The specific aims of the portion of the RIOPA study reported here were to:

  1. Compare indoor, outdoor, and personal air concentrations (and in-vehicle concentrations for carbonyl compounds) of the pollutants measured.
  2. Examine the effects of season, home type, and other variables on measured concentrations.
  3. Quantify (1) the contribution of outdoor sources to indoor concentrations and (2) the indoor source strength of the measured pollutants using measured air exchange rates (AERs). The investigators also planned to estimate the fractional concentration that outdoor sources contribute to indoor concentrations as a function of distance from those sources and to collect a data set that could be used to address important questions about exposure assessment in the future. The analysis of the effect of distance from sources was not conducted as part of this study due to time and budgetary constraints. However, this evaluation is currently under way and the results of the initial analyses are being published elsewhere.

Progress Summary:

Indoor, Outdoor, and Personal Concentrations in Three Cities
For most VOCs and carbonyls, mean and median personal and indoor concentrations were similar, and both were higher than outdoor concentrations. Exceptions were (1) median outdoor concentrations of acrolein, which in Houston were higher than indoor and personal concentrations; and (2) median and mean personal concentrations of acetone, which in Elizabeth and Houston were higher than indoor concentrations. For PM2.5, mean and median personal exposure concentrations were higher than indoor and outdoor concentrations, which were similar. For all species, personal samples showed the largest differences between mean and median values, and they showed a larger range of measured concentrations than indoor and outdoor samples. In personal samples, compounds with the widest range of values were MTBE, tetrachloroethylene, d-limonene, p-dichlorobenzene, toluene, acrolein, and acetone. Acetone was especially high in personal samples from Elizabeth and Houston, and acrolein was especially high in personal samples from Houston. For outdoor samples of VOCs, median concentrations differed slightly by city. Compared with Houston and Elizabeth, Los Angeles had a higher percentage of outdoor VOC samples with detectable concentrations; and it had higher outdoor concentrations of some VOCs, including MTBE, ethyl benzene, and the xylenes. All of these VOCs are emitted primarily from motor vehicles, gas stations, and oil refineries. For outdoor samples of carbonyls among the three cities, median concentrations were more variable than those for VOCs (with the exception of formaldehyde and acetone concentrations, which were similar in all three cities). Several VOCs were present only at low levels in all environments and were not detected in many outdoor samples. The species detected in more than 60% of outdoor samples common to all three cities were MTBE, carbon tetrachloride, benzene, ethyl benzene, m- & p-xylenes, and o-xylene.MTBE had the highest outdoor concentrations.

Indoor concentrations of several VOCs and carbonyls differed among cities. The species with the highest indoor concentrations were the VOCs MTBE, toluene, and d-limonene and the carbonyls formaldehyde, acetaldehyde, and acetone.

Compared with Los Angeles and Elizabeth homes, Houston homes had several-fold higher indoor mean and median concentrations of several VOCs (including some of indoor origin such as _-pinene, d-limonene, and p-dichlorobenzene) and of some carbonyls (acetone and acrolein).

Personal exposure concentrations for several VOCs and some carbonyls also differed, especially between Houston and the other two cities. In particular, Houston subjects had very high personal exposures to _-pinene, d-limonene, p-dichlorobenzene, and several carbonyls; these reflect higher indoor concentrations.

Among the three cities, indoor and outdoor PM2.5 concentrations differed only slightly, but differences in personal exposures were more pronounced.

In-Vehicle Concentrations of Carbonyls
Most in-vehicle samples were collected in Los Angeles (72), followed by Houston (33), and Elizabeth (10). Formaldehyde was detected in 76% to 100% of the samples in each city; acetaldehyde was detected in less than 30% of samples from Elizabeth and Houston but in 86% of samples from Los Angeles.

For the three cities combined, the in-vehicle concentrations of these two species (formaldehyde and acetaldehyde) had wider ranges than the indoor, outdoor, and personal exposure concentrations. The in-vehicle concentrations of formaldehyde (mean 39.7 μg/m3; median 20.2 μg/m3) and acetaldehyde (mean 25.2 μg/m3; median 5.92 μg/m3) were higher than the outdoor concentrations (3 μg/m3 approximate mean and median for both species). This trend persisted when data were broken down by city.

Comparison of Personal Exposures for Adults and Children
For all three cities combined: (1) personal VOC samples were collected from 107 children during the first visit and 102 children during the second visit; (2) personal carbonyl samples were collected from 81 and 99 children, respectively; and (3) personal PM samples were collected from 14 and 13 children, respectively. The majority of children that contributed VOC and carbonyl data were in Houston (65% and 63%, respectively), whereas most of the children that contributed PM2.5 data were in Los Angeles (85%). The authors reported small but significant differences between paired adult–child concentrations for some carbonyls (acrolein and formaldehyde) and some VOCs (MTBE and toluene). In general, however, the median adult and child personal exposures were similar for all species. For PM2.5 the sample size for children was insufficient for analysis.

Air Exchange Rates
Homes had AERs that ranged from 0.14/hr to 4.75/hr in Los Angeles, 0.11/hr to 4.48/hr in Elizabeth, and 0.08/hr to 4.3/hr in Houston. The median AER was substantially lower for Houston homes (0.47/hr) than for Los Angeles homes (0.87/hr) and Elizabeth homes (0.88/hr). The AER also varied among the cities by season, by type and age of the homes.

Outdoor Contributions to Indoor Concentrations of Pollutants
For all three cities combined, the mass balance model showed that, for the VOC species MTBE, carbon tetrachloride, and trichloroethylene, 100% of indoor concentrations were contributed by outdoor air; for benzene it was 90%. Accordingly, these species also had the lowest indoor source strengths. Those with the lowest outdoor contributions were d-limonene, _-pinene, _-pinene, and chloroform (13% to 31%). For the remaining VOCs, the median fractional outdoor contribution to indoor concentrations ranged from 50% to 74%. For carbonyls, the fractional outdoor contributions to indoor concentrations were lower than for VOCs (19% to 61%) and the indoor source strengths were higher. Of the carbonyls, formaldehyde and acetaldehyde had the lowest fractional outdoor contributions (and the highest indoor source strengths) and acrolein, crotonaldehyde, and propionaldehyde had the highest outdoor contributions.

Conclusions:

This study generated a large database on the concentrations of air toxics and PM2.5 for a large number of subjects and their homes selected on the basis of distances from various sources. Using passive samplers to measure air toxics enabled a large data set of concurrent measurements to be collected from indoor, outdoor, and personal air samples. The VOC sampler performed well for most species; however uncertainties remain about outdoor levels of several VOCs because their low ambient levels, high limits of detection, or low extraction efficiencies made them difficult to measure. The inability of the passive OVM badge to measure 1,3-butadiene is also a limitation. These uncertainties suggest that new technologies or improvements in air sampling and analytic methods will be needed to draw further conclusions about some of these compounds.

The newly developed passive carbonyl sampler appeared to perform well for most species. PM2.5 active samplers performed well, but a small bias was noted between the personal exposure monitor and the Harvard impactors used for outdoor and indoor measurements.

The data presented in the Investigators’ Report are the results of descriptive analyses for each species measured. Values were highly variable for all species within and across the three cities. However, the overall relations that compare indoor, outdoor, and personal air samples for most compounds were similar for all three cities. This was unexpected given the wide variety of pollutant sources and weather. With a few exceptions, mean and median personal exposure and indoor levels of VOCs and carbonyls were similar and higher than the outdoor levels within the whole data set and within individual cities. Mean and median personal PM2.5 exposure concentrations were higher than indoor and outdoor levels, and indoor and outdoor levels were very similar. The finding that personal exposure levels were higher than outdoor levels of these compounds is consistent with those of many other studies. Personal exposures of adults and children were similar for most compounds. The clustering of homes based on proximity to pollutant sources within a defined geographic area differed by city, as did the home-sampling schemes. Because the population of the study was not a probability based sample, the results may not be extrapolated to the general population or attributed to a city or a region.

Time and budget constraints did not allow full use of the database; for example, determining how levels of different pollutants are related to each other and nearby sources for each single home was not done. As a first step in determining how types of sources may impact personal exposure, the investigators calculated the contributions of outdoor air to indoor air concentrations for each species for all homes combined. Several compounds with highly correlated and similar outdoor and indoor levels, low indoor source strengths, and high fractional outdoor contributions were identified as primarily of outdoor origin (eg, MTBE, carbon tetrachloride, trichloroethylene). Another group of compounds with elevated indoor levels compared with outdoor levels, high indoor source strengths, and low fractional outdoor contributions (eg, 1,2- dichlorobenzene, chloroform, styrene, _-pinene, _-pinene, d-limonene, formaldehyde, acetaldehyde, butyraldehyde, isovaleraldehyde, valeraldehyde, and hexaldehyde) were identified as primarily indoor origin. A third group of compounds (including m- & p-xylenes, o-xylene, propionaldehyde, acrolein, crotonaldehyde, glyoxal, methylglyoxal, and PM2.5) showed intermediate values for indoor source strengths and for the fractional outdoor contributions to indoor concentrations, which indicates they are derived from both indoor and outdoor sources.

The results of the RIOPA study confirm and extend earlier findings by others for VOCs and PM2.5 and have yielded new information for a large number of carbonyls. Few investigators have looked at personal, indoor, and outdoor concentrations of a suite of VOCs, carbonyls, and PM2.5 in the same large set of subjects in multiple urban centers. The information on PM2.5 composition in the RIOPA study (Part II of this Research Report) provides needed information about exposure to the components of PM. Overall, the data collected in the RIOPA study increase the database on the distribution of levels of a large number of air toxics and PM2.5; these data can be used to assess whether these levels pose health concerns, to understand the sources of air toxics, and how individual factors may be associated with high exposures.


Journal Articles on this Report : 11 Displayed | Download in RIS Format

Other subproject views: All 40 publications 21 publications in selected types All 19 journal articles
Other center views: All 144 publications 62 publications in selected types All 53 journal articles
Type Citation Sub Project Document Sources
Journal Article Kwon J, Weisel CP, Turpin BJ, Zhang J, Korn LR, Morandi MT, Stock TH, Colome S. Source proximity and outdoor-residential VOC concentrations: results from the RIOPA study. Environmental Science & Technology 2006;40(13):4074-4082. R828678C006 (2006)
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  • Journal Article Liu W, Zhang J, Zhang L, Turpin BJ, Weisel CP, Morandi MT, Stock TH, Colome S, Korn LR. Estimating contributions of indoor and outdoor sources to indoor carbonyl concentrations in three urban areas of the United States. Atmospheric Environment 2006;40(12):2202-2214. R828678C006 (2006)
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  • Journal Article Liu W, Zhang J, Korn LR, Zhang L, Weisel CP, Turpin B, Morandi M, Stock T, Colome S. Predicting personal exposure to airborne carbonyls using residential measurements and time/activity data. Atmospheric Environment 2007;41(25):5280-5288. R828678C006 (2006)
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  • Journal Article Meng QY, Turpin BJ, Korn L, Weisel CP, Morandi M, Colome S, Zhang JJ, Stock T, Spektor D, Winer A, Zhang L, Lee JH, Giovanetti R, Cui W, Kwon J, Alimokhtari S, Shendell D, Jones J, Farrar C, Maberti S. Influence of ambient (outdoor) sources on residential indoor and personal PM2.5 concentrations: analyses of RIOPA data. Journal of Exposure Analysis and Environmental Epidemiology 2005;15(1):17-28. R828678C006 (2005)
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  • Journal Article Meng QY, Turpin BJ, Polidori A, Lee JH, Weisel C, Morandi M, Colome S, Stock T, Winer A, Zhang J. PM2.5 of ambient origin: estimates and exposure errors relevant to PM epidemiology. Environmental Science & Technology 2005;39(14):5105-5112. R828678C006 (2006)
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  • Journal Article Naumova YY, Eisenreich SJ, Turpin BJ, Weisel CP, Morandi MT, Colome SD, Totten LA, Stock TH, Winer AM, Alimokhtari S, Kwon J, Shendell D, Jones J, Maberti S, Wall SJ. Polycyclic aromatic hydrocarbons in the indoor and outdoor air of three cities in the U.S. Environmental Science & Technology 2002;36(12):2552-2559. R828678C006 (2002)
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  • Journal Article Offenberg JH, Naumova YY, Turpin BJ, Eisenreich SJ, Morandi MT, Stock T, Colome SD, Winer AM, Spektor DM, Zhang J, Weisel CP. Chlordanes in the indoor and outdoor air of three U.S. cities. Environmental Science & Technology 2004;38(10):2760-2768. R828678C006 (2005)
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  • Journal Article Reff A, Turpin BJ, Porcja RJ, Giovennetti R, Cui W, Weisel CP, Zhang J, Kwon J, Alimokhtari S, Morandi M, Stock T, Maberti S, Colome S, Winer A, Shendell D, Jones J, Farrar C. Functional group characterization of indoor, outdoor, and personal PM2.5: results from RIOPA. Indoor Air 2005;15(1):53-61. R828678C006 (2005)
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  • Journal Article Weisel CP. Assessing exposure to air toxics relative to asthma. Environmental Health Perspectives 2002;110(Suppl 4):527-537. R828678C006 (2002)
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  • Journal Article Weisel CP, Zhang J, Turpin BJ, Morandi MT, Colome S, Stock TH, Spektor DM, Korn L, Winer A, Alimokhtari S, Kwon J, Mohan K, Harrington R, Giovanetti R, Cui W, Afshar M, Maberti S, Shendell D. Relationship of Indoor, Outdoor and Personal Air (RIOPA) study: study design, methods and quality assurance/control results. Journal of Exposure Analysis and Environmental Epidemiology 2005;15(2):123-137. R828678C006 (2004)
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  • Journal Article Zhang J, Zhang L, Fan Z, Ilacqua V. Development of the personal aldehydes and ketones sampler based upon DNSH derivatization on solid sorbent. Environmental Science & Technology 2000;34(12):2601-2607. R828678C006 (2003)
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  • Supplemental Keywords:

    RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, POLLUTANTS/TOXICS, HUMAN HEALTH, Air Pollution, particulate matter, air toxics, Environmental Chemistry, Health Risk Assessment, Exposure, Chemicals, Risk Assessments, Physical Processes, Atmospheric Sciences, Biology, copollutant exposures, atmospheric particulate matter, air pollutants, fine particles, PM 2.5, acute lung injury, chemical mixtures, chronic health effects, human exposure, industrial air pollution, lung inflammation, particulate exposure, residential air exchange rates, Acute health effects, inhaled, indoor/outdoor relationships, Volatile Organic Compounds (VOCs), acute exposure, atmospheric chemistry, human health risk

    Relevant Websites:

    http://www.healtheffects.org Exit

    Progress and Final Reports:

    Original Abstract
  • 1997
  • 1998
  • 1999
  • 2000
  • 2001 Progress Report
  • 2002 Progress Report
  • 2003 Progress Report
  • 2004 Progress Report
  • Final Report

  • Main Center Abstract and Reports:

    R824834    Mickey Leland National Urban Air Toxics Research Center (NUATRC)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R824834C001 Air Toxics Exposures Among Teenagers in New York City and Los Angeles - A Columbia-Harvard Study (TEACH)
    R824834C002 Cardiopulmonary Response to Particulate Exposure
    R824834C003 VOC Exposure in an Industry Impacted Community
    R824834C004 A Study of Personal Exposure to Air Toxics Among a Subset of the Residential U.S. Population (VOC Project)
    R824834C005 Methods Development Project for a Study of Personal Exposures to Toxic Air Pollutants
    R824834C006 Relationship Between Indoor, Outdoor and Personal Air (RIOPA)
    R824834C007 Development of the "Leland Legacy" Air Sampling Pump
    R824834C008 Source Apportionment of Indoor Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Residences
    R824834C009 Development of a Personal Cascade Impactor Sampler (PCIS)
    R824834C010 Testing the Metals Hypothesis in Spokane
    R828678C001 Air Toxics Exposures Among Teenagers in New York City and Los Angeles—A Columbia-Harvard Study (TEACH)
    R828678C002 Cardiopulmonary Effects of Metal-Containing Particulate Exposure
    R828678C003 VOC Exposure in an Industry Impacted Community
    R828678C004 A Study of Personal Exposure to Air Toxics Among a Subset of the Residential U.S. Population (VOC Project)
    R828678C005 Oxygenated Urban Air Toxics and Asthma Variability in Middle School Children: A Panel Study (ATAC–Air Toxics and Asthma in Children)
    R828678C006 Relationship between Indoor, Outdoor and Personal Air (RIOPA). Part II: Analyses of Concentrations of Particulate Matter Species
    R828678C007 Development of the “Leland Legacy” Air Sampling Pump
    R828678C008 Source Apportionment of Indoor PAHs in Urban Residences 98-03B
    R828678C009 Development of a Personal Cascade Impactor Sampler (PCIS)
    R828678C010 Testing the Metals Hypothesis in Spokane
    R828678C011 A Pilot Geospatial Analysis of Exposure to Air Pollutants (with Special Attention to Air Toxics) and Hospital Admissions in Harris County, Texas
    R828678C012 Impact of Exposure to Urban Air Toxics on Asthma Utilization for the Pediatric Medicaid Population in Dearborn, Michigan
    R828678C013 Field Validation of the Sioutas Sampler and Leland Legacy Pump – Joint Project with EPA’s Environmental Technology Validation Program (ETV)
    R828678C014 Performance Evaluation of the 3M Charcoal Vapor Monitor for Monitor Low Ambient Concentrations of VOCs
    R828678C015 RIOPA Database Development
    R828678C016 Contributions of Outdoor PM Sources to Indoor and Personal Exposures: Analysis of PM Species Concentrations” Focused on the PM Speciation and Apportioning of Sources
    R828678C017 The Short and Long-Term Respiratory Effects of Exposure to PAHs from Traffic in a Cohort of Asthmatic Children