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Volatile organic compounds (VOCs) represent a broad class of chemicals, many of which can be found in indoor air including residential indoor air. VOCs derive from a variety of sources including cleaning products, cooking practices, fragrances and fresheners, hobbies and at-home work behaviors. This study examined residential indoor air in homes (n = 99) in southeast Louisiana using passive organic vapor monitors and gas chromatography/mass spectrometry to determine if select VOCs were present, at what concentrations, and if those posed any potential long-term health risks. Twenty-nine VOCs were targeted in cross-sectional analyses using a 48-h sampling period. Twelve VOCs were detected in most of the homes sampled including xylenes, pinenes, benzene, toluene, ethylbenzene, hexane, pentane, chloroform, and carbon tetrachloride. Concentrations of alkanes and BTEX compounds were highly correlated (Spearman's r > 0.63, p < 0.0001). Using health risk measures (i.e. reference concentrations [RfCs] and inhalation unit risks [IURs]) available from the USEPA non-cancer risk assessments and cancer risk assessments were developed for some of these VOCs. Alkanes and BTEX compounds likely come from the same indoor source(s). Using existing health standards published by the USEPA, no unacceptable non-cancer risks were evident except under extremely high concentrations. Lifetime cancer risks, on the other hand, may well be considered unacceptable for chloroform and benzene (upper IUR) and for the combination of chloroform, benzene, and carbon tetrachloride. These exceeded a 1 in 10,000 cancer risk threshold in 35–50% of our simulations. Further study of residential indoor air in low-income women's homes in this area is needed. Including a larger number of VOCs may reveal yet more potential health risks. [ABSTRACT FROM AUTHOR]

Abstract: Children spend substantial amount of time within school microenvironments; therefore, assessing school-based exposures is essential for characterizing and preventing children's health risks to air pollutants. Indeed, the importance of characterizing children's exposures in schools is recognized by the US Environmental Protection Agency's recent initiative to promote outdoor air monitoring networks near schools. As part of a health effects study investigating the impact of traffic-related air pollution on asthmatic children along the US–Mexico border, this research examines children's exposures to, and spatio-temporal heterogeneity in concentrations of, traffic-related air pollutants at four elementary schools in El Paso, Texas. Three schools were located in an area of high traffic density and one school in an area of low traffic density. Paired indoor and outdoor concentrations of 48-h fine and coarse particulate matter (PM2.5 and PM10–2.5), 48-h black carbon (BC), 96-h nitrogen dioxide (NO2), and 96-h volatile organic compounds (VOCs) were measured for 13 weeks at each school. Outdoor concentrations of PM, NO2, BC, and BTEX (benzene, toluene, ethylbenzene, m,p-xylene, o-xylene) compounds were similar among the three schools in the high-traffic zone in contrast to the school in the low-traffic zone. Results from this study and previous studies in this region corroborate the fact that PM pollution in El Paso is dominated by coarse PM (PM10–2.5) and fine fraction (PM2.5) accounts for only 25–30% of the total PM mass in PM10. BTEX species and BC are better surrogates for traffic air pollution in this region. Correlation analyses indicate a range of association between indoor and outdoor pollutant concentrations due to uncontrollable factors like student foot traffic and varying building and ventilation configurations across the four schools. Results suggest the need of micro-scale monitoring for children's exposure assessment, which may not be adequately characterized by the measurements from a centralized monitoring site. [Copyright &y& Elsevier]

Abstract: On August 29, 2005, Hurricane Katrina made landfall near New Orleans, Louisiana, a major metroplex with petroleum industries. In response to the potential impact of the storm on air quality and to assess the exposures to toxic air pollutants of public health concern, the United States Environmental Protection Agency conducted passive monitoring of air toxics for three months, starting in late October 2005 through early February 2006, at up to 18 sites in the New Orleans area affected by Hurricane Katrina. The overall results of the passive ambient monitoring are summarized with the concentrations for the twenty-nine observed volatile organic chemicals, which include benzene, toluene, ethylbenzene, and xylenes, and the measured concentrations are compared with available health-based screening levels. The results of passive monitoring are also compared with those of the collocated canister sampling at one of the sites. The overall results showed that the outdoor levels of atmospheric volatile organic chemcals in the post-Katrina New Orleans area were very low and far below the available screening levels. The results also confirm the effectiveness of passive monitoring in a large geographical area where conventional methods are not feasible, electrical power is not available, and the need for sampling is urgent, as in the aftermath of natural disasters and other catastrophes. [Copyright &y& Elsevier]

Abstract: Objective: We investigated associations of short-term changes in ambient ozone (O3), fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and the timing of new-onset asthma, using a large, high-risk population in an area with historically high ozone levels. Methods: The study population included 18,289 incident asthma cases identified among Medicaid-enrolled children in Harris County Texas between 2005–2007, using Medicaid Analytic Extract enrollment and claims files. We used a time-stratified case-crossover design and conditional logistic regression to assess the effect of increased short-term pollutant concentrations on the timing of asthma onset. Results: Each 10ppb increase in ozone was significantly associated with new-onset asthma during the warm season (May–October), with the strongest association seen when a 6-day cumulative average period was used as the exposure metric (odds ratio [OR]=1.05, 95% confidence interval [CI], 1.02–1.08). Similar results were seen for NO2 and PM2.5 (OR=1.07, 95% CI, 1.03–1.11 and OR=1.12, 95% CI, 1.03–1.22, respectively), and PM2.5 also had significant effects in the cold season (November–April), 5-day cumulative lag (OR=1.11. 95% CI, 1.00–1.22). Significantly increased ORs for O3 and NO2 during the warm season persisted in co-pollutant models including PM2.5. Race and age at diagnosis modified associations between ozone and onset of asthma. Conclusion: Our results indicate that among children in this low-income urban population who developed asthma, their initial date of diagnosis was more likely to occur following periods of higher short-term ambient pollutant levels. [Copyright &y& Elsevier]

Recent state and federal public school class-size reduction initiatives, increased elementary and pre-K enrollment driven by population growth and immigration, and limited resources for capital projects, modernization, and maintenance at aging schools have increased the prevalence of prefabricated, portable classrooms (portables). At present, approximately one of three California students are taught in portables, whose use is especially prevalent in more populated counties such as Los Angeles, home to the nation's second largest school district. Limited data existed on chemical compound air concentrations, and thus exposures, inside American public schools. Measurements have been limited, usually performed in complaint schools, and varied in sampling protocols and analysis methods. To address a school environment and children's health issue of present concern, an assessment of public school portables was conducted in Los Angeles County. Seven schools in two school districts were recruited, from which 20 classrooms - 13 portables, seven in main buildings - were randomly selected. We report indoor air concentrations of 21 target toxic and odorous volatile organic compounds (VOCs), including formaldehyde and acetaldehyde, measured with passive samplers (DNSH PAKS and 3M OVM 3500) in the cooling and heating seasons between June 2000 and June 2001. None of the measured indoor air formaldehyde concentrations exceeded the existing California Air Resources Board guideline (50?ppb, or 60?µg/m3). The main sources of aldehydes in classrooms, especially portables, were likely interior finish materials and furnishings made of particleboard without lamination. Indoor air VOC concentrations were generally low in this pilot study. The four most prevalent VOCs measured were toluene, m-/p-xylene, a-pinene, and d-limonene; likely indoor sources were personal, teaching, and cleaning products. Future schools research should attempt larger samples over larger geographical areas.Journal of Exposure Analysis and Environmental Epidemiology (2004) 14, 44-59. doi:10.1038/sj.jea.7500297 [ABSTRACT FROM AUTHOR]

Background: Hispanics are the fastest growing minority group in the United States; however, minimal information is available on their cancer risks from exposures to hazardous air pollutants (HAPs) and how these risks compare to risks to non-Hispanic whites. Methods: We estimated the personal exposure and cancer risk of Hispanic and white adults who participated in the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study. We evaluated 12 of the sampled volatile organic compounds and carbonyls and identified the HAPs of most concern and their possible sources. Furthermore, we examined sociodemographic factors and building characteristics. Results: Cumulative cancer risks (CCRs) estimated for Hispanics (median = 519 × 10-6, 90th percentile = 3,968 × 10-6) and for whites (median = 443 × 10-6, 90th percentile = 751 × 10-6) were much greater than the U.S. Environmental Protection Agency (EPA) benchmark of 10-6. Cumulative risks were dominated by formaldehyde and p-dichlorobenzene (p-DCB) and, to a lesser extent, by acetaldehyde, chloroform, and benzene. Exposure to all of these compounds except benzene was primarily due to indoor residential sources. Hispanics had statistically higher CCRs than did whites (p ⩽ 0.05) because of differences in exposure to p-DCB, chloroform, and benzene. Formaldehyde was the largest contributor to CCR for 69% of Hispanics and 88% of whites. Cancer risks for pollutants emitted indoors increased in houses with lower ventilation rates. Conclusions: Hispanics appear to be disproportionately affected by certain HAPs from indoor and outdoor sources. Policies that aim to reduce risk from exposure to HAPs for the entire population and population subgroups should consider indoor air pollution. [ABSTRACT FROM AUTHOR]

The Relationship of Indoor, Outdoor and Personal Air (RIOPA) Study was undertaken to evaluate the contribution of outdoor sources of air toxics, as defined in the 1990 Clean Air Act Amendments, to indoor concentrations and personal exposures. The concentrations of 18 volatile organic compounds (VOCs), 17 carbonyl compounds, and fine particulate matter mass (PM2.5) were measured using 48-h outdoor, indoor and personal air samples collected simultaneously. PM2.5 mass, as well as several component species (elemental carbon, organic carbon, polyaromatic hydrocarbons and elemental analysis) were also measured; only PM2.5 mass is reported here. Questionnaires were administered to characterize homes, neighborhoods and personal activities that might affect exposures. The air exchange rate was also measured in each home. Homes in close proximity (<0.5?km) to sources of air toxics were preferentially (2:1) selected for sampling. Approximately 100 non-smoking households in each of Elizabeth, NJ, Houston, TX, and Los Angeles, CA were sampled (100, 105, and 105 respectively) with second visits performed at 84, 93, and 81 homes in each city, respectively. VOC samples were collected at all homes, carbonyls at 90%and PM2.5 at 60%of the homes. Personal samples were collected from nonsmoking adults and a portion of children living in the target homes. This manuscript provides the RIOPA study design and quality control and assurance data. The results from the RIOPA study can potentially provide information on the influence of ambient sources on indoor air concentrations and exposure for many air toxics and will furnish an opportunity to evaluate exposure models for these compounds.Journal of Exposure Analysis and Environmental Epidemiology (2005) 15, 123-137. doi:10.1038/sj.jea.7500379 Published online 23 June 2004 [ABSTRACT FROM AUTHOR]

We measured volatile organic compound (VOC) exposures in multiple locations for a diverse population of children who attended two inner-city schools in Minneapolis, Minnesota. Fifteen common VOCs were measured at four locations: outdoors (0), indoors at school (S), indoors at home (H), and in personal samples (P). Concentrations of most VOCs allowed the general pattern O &ap; S < P < H across the measured microenvironments. The S and O environments had the smallest and H the largest influence on personal exposure to most compounds. A time-weighted model of P exposure using all measured microenvironments and time-activity data provided little additional explanatory power beyond that provided by using the H measurement alone. Although H and P concentrations of most VOCs measured in this study were similar to or lower than levels measured in recent personal monitoring studies of adults and children in the United States, p-dichlorobenzene was the notable exception to this pattern, with upper-bound exposures more than 100 times greater than those found in other studies of children. Median and upper-bound H and P exposures were well above health benchmarks for several compounds, so outdoor measurements likely underestimate long-term health risks from children's exposure to these compounds. [ABSTRACT FROM AUTHOR]

Concentrations of polycyclic aromatic hydrocarbons (PAHs), PM2.5, and organic and elemental carbon (OC and EC) were measured in 48 h integrated samples collected in the indoor and outdoor air in Los Angeles, CA, Houston, TX, and Elizabeth, NJ from July 1999 to June 2000. The objective of the study was to evaluate the hypothesis that outdoor air pollution contributed strongly to indoor air pollution. The measured partition coefficients of PAHs, Kp,meas, in the individual samples were well correlated with the compounds’ sub-cooled liquid vapor pressure, pLo. Values of Kp,meas varied by about two orders of magnitude for any given value of vapor pressure. These variations in gas/particle partitioning of PAHs were higher than the estimated systematic and random error of Kp,meas and are related to the aerosol characteristics and sampling conditions. Stepwise multiple linear regression analysis (MLR) of the pooled data, which included pLo at 25°C, temperature, fOC and fEC as independent variables, explains 84.5% of the variability of the partition coefficients. This is higher than the explained variance when pLo is used as a single parameter (77.5%). The relative importance of each variable for prediction of PAH partition coefficient is determined by partial coefficients of determination. Vapor pressure at 25°C (RpoL2=0.84) and temperature (RT2=0.21) are the two most important predictors followed by fEC (RfEC2=0.12) and fOC (RfOC2=0.038). Both EC and OC carbon are important predictors of gas/particle partitioning of PAHs, with EC being a better predictor. Because EC is highly correlated with (and is a good tracer of) primary combustion-generated OC, this result suggests that PAHs more readily sorb on combustion-generated aerosol containing EC. Enrichment of the indoor aerosol in non-combustion OC suggests that sorption of PAHs is more important in the indoor air compared to the outdoor air. The MLR developed in this work will improve prediction of gas/particle partitioning of PAHs in indoor and outdoor air. [Copyright &y& Elsevier]