Air toxics and health risks in California: the public health implications of outdoor concentrations

Subclinical markers of cardiovascular toxicity of benzene inhalation in mice

Benzene is a ubiquitous environmental pollutant. Recent population-based studies suggest that benzene exposure is associated with an increased risk for cardiovascular disease. However, it is unclear whether benzene exposure by itself is sufficient to induce cardiovascular toxicity. We examined the effects of benzene inhalation (50 ppm, 6 h/day, 5 days/week, 6 weeks) or HEPA-filtered air exposure on the biomarkers of cardiovascular toxicity in male C57BL/6J mice. Benzene inhalation significantly increased the biomarkers of endothelial activation and injury including endothelial microparticles, activated endothelial microparticles, endothelial progenitor cell microparticles, lung endothelial microparticles, and activated lung and endothelial microparticles while having no effect on circulating levels of endothelial adhesion molecules, endothelial selectins, and biomarkers of angiogenesis. To understand how benzene may induce endothelial injury, we exposed human aortic endothelial cells to benzene metabolites. Of the metabolites tested, trans,trans-mucondialdehyde (10 μM, 18h) was the most toxic. It induced caspases-3, -7 and -9 (intrinsic pathway) activation and enhanced microparticle formation by 2.4-fold. Levels of platelet-leukocyte aggregates, platelet macroparticles, and a proportion of CD4+ and CD8+ T-cells were also significantly elevated in the blood of the benzene-exposed mice. We also found that benzene exposure increased the transcription of genes associated with endothelial cell and platelet activation in the liver; and induced inflammatory genes and suppressed cytochrome P450s in the lungs and the liver. Together, these data suggest that benzene exposure induces endothelial injury, enhances platelet activation and inflammatory processes; and circulatory levels of endothelial cell and platelet-derived microparticles and platelet-leukocyte aggregates are excellent biomarkers of cardiovascular toxicity of benzene.

Spatial variability of nitrogen dioxide and formaldehyde and residential exposure of children in the industrial area of Viadana, Northern Italy

Chipboard production is a source of ambient air pollution. We assessed the spatial variability of outdoor pollutants and residential exposure of children living in proximity to the largest chipboard industry in Italy and evaluated the reliability of exposure estimates obtained from a number of available models. We obtained passive sampling data on NO₂ and formaldehyde collected by the Environmental Protection Agency of Lombardy region at 25 sites in the municipality of Viadana during 10 weeks (2017-2018) and compared NO₂ measurements with average weekly concentrations from continuous monitors. We compared interpolated NO₂ and formaldehyde surfaces with previous maps for 2010. We assessed the relationship between residential proximity to the industry and pollutant exposures assigned using these maps, as well as other available countrywide/continental models based on routine data on NO₂, PM₁₀, and PM_2.5. The correlation between NO₂ concentrations from continuous and passive sampling was high (Pearson's r = 0.89), although passive sampling underestimated NO₂ especially during winter. For both 2010 and 2017-2018, we observed higher NO₂ and formaldehyde concentrations in the south of Viadana, with hot-spots in proximity to the industry. PM₁₀ and PM_2.5 exposures were higher for children at < 1 km compared to the children living at > 3.5 km to the industry, whereas NO₂ exposure was higher at 1-1.7 km to the industry. Road and population densities were also higher close to the industry. Findings from a variety of exposure models suggest that children living in proximity to the chipboard industry in Viadana are more exposed to air pollution and that exposure gradients are relatively stable over time.

Impact of industrial activities on atmospheric volatile organic compounds in Sihwa-Banwol, the largest industrial area in South Korea

The impact of industrial activities on atmospheric volatile organic compounds (VOCs) in the Sihwa-Banwol complexes, i.e., the largest industrial area in Korea, was investigated. More than 60 VOCs were determined from 850 samples collected from four sites in and around the complexes through a 2-year monitoring campaign from 2005 to 2007. The VOCs of particular concern found in the area were benzene, toluene, ethylbenzene, xylenes, trichloroethylene, and formaldehyde, given their toxicity, concentration, and detection frequency. Toluene was the most abundant one. The VOC concentration rankings were consistent with their emission rankings. Most VOCs had higher concentrations at the industrial sites than at residential sites, indicating a significant impact of industrial emissions. The ambient levels of benzene and formaldehyde were additionally affected by vehicular emissions and secondary formation, respectively. Overall, the VOC levels increased in winter and at night, because of the local weather conditions. In contrast, the formaldehyde concentration increased in summer, owing to its secondary formation in the atmosphere. The ambient VOC levels in Sihwa-Banwol were higher than those in other parts of Korea. Additionally, the cumulative cancer risks posed by the toxic VOCs exceeded a tolerable risk level of 1 × 10^-4 in not only the industrial areas but also the residential areas. The sum of the non-cancer risks in both areas significantly exceeded the threshold criterion of 1. The large amounts of aromatic compounds emitted from the industrial complexes are believed to play a crucial role in the elevated levels of surface ozone in the Seoul metropolitan area during the summer season. Therefore, comprehensive measures for controlling the VOC emissions in the Sihwa-Banwol area need to be prioritized to reduce the health risks for residents of not only this area but also the capital Seoul and its surrounding areas.

Cancer Risk Assessment for Workers Exposed to Pollution Source, a Petrochemical Company, Iran

Background:

Air pollution have led to severe problem of adverse health effect in the world. This study aimed to conduct the health risk assessment, cancer risk analysis, and non-cancer risk for exposure to volatile organic compounds (VOCs) and hydrogen sulfide (H ₂ S) in petrochemical industry.

Methods:

In this cross-sectional research, 123 samples were collected in the ambient air in Iran during winter 2016. For sampling and analysis of VOCs and H ₂ S, 3 methods (numbers 1500, 1501, and 6013) presented by the National Institute of Occupational Safety and Health (NIOSH) were used. For determination of risk assessment of chemical pollutants, semi-quantitative method presented by the Occupational Safety and Health Division, Singapore was used. Finally, for calculation of cancer risk analysis, Chronic Daily Intake (CDI) and calculation of non-cancer risk, Exposure Concentration (EC) were used.

Results:

Average concentration of benzene (2.12±0.95) in breathing zone of workers were higher than the Threshold Limit Values-Time Weighted Average (TLV-TWA) (P<0.05). Among chemical substance, benzene had very high rank of risk in petrochemical industry. Rank of risk for H ₂ S, toluene, and xylene present in the breathing zone of workers was low. The mean cancer risk for workers exposed to benzene was estimated 8.78×10^−3, in other words, 8.7 cancer per 1000 i.e. higher than the acceptable standard of 10⁻⁶. In our study, non-cancer risk for BTX was higher than the acceptable standard of 1.

Conclusion:

In particular, overall cancer and toxic risk can be associated with long term exposure to benzene.

Spatiotemporal Variations and Health Implications of Hazardous Air Pollutants in Ulsan, a Multi-Industrial City in Korea

We measured a wide range of hazardous air pollutants (HAPs) simultaneously at five sites over four seasons in 2009–2010 in Ulsan, the largest industrial city in Korea. Target analytes included volatile organic compounds (VOCs), carbonyls, polycyclic aromatic hydrocarbons (PAHs), phthalates, and heavy metals (HMs). The objectives of this study were to evaluate the occurrence and spatiotemporal distributions of HAPs, and to identify important HAPs based on health risk assessment. Industrial emissions affected ambient levels of VOCs and HMs, as demonstrated by spatial distribution analysis. However, concentrations of PAHs and phthalates were relatively uniform at all sites. VOCs and HMs exhibited little seasonal variation, while formaldehyde increased in the summer due to its secondary formation. PAHs exhibited notable seasonal variation; higher in cold seasons and lower in warm seasons. Cumulative cancer risks imposed by 35 HAPs were 4.7 × 10−4 and 1.7 × 10−4 in industrial and residential areas, respectively. The top five major cancer risk drivers appeared to be formaldehyde, benzene, benzo[a]pyrene, As, and Co. The sums of hazard quotients (HQ) derived by 47 HAPs were 10.0 (industrial) and 2.4 (residential). As the individual species, only two HAPs exceeded the HQ of 1, which are As (3.1) and Pb (2.1) in the industrial area. This study demonstrated the importance of a comprehensive monitoring and health risk assessment to prioritize potentially toxic pollutants in the ambient air of a large industrial city.

Comparing the lung cancer burden of ambient particulate matter using scenarios of air quality standards versus acceptable risk levels

OBJECTIVES

Ambient particulate matter (PM) is regulated with science-based air quality standards, whereas carcinogens are regulated with a number of "acceptable" cases. Given that PM is also carcinogenic, we identify differences between approaches.

METHODS

We assessed the lung cancer deaths for Switzerland attributable to exposure to PM up to 10 µm (PM10) and to five particle-bound carcinogens. For PM10, we used an epidemiological approach based on relative risks with four exposure scenarios compared to two counterfactual concentrations. For carcinogens, we used a toxicological approach based on unit risks with four exposure scenarios.

RESULTS

The lung cancer burden using concentrations from 2010 was 10-14 times larger for PM10 than for the five carcinogens. However, the burden depends on the underlying exposure scenarios, counterfactual concentrations and number of carcinogens. All scenarios of the toxicological approach for five carcinogens result in a lower burden than the epidemiological approach for PM10.

CONCLUSIONS

Air quality standards-promoted so far by the WHO Air Quality Guidelines-provide a more appealing framework to guide health risk-oriented clean air policymaking than frameworks based on a number of "acceptable" cases.

Associations among particulate matter, hazardous air pollutants and methane emissions from the Aliso Canyon natural gas storage facility during the 2015 blowout

In October of 2015, a large underground storage well at the Aliso Canyon natural gas storage facility experienced a massive methane leak (also referred to as "natural gas blowout"), which resulted in the largest ever anthropogenic release of methane from a single point source in the United States. Additional sampling conducted during the event revealed unique gas and particle concentrations in ambient air and a characteristic "fingerprint" of metals in the indoor dust samples similar to samples taken at the blowout site. We further investigated the association between the Aliso Canyon natural gas storage site and several measured air pollutants by: (a) conducting additional emission source studies using meteorological data and correlations between particulate matter, methane, and hazardous air pollutants (HAPs) collected during the natural gas blowout at distances ranging from 1.2 to 7.3 km due south of well SS25, (b) identifying the unique i/n-pentane ratio signature associated with emissions from the blowout event, and (c) identifying characteristics unique to the homes that tested positive for air pollutants using data collected from extensive indoor environmental assessment surveys. Results of air quality samples collected near Aliso Canyon during the final weeks of the event revealed that elevated levels of several HAP compounds were likely influenced by the active natural gas blowout. Furthermore, the final attempts to plug the well during the days preceding the well kill were associated with particle emissions likely from the well site. Together, this investigation suggests uncontrolled leaks or blowout events at natural gas storage facilities have the potential to release harmful pollutants with adverse health and environmental consequences into proximate communities. With this evidence, our recommendations include facility-specific meteorological and air quality data-collection equipment installed at natural gas storage facilities and support of environmental surveillance after severe off-normal operation events.

Cumulative risk analysis of carcinogenic contaminants in United States drinking water

Cumulative risk analysis of contaminant occurrence in United States drinking water for the period of 2010-2017 indicates that over 100,000 lifetime cancer cases could be due to carcinogenic chemicals in tap water. The majority of this risk is due to the presence of arsenic, disinfection byproducts and radioactive contaminants. For different states within the U.S., cumulative cancer risk for drinking water contaminants ranges between 1 × 10^-4 and 1 × 10^-3, similar to the range of cumulative cancer risks reported for air pollutants. Overall, national attributable risk due to tap water contaminants is approximately 4 × 10^-4, which is two orders of magnitude higher than the de minimus cancer risk of one-in-a-million. Thus, decreasing the levels of chemical contaminants in drinking water represents an important opportunity for protecting public health.

Hazardous Air Pollutants Associated with Upstream Oil and Natural Gas Development: A Critical Synthesis of Current Peer-Reviewed Literature

Increased energy demands and innovations in upstream oil and natural gas (ONG) extraction technologies have enabled the United States to become one of the world's leading producers of petroleum and natural gas hydrocarbons. The US Environmental Protection Agency (EPA) lists 187 hazardous air pollutants (HAPs) that are known or suspected to cause cancer or other serious health effects. Several of these HAPs have been measured at elevated concentrations around ONG sites, but most have not been studied in the context of upstream development. In this review, we analyzed recent global peer-reviewed articles that investigated HAPs near ONG operations to ( a) identify HAPs associated with upstream ONG development, ( b) identify their specific sources in upstream processes, and ( c) examine the potential for adverse health outcomes from HAPs emitted during these phases of hydrocarbon development.

Integrating site-specific dispersion modeling into life cycle assessment, with a focus on inhalation risks in chemical production

It has become increasingly important for environmental managers to evaluate the human health (HH) impact of chemicals in their supply chain. Current life cycle assessment (LCA) methods are limited because they often only address the HH impact at large geographical scales. This paper aims to develop a method that derives a regionalized life cycle inventory data set and site-specific air dispersion modeling to evaluate the HH impact of chemicals along the life cycle phases at finer geographical scales to improve decision-making, with focus on inhalation pathway. More specifically, cancer risk and noncancer hazard index (HI) are quantified at the county level to identify high-risk regions and at the census tract level to reveal the geographical pattern of health impacts. The results showed that along the cradle-to-gate life cycle stages of a widely used chemical, methylene diphenyl diisocyanate (MDI), the accumulative inhalation risk was 3 orders of magnitude below the U.S. Environmental Protection Agency (EPA) risk management thresholds for both cancer risk (2.16 × 10^-9) and noncancer HI (1.53 × 10^-3). However, the absolute value of inhalation risks caused by the case study chemicals varied significantly in different geographical areas, up to 4 orders of magnitude. This paper demonstrates a feasible approach to improve human health impact assessment (HHIA) by combining site-specific air dispersion modeling and LCA using publicly available inventory data. This proposed method complements existing life cycle impact assessment (LCIA) models to improve HHIA by employing both HH risk assessment and LCA techniques. One potential outcome is to prioritize pollution prevention and risk reduction measures based on the risk maps derived from this method. Implications: It has become increasingly important for environmental managers to evaluate the human health impacts of chemicals in their supply chain. Regionalized life cycle inventory data sets should be developed using publically available databases such as EPA's toxic release inventory. The combination of site-specific dispersion modeling and life cycle assessment modeling can improve human health impact assessment of chemicals by providing more regionalized results along their supply chain.

Benzene exposure is associated with cardiovascular disease risk

Benzene is a ubiquitous, volatile pollutant present at high concentrations in toxins (e.g. tobacco smoke) known to increase cardiovascular disease (CVD) risk. Despite its prevalence, the cardiovascular effects of benzene have rarely been studied. Hence, we examined whether exposure to benzene is associated with increased CVD risk. The effects of benzene exposure in mice were assessed by direct inhalation, while the effects of benzene exposure in humans was assessed in 210 individuals with mild to high CVD risk by measuring urinary levels of the benzene metabolite trans,trans-muconic acid (t,t-MA). Generalized linear models were used to assess the association between benzene exposure and CVD risk. Mice inhaling volatile benzene had significantly reduced levels of circulating angiogenic cells (Flk-1⁺/Sca-1⁺) as well as an increased levels of plasma low-density lipoprotein (LDL) compared with control mice breathing filtered air. In the human cohort, urinary levels of t,t-MA were inversely associated several populations of circulating angiogenic cells (CD31⁺/34⁺/45⁺, CD31⁺/34⁺/45⁺/AC133^–, CD34⁺/45⁺/AC133⁺). Although t,t-MA was not associated with plasma markers of inflammation or thrombosis, t,t-MA levels were higher in smokers and in individuals with dyslipidemia. In smokers, t,t-MA levels were positively associated with urinary metabolites of nicotine (cotinine) and acrolein (3-hydroxymercapturic acid). Levels of t,t-MA were also associated with CVD risk as assessed using the Framingham Risk Score and this association was independent of smoking. Thus, benzene exposure is associated with increased CVD risk and deficits in circulating angiogenic cells in both smokers and non-smokers.

Pilot study investigating ambient air toxics emissions near a Canadian kraft pulp and paper facility in Pictou County, Nova Scotia

Air toxics are airborne pollutants known or suspected to cause cancer or other serious health effects, including certain volatile organic compounds (VOCs), prioritized by the US Environmental Protection Agency (EPA). While several EPA-designated air toxics are monitored at a subset of Canadian National Air Pollution Surveillance (NAPS) sites, Canada has no specific "air toxics" control priorities. Although pulp and paper (P&P) mills are major industrial emitters of air pollutants, few studies quantified the spectrum of air quality exposures. Moreover, most NAPS monitoring sites are in urban centers; in contrast, rural NAPS sites are sparse with few exposure risk records. The objective of this pilot study was to investigate prioritized air toxic ambient VOC concentrations using NAPS hourly emissions data from a rural Pictou, Nova Scotia Kraft P&P town to document concentration levels, and to determine whether these concentrations correlated with wind direction at the NAPS site (located southwest of the mill). Publicly accessible Environment and Climate Change Canada data (VOC concentrations [Granton NAPS ID: 31201] and local meteorological conditions [Caribou Point]) were examined using temporal (2006-2013) and spatial analytic methods. Results revealed several VOCs (1,3-butadiene, benzene, and carbon tetrachloride) routinely exceeded EPA air toxics-associated cancer risk thresholds. 1,3-Butadiene and tetrachloroethylene were significantly higher (p < 0.05) when prevailing wind direction blew from the northeast and the mill towards the NAPS site. Conversely, when prevailing winds originated from the southwest towards the mill, higher median VOC air toxics concentrations at the NAPS site, except carbon tetrachloride, were not observed. Despite study limitations, this is one of few investigations documenting elevated concentrations of certain VOCs air toxics to be associated with P&P emissions in a community. Findings support the need for more research on the extent to which air toxics emissions exist in P&P towns and contribute to poor health in nearby communities.

Exposure to polycyclic aromatic hydrocarbons in atmospheric PM1.0 of urban environments: Carcinogenic and mutagenic respiratory health risk by age groups

We investigated the carcinogenic and mutagenic respiratory health risks related to the exposure to atmospheric PAHs in an urban area. Our study focused in the association of these pollutants and their possible effect in human health, principally respiratory and circulatory diseases. Also, we determined a relationship between the inhalation risk of PAHs and meteorological conditions. We validated the hypothesis that in winter PAHs with high molecular weight associated to submicron particles (PM₁) may increase exposure risk, especially for respiratory diseases, bronchitis and pneumonia diseases. Moreover, in our study we verified the relationship between diseases and several carcinogenic PAHs (Ind, BbkF, DahA, BaP, and BghiP). These individual PAHs contributed the most to the potential risk of exposure for inhalation of PM_1.0. Even at lower ambient concentrations of BaP and DahA in comparison with individual concentrations of other PAHs associated to PM_1.0. Mainly, research suggests to include carcinogenic and mutagenic PAHs in future studies of environmental health risk due to their capacity to associate to PM₁₀. Such carcinogenic and mutagenic PAHs are likely to provide the majority of the human exposure, since they originate from dense traffic urban areas were humans congregate.

Reading, Writing, and Toxics: Children's Health, Academic Performance, and Environmental Justice in Los Angeles

A significant body of previous research on environmental justice has demonstrated a disproportionate burden of environmental hazards on low-income and minority residents. In this paper we evaluate spatially indexed data on estimated respiratory and cancer risks associated with exposures to ambient air toxics to show that children of color in the Los Angeles Unified School District suffer potentially disparate health impacts, and that disparities in environmental risks may be associated with diminished school performance—even after controlling for socioeconomic and demographic covariates that generally explain much of the variation in student scores. Remediating environmental health risks in distressed neighborhoods could, therefore, improve both health and human capital.

Neighborhood deprivation, race/ethnicity, and urinary metal concentrations among young girls in California

BACKGROUND

Although metals can adversely impact children's health, the distribution of exposures to many metals, particularly among vulnerable subpopulations, is not well characterized.

OBJECTIVES

We sought to determine whether neighborhood deprivation was associated with urinary concentrations of thirteen metals and whether observed relationships varied by race/ethnicity.

METHODS

We obtained neighborhood characteristics from the 2005-2009 American Community Survey. Demographic information and urine samples from 400 healthy young girls in Northern California were obtained during a clinical visit. Urine samples were analyzed for metals using inductively-coupled plasma-mass spectrometry and levels were corrected for creatinine. We ran analysis of variance and generalized linear regression models to estimate associations of urinary metal concentrations with neighborhood deprivation and race/ethnicity and stratified multivariable models to evaluate possible interactions among predictors on metals concentrations.

RESULTS

Urinary concentrations of three metals (barium, lead, antimony) varied significantly across neighborhood deprivation quartiles, and four (barium, lead, antimony, tin) varied across race/ethnicity groups. In models adjusted for family income and cotinine, both race/ethnicity (F3,224=4.34, p=0.01) and neighborhood deprivation (F3,224=4.32, p=0.01) were associated with antimony concentrations, but neither were associated with lead, barium, or tin, concentrations. Examining neighborhood deprivation within race/ethnicity groups, barium levels (pinteraction<0.01) decreased with neighborhood deprivation among Hispanic girls (ptrend<0.001) and lead levels (pinteraction=0.06) increased with neighborhood deprivation among Asian girls (ptrend=0.04).

CONCLUSIONS

Our results indicate that children's vulnerability to some metals varies by neighborhood deprivation quartile and race/ethnicity. These differential distributions of exposures may contribute to environmental health disparities later in life.

Adult air pollution exposure and risk of infertility in the Nurses' Health Study II

STUDY QUESTION

Is there an association between air pollution exposures and incident infertility?

SUMMARY ANSWER

Increased exposure to air pollution is associated with an increased incidence of infertility.

WHAT IS KNOWN ALREADY

Exposures to air pollution have been associated with lower conception and fertility rates. However, the impact of pollution on infertility incidence is unknown.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study using data collected from 116 430 female nurses from September 1989 to December 2003 as part of the Nurses' Health Study II cohort.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Infertility was defined by report of attempted conception for ≥12 months without success. Participants were able to report if evaluation was sought and if so, offer multiple clinical indications for infertility. After exclusion, 36 294 members were included in the analysis. Proximity to major roadways and ambient exposures to particulate matter less than 10 microns (PM10), between 2.5 and 10 microns (PM2.5-10), and less than 2.5 microns (PM2.5) were determined for residential addresses for the 36 294 members between the years of 1993 and 2003. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using multivariable adjusted Cox proportional hazard models with time-varying covariates.

MAIN RESULTS AND THE ROLE OF CHANCE

Over 213 416 person-years, there were 2508 incident reports of infertility. Results for overall infertility were inconsistent across exposure types. We observed a small increased risk for those living closer to compared to farther from a major road, multivariable adjusted HR = 1.11 (CI: 1.02-1.20). This was consistent for those reporting primary or secondary infertility. For women living closer to compared to farther from a major road, for primary infertility HR = 1.05 (CI: 0.94-1.17), while for secondary infertility HR = 1.21 (CI: 1.07-1.36). In addition, the HR for every 10 µg/m(3) increase in cumulative PM2.5-10 among women with primary infertility was 1.10 (CI: 0.96-1.27), and similarly was 1.10 (CI: 0.94-1.28) for those with secondary infertility.

LIMITATIONS, REASONS FOR CAUTION

Within the 2 year window of infertility diagnosis, we do not have the exact date of diagnosis or the exact timing of the start of attempting conception. As infertility status and subtypes of infertility were prospectively collected biennially, we were unable to tightly examine the timing of exposures on incidence of infertility. In terms of exposure quantification, we used ambient air pollution exposures as a proxy for personal exposures, potentially leading to exposure misclassification. However, several studies suggest that ambient measurements are an acceptable surrogate for individual level exposures in most populations.

WIDER IMPLICATIONS OF THE FINDINGS

We observed an association between all size fractions of PM exposure, as well as traffic-related air pollution, and incidence of infertility. Of note, the strongest association was observed between cumulative average exposures over the course of follow-up and the risk of infertility, suggesting that chronic exposures may be of greater importance than short-term exposures.

STUDY FUNDING/COMPETING INTERESTS

The work for this paper was supported by the following: S.M.: Reproductive Scientist Development Program HD000849, and the Building Interdisciplinary Research Careers in Women's Health HD043444, the Boston University CTSI 1UL1TR001430, and a research grant from the Boston University Department of Obstetrics and Gynecology, S.A.M.: R01HD57210 from the National Institute of Child Health and Human Development and the Massachusetts Institute of Technology Center for Environmental Health Sciences Translational Pilot Project Program, R01CA50385 from the National Cancer Institute, J.E.H. and F.L.: 5R01ES017017 from the National Institute for Environmental Health Sciences, 5 P42 ES007381 from the National Institute of Environmental Health at the National Institute of Health. L.V.F.: T32HD060454 in reproductive, perinatal, and pediatric epidemiology from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The Nurses' Health Study II is additionally supported by infrastructure grant UM1CA176726 from the National Cancer Institute, NIH, U.S. Department of Health and Human Services. The authors have no actual or potential competing financial interests to disclose.

Ground-Truthing Validation to Assess the Effect of Facility Locational Error on Cumulative Impacts Screening Tools

Researchers and government regulators have developed numerous tools to screen areas and populations for cumulative impacts and vulnerability to environmental hazards and risk. These tools all rely on secondary data maintained by government agencies as part of the regulatory and permitting process. Stakeholders interested in cumulative impacts screening results have consistently questioned the accuracy and completeness of some of these datasets. In this study, three cumulative impacts screening tools used in California were compared, and ground-truth validation was used to determine the effect database inaccuracy. Ground-truthing showed substantial locational inaccuracy and error in hazardous facility databases and statewide air toxics emission inventories of up to 10 kilometers. These errors resulted in significant differences in cumulative impact screening scores generated by one screening tool, the Environmental Justice Screening Method.

Assessment of sociodemographic and geographic disparities in cancer risk from air toxics in South Carolina

Populations of color and low-income communities are often disproportionately burdened by exposures to various environmental contaminants, including air pollution. Some air pollutants have carcinogenic properties that are particularly problematic in South Carolina (SC), a state that consistently has high rates of cancer mortality for all sites. The purpose of this study was to assess cancer risk disparities in SC by linking risk estimates from the U.S. Environmental Protection Agency's 2005 National Air Toxics Assessment (NATA) with sociodemographic data from the 2000 US Census Bureau. Specifically, NATA risk data for varying risk categories were linked by tract ID and analyzed with sociodemographic variables from the 2000 census using R. The average change in cancer risk from all sources by sociodemographic variable was quantified using multiple linear regression models. Spatial methods were further employed using ArcGIS 10 to assess the distribution of all source risk and percent non-white at each census tract level. The relative risk (RR) estimates of the proportion of high cancer risk tracts (defined as the top 10% of cancer risk in SC) and their respective 95% confidence intervals (CIs) were calculated between the first and latter three quartiles defined by sociodemographic factors, while the variance in the percentage of high cancer risk between quartile groups was tested using Pearson's chi-square. The average total cancer risk for SC was 26.8 people/million (ppl/million). The risk from on-road sources was approximately 5.8 ppl/million, higher than the risk from major, area, and non-road sources (1.8, 2.6, and 1.3 ppl/million), respectively. Based on our findings, addressing on-road sources may decrease the disproportionate cancer risk burden among low-income populations and communities of color in SC.

Advancing research on racial-ethnic health disparities: improving measurement equivalence in studies with diverse samples

To conduct meaningful, epidemiologic research on racial-ethnic health disparities, racial-ethnic samples must be rendered equivalent on other social status and contextual variables via statistical controls of those extraneous factors. The racial-ethnic groups must also be equally familiar with and have similar responses to the methods and measures used to collect health data, must have equal opportunity to participate in the research, and must be equally representative of their respective populations. In the absence of such measurement equivalence, studies of racial-ethnic health disparities are confounded by a plethora of unmeasured, uncontrolled correlates of race-ethnicity. Those correlates render the samples, methods, and measures incomparable across racial-ethnic groups, and diminish the ability to attribute health differences discovered to race-ethnicity vs. to its correlates. This paper reviews the non-equivalent yet normative samples, methodologies and measures used in epidemiologic studies of racial-ethnic health disparities, and provides concrete suggestions for improving sample, method, and scalar measurement equivalence.

Exposure to polycyclic aromatic hydrocarbons in urban environments: health risk assessment by age groups

A detailed investigation was conducted into the concentration of polycyclic aromatic hydrocarbons (PAHs) associated with PM10 particles collected during 2012 in an urban area in Cordoba, Argentina. Their composition was studied and the lifetime lung cancer risk resulting from exposure to total and individual PAHs was estimated. Samples of PM10 were collected daily on fiber glass filters with PAHs being extracted with methylene chloride and analyzed by HPLC. Mean PAH concentrations were higher during autumn and winter. In contrast, during warm months, high ambient temperature and wind speed contributed to a decrease in the PAH ambient concentrations. The PAH levels found in the present study were within the range of those reported in other polluted urban areas. However risk factors calculated for exposure to individual and cumulative PAHs exceeded the carcinogenic benchmark level of 1×10(-6) early in childhood, implying that these PAH concentrations represent a serious risk to public health.

Ambient acrolein concentrations in coastal, remote, and urban regions in California

Acrolein (2-propenal) is a reactive chemical that is very toxic and has many sources. Acrolein is commonly detected in the atmosphere, but understanding the ambient concentrations of this compound has been hampered by analytical difficulties. The objective of this research was to utilize an analytical method specifically designed for acrolein to determine acrolein concentrations in remote regions. The purpose was to determine the natural background concentrations of acrolein which were simply lacking in the literature. In addition, rural and urban areas were sampled to determine the degree of anthropogenic enrichment in polluted environments. The results from the coastal and remote inland areas suggest that the median natural summertime background of acrolein was near 40 ng/m(3), which was higher than the Environmental Protection Agency's Reference Concentration (RfC) of 20 ng/m(3). Acrolein concentrations in urban areas were approximately 3- to 8-fold higher than background concentrations, which was a lower degree of urban enrichment than expected. The results suggest that additional research is needed to understand the natural background concentrations of acrolein.

Characterization and risk assessment of exposure to volatile organic compounds in apartment buildings in Harbin, China

This study analyzed the risk of exposure to volatile organic compounds (VOCs) in the apartment buildings (including bedrooms, living rooms, kitchens and study rooms) in Harbin, China. The concentration of total VOCs in bedrooms showed the lowest value with an average of 482.6 mg/m(3). 32.33 % of total measured VOCs correspond to aromatic hydrocarbons. The major chemical forms of the identified VOCs in other 3 types of rooms were alcohols which contributed to 30.66 % (in living rooms), 36.55 % (in kitchens) and 35.43 % (in study rooms) separately. Formaldehyde was the pollutant of highest concern given its high chronic toxic and carcinogenic risk levels according to the health assessment. Other pollutants of concern for human heal risks were benzene and naphthalene. The non-cancer risk by the exposure to naphthalene ranged from 2.39 to 2.80 in 4 target groups, which is more than 1.0 considered as a hazarded level to human health.

Health risk assessment of occupational exposure to hazardous volatile organic compounds in swine gestation, farrowing and nursery barns

Livestock producers are exposed to a high number of airborne pollutants during their daily duties of cleaning, feeding and maintenance activities. Hazardous air pollutants (HAPs) are a major group of pollutants that may cause cancer or other serious health effects including neurological, respiratory, reproductive and developmental disorders. In this study, health risks of occupational exposure to eight hazardous VOCs (phenol, p-cresol, o/m-cresol, benzene, toluene, ethylbenzene, o-xylene, and m/pxylene) that are most likely to be emitted from swine buildings were assessed using Monte Carlo simulation. The purpose of the study was to calculate emission rates and to quantify cancer and hazard risks of the target VOCs. Cancer and hazard risks were calculated for workers A, B, and C, who spent six hours in the gestation, farrowing and nursery barns, respectively, and one hour in the office space every day. Concentrations of the target VOCs did not exceed their recommended exposure limits (RELs). But, concentrations of p-cresol and benzene exceeded their preliminary remediation goals (PRGs). The highest emission rates in mg s(-1) were measured from the gestation rooms while the highest emission rates in mg per s per head were measured from the farrowing rooms. Cancer risks of ethylbenzene, benzene and p-cresol were higher than EPA's benchmark of one per million. Hazard risks of benzene, toluene, p-cresol, and o/m-cresol were higher than the maximum acceptable risk threshold (10(-4)). Worker B (farrowing) had the highest cumulative cancer (16.6 in one million) and hazard (11 342 in one million) risks. It was followed by workers A (gestation) and C (nursery). Sensitivity analysis showed that inhalation unit risk (IUR) had the highest impact on cancer risk assessment while recommended exposure limit (REL) had the highest impact on hazard risk assessment.

Chronic risk assessment of exposure to volatile organic compounds in the atmosphere near the largest Mediterranean industrial site

This study focuses on characterising the risk of exposure to volatile organic compounds (VOCs) by means of inhalation in people living in the vicinity of the largest chemical production site in the Mediterranean area. Eighty-six VOCs were initially selected for this study based on their adverse environmental and health effects. The monitoring campaign was conducted for 276 days in three different locations around the chemical site. The analytical method used for the characterisation was based on European standard method EN-14662-2, which consists of the active sampling of air for 24h in charcoal tubes, followed by extraction with carbon disulphide and GC-MS analysis. Forty-four VOCs with toxicological data available concerning their carcinogenic and non-carcinogenic health effects were quantified during the monitoring campaign. None of the quantified VOCs showed average concentrations exceeding their chronic reference concentrations and, therefore, no non-carcinogenic health effects are expected as a result of this exposure. However, the global average cancer risk due to VOC exposure in the area (3.3×10(-4)) was found to be above the values recommended by the WHO and USEPA. The influence of the analytical method was also evaluated by comparing cancer risk estimates using a thermal desorption (TD) method based on method EN-14662-1. The results of the 24-h samples for the solvent extraction method were compared with the average of 12 daily samples of 2-h for the TD method for 24 sampling days. Although the global estimated lifetime cancer risk was statistically comparable for both methods, some differences were found in individual VOC risks. To our knowledge, this is the first study that estimates the carcinogenic and non-carcinogenic risks posed by the inhalation of VOCs in people living near a chemical site of this size, and compares the estimated cancer risk obtained using two different standard analytical methods.

VOC amounts in ambient areas of a high-technology science park in Taiwan: their reciprocal correlations and impact on inhabitants

INTRODUCTION

This study presents bihourly, seasonal, and yearly concentration changes in volatile organic compounds (VOCs) in the inlet and effluent water of the wastewater treatment plant (WWTP) of a high-technology science park (HTIP) in Taiwan, with the VOC amounts at different sites correlated geologically.

MATERIALS AND METHODS

This research adopted a combination of two systems, solid-phase microextraction with a gas chromatography/flame ionization detector and an assembly of purge and trap coupled with gas chromatography/mass spectrometry, to monitor polar and nonpolar VOCs in wastewater. This paper investigated the total VOCs, acetone, isopropyl alcohol (IPA), and dimethylsulfide (DMS) concentrations in real water samples collected in the ambient area of the HTIP.

RESULTS AND DISCUSSION

The major contents of VOCs measured in the effluent of the WWTP in the HTIP and the surrounding river region were DMS (14-176 ppb), acetone (5-95 ppb), and IPA (15-316 ppb). In comparison with the total VOCs in the inlet wastewater of the WWTP, no corresponding relationship for total VOC concentration in the wastewater was observed between the inlet water and effluent water of the WWTP.

CONCLUSIONS

The peak VOC concentrations appeared in the third season, and the correlation of different VOC amounts reflects the production situation of the factories. In addition, VOC concentrations at different sites indicate that the Ke-Ya River is seemingly an effective channel for transporting wastewater to its final destination. The data are good indications for the management of environmental pollution near the HTIP.

Beyond dose assessment: using risk with full disclosure of uncertainty in public and scientific communication

Evaluations of radiation exposures of workers and the public traditionally focus on assessments of radiation dose, especially annual dose, without explicitly evaluating the health risk associated with those exposures, principally the risk of radiation-induced cancer. When dose is the endpoint of an assessment, opportunities to communicate the significance of exposures are limited to comparisons with dose criteria in regulations, doses due to natural background or medical x-rays, and doses above which a statistically significant increase of disease has been observed in epidemiologic studies. Risk assessment generally addresses the chance (probability) that specific diseases might be induced by past, present, or future exposure. The risk of cancer per unit dose will vary depending on gender, age, exposure type (acute or chronic), and radiation type. It is not uncommon to find that two individuals with the same effective dose will have substantially different risks. Risk assessment has shown, for example, that: (a) medical exposures to computed tomography scans have become a leading source of future risk to the general population, and that the risk would be increased above recently published estimates if the incidence of skin cancer and the increased risk from exposure to x-rays compared with high-energy photons were taken into account; (b) indoor radon is a significant contributor to the baseline risk of lung cancer, particularly among people who have never smoked; and (c) members of the public who were exposed in childhood to I in fallout from atmospheric nuclear weapons tests and were diagnosed with thyroid cancer later in life would frequently meet criteria established for federal compensation of cancers experienced by energy workers and military participants at atmospheric weapons tests. Risk estimation also enables comparisons of impacts of exposures to radiation and chemical carcinogens and other hazards to life and health. Communication of risk with uncertainty is essential for reaching informed consent, whether communicating to a larger community debating the tradeoffs of risks and benefits of an action that involves radiation exposure or communicating at the level of a physician and patient.

Risk assessment related to atmospheric polycyclic aromatic hydrocarbons in gas and particle phases near industrial sites

BACKGROUND

Inhalation is one of the main means of human exposure to polycyclic aromatic hydrocarbons (PAHs) because of their ubiquitous presence in the atmosphere. However, most studies have considered only PAHs found in the particle phase and have omitted the contribution of the gas-phase PAHs to the risk.

OBJECTIVE

We estimated the lifetime lung cancer risk from PAH exposure by inhalation in people living next to the largest chemical site in Southern Europe and the Mediterranean area.

METHODS

We determined 18 PAHs in the atmospheric gas and particle phase. We monitored the PAHs for 1 year in three locations near the chemical site in different seasons. We used toxic equivalence factors to calculate benzo[a]pyrene (BaP) equivalents (BaP-eq) for individual PAHs and applied the World Health Organization unit risk (UR) for BaP (UR = 8.7 × 10-5) to estimate lifetime cancer risks due to PAH exposures.

RESULTS

We observed some spatial and seasonal variability in PAH concentrations. The contribution of gas-phase PAHs to the total BaP-eq value was between 34% and 86%. The total estimated average lifetime lung cancer risk due to PAH exposure in the study area was 1.2 × 10-4.

CONCLUSIONS

The estimated risk was higher than values recommended by the World Health Organization and U.S. Environmental Protection Agency but lower than the threshold value of 10-3 that is considered an indication of definite risk according to similar risk studies. The results also showed that risk may be underestimated if the contributions of gas-phase PAHs are not considered.

DNA-adducts in subjects exposed to urban air pollution by benzene and polycyclic aromatic hydrocarbons (PAHs) in Cotonou, Benin

Air pollution effect on humans represents a major public health problem. Exposure to genotoxic compounds in the ambient air is evaluated using different biomarkers. In the present study we assessed DNA-adducts levels in apparently healthy people living and working in the city of Cotonou (Benin) in which exposure to air pollutants such as benzene and polycyclic aromatic hydrocarbons (PAHs) mainly benzo(a)pyrene has been evidenced. Rural inhabitants were enrolled as control group. Taxi-motorbike drivers, street food vendors, and gasoline salesmen were recruited in Cotonou whereas suburban residents were recruited in Godomey, 12 km from Cotonou. We found that taxi-motorbike drivers, roadside residents, street vendors, taxi-motor-bike drivers and gasoline sellers had significantly higher levels of DNA-adducts than suburban and village inhabitants (P < 0.001; post hoc, LSD). Means values were 24.6 ± 6.4, 23.78 ± 6.9, 34.7 ± 9.8, and 37.2 ± 8.1 in the exposed groups versus 2.1 ± 0.6 and 3.1 ± 0.8 adducts/10(8) nucleotides, in the two control groups, respectively. We did not find any significant difference within the high exposure groups and inside low exposure subgroups (namely suburban residents and villagers) because the mean individual exposure values to both PAHs and benzene were similar among subjects exposed in the city of Cotonou and those in suburban and village areas. However, there is significant interindividual variations in adducts levels that may reflect variation of genetic susceptibility factors. Ranges of adduct level/10(8) nucleotides were: 1-69, 1-76, 3-169, 4-124, 0-9, 0-8 adducts/10(8) for taxi-motorbike drivers, roadside residents, street vendors, gasoline sellers, suburban and village inhabitants, respectively. Our study demonstrated a clear-cut elevated level of DNA adducts in city residents than in none exposed people (or very low exposure levels people) and designate these city residents groups as people at risks for the chronic diseases possibly caused by benzene and PAHs.

Using charcoal as base material reduces mosquito coil emissions of toxins

Mosquito coils are used to prevent mosquito exposures indoors by approximately 2 billion people worldwide. However, the smoldering of organic matters used as base materials of mosquito coils emits particulate and gaseous toxic compounds. A previous study indicates that emission rates of toxic compounds depend on types of base materials and can be high enough to generate room concentrations markedly higher than health based standards or references. The objective of this study is to evaluate a new type of mosquito coil that uses charcoal powder as base material and to compare its emission rates with those of several current-market brands and several brands tested in the previous study. Results show that the charcoal-based coil had emission rates of PM(2.5) mass, total particle number, polycyclic aromatic hydrocarbons (PAH), and aldehydes, substantially (up to 10 times) lower than other tested conventional mosquito coils. Results also show that particles freshly generated from burning mosquito coils were all fine and mostly ultrafine in size. This study presents emission rates for PM(2.5) mass, total particle number, gas-phase and particle-phase PAHs, 14 aldehydes and acetone, and 10 volatile hydrocarbons. These data, along with emission rates presented in the previous study are useful for estimating indoor concentrations of toxic compounds generated from mosquito coil uses. Practical Implications Mosquito coils are widely used indoors to prevent mosquitoes from entering indoor environments. This is achieved through the release of insecticides impregnated in biomass base materials of mosquito coils during coil combustion. A previous study reported that burning one mosquito coil releases the same amount of fine particles as burning 75-135 cigarettes, largely depending on what biomass (saw dust or coconut husk) is used as base material. This 'follow-up' study measured several current-market brands of mosquito coils, including a new charcoal-based coil labeled as smokeless coil by the China Environmental Labeling, for their emissions of particulate and gaseous pollutants. Results show that using charcoal powder as base material reduces fine particle emissions by a factor of 5-10 and also reduces emissions of pollutants such as formaldehyde and PAHs substantially.

Chemicals present in automobile traffic tunnels and the possible community health hazards: a review of the literature

Dozens of volatile and semivolatile organic compounds can be detected in vehicle exhaust, along with numerous metals and oxides of sulfur, nitrogen, and carbon. While the adverse effects of these chemicals have been extensively studied surrounding open roadways, the hazards to local residents and commuters resulting from the presence of tunnel emission chemicals are less well known. Commuters and workers within tunnels are also exposed to tunnel atmospheres, and the risks have only been evaluated to a limited extent. Approximately 50 studies conducted at more than 35 different international traffic tunnels were reviewed in order to characterize the potential health impact on individuals residing near these tunnels. One objective of this article is to identify those chemicals that deserve further study in order to understand the hazards to humans who work in these tunnels, as well as the risks to those in the surrounding community. The second objective is to present the available information regarding the hazards to those living near these tunnels. The published information, for the most part, indicates that the concentration of most toxicants detected in communities exposed to tunnel emissions are below those concentrations that are generally considered to pose either a significant acute or chronic health hazard. However, there have been no comprehensive studies that have evaluated the concentration of all of the relevant toxicants on a real-time basis or using repetitive time-weighted average sampling. Based on our analysis of the existing information appearing in peer-reviewed literature and government reports, additional information on the variation of concentrations of various chemicals over time near the tunnel exits would be helpful. Optimally, these would be better if evaluated in conjunction with traffic magnitude and vehicle type. It would also be useful to further characterize acute exposures to commuters or tunnel workers during times of heavy volume or slow-moving traffic due to accidents within the tunnel structure, when tunnel pollutant levels would be expected to be substantially elevated. A recent review by the Australia's National Health and Medical Research Council also discusses tunnel and air quality in detail (2008). Nearly 300 references are cited.

Cancer risk assessment of selected hazardous air pollutants in Seattle

The risk estimates calculated from the conventional risk assessment method usually are compound specific and provide limited information for source-specific air quality control. We used a risk apportionment approach, which is a combination of receptor modeling and risk assessment, to estimate source-specific lifetime excess cancer risks of selected hazardous air pollutants. We analyzed the speciated PM(2.5) and VOCs data collected at the Beacon Hill in Seattle, WA between 2000 and 2004 with the Multilinear Engine to first quantify source contributions to the mixture of hazardous air pollutants (HAPs) in terms of mass concentrations. The cancer risk from exposure to each source was then calculated as the sum of all available species' cancer risks in the source feature. We also adopted the bootstrapping technique for the uncertainty analysis. The results showed that the overall cancer risk was 6.09 x 10(-5), with the background (1.61 x 10(-5)), diesel (9.82 x 10(-6)) and wood burning (9.45 x 10(-6)) sources being the primary risk sources. The PM(2.5) mass concentration contributed 20% of the total risk. The 5th percentile of the risk estimates of all sources other than marine and soil were higher than 110(-6). It was also found that the diesel and wood burning sources presented similar cancer risks although the diesel exhaust contributed less to the PM(2.5) mass concentration than the wood burning. This highlights the additional value from such a risk apportionment approach that could be utilized for prioritizing control strategies to reduce the highest population health risks from exposure to HAPs.

Acrolein environmental levels and potential for human exposure

This article provides environmental information on acrolein including environmental fate, potential for human exposure, analytical methods, and a listing of regulations and advisories. Acrolein may be released to the environment in emissions and effluents from its manufacturing and use facilities, in emissions from combustion processes (including cigarette smoking and combustion of petrochemical fuels), from direct application to water and waste water as a slimicide and aquatic herbicide, as a photooxidation product of various hydrocarbon pollutants found in air (including propylene and 1,3-butadiene), and from land disposal of some organic waste materials. Acrolein is a reactive compound and is unstable in the environment. The general population may be exposed to acrolein through inhalation of contaminated air and through ingestion of certain foods. Important sources of acrolein exposure are via inhalation of tobacco smoke and environmental tobacco smoke and via the overheating of fats contained in all living matter. There is potential for exposure to acrolein in many occupational settings as the result of its varied uses and its formation during the combustion and pyrolysis of materials such as wood, petrochemical fuels, and plastics.

QSPR analysis of air-to-blood distribution of volatile organic compounds

Quantitative structure property relationship (QSPR) models for the prediction of human blood:air partition coefficient (log K(blood)) of volatile organic compounds (VOCs) has been developed based on the linear heuristic method (HM) and non-linear radial basis function neural networks (RBFNNs). Molecular descriptors that are calculated from the structures alone were used to represent the characteristics of the compounds. HM was used both to pre-select the whole descriptor sets and to build the linear model. RBFNN was performed to obtain more accurate models. Both the linear and the non-linear models can give very satisfactory prediction results: the correlation coefficient R was 0.964 and 0.979, and the root-mean-square (RMS) error was 0.3303 and 0.2542 for the whole data set, respectively. The prediction result of the non-linear model is better than that obtained by the linear model. In addition, this paper provides an effective method for predicting log K(blood) from its structures and gives some insight into the structural features related to the solubility of VOCs in human blood.

Role of exhaled breath biomarkers in environmental health science

As a discipline of public health, environmental health science is the study of the linkage from environmental pollution sources to eventual adverse health outcome. This progression may be divided into two components, (1) "exposure assessment," which deals with the source terms, environmental transport, human exposure routes, and internal dose, and (2) "health effects," which deals with metabolism, cell damage, DNA changes, pathology, and onset of disease. The primary goal of understanding the linkage from source to health outcome is to provide the most effective and efficient environmental intervention methods to reduce health risk to the population. Biomarker measurements address an individual response to a common external environmental stressor. Biomarkers are substances within an individual and are subdivided into chemical markers, exogenous metabolites, endogenous response chemicals, and complex adducts (e.g., proteins, DNA). Standard biomarker measurements are performed in blood, urine, or other biological media such as adipose tissue and lavage fluid. In general, sample collection is invasive, requires medical personnel and a controlled environment, and generates infectious waste. Exploiting exhaled breath as an alternative or supplement to established biomarker measurements is attractive primarily because it allows a simpler collection procedure in the field for numerous individuals. Furthermore, because breath is a gas-phase matrix, volatile biomarkers become more readily accessible to analysis. This article describes successful environmental health applications of exhaled breath and proposes future research directions from the perspective of U.S. Environmental Protection Agency (EPA) human exposure research.

Diurnal cycles of acrolein and other small aldehydes in regions impacted by vehicle emissions

This research determined the diurnal and seasonal differences in the ambient atmospheric concentrations of acrolein and several small aldehydes and attempted to link the chemicals to their potential sources. Two summertime and two wintertime sampling episodes were conducted in Roseville, CA at a site located near several busy roadways. One additional sampling episode was conducted at a remote site in the summer to estimate regional background concentrations of aldehydes. Each sampling episode consisted of duplicate samples collected every two hours around the clock for three days. Acrolein concentrations did not correlate with traffic density, ozone concentrations, or tracers of direct vehicle emissions, which argues against vehicles being a dominant source of ambient acrolein through primary emissions or secondary oxidation products. The results showed that wintertime acrolein concentrations correlated well with 2-furaldehyde, which is a tracer of biomass burning, thus suggesting that wood smoke is an important source of ambient acrolein. Other regularly detected carbonyls were tentatively assigned to different source classes (direct vehicle emissions, photochemical oxidation, wood smoke or transport from the Sierra Nevada Mountains) based on time series patterns and correlations with indicators of potential sources (e.g., ozone, traffic density, etc.).

ATSDR evaluation of potential for human exposure to benzene

As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals found at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) sites that have the greatest public health impact. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of portions of the toxicological profile for benzene. The primary purpose of this article is to provide interested individuals with environmental information on benzene that includes production data, environmental fate, potential for human exposure, analytical methods, and a listing of regulations and advisories.

Comparative assessment of air pollution-related health risks in Houston

BACKGROUND

Airborne emissions from numerous point, area, and mobile sources, along with stagnant meteorologic conditions, contribute to frequent episodes of elevated air pollution in Houston, Texas. To address this problem, decision makers must set priorities among thousands of individual air pollutants as they formulate effective and efficient mitigation strategies.

OBJECTIVES

Our aim was to compare and rank relative health risks of 179 air pollutants in Houston using an evidence-based approach supplemented by the expert judgment of a panel of academic scientists.

METHODS

Annual-average ambient concentrations by census tract were estimated from the U.S. Environmental Protection Agency's National-scale Air Toxics Assessment and augmented with measured levels from the Houston monitoring network. Each substance was assigned to one of five risk categories (definite, probable, possible, unlikely, uncertain) based on how measured or monitored concentrations translated into comparative risk estimates. We used established unit risk estimates for carcinogens and/or chronic reference values for noncarcinogens to set thresholds for each category. Assignment to an initial risk category was adjusted, as necessary, based on expert judgment about the quality and quantity of information available.

RESULTS

Of the 179 substances examined, 12 (6.7%) were deemed definite risks, 9 (5.0%) probable risks, 24 (13.4%) possible risks, 16 (8.9%) unlikely risks, and 118 (65.9%) uncertain risks.

CONCLUSIONS

Risk-based priority setting is an important step in the development of cost-effective solutions to Houston's air pollution problem.

If cumulative risk assessment is the answer, what is the question?

Cumulative risk refers to the combined threats from exposure via all relevant routes to multiple stressors including biological, chemical, physical, and psychosocial entities. Cumulative risk assessment is a tool for organizing and analyzing information to examine, characterize, and possibly quantify the combined adverse effects on human health or ecologic resources from multiple environmental stressors. The U.S. Environmental Protection Agency (EPA) has initiated a long-term effort to develop future guidelines for cumulative risk assessment, including publication in 2003 of a framework that describes important features of the process and discusses theoretical issues, technical matters, and key definitions. The framework divides the process of cumulative risk assessment into three interrelated phases: a) planning, scoping, and problem formulation; b) analysis; and c) interpretation and risk characterization. It also discusses the additional complexities introduced by attempts to analyze cumulative risks from multiple stressors and describes some of the theoretical approaches that can be used. The development of guidelines for cumulative risk assessment is an essential element in the transition of the U.S. EPA risk assessment methodology from a narrow focus on a single stressor, end point, source, pathway, and exposure route to a broader, more holistic approach involving analysis of combined effects of cumulative exposure to multiple stressors via all relevant sources, pathways, and routes.

Assessing cumulative health risks from exposure to environmental mixtures - three fundamental questions

Differential exposure to mixtures of environmental agents, including biological, chemical, physical, and psychosocial stressors, can contribute to increased vulnerability of human populations and ecologic systems. Cumulative risk assessment is a tool for organizing and analyzing information to evaluate the probability and seriousness of harmful effects caused by either simultaneous and/or sequential exposure to multiple environmental stressors. In this article we focus on elucidating key challenges that must be addressed to determine whether and to what degree differential exposure to environmental mixtures contributes to increased vulnerability of exposed populations. In particular, the emphasis is on examining three fundamental and interrelated questions that must be addressed as part of the process to assess cumulative risk: a) Which mixtures are most important from a public health perspective? and b) What is the nature (i.e., duration, frequency, timing) and magnitude (i.e., exposure concentration and dose) of relevant cumulative exposures for the population of interest? c) What is the mechanism (e.g., toxicokinetic or toxicodynamic) and consequence (e.g., additive, less than additive, more than additive) of the mixture's interactive effects on exposed populations? The focus is primarily on human health effects from chemical mixtures, and the goal is to reinforce the need for improved assessment of cumulative exposure and better understanding of the biological mechanisms that determine toxicologic interactions among mixture constituents.

Estimating volatile organic compound concentrations in selected microenvironments using time-activity and personal exposure data

Repeated measures of personal exposure to 14 volatile organic compounds (VOC) were obtained over 3 seasons for 70 healthy, nonsmoking adults living in Minneapolis-St. Paul. Matched data were also available for participants' time-activity patterns, and measured VOC concentrations outdoors in the community and indoors in residences. A novel modeling approach employing hierarchical Bayesian techniques was used to estimate VOC concentrations (posterior mode) and variability (credible intervals) in five microenvironments: (1) indoors at home; (2) indoors at work/school; (3) indoors in other locations; (4) outdoors in any location; and (5) in transit. Estimated concentrations tended to be highest in "other" indoor microenvironments (e.g., grocery stores, restaurants, shopping malls), intermediate in the indoor work/school and residential microenvironments, and lowest in the outside and in-transit microenvironments. Model estimates for all 14 VOC were reasonable approximations of measured median concentrations in the indoor residential microenvironment. The largest predicted contributor to cumulative (2-day) personal exposure for all 14 VOC was the indoor residential environment. Model-based results suggest that indoors-at-work/school and indoors-at-other-location microenvironments were the second or third largest contributors for all VOC, while the outside-in-any-location and in-transit microenvironments appeared to contribute negligibly to cumulative personal exposure. Results from a mixed-effects model indicate that being in or near a garage increased personal exposure to o-xylene, m/p-xylene, benzene, ethylbenzene, and toluene, and leaving windows and doors at home open for 6 h or more decreased personal exposure to 13 of 14 VOC, all except trichloroethylene.

Developing risk-based priorities for reducing air pollution in urban settings in Ukraine

Ukraine, when part of the former Soviet Union, was responsible for about 25% of its overall industrial production. This aging industrial infrastructure continues to emit enormous volumes of air and water pollution and wastes. The National Report on the State of Environment in Ukraine 1999 (Ukraine Ministry of Environmental Protection [MEP], 2000) shows significant air pollution. There are numerous emissions that have been associated with developmental effects, chronic long-term health effects, and cancer. Ukraine also has been identified as a major source of transboundary air pollution for the eastern Mediterranean region. Ukraine's Environment Ministry is not currently able to strategically target high-priority emissions and lacks the resources to address all these problems. For these reasons, the U.S. Environmental Protection Agency set up a partnership with Ukraine's Ministry of Environmental Protection to strengthen its capacity to set environmental priorities through the use of comparative environmental risk assessment and economic analysis--the Capacity Building Project. The project is also addressing improvements in the efficiency and effectiveness of the use of its National Environmental Protection Fund. The project consists of a series of workshops with Ukrainian MEP officials in comparative risk assessment of air pollutant emissions in several heavily industrialized oblasts; cost-benefit and cost-effectiveness analysis; and environmental finance. Pilot risk assessment analyses have been completed. At the end of the Capacity Building Project it is expected that the use of the National Environmental Protection fund and the regional level oblast environmental protection funds will begin to target and identify the highest health and environmental risk emissions.

A cancer risk assessment of inner-city teenagers living in New York City and Los Angeles

BACKGROUND

The Toxics Exposure Assessment Columbia-Harvard (TEACH) project assessed exposures and cancer risks from urban air pollutants in a population of high school teenagers in New York City (NYC) and Los Angeles (LA). Forty-six high school students participated in NYC and 41 in LA, most in two seasons in 1999 and 2000, respectively.

METHODS

Personal, indoor home, and outdoor home 48-hr samples of volatile organic compounds (VOCs), aldehydes, particulate matter with aerodynamic diameter < or = 2.5 microm, and particle-bound elements were collected. Individual cancer risks for 13 VOCs and 6 particle-bound elements were calculated from personal concentrations and published cancer unit risks.

RESULTS

The median cumulative risk from personal VOC exposures for this sample of NYC high school students was 666 per million and was greater than the risks from ambient exposures by a factor of about 5. In the LA sample, median cancer risks from VOC personal exposures were 486 per million, about a factor of 4 greater than ambient exposure risks. The VOCs with the highest cancer risk included 1,4-dichlorobenzene, formaldehyde, chloroform, acetaldehyde, and benzene. Of these, benzene had the greatest contributions from outdoor sources. All others had high contributions from indoor sources. The cumulative risks from personal exposures to the elements were an order of magnitude lower than cancer risks from VOC exposures.

CONCLUSIONS

Most VOCs had median upper-bound lifetime cancer risks that exceeded the U.S. Environmental Protection Agency (EPA) benchmark of 1 x 10-6 and were generally greater than U.S. EPA modeled estimates, more so for compounds with predominant indoor sources. Chromium, nickel, and arsenic had median personal cancer risks above the U.S. EPA benchmark with exposures largely from outdoors and other microenvironments. The U.S. EPA-modeled concentrations tended to overestimate personal cancer risks for beryllium and chromium but underestimate risks for nickel and arsenic.

Behavior of the GABIE, 3M 3500, PerkinElmer Tenax TA, and RADIELLO 145 diffusive samplers exposed over a long time to a low concentration of VOCs

Diffusive sampling is particularly suited to determine time-weighted average volatile organic compound (VOC) concentration in occupational hygiene and environmental air monitoring. The purpose of this study was to measure the sampling rate variation of four different samplers in a special use--the exposure to a low concentration of volatile organic compound (10 to 200 ppb) for a long period (1 to 14 days). PerkinElmer tube-type adsorbent was packed with Tenax TA and RADIELLO cartridge packed with Carbograph 4. Badge-type activated carbon diffusive samplers 3M 3500 and GABIE were exposed to the same controlled atmospheres of benzene as meta-xylene (BTX) during the same exposure times. Performance samplers were observed for variability of uptake rates according to concentration levels, exposure duration, back diffusion, and competition phenomena at the adsorption sites. Particular benzene behavior has been noted for the thermally desorbable tube-type diffusive sampler: the measured sampling rates decrease with time following an exponential profile. With badge-type active charcoal diffusive samplers, the uptake rates were found to be highly stable and unaffected by time exposure. Overall, in the region of a few tens of ppb, for long-time exposure and for the lightest compounds, 3M 3500 and GABIE diffusive samplers seem the most appropriate diffusive sampling technique in terms of performance and facility in use.