Exhaust from diesel combustion engines is an important contributor to urban air pollution and poses significant risk to human health. Diesel exhaust contains a chemical class known as nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and is enriched in 1-nitropyrene (1-NP), which has the potential to serve as a marker of diesel exhaust. The isomeric nitro-PAHs 2-nitropyrene (2-NP) and 2-nitrofluoranthene (2-NFL) are secondary pollutants arising from photochemical oxidation of pyrene and fluoranthene, respectively. Like other important air toxics, there is not extensive monitoring of nitro-PAHs, leading to gaps in knowledge about relative exposures and urban hotspots. Epiphytic moss absorbs water, nutrients, and pollutants from the atmosphere and may hold potential as an effective biomonitor for nitro-PAHs. In this study we investigate the suitability of Orthotrichum lyellii as a biomonitor of diesel exhaust by analyzing samples of the moss for 1-NP, 2-NP, and 2-NFL in the Seattle, WA metropolitan area. Samples were collected from rural parks, urban parks, residential, and commercial/industrial areas (N = 22 locations) and exhibited increasing concentrations across these land types. Sampling and laboratory method performance varied by nitro-PAH, but was generally good. We observed moderate to moderately strong correlation between 1-NP and select geographic variables, including summer normalized difference vegetation index (NDVI) within 250 m (r = -0.88, R2 = 0.77), percent impervious surface within 50 m (r = 0.83, R2 = 0.70), percent high development land use within 500 m (r = 0.77, R2 = 0.60), and distance to nearest secondary and connecting road (r = -0.75, R2 = 0.56). The relationships between 2-NP and 2-NFL and the geographic variables were generally weaker. Our results suggest O. lyellii is a promising biomonitor of diesel exhaust, specifically for 1-NP. To our knowledge this pilot study is the first to evaluate using moss concentrations of nitro-PAHs as biomonitors of diesel exhaust.

Amid the growing concerns about air toxics from pollution sources, much emphasis has been placed on their impacts on human health. However, there has been limited research conducted to assess the cumulative country-wide impact of air toxics on both terrestrial and aquatic ecosystems, as well as the complex interactions within food webs. Traditional approaches, including those of the United States Environmental Protection Agency (US EPA), lack versatility in addressing diverse emission sources and their distinct ecological repercussions. This study addresses these gaps by introducing the Ecological Health Assessment Methodology (EHAM), a novel approach that transcends traditional methods by enabling both comprehensive country-wide and detailed regional ecological risk assessments across terrestrial and aquatic ecosystems. EHAM also advances the field by developing new food-chain multipliers (magnification factors) for localized ecosystem food web models. Employing traditional ecological multimedia risk assessment of toxics\' fate and transport techniques as its foundation, this study extends US EPA methodologies to a broader range of emission sources. The quantification of risk estimation employs the quotient method, which yields an ecological screening quotient (ESQ). Utilizing Kuwait as a case study for the application of this methodology, this study\'s findings for data from 2017 indicate a substantial ecological risk in Kuwait\'s coastal zone, with cumulative ESQ values reaching as high as 3.12 × 103 for carnivorous shorebirds, contrasted by negligible risks in the inland and production zones, where ESQ values for all groups are consistently below 1.0. By analyzing the toxicity reference value (TRV) against the expected daily exposure of receptors to air toxics, the proposed methodology provides valuable insights into the potential ecological risks and their subsequent impacts on ecological populations. The present contribution aims to deepen the understanding of the ecological health implications of air toxics and lay the foundation for informed, ecology-driven policymaking, underscoring the need for measures to mitigate these impacts.

UNASSIGNED: Exposure misclassification based solely on the address at cancer diagnosis has been widely recognized though not commonly assessed.
UNASSIGNED: We linked 1,015 mesothelioma cases diagnosed during 2011-2015 from the New York State Cancer Registry to inpatient claims and LexisNexis administrative data and constructed residential histories. Percentile ranking of exposure to ambient air toxics and socioeconomic status (SES) were based on the National Air Toxic Assessment and United States Census data, respectively. To facilitate comparisons over time, relative exposures (REs) were calculated by dividing the percentile ranking at individual census tract by the state-level average and subtracting one. We used generalized linear regression models to compare the RE in the past with that at cancer diagnosis, adjusting for patient-level characteristics.
UNASSIGNED: Approximately 43.7% of patients had residential information available for up to 30 years, and 96.0% up to 5 years. The median number of unique places lived was 4 [interquartile range (IQR), 2-6]. The time-weighted-average RE from all addresses available had a median of -0.11 (IQR, -0.50 to 0.30) for air toxics and -0.28 (IQR, -0.65 to 0.25) for SES. RE associated with air toxics (but not SES) was significantly higher for earlier addresses than addresses at cancer diagnosis for the 5-year [annual increase =1.24%; 95% confidence interval (CI): 0.71-1.77%; n=974] and 30-year (annual increase =0.36%; 95% CI: 0.25-0.48%; n=444) look-back windows, respectively.
UNASSIGNED: Environmental exposure to non-asbestos air toxics among mesothelioma patients may be underestimated if based solely on the address at diagnosis. With geospatial data becoming more readily available, incorporating cancer patients\' residential history would lead to reduced exposure misclassification and accurate health risk estimates.

Paddy-residue burning is associated with poor air quality in north-west India during October-November every year. However, till date a quantitative study of its contribution to ambient volatile organic compounds (VOCs) using highly time-resolved measurements within the region has been lacking. Several VOCs like benzene are carcinogenic and also fuel formation of secondary pollutants such as secondary organic aerosol (SOA) and ozone. Here, we undertake quantitative source-apportionment using a PMF source-receptor model on a high-quality in-situ measured dataset of 54 VOCs in Punjab, India, and validate the model results using source profiles. The contribution of the seven most dominant sources to the total VOC mass concentrations were: daytime photochemistry and biogenic VOCs (BVOCs) (26%), followed by solid-fuel usage and waste-disposal (18%), traffic (two-wheeler 14% and four-wheeler 10%), photochemically aged biomass burning (17%), industries and solvent usage (9%), and fresh paddy residue burning (6%). Ozone production potential was dominated by solid fuel usage and waste disposal (25%), followed by traffic (two-wheeler 11% and four-wheeler 12%), BVOCs and photooxidation products (21%), photochemically aged biomass burning (16%), industries & solvent usage (9%) and fresh paddy residue burning (6%). SOA production was dominated by traffic (two-wheeler 26% and four-wheeler 28%) followed by solid fuel usage and waste disposal (22%), photochemically aged biomass burning emissions (15%) with minor contribution from industries & solvents (6%), fresh paddy residue burning (2%) and photochemistry and biogenic VOCs (1%). Comparisons with global emission inventories REASv3.2.1 and EDGARv4.3.2, showed both overestimate the industry and solvent source. Further, EDGARv4.3.2 underestimated the traffic source whereas paddy residue burning emissions are absent in REASv3.2.1. Although the overall mass contribution of paddy-residue burning emissions isn\'t high, our results show that health-relevant compounds emitted directly and formed photochemically from biomass burning sources active at this time are majorly responsible for the unhealthy air.

Ethylene oxide (EtO) is an industrial gas that was recently reassessed to pose significant additional cancer risk at low ambient concentrations. The objective of this study is to evaluate the capabilities of existing and novel techniques to measure ambient EtO at concentrations relevant for assessing cancer risk. We present the first comparison of background ambient EtO measurements between the standard offline TO-15 techniques and two new cavity ringdown spectroscopy (CRDS) instruments, the Picarro G2920 Ethylene Oxide Gas Analyzer and the Entanglement Technologies AROMA-ETO, at a site in Atlanta, GA. Then, we analyzed background EtO measured at EPA NATTS sites across the US. Finally, we used TO-15 measurement data to assess EtO cancer risk at three near-source sites. We find that the TO-15 method has low precision for collocated samples (NME ranges from 24% to 63%), and measurements made with TO-15 pressurized samplers are biased 27% low compared to those from TO-15 passive samplers. Both CRDS methods are biased low compared to TO-15 methods (88% and 31% low bias for Picarro and AROMA, respectively), and TO-15 methods observe a seasonal peak during summer (June to September) whereas Picarro observes no seasonal trend. From our near-source assessment, we find only one site with notable elevation in cancer risk prior to EtO controls installation. Our results suggest that measurement techniques need further development to accurately assess near-source EtO cancer risk. Because different techniques measure distinct EtO trends, EtO cancer risk studies that rely on current measurement capabilities should subtract simultaneous background observations from near-source observations measured by the same method to account for these real or artificial background trends.

POD diffusive samplers loaded with Carbopack X and Carbograph 5TD were exposed to certified calibration mixtures containing a total of 110 different ozone precursor and air toxic compounds. Constant sampling rates were identified for 39 ozone precursors and 33 air toxics. As 9 of these compounds were included in both mixtures, this meant a total of 63 different volatile and very volatile compounds were sampled using the POD with overall expanded uncertainties below 30 % for the sampling rate associated with the whole range of sampling times from 2 to 24 h. Carbograph 5TD exhibited superior performance for diffusive sampling of oxygenated and halogenated compounds in the air toxics mixture, while Carbopack X showed higher sampling efficiencies for aliphatic and aromatic hydrocarbons, as well as halogenated compounds derived from benzene and C2 carbon number hydrocarbons. A model has been developed and applied to estimate sampling rates, primarily for the more volatile and weakly adsorbed compounds, as a function of the collected amount of analyte and the exposure time. For an additional 9 ozone precursors on Carbopack X, and 11 air toxics on Carbograph 5TD, the expanded uncertainties of modelled sampling rates were reduced to below 30 % and have a significantly reduced uncertainty compared to those associated with an averaged sampling rate. The paper provides Freundlich\'s isotherm parameters for the estimated (modelled) sampling rates and defines a pragmatic approach to their application. It does so by identifying the best sampling time to use for the expected exposure concentrations and associated analyte masses. This allows for expansion of the sampling concentration range from hundreds ng m-3 to mg m-3, while avoiding saturation of the adsorbent. Finally, field measurement comparisons of POD samplers, pumped tube samplers and online gas chromatography (GC), for sampling periods of 3 and 7 days in a semi-rural background area, showed no significant differences between reported concentrations.

Hypertension is a leading risk factor for disease burden, with more than 200 million disability-adjusted life-years attributed to high blood pressure in 2015. While outdoor air pollution is associated with cardiovascular disease, the joint effect of exposure to air pollution from combustion products on hypertension has rarely been studied. We conducted a cross-sectional analysis to explore the association between combustion-related air pollution and hypertension. Census-tract levels of ambient concentrations of nine fossil-fuel and combustion-related air toxics (biphenyl, naphthalene, polycyclic organic matter, diesel emissions, 1,3-butadiene, acetaldehyde, benzene, acrolein, and formaldehyde) from the 2005 National Air Toxics Assessment database and NO2 from 2005 monitoring data were linked to baseline residential addresses of 47,467 women in the Sister Study cohort. Hypertension at enrollment (2003-2009) was defined as high systolic (≥140 mm Hg) or diastolic (≥90 mm Hg) blood pressure or taking antihypertensive medication. We used log-binomial regression and quantile-based g-computation to estimate the individual and joint effects of fossil-fuel and combustion-related air pollution on hypertension. Comparing the highest to lowest quartiles, diesel emissions (prevalence ratio (PR) = 1.05, 95% confidence interval (CI) = 1.01,1.08), 1,3-butadiene (PR = 1.04, 95%CI = 1.00,1.07), acetaldehyde (PR = 1.08, 95%CI = 1.04,1.12), benzene (PR = 1.05, 95%CI = 1.02,1.08), formaldehyde (PR = 1.08, 95%CI = 1.04,1.11), and NO2 (PR = 1.08, 95%CI = 1.05,1.12) were individually associated with higher prevalence of hypertension. The PR for the joint effect of increasing all ambient air toxics and NO2 by one quartile was 1.02 (95%CI = 1.01,1.04). Associations varied by race/ethnicity, with stronger associations observed among women reporting races/ethnicities (Hispanic/Latina, non-Hispanic Black and other) other than non-Hispanic White. In conclusion, we found that air pollution from fossil fuel and combustion may be a risk factor for hypertension.

Evidence on environmental justice studies linking adverse health effects and on-roadair pollution showing spatial nonstationarity is limited.This study uses cancer and noncancer risk estimates from on-road sources of hazardous air pollutants modeled by the National-Scale Air Toxics Assessment (NATA) at the census tract (N = 5265) level and sociodemographic variables from U.S. Census Bureau to examine the nonstationarity spatial relationship by comparing aspatial and spatial regression modelsglobal ordinary least squares, spatial error model, geographically weighted regression, and multiscale geographically weighted regression. At first glance, census tracts within the highest quartile of cancer and noncancer risks were clustered in the major urban areas. Spatial regression indicates that cancer and non-cancer risk were associated with census tract level percentages of Black, Indigenous, and People of Color (BIPOC). These findings can serve as geospatial guidance for intervening in the processes that drive socio-spatial disparity in air pollution exposure.

Previous research has observed relationships between higher prenatal exposure to air pollutants and neurodevelopmental and academic outcomes later in childhood. Identifying intermediate outcomes mediating this relationship would inform prevention and intervention efforts. We aimed to investigate if previously observed associations between prenatal exposure to common urban air pollutants, diesel and perchloroethylene, and performance on third grade standardized tests were mediated through increased risk of preterm birth.
Data from the 1994-1998 birth cohorts within the New York City Longitudinal Study of Early Development were included in this analysis. Exposure was determined by linking the mother\'s residence at the time of delivery to the U.S. EPA\'s 1996 National Air Toxic Assessment of estimated ambient concentrations of diesel and perchloroethylene. Children\'s third grade standardized math and language tests were used as the markers for academic achievement. Missing data on covariates were imputed, while participants with missing information on gestational age and test scores were excluded. Linear regression models and causal mediation analysis were used to examine potential mediation by preterm birth.
In total, 187,723 and 196,122 participants were included in language and math analyses, respectively. Children with exposure to the fourth quartile of diesel or perchloroethylene had approximately 0.03 (95%CI: 0.02, 0.04) lower math z-scores when compared to individuals with exposure in the first quartile, although there was no consistent decreasing trend in math z-scores over increasing quartiles of diesel or perchloroethylene. We did not find evidence of mediation by preterm birth or exposure-mediator interaction in our models.
We did not find evidence that observed relationships between exposure to common urban air pollutants and test z-scores in childhood were mediated through an increased risk of preterm birth. This suggests other pathways between early exposure to air pollution and neurodevelopment should be investigated with causal mediation approaches.

Wildfires emit smoke particles and gaseous pollutants that greatly aggravate air quality and cause adverse health impacts in the western US (WUS). This study evaluates how wildfire impacts on air pollutants and air toxics evolve from the present climate to the future climate under a high anthropogenic emission scenario at regional and city scales. Through employing multiple climate and chemical transport models, small changes in domain-averaged air pollutant concentrations by wildfires are simulated over WUS. However, such changes significantly increase future city-scale pollutant concentrations by up to 53 ppb for benzene, 158 ppb for formaldehyde, 655 μg/m3 for fine particulate matter (PM2.5), and 102 ppb for ozone, whereas that for the present climate are 104 ppb for benzene, 332 ppb for formaldehyde, 1,378 μg/m3 for PM2.5, and 140 ppb for ozone. Despite wildfires induce smaller changes in the future, the wildfire contribution ratios can increase by more than tenfold compared to the present climate, indicating wildfires become a more critical contributor to future air pollution in WUS. In addition, additional 6 exceedance days/year for formaldehyde and additional 3 exceedance days/year for ozone suggest increasing health impacts by wildfires in the future.