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A preliminary investigation was carried out by the US Environmental Protection Agency (EPA) on the impact of regional ozone concentrations on climate change in the country. The main objective of the investigation was to enhance the ability of air quality managers to consider global change in their decisions through improved characterization of the potential effects of global change on air quality, including O3, PM, and Hg. An integrated assessment framework was designed that supported the research and development efforts within the EPA and the academic research professionals. This design recognized the challenges of bridging spatial scales, temporal scales, and disciplines that characterize the global change and regional air quality problem. A major component of the assessment approach involved the development and application of global to regional climate and air quality modeling systems.

We develop a source-specific high-resolution emission inventory for the Shandong region of eastern China for 2000 and 2020. Our emission estimates for year 2000 are higher than other studies for most pollutants, due to our inclusion of rural coal consumption, which is significant but often underestimated. Still, our inventory evaluation suggests that we likely underestimate actual emissions. We project that emissions will increase greatly from 2000 to 2020 if no additional emission controls are implemented. As a result, PM2.5 concentrations will increase; however O3 concentrations will decrease in most areas due to increased NOx emissions and VOC-limited O3 chemistry. Taking Zaozhuang Municipality in this region as a case study, we examine possible changes in emissions in 2020 given projected growth in energy consumption with no additional controls utilized (BAU), with adoption of best available end-of-pipe controls (BACT), and with advanced, low-emission coal gasification technologies (ACGT) which are capable of gasifying the high-sulfur coal that is abundant in China. Emissions of NH3 are projected to be 20% higher, NMVOC 50% higher, and all other species 130-250% higher in 2020 BAU than in 2000. Both alternative 2020 emission scenarios would reduce emissions relative to BAU. Adoption of ACGT, which meets only 24% of energy service demand in Zaozhuang in 2020 would reduce emissions more than BACT with 100% penetration. In addition, coal gasification technologies create an opportunity to reduce greenhouse gas emissions by capturing and sequestering CO2 emissions below ground. © 2005 Elsevier Ltd. All rights reserved.

Mexico City is far advanced in its urban evolution, and cities in currently developing nations may soon follow a similar course. This paper investigates the strengths and weaknesses of infrastructures for the emerging megacities. The major driving force for infrastructure change in Mexico City is concern over air quality. Air chemistry data from recent field campaigns have been used to calculate fluxes in the atmosphere of the Valley of Mexico, for compounds that are important to biogeochemistry including methane (CH4), carbon monoxide (CO), nonmethane hydrocarbons (NMHCs), ammonia (NH3), sulfur dioxide (SO2), nitrogen oxides (NOx and NOy), soot, and dust. Leakage of liquified petroleum gas approached 10% during sampling periods, and automotive pollutant sources in Mexico City were found to match those in developed cities, despite a lower vehicle-to-person ratio of 0.1. Ammonia is released primarily from residential areas, at levels sufficient to titrate pollutant acids into particles across the entire basin. Enhancements of reduced nitrogen and hydrocarbons in the vapor phase skew the distribution of NOy species towards lower average deposition velocities. Partly as a result, downwind nutrient deposition occurs on a similar scale as nitrogen fixation across Central America, and augments marine nitrate upwelling. Dust suspension from unpaved roads and from the bed of Lake Texcoco was found to be comparable to that occurring on the periphery of the Sahara, Arabian, and Gobi deserts. In addition, sodium chloride (NaCl) in the dust may support heterogeneous chlorine oxide (ClOx) chemistry. The insights from our Mexico City analysis have been tentatively applied to the upcoming urbanization of Asia.

The People's Republic of China, the world's most populous nation, is considering extensive development of its automotive transportation infrastructure. Upper limits to the associated pollution increases can be defined through scenarios with Western style vehicles and vehicle-to-person ratios. Here we construct estimates of fundamental changes to chemistry of the Pacific ocean/ atmosphere system through simple budgeting procedures. Regional increases in tropospheric ozone could reach tens of parts per billion. Observations/experiments suggest that enhanced nitrogen oxides will react with sea salt aerosols to yield chlorine atoms in the marine boundary layer. Nitrate deposition onto the open sea surface would support several percent of exported North Pacific carbon production. Transport of biologically active iron to surface waters may follow from increases in mineral dust and acid sulfate aerosols. Altered plankton ecodynamics will feed back into climate processes through sea to air flux of reduced sulfur gases and through carbon dioxide drawdown. Copyright 1997 by the American Geophysical Union.

Local surface travel needs in the People's Republic of China (mainland China) have traditionally been met largely by nonpolluting bicycles. A major automobile manufacturing/importing effort has begun in the country over the last decade, and planning documents indicate that the Chinese may strive to acquire more than 100 million vehicles early in the next century. By analogy with large automotive fleets already existing in the western world, both regional and global scale pollution effects are to be expected from the increase. The present work adopts the latest projections of Chinese automobile manufacture and performs some quantitative assessments of the extent of pollution generation. Focus for the investigation is placed upon the oxidant ozone. Emissions of the precursor species nitrogen oxides and volatile organics are constructed based on data for the current automotive sector in the eastern portion of the United States. Ozone production is first estimated from measured values for continental/oceanic scale yields relative to precursor oxidation. The estimates are then corroborated through idealized two dimensional modeling of the photochemistry taking place in springtime air flow off the Asian land mass and toward the Pacific Ocean. The projected fleet sizes could increase coastal and remote oceanic ozone concentrations by tens of parts per billion (ppb) in the lower troposphere. Influences on the tropospheric aerosol system and on the major greenhouse gas carbon dioxide are treated peripherally. Nitrogen oxides created during the vehicular internal combustion process will contribute to nitrate pollution levels measured in the open Pacific. The potential for soot and fugitive dust increases should be considered as the automotive infrastructure develops. Since the emerging Chinese automotive transportation system will represent a substantial addition to the global fleet and all the carbon in gasoline is eventually oxidized completely, a significant rise in global carbon dioxide inputs will ensue as well. Some policy issues are treated preliminary. The assumption is made that alterations to regional oxidant/aerosol systems and to terrestrial climate are conceivable. The likelihood that the Chinese can achieve the latest vehicle fleet goals is discussed, from the points of view of new production, positive pollution feedbacks from a growing automobile industry, and known petroleum reserves. Vehicular fuel and maintenance options lying before the Chinese are outlines and compared. To provide some perspective on the magnitude of the environmental changes associated with an Asian automotive buildup, recent estimates of the effects of future air traffic over the Pacific Rim are described.

Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Roya Bahreini, Haroula D. Baliaka, Ann M. Dillner, Richard C. Flagan, Nga L. Ng, Armistead G. Russell, John H. Seinfeld, Ryan X. Ward, and Paul O. Wennberg report support for the Atmospheric Science and Chemistry mEasurement NeTwork project by the National Science Foundation; John H. Seinfeld and Paul O. Wennberg also report receipt of consulting fees from MethaneSAT Science Advisory Group for evaluation of methane emissions from the Altadena fire. John H. Seinfeld reports uncompensated participation on a United Nations Environment Programme International Methane Emissions Observatory advisory group. Armistead G. Russell reports institutional support from the Health Effects Institute, the National Aeronautics and Space Administration, and the Environmental Protection Agency; receipt of consulting fees from the Health Effects Institute for committee service; and ownership of varied stocks, mutual funds, and retirement funds. Richard C. Flagan reports unpaid membership on the Board of Directors of the California Council on Science and Technology. No other potential conflicts of interest were disclosed.

We examined the association between ambient air pollution exposure and risk of spontaneous abortion (SAB) using Georgia state-wide fetal death records from 2005-2014. Each SAB case was matched to four non-SAB pregnancies by maternal residential county and conception month. Daily concentrations of ten pollutants were estimated and linked to maternal residential census tracts. Cox regression was used to estimate hazard ratios (HR) across four prenatal exposure windows (first month, weekly, cumulative weekly average over the first trimester, cumulative weekly average over the second trimester). Our dataset contained 47,649 SABs with a median gestational age of nine weeks. Carbon monoxide (CO) showed the strongest association, with an HR of 1.12 (1.05, 1.20) per 0.43 ppm increase in average first month exposure, and 1.06 (1.02, 1.10) per 0.42 ppm increase in average weekly exposure. Nitrogen dioxide (NO2) also exhibited elevated HRs. Other pollutants like nitrate compounds (NO3), nitrogen oxides (NOx), and organic carbon (OC) showed positive associations, while ozone (O3), PM2.5, PM10, elemental carbon (EC), and ammonium ions (NH4) were null. Early pregnancy exposure to traffic-related pollutants may increase SAB risk, highlighting potential benefits of air pollution regulation., (© The Author(s) 2025. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Prescribed burning is an effective land management tool that provides a range of benefits, including ecosystem restoration and wildfire risk reduction. However, prescribed fires, just like wildfires, introduce smoke that degrades air quality. Furthermore, while prescribed fires help manage wildfire risk, they do not eliminate the possibility of wildfires. It is therefore important to also evaluate fire and smoke impacts from wildfires that may occur after a prescribed burn. In this study, we developed a framework for understanding the air quality and health related trade-offs between wildfires and prescribed fires by simulating a set of counterfactual scenarios including wildfires, prescribed fires, and postprescribed burn wildfires. We applied this framework to the case of the Gatlinburg wildfire and found that emissions from prescribed burns and subsequent wildfire were slightly lower than those from the wildfire itself. This reduction resulted in lower daily average concentrations and exposures of PM 2.5 , O 3 , and NO 2 . Even considering the possibility of a postprescribed burn wildfire, prescribed fires reduced population-weighted daily average PM 2.5 , daily maximum 8-h average O 3 , and 1-h maximum NO 2 concentrations. In Sevier County, Tennessee where the wildfire occurred, these reductions reached 5.28 μg/m 3 , 0.18 ppb, and 1.68 ppb, respectively. The prescribed fires also reduced the person-days smoke exposures from the wildfire. Our results suggest that although prescribed fires cannot eliminate the air quality impacts of wildfires, they can greatly reduce smoke exposure in downwind areas distant from the burn sites., Competing Interests: The authors declare no competing financial interest., (© 2025 The Authors. Published by American Chemical Society.)

United States (US) background ozone (O 3 ) is the counterfactual O 3 that would exist with zero US anthropogenic emissions. Estimates of US background O 3 typically come from chemical transport models (CTMs), but different models vary in their estimates of both background and total O 3 . Here, a measurement-model data fusion approach is used to estimate CTM biases in US anthropogenic O 3 and multiple US background O 3 sources, including natural emissions, long-range international emissions, short-range international emissions from Canada and Mexico, and stratospheric O 3 . Spatially and temporally varying bias correction factors adjust each simulated O 3 component so that the sum of the adjusted components evaluates better against observations compared to unadjusted estimates. The estimated correction factors suggest a seasonally consistent positive bias in US anthropogenic O 3 in the eastern US, with the bias becoming higher with coarser model resolution and with higher simulated total O 3 , though the bias does not increase much with higher observed O 3 . Summer average US anthropogenic O 3 in the eastern US was estimated to be biased high by 2, 7, and 11 ppb (11%, 32%, and 49%) for one set of simulations at 12, 36, and 108 km resolutions and 1 and 6 ppb (10% and 37%) for another set of simulations at 12 and 108 km resolutions. Correlation among different US background O 3 components can increase the uncertainty in the estimation of the source-specific adjustment factors. Despite this, results indicate a negative bias in modeled estimates of the impact of stratospheric O 3 at the surface, with a western US spring average bias of -3.5 ppb (-25%) estimated based on a stratospheric O 3 tracer. This type of data fusion approach can be extended to include data from multiple models to leverage the strengths of different data sources while reducing uncertainty in the US background ozone estimates., Competing Interests: Competing interests. The contact author has declared that none of the authors has any competing interests.

Across four studies ( N = 1544), we examined the relationship between individuals' gender role mindsets, or beliefs about the malleability versus fixedness of traditional gender roles, and work-family conflict. We found that undergraduate women (but not men) business students holding a fixed, compared to growth, gender role mindset anticipated more work-family conflict. Next, we manipulated gender role mindset and demonstrated a causal link between women's growth mindsets (relative to fixed mindsets and control conditions) and reduced work-family conflict. We showed mechanistically that growth gender role mindsets unburden women from prescriptive gender roles, reducing work-family conflict. Finally, during COVID-19, we demonstrated a similar pattern among working women in high-achieving dual-career couples. We found an indirect effect of women's gender role mindset on job and relationship satisfaction, mediated through work-family conflict. Our preregistered studies suggest that holding the belief that gender roles can change mitigates women's work-family conflict., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Ambient air quality across the southeastern US has improved substantially in recent decades. However, emissions from prescribed burns remain high, which may pose a substantial health threat. We employed a multistage modeling framework to estimate year-round, long-term effects of prescribed burns on air quality and premature deaths. The framework integrates a chemical transport model with a data-fusion approach to estimate 24-h average PM 2.5 and maximum daily 8-h averaged O 3 (MDA8-O 3 ) concentrations attributable to prescribed burns for the period 2013-2020. The Global Exposure Mortality Model and a log-linear exposure-response function were used to estimate the premature deaths ascribed to long-term prescribed burn PM 2.5 and MDA8-O 3 exposure in ten southeastern states. Our results indicate that prescribed burns contributed on annual average 0.59 ± 0.20 µg/m 3 of PM 2.5 (∼10 % of ambient PM 2.5 ) over the ten southeastern states during the study period. On average around 15 % of the state-level ambient PM 2.5 concentrations were contributed by prescribed burns in Alabama (0.90 ± 0.15 µg/m 3 ), Florida (0.65 ± 0.19 µg/m 3 ), Georgia (0.91 ± 0.19 µg/m 3 ), Mississippi (0.65 ± 0.10 µg/m 3 ) and South Carolina (0.65 ± 0.09 µg/m 3 ). In the extensive burning season (January-April), daily average contributions to ambient PM 2.5 increased up to 22 % in those states. A large part of Alabama and Georgia experiences ≥3.5 µg/m 3 prescribed burn PM 2.5 over 30 days/year. Additionally, prescribed burns are responsible for an average increase of 0.32 ± 0.12 ppb of MDA8-O 3 (0.8 % of ambient MDA8-O 3 ) over the ten southeastern states. The combined effect of prescribed burn PM 2.5 exposure, population growth, and increase of baseline mortality over time resulted in a total of 20,416 (95 % confidence interval (CI): 16,562-24,174) excess non-accidental premature deaths in the ten southeastern states, with 25 % of these deaths in Georgia. Prescribed burn MDA8-O 3 was responsible for an additional 1,332 (95 % CI: 858-1,803) premature deaths in the ten southeastern states. These findings indicate significant impacts from prescribed burns, suggesting potential benefits of enhanced forest management strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Studies on air pollution and outcomes of in vitro fertilization (IVF) have focused on couples undergoing autologous IVF, in which it is challenging to disentangle maternal and paternal exposures during gametogenesis. We sought to evaluate the independent associations between air pollution exposure during oogenesis and spermatogenesis on fertilization and embryo quality in non-identified donor oocyte IVF cycles., Methods: Our study included 500 oocyte donors and 915 male recipient partners who contributed 1,095 oocyte thaw cycles (2008-2019). Daily ambient air pollutant exposure was estimated using spatio-temporal models based on residential address and averaged over folliculogenesis (i.e., three months prior to initiation of controlled ovarian stimulation), controlled ovarian stimulation, and spermatogenesis (i.e., 72 days prior to oocyte thaw). We used multivariable generalized estimating equations to estimate the adjusted odds ratios (aOR) and 95 % confidence intervals (CI) for an interquartile range increase in pollutant exposure in relation to the proportion of oocytes surviving thaw, oocytes fertilized, and usable embryos., Results: Oocyte donors with higher exposure to organic carbon (OC) (aOR = 0.86 95 %CI 0.79,0.94) and particulate matter < 10 µm (aOR = 0.69 95 %CI 0.54,0.90) during folliculogenesis had a lower proportion of oocytes surviving thaw. During ovarian stimulation, higher particulate matter < 2.5 µm (aOR = 0.78 95 %CI 0.66, 0.91), nitrate (aOR = 0.83 95 % CI 0.69,0.99), and OC (aOR = 0.86 95 % CI 0.80,0.93) exposure was associated with a lower proportion of surviving oocytes while nitrogen dioxide (aOR = 1.11 95 %CI 1.00,1.23) and ozone (aOR = 1.19 95 %CI 1.04,1.37) exposure was associated with a higher proportion of fertilized oocytes and usable embryos. Elemental carbon (aOR = 0.93 95 %CI 0.87,1.00) and OC (aOR = 0.95 95 %CI 0.90,1.00) exposure during spermatogenesis was associated with a slightly lower proportion of usable embryos. On the day of oocyte thaw, higher ambient OC at the IVF clinic was associated with lower oocyte survival and higher ozone was associated with lower fertilization., Conclusions: Both maternal and paternal air pollution exposures during gametogenesis have independent, largely detrimental, effects on early embryological outcomes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Audrey J. Gaskins reports financial support was provided by National Institute of Environmental Health Sciences. Zsolt P. Nagy reports a relationship with CooperSurgical Inc that includes: board membership. Zsolt P. Nagy reports a relationship with Prelude Fertility Inc that includes: equity or stocks. Daniel B. Shapiro reports a relationship with Prelude Fertility Inc that includes: equity or stocks. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The 2022 wildfires in New Mexico, United States, were unparalleled compared to past wildfires in the state in both their scale and intensity, resulting in poor air quality and a catastrophic loss of habitat and livelihood. Among all wildfires in New Mexico in 2022, six wildfires were selected for our study based on the size of the burn area and their proximity to populated areas. These fires accounted for approximately 90 % of the total burn area in New Mexico in 2022. We used a regional chemical transport model and data-fusion technique to quantify the contribution of these six wildfires (April 6 to August 22) on particulate matter (PM 2.5 : diameter ≤ 2.5 μm) and ozone (O 3 ) concentrations, as well as the associated health impacts from short-term exposure. We estimated that these six wildfires emitted 152 thousand tons of PM 2.5 and 287 thousand tons of volatile organic compounds to the atmosphere. We estimated that the average daily wildfire smoke PM 2.5 across New Mexico was 0.3 μg/m 3 , though 1 h maximum exceeded 120 μg/m 3 near Santa Fe. Average wildfire smoke maximum daily average 8-h O 3 (MDA8-O 3 ) contribution was 0.2 ppb during the study period over New Mexico. However, over the state 1 h maximum smoke O 3 exceeded 60 ppb in some locations near Santa Fe. Estimated all-cause excess mortality attributable to short term exposure to wildfire PM 2.5 and MDA8-O 3 from these six wildfires were 18 (95 % Confidence Interval (CI), 15-21) and 4 (95 % CI: 3-6) deaths. Additionally, we estimate that wildfire PM 2.5 was responsible for 171 (95 %: 124-217) excess cases of asthma emergency department visits. Our findings underscore the impact of wildfires on air quality and human health risks, which are anticipated to intensify with global warming, even as local anthropogenic emissions decline., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier B.V.)

This study assessed the spatial variability of PM 2.5 source contributions across ten sites located in the South Coast Air Basin, California. Eight pollution sources and their contributions were obtained using positive matrix factorization (PMF) from the PM 2.5 compositional data collected during the two sampling campaigns (2012/13 and 2018/19) of the Multiple Air Toxics Exposure Study (MATES). The identified sources were "gasoline vehicles", "aged sea salt", "biomass burning", "secondary nitrate", "secondary sulfate", "diesel vehicles", "soil/road dust" and "OP-rich". Among them, "gasoline vehicle" was the largest contributor to the PM 2.5 mass. The spatial distributions of source contributions to PM 2.5 at the sites were characterized by the Pearson correlation coefficients as well as coefficients of determination and divergence. The highest spatial variability was found for the contributions from the "OP-rich" source in both MATES campaigns suggesting varying influences of the wildfires in the Los Angeles Basin. Alternatively, the smallest spatial variabilities were observed for the contributions of the "secondary sulfate" and "aged sea salt" sources resolved for the MATES campaign in 2012/13. The "soil/road dust" contributions of the sites from the 2018/19 campaign were also highly correlated. Compared to the other sites, the source contribution patterns observed for Inland Valley and Rubidoux were the most diverse from the others likely due to their remote locations from the other sites, the major urban area, and the Pacific Ocean., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:David Q. Rich reports financial support was provided by Health Effects Institute. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Smoke from wildfires poses a substantial threat to health in communities near and far. To mitigate the extent and potential damage of wildfires, prescribed burning techniques are commonly employed as land management tools; however, they introduce their own smoke-related risks. This study investigates the impact of prescribed fires on daily average PM 2.5 and maximum daily 8-h averaged O 3 (MDA8-O 3 ) concentrations and estimates premature deaths associated with short-term exposure to prescribed fire PM 2.5 and MDA8-O 3 in Georgia and surrounding areas of the Southeastern US from 2015 to 2020. Our findings indicate that over the study domain, prescribed fire contributes to average daily PM 2.5 by 0.94 ± 1.45 μg/m 3 (mean ± standard deviation), accounting for 14.0% of year-round ambient PM 2.5 . Higher average daily contributions were predicted during the extensive burning season (January-April): 1.43 ± 1.97 μg/m 3 (20.0% of ambient PM 2.5 ). Additionally, prescribed burning is also responsible for an annual average increase of 0.36 ± 0.61 ppb in MDA8-O 3 (approximately 0.8% of ambient MDA8-O 3 ) and 1.3% (0.62 ± 0.88 ppb) during the extensive burning season. We estimate that short-term exposure to prescribed fire PM 2.5 and MDA8-O 3 could have caused 2665 (95% confidence interval (CI): 2249-3080) and 233 (95% CI: 148-317) excess deaths, respectively. These results suggest that smoke from prescribed burns increases the mortality. However, refraining from such burns may escalate the risk of wildfires; therefore, the trade-offs between the health impacts of wildfires and prescribed fires, including morbidity, need to be taken into consideration in future studies.

China's strategy to concurrently address climate change and air pollution mitigation is hindered by a lack of comprehensive information on source contributions to health damage and carbon emissions. Here we show notable discrepancies between source contributions to CO 2 emissions and fine particulate matter (PM 2.5 )-related mortality by using adjoint emission sensitivity modeling to attribute premature mortality in 2017 to 53 sector and fuel/process combinations with high spatial resolution. Our findings reveal that monetized PM 2.5 health damage exceeds climate impacts in over half of the analyzed subsectors. In addition to coal-fired energy generators and industrial boilers, the combined health and climate costs from energy-intensive processes, diesel-powered vehicles, domestic coal combustion, and agricultural activities exceed 100 billion US dollars, with health-related costs predominating. This research highlights the critical need to integrate the social costs of health damage with climate impacts to develop more balanced mitigation strategies toward these dual goals, particularly during fuel transition and industrial structure upgrading., (© 2024. The Author(s).)

Nearly 56% of the global population lives in cities, with this number expected to increase to 6.6 billion or >70% of the world's population by 2050. Given that cardiometabolic diseases are the leading causes of morbidity and mortality in people living in urban areas, transforming cities and urban provisioning systems (or urban systems) toward health, equity, and economic productivity can enable the dual attainment of climate and health goals. Seven urban provisioning systems that provide food, energy, mobility-connectivity, housing, green infrastructure, water management, and waste management lie at the core of human health, well-being, and sustainability. These provisioning systems transcend city boundaries (eg, demand for food, water, or energy is met by transboundary supply); thus, transforming the entire system is a larger construct than local urban environments. Poorly designed urban provisioning systems are starkly evident worldwide, resulting in unprecedented exposures to adverse cardiometabolic risk factors, including limited physical activity, lack of access to heart-healthy diets, and reduced access to greenery and beneficial social interactions. Transforming urban systems with a cardiometabolic health-first approach could be accomplished through integrated spatial planning, along with addressing current gaps in key urban provisioning systems. Such an approach will help mitigate undesirable environmental exposures and improve cardiovascular and metabolic health while improving planetary health. The purposes of this American Heart Association policy statement are to present a conceptual framework, summarize the evidence base, and outline policy principles for transforming key urban provisioning systems to heart-health and sustainability outcomes.

Food consumption contributes to the degradation of air quality in regions where food is produced, creating a contrast between the health burden caused by a specific population through its food consumption and that faced by this same population as a consequence of food production activities. Here we explore this inequality within China's food system by linking air-pollution-related health burden from production to consumption, at high levels of spatial and sectorial granularity. We find that low-income groups bear a 70% higher air-pollution-related health burden from food production than from food consumption, while high-income groups benefit from a 29% lower health burden relative to their food consumption. This discrepancy largely stems from a concentration of low-income residents in food production areas, exposed to higher emissions from agriculture. Comprehensive interventions targeting both production and consumption sides can effectively reduce health damages and concurrently mitigate associated inequalities, while singular interventions exhibit limited efficacy., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Studies in mice and older, subfertile women have found that air pollution exposure may compromise female reproduction. Our objective was to evaluate the effects of air pollution on ovarian reserve and outcomes of ovarian stimulation among young, healthy females. We included 472 oocyte donors who underwent 781 ovarian stimulation cycles at a fertility clinic in Atlanta, Georgia, USA (2008-2019). Antral follicle count (AFC) was assessed with transvaginal ultrasonography and total and mature oocyte count was assessed following oocyte retrieval. Ovarian sensitivity index (OSI) was calculated as the total number of oocytes divided by total gonadotrophin dose × 1000. Daily ambient exposure to nitric oxide (NO x ), carbon monoxide (CO), and particulate matter ≤ 2.5 (PM 2.5 ) was estimated using a fused regional + line-source model for near-surface releases at a 250 m resolution based on residential address. Generalized estimating equations were used to evaluate the associations of an interquartile range (IQR) increase in pollutant exposure with outcomes adjusted for donor characteristics, census-level poverty, and meteorological factors. The median (IQR) age among oocyte donors was 25.0 (5.0) years, and 31% of the donors were racial/ethnic minorities. The median (IQR) exposure to NO x , CO, and PM 2.5 in the 3 months prior to stimulation was 37.7 (32.0) ppb, 612 (317) ppb, and 9.8 (2.9) µg/m 3 , respectively. Ambient air pollution exposure in the 3 months before AFC was not associated with AFC. An IQR increase in PM 2.5 in the 3 months before AFC and during stimulation was associated with -7.5% (95% CI -14.1, -0.4) and -6.4% (95% CI -11.0, -1.6) fewer mature oocytes, and a -1.9 (95% CI -3.2, -0.5) and -1.0 (95% CI -1.8, -0.2) lower OSI, respectively. Our results suggest that lowering the current 24-h PM 2.5 standard in the US to 25 µg/m 3 may still not adequately protect against the reprotoxic effects of short-term PM 2.5 exposure., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Zsolt P Nagy reports a relationship with CooperSurgical Inc that includes: board membership. Zsolt P Nagy reports a relationship with Prelude Fertility Inc that includes: equity or stocks. Daniel B Shapiro reports a relationship with Prelude Fertility Inc that includes: equity or stocks., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The effects of air quality control policies implemented in California from 2005 to 2019 targeting sources contributing to ambient PM 2.5 concentrations, were assessed at two sampling sites in the Los Angeles Basin (N. Main Street and Rubidoux). The spatial and temporal variations of pollution source contributions obtained from dispersion-normalized positive matrix factorization, (DN-PMF) were interpreted with respect to site specific locations. Secondary nitrate and secondary sulfate were the major contributors to the ambient PM 2.5 mass concentrations at both sites with substantial concentration decreases after 2008 that were likely due to the implementation of California specific programs including stricter NO x emissions control on motor vehicles. Biomass burning emissions also decreased over the study period at both sampling sites except for one event in December 2005 when strong winter storms and multiple floods led to unusually low atmospheric temperatures and likely increased residential wood burning. The large number of wildfires, trans-Pacific transport of mineral dust and regional dust transported by strong Santa Ana winds and agriculturally generated dust in Rubidoux contributed to poor air quality. Severe storms and devastating wildfires were also linked to the elevated pyrolyzed organic carbon (OP-rich) concentrations. The two distinct region-specific sources, describing fuel combustion in LA, were "residual oil" and "traffic", while separate "gasoline" and "diesel" vehicles sources were identified in Rubidoux. California emissions standards program which required replacement of conventional cars with electric or hybrid vehicles and standards for gasoline and diesel fuels, led to lower "traffic" contributions. Gasoline vehicle emissions after 2017 in Rubidoux also decreased. "Diesel" concentrations declined between 2007 and 2011 because of the recession from late 2007 to early 2009 and the Federal Heavy-Duty Diesel Rule., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Air pollution accountability studies examine the relationship(s) between an intervention, regulation, or event and the resulting downstream impacts, if any, on emissions, exposure, and/or health. The sequence of events has been schematically described as an accountability chain. Here, we update the existing framework to capture real-life complexities and to highlight important factors that fall outside the linear chain. This new "accountability web" is intended to convey the intricacies associated with conducting an accountability study to various audiences, including researchers, policy makers, and stakeholders. We also identify data considerations for planning and completing a robust accountability study, including those relevant to novel and innovative air pollution and exposure data. Finally, we present a series of recommendations for the accountability research community that can serve as a guide for the next generation of accountability studies., Competing Interests: Support for the Workshop was provided by the 10.13039/100011253American Petroleum Institute (API). API was not involved in the Workshop deliberations nor in the preparation or approval of the manuscript. The authors retain sole responsibility for the writing and content of this paper, which represent the professional opinions of the authors and not necessarily those of API or its member companies. As Workshop facilitators, CJB, JEG, and JSL received compensation and travel support from 10.13039/100011253API. Travel support was also provided to all authors except AMR, HSE, and SL. Honoraria were provided to SE, LRFH, MN, AGR, and JWH. JSL, JEG, JWH, and CJB consult to governmental and private organizations, including API, on issues related to air pollution epidemiology. The views expressed in this manuscript are those of the authors and do not necessarily represent the views or policies of EPA, API (or its member companies), or co-authors' employers., (© 2023 The Authors. Published by Elsevier Inc.)

The chemical composition of PM 2.5 has a significant impact on human health and air quality, and its accurate knowledge can be used to identify contributing emission sources. Assessing and quantifying the impacts of various factors (e.g., emissions, meteorology, and large-scale climate patterns) on the main PM 2.5 chemical components can give guidance for implementing effective regulations to improve air quality in the future. In this study, we developed generalized additive models (GAMs) to assess how emissions, meteorological factors, and large-scale climate indices affected ammonium, sulfate, nitrate, elemental carbon, and organic carbon from 2002 to 2019 in the South Coast Air Basin (SoCAB). Concentration trends from three sites in the SoCAB are studied. The statistical results showed that GAMs can capture the variability of these species' daily concentrations (R 2  = 0.6 to 0.7) and annual concentrations (R 2  = 0.93 to 0.99). Precursor emissions most significantly affect PM 2.5 species production, though meteorological factors like maximum temperature, relative humidity, wind speed, and boundary layer height, also influence PM 2.5 composition. In the future, these meteorological factors will become more significant in affecting PM 2.5 speciation, although emissions will continue to strongly affect formation. Results show that the composition of most PM 2.5 species will decrease in the future except for OC, which will become the largest contributor to PM 2.5 ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Nitrate is formed through the chemical production of gas-phase nitric acid and subsequent partitioning to the aerosol phase during the daytime. Many studies in the past separated these two aspects, even though they occur simultaneously in the atmosphere. To better understand the nitrate formation mechanism and effectively mitigate its production, it is necessary to consider the synergy between these two mechanisms. For this, we analyze hourly-speciated ambient observations data, with EK&TMA (Empirical Kinetic & Thermodynamic Modeling Approach) map to comprehensively explore the factors controlling nitrate production. Results show that precursor NO 2 concentration and aerosol pH, which are related to anthropogenic activities, are the two major factors for chemical kinetics production and gas/particle thermodynamic partitioning processes respectively. Abundant NO 2 and weakly acidic environments are favorable conditions for daytime particulate nitrate pollution, thus collaborative control of coal source, vehicle source, and dust source is needed to alleviate nitrate pollution., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Air pollution exposure is a significant risk factor for morbidity and mortality, especially for those with pre-existing chronic disease. Previous studies highlighted the risks that long-term particulate matter exposure has for readmissions. However, few studies have evaluated source and component specific associations particularly among vulnerable patient populations., Objectives: Use electronic health records from 5556 heart failure (HF) patients diagnosed between July 5, 2004 and December 31, 2010 that were part of the EPA CARES resource in conjunction with modeled source-specific fine particulate matter (PM 2.5 ) to estimate the association between exposure to source and component apportioned PM 2.5 at the time of HF diagnosis and 30-day readmissions., Methods: We used zero-inflated mixed effects Poisson models with a random intercept for zip code to model associations while adjusting for age at diagnosis, year of diagnosis, race, sex, smoking status, and neighborhood socioeconomic status. We undertook several sensitivity analyses to explore the impact of geocoding precision and other factors on associations and expressed associations per interquartile range increase in exposures., Results: We observed associations between 30-day readmissions and an interquartile range increase in gasoline- (16.9% increase; 95% confidence interval = 4.8%, 30.4%) and diesel-derived PM 2.5 (9.9% increase; 95% confidence interval = 1.7%, 18.7%), and the secondary organic carbon component of PM 2.5 (SOC; 20.4% increase; 95% confidence interval = 8.3%, 33.9%). Associations were stable in sensitivity analyses, and most consistently observed among Black study participants, those in lower income areas, and those diagnosed with HF at an earlier age. Concentration-response curves indicated a linear association for diesel and SOC. While there was some non-linearity in the gasoline concentration-response curve, only the linear component was associated with 30-day readmissions., Discussion: There appear to be source specific associations between PM 2.5 and 30-day readmissions particularly for traffic-related sources, potentially indicating unique toxicity of some sources for readmission risks that should be further explored., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Cavin Ward-Caviness reports a relationship with Clock Foundation that includes: consulting or advisory., (Published by Elsevier Inc.)

Annual fine particulate matter (PM 2.5 ) mass concentrations in the South Coast Air Basin (SoCAB) of California decreased from around 30 μg/m 3 to 11 μg/m 3 between 2000 and 2013 but rose from 11 μg/m 3 to 13 μg/m 3 between 2014 and 2018, raising important questions about the effectiveness of ongoing emission control policies. A two-step generalized additive model (GAM)-least squares approach was developed to explore the effects of emissions, large-scale climate events and meteorological factors on daily PM 2.5 mass concentrations from 2000 to 2019 to quantitatively link impacts of emissions and meteorological on PM 2.5 and to assess factors leading to the increase. The GAM had an R 2  = 0.99 and root mean square error (RMSE) = 0.7 μg/m 3 for the annual average PM 2.5 concentrations. The two-step method had an R 2  = 0.93 and RMSE = 4.07 μg/m 3 for the 98th percentile 24-hr average PM 2.5 concentrations. Variations in both emissions and relative humidity were of high importance compared with other included factors. Interactions of NH 3 emissions with NOx and SO 2 emissions, which lead to ammonium nitrate and sulfate aerosol formation, were the most important factors. Meteorological effects on PM 2.5 explained the majority of the daily PM 2.5 fluctuations. Emission changes (increases in SO 2 and PM 2.5 ) led to increases in predicted PM 2.5 between 2014 and 2018. Predicted future PM 2.5 , using projected emissions and meteorological data from model simulations of representative concentration pathway (RCP) scenarios, are around 12 μg/m 3 (annual) and 30 μg/m 3 (98th percentile daily), which are both close to the current National Ambient Air Quality Standards (NAAQS) for PM 2.5 . Meteorological impacts on the predicted PM 2.5 in future years lead to variations of ±2 μg/m 3 for the annual average and ±5 μg/m 3 for the 98th percentile daily level. Future climate changes lead to a probable year-to-year variation that will let PM 2.5 levels in some years exceed the standard., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Prescribed burning is a major source of a fine particular matter, especially in the southeastern United States, and quantifying emissions from burning operations accurately is an integral part of ascertaining air quality impacts. For instance, a critical factor in calculating fire emissions is identifying fire activity information (e.g., location, date/time, fire type, and area burned) and prior estimations of prescribed fire activity used for calculating emissions have either used burn permit records or satellite-based remote sensing products. While burn permit records kept by state agencies are a reliable source, they are not always available or readily accessible. Satellite-based remote sensing products are currently used to fill the data gaps, especially in regional studies; however, they cannot differentiate prescribed burns from the other types of fires. In this study, we developed novel algorithms to distinguish prescribed burns from wildfires and agricultural burns in a satellite-derived product, Fire INventory from NCAR (FINN). We matched and compared the burned areas from permit records and FINN at various spatial scales: individual fire level, 4 km grid level, and state level. The methods developed in this study are readily usable for differentiating burn type, matching and comparing the burned area between two datasets at various resolutions, and estimating prescribed burn emissions. The results showed that burned areas from permits and FINN have a weak correlation at the individual fire level, while the correlation is much higher for the 4 km grid and state levels. Since matching at the 4 km grid level showed a relatively higher correlation and chemical transport models typically use grid-based emissions, we used the linear regression relationship between FINN and permit burned areas at the grid level to adjust FINN burned areas. This adjustment resulted in a reduction in FINN-burned areas by 34%. The adjusted burned area was then used as input to the BlueSky Smoke Modeling Framework to provide long-term, three-dimensional prescribed burning emissions for the southeastern United States. In this study, we also compared emissions from different methods (FINN or BlueSky) and different data sources (adjusted FINN or permits) to evaluate uncertainties of our emission estimation. The comparison results showed the impacts of the burned area, method, and data source on prescribed burning emission estimations., Competing Interests: Conflicts of Interest: The authors declare no conflict of interest.

High energy consumption and high cost have been the obstacles for large-scale deployment of all state-of-the-art CO 2 capture technologies. Finding a transformational way to improve mass transfer and reaction kinetics of the CO 2 capture process is timely for reducing carbon footprints. In this work, commercial single-walled carbon nanotubes (CNTs) were activated with nitric acid and urea under ultrasonication and hydrothermal methods, respectively, to prepare N-doped CNTs with the functional group of -COOH, which possesses both basic and acid functionalities. The chemically modified CNTs with a concentration of 300 ppm universally catalyze both CO 2 sorption and desorption of the CO 2 capture process. The increases in the desorption rate achieved with the chemically modified CNTs can reach as high as 503% compared to that of the sorbent without the catalyst. A chemical mechanism underlying the catalytic CO 2 capture is proposed based on the experimental results and further confirmed by density functional theory computations.

Following the outbreak of the COVID-19 pandemic, several papers have examined the effect of the pandemic response on urban air pollution worldwide. This study uses observed traffic volume and near-road air pollution data for black carbon (BC), oxides of nitrogen (NO x ), and carbon monoxide (CO) to estimate the emissions contributions of light-duty and heavy-duty diesel vehicles in five cities in the continental United States. Analysis of mobile source impacts in the near-road environment has several health and environmental justice implications. Data from the initial COVID-19 response period, defined as March to May in 2020, were used with data from the same period over the previous two years to develop general additive models (GAMs) to quantify the emissions impact of each vehicle class. The model estimated that light-duty traffic contributes 4-69%, 14-65%, and 21-97% of BC, NO x , and CO near-road levels, respectively. Heavy-duty diesel traffic contributes an estimated 26-46%, 17-63%, and -7-18% of near-road levels of the three pollutants. The estimated mobile source impacts were used to calculate NO x to CO and BC to NO x emission ratios, which were between 0.21-0.32 μg m -3 NO x (μg m -3 CO) -1 and 0.013-0.018 μg m -3 BC (μg m -3 NO x ) -1 . These ratios can be used to assess existing emission inventories for use in determining air pollution standards. These results agree moderately well with recent National Emissions Inventory estimates and other empirically-derived estimates, showing similar trends among the pollutants. However, a limitation of this study was the recurring presence of an implausible air pollution impact estimate in 41% of the site-pollutant combinations, where a vehicle class was estimated to account for either a negative impact or an impact higher than the total estimated pollutant concentration. The variations seen in the GAM estimates are likely a result of location-specific factors, including fleet composition, external pollution sources, and traffic volumes. Implications : Drastic reductions in traffic and air pollution during the lockdowns of the COVID-19 pandemic present a unique opportunity to assess vehicle emissions. A General Additive Modeling approach is developed to relate traffic levels, observed air pollution, and meteorology to identify the amount vehicle types contribute to near-road levels of traffic-related air pollutants (TRAPs), which is important for future emission regulation and policy, given the significant health and environmental justice implications of vehicle-related pollution along major roadways. The model is used to evaluate emission inventories in the near-road environment, which can be used to refine existing estimates. By developing a locally data-driven method to readily characterize impacts and distinguish between heavy and light duty vehicle effects, local regulations can be used to target policies in major cities around the country, thus addressing local health disbenefits and disparities occurring as a result of exposure to near-road air pollution.

Background: Previous studies of short-term ambient air pollution exposure and asthma morbidity in the United States have been limited to a small number of cities and/or pollutants and with limited consideration of effects across ages., Objectives: To estimate acute age group-specific effects of fine and coarse particulate matter (PM), major PM components, and gaseous pollutants on emergency department (ED) visits for asthma during 2005-2014 across the United States., Methods: We acquired ED visit and air quality data in regions surrounding 53 speciation sites in 10 states. We used quasi-Poisson log-linear time-series models with unconstrained distributed exposure lags to estimate site-specific acute effects of air pollution on asthma ED visits overall and by age group (1-4, 5-17, 18-49, 50-64, and 65 + y), controlling for meteorology, time trends, and influenza activity. We then used a Bayesian hierarchical model to estimate pooled associations from site-specific associations., Results: Our analysis included 3.19  million asthma ED visits. We observed positive associations for multiday cumulative exposure to all air pollutants examined [e.g., 8-d exposure to PM 2.5 : rate ratio of 1.016 with 95% credible interval (CI) of (1.008, 1.025) per 6.3 - μ g / m 3 increase, PM 10 - 2.5 : 1.014 (95% CI: 1.007, 1.020) per 9.6 - μ g / m 3 increase, organic carbon: 1.016 (95% CI: 1.009, 1.024) per 2.8 - μ g / m 3 increase, and ozone: 1.008 (95% CI: 0.995, 1.022) per 0.02 -ppm increase]. PM 2.5 and ozone showed stronger effects at shorter lags, whereas associations of traffic-related pollutants (e.g., elemental carbon and oxides of nitrogen) were generally stronger at longer lags. Most pollutants had more pronounced effects on children ( < 18 y old) than adults; PM 2.5 had strong effects on both children and the elderly ( > 64 y old); and ozone had stronger effects on adults than children., Conclusions: We reported positive associations between short-term air pollution exposure and increased rates of asthma ED visits. We found that air pollution exposure posed a higher risk for children and older populations. https://doi.org/10.1289/EHP11661.

Growing evidence suggests that fine particulate matter (PM 2.5 ) likely increases the risks of dementia, yet little is known about the relative contributions of different constituents. Here, we conducted a nationwide population-based cohort study (2000 to 2017) by integrating the Medicare Chronic Conditions Warehouse database and two independently sourced datasets of high-resolution PM 2.5 major chemical composition, including black carbon (BC), organic matter (OM), nitrate (NO 3 - ), sulfate (SO 4 2- ), ammonium (NH 4 + ), and soil dust (DUST). To investigate the impact of long-term exposure to PM 2.5 constituents on incident all-cause dementia and Alzheimer's disease (AD), hazard ratios for dementia and AD were estimated using Cox proportional hazards models, and penalized splines were used to evaluate potential nonlinear concentration-response (C-R) relationships. Results using two exposure datasets consistently indicated higher rates of incident dementia and AD for an increased exposure to PM 2.5 and its major constituents. An interquartile range increase in PM 2.5 mass was associated with a 6 to 7% increase in dementia incidence and a 9% increase in AD incidence. For different PM 2.5 constituents, associations remained significant for BC, OM, SO 4 2- , and NH 4 + for both end points (even after adjustments of other constituents), among which BC and SO 4 2- showed the strongest associations. All constituents had largely linear C-R relationships in the low exposure range, but most tailed off at higher exposure concentrations. Our findings suggest that long-term exposure to PM 2.5 is significantly associated with higher rates of incident dementia and AD and that SO 4 2- , BC, and OM related to traffic and fossil fuel combustion might drive the observed associations.

Ionic liquids (ILs) have been used for carbon dioxide (CO 2 ) capture, however, which have never been used as catalysts to accelerate CO 2 capture. The record is broken by a uniquely designed IL, [EMmim][NTf 2 ]. The IL can universally catalyze both CO 2 sorption and desorption of all the chemisorption-based technologies. As demonstrated in monoethanolamine (MEA) based CO 2 capture, even with the addition of only 2000 ppm IL catalyst, the rate of CO 2 desorption-the key to reducing the overall CO 2 capture energy consumption or breaking the bottleneck of the state-of-the-art technologies and Paris Agreement implementation-can be increased by 791% at 85 °C, which makes use of low-temperature waste heat and avoids secondary pollution during CO 2 capture feasible. Furthermore, the catalytic CO 2 capture mechanism is experimentally and theoretically revealed., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Ammonia, primarily made with Haber-Bosch process developed in 1909 and winning two Nobel prizes, is a promising noncarbon fuel for preventing global warming of 1.5 °C above pre-industrial levels. However, the undesired characteristics of the process, including high carbon footprint, necessitate alternative ammonia synthesis methods, and among them is chemical looping ammonia production (CLAP) that uses nitrogen carrier materials and operates at atmospheric pressure with high product selectivity and energy efficiency. To date, neither a systematic review nor a perspective in nitrogen carriers and CLAP has been reported in the critical area. Thus, this work not only assesses the previous results of CLAP but also provides perspectives towards the future of CLAP. It classifies, characterizes, and holistically analyzes the fundamentally different CLAP pathways and discusses the ways of further improving the CLAP performance with the assistance of plasma technology and artificial intelligence (AI)., Competing Interests: Conflict of interest The authors declare that they have no conflict of interest., (Copyright © 2022 Science China Press. Published by Elsevier B.V. All rights reserved.)

Background: Air pollution has been associated with cognitive function in the elderly. Previous studies have not evaluated the simultaneous effect of neighborhood-level socioeconomic status (N-SES), which can be an essential source of bias., Objectives: We explored N-SES as a confounder and effect modifier in a cross-sectional study of air pollution and subjective cognitive function., Methods: We included 12,058 participants age 50+ years from the Emory Healthy Aging Study in Metro Atlanta using the Cognitive Function Instrument (CFI) score as our outcome, with higher scores representing worse subjective cognitive function. We estimated 9-year average ambient carbon monoxide (CO), nitrogen oxides (NO x ), and fine particulate matter (PM 2.5 ) concentrations at residential addresses using a fusion of dispersion and chemical transport models. We collected census-tract level N-SES indicators and created two composite measures via principal component analysis and k-means clustering. Associations between pollutants and CFI and effect modification by N-SES were estimated via linear regression models adjusted for age, education, race and N-SES., Results: N-SES confounded the association between air pollution and CFI, independent of individual characteristics. We found significant effect modifications by N-SES for the association between air pollution and CFI (p-values<0.001) suggesting that effects of air pollution differ depending on N-SES. Participants living in areas with low N-SES were most vulnerable to air pollution. In the lowest N-SES urban areas, interquartile range (IQR) increases in CO, NO x , and PM 2.5 were associated with 5.4% (95%-confidence interval, -0.2,11.3), 4.9% (-0.4,10.4), and 9.8% (2.2,18.0) changes in CFI, respectively. In lowest N-SES suburban areas, IQR increases in CO, NO x , and PM 2.5 were associated with higher changes in CFI, namely 13.0% (0.9,26.5), 13.0% (-0.1,27.8), and 17.3% (2.5,34.2), respectively., Discussion: N-SES is an important confounder and effect modifier in our study. This finding could have implications for studying health effects of air pollution and identifying susceptible populations., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Ozone levels have been declining in the Los Angeles, CA, USA area for the last four decades, but there was a recent uptick in the 4th highest daily maximum 8-h (MDA8) ozone concentrations from 2014 to 2018 despite continued reductions in the estimated precursor emissions. In this study, we assess the emissions and meteorological impacts on the 4th highest MDA8 ozone concentrations to better understand the factors affecting the observed MDA8 ozone using a two-step generalized additive model (GAM)/least squares approach applied to the South Coast Air Basin (SoCAB) for the 1990 to 2019 period. The GAM model includes emissions, meteorological factors, large-scale climate variables, date, and the interactions between meteorology and emissions. A least squares method was applied to the GAM output to better capture the 4th highest MDA8 ozone. The resulting two-step model had an R 2 of 0.98 and a slope of 1 between the observed and predicted 4th highest MDA8 ozone. Emissions and the interactions between the maximum temperature and emissions explain most of the variation in the peak MDA8 ozone concentrations. Declining emissions have lowered the 4th highest MDA8 ozone concentration. Meteorology explains the higher than expected 4th-high, ozone levels observed in 2014-2018, indicating that meteorology was a stronger forcer than the continued reductions in emissions during that time period. The model was applied to estimate future ozone levels. Meteorology developed from climate modeling of the representative concentration pathway (RCP) scenarios, and two sets of emissions were used in the application. The modeling results indicated climate trends will push ozone levels slightly higher if no further emissions reductions are realized and that of two emissions trajectories modeled, the more stringent is required to reliably meet the federal ozone standard given annual meteorological variability., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Particulate sulfate is one of the most important components in the atmosphere. The observation of rapid sulfate aerosol production during haze events provoked scientific interest in the multiphase oxidation of SO 2 in aqueous aerosol particles. Diverse oxidation pathways can be enhanced or suppressed under different aerosol acidity levels and high ionic strength conditions of atmospheric aerosol. The importance of ionic strength to sulfate multiphase chemistry has been verified under laboratory conditions, though studies in the actual atmosphere are still limited. By utilizing online observations and developing an improved solute strength-dependent chemical thermodynamics and kinetics model (EF-T&K model, EF is the enhancement factor that represents the effect of ionic strength on an aerosol aqueous-phase reaction), we provided quantitative evidence that the H 2 O 2 pathway was enhanced nearly 100 times and dominated sulfate formation for entire years (66%) in Tianjin (a northern city in China). TMI (oxygen catalyzed by transition-metal ions) (14%) and NO 2 (14%) pathways got the second-highest contributions. Machine learning supported the result that aerosol sulfate production was more affected by the H 2 O 2 pathway. The collaborative effects of atmospheric oxidants and SO 2 on sulfate aerosol production were further investigated using the improved EF-T&K model. Our findings highlight the effectiveness of adopting target oxidant control as a new direction for sustainable mitigation of sulfate, given the already low SO 2 concentrations in China.

India is home to 1.3 billion people who are exposed to some of the highest levels of ambient air pollution in the world. In addition, India is one of the fastest-growing carbon-emitting countries. Here, we assess how two strategies to reuse waste-heat from coal-fired power plants and other large sources would impact PM 2.5 -air quality, human health, and CO 2 emissions in 2015 and a future year, 2050, using varying levels of policy adoption (current regulations, proposed single-sector policies, and ambitious single-sector strategies). We find that power plant and industrial waste-heat reuse as input to district heating systems (DHSs), a novel, multisector strategy to reduce local biomass burning for heating emissions, can offset 71.3-85.2% of residential heating demand in communities near a power plant (9.3-12.4% of the nationwide heating demand) with the highest benefits observed during winter months in areas with collocated industrial activity and higher residential heating demands (e.g., New Delhi). Utilizing waste-heat to generate electricity via organic Rankine cycles (ORCs) can generate an additional 22 (11% of total coal-fired generating capacity), 41 (8%), 32 (13%), and 6 (5%) GW of electricity capacity in the 2015, 2050-current regulations, 2050-single-sector, and 2050-ambitious-single-sector scenarios, respectively. Emission estimates utilizing these strategies were input to the GEOS-Chem model, and population-weighted, simulated PM 2.5 showed small improvements in the DHS (0.2-0.4%) and ORC (0.3-3.4%) scenarios, where the minimal DHS PM 2.5 -benefit is attributed to the small contribution of biomass burning for heating to nationwide PM 2.5 emissions (much of the biomass burning activity is for cooking). The PM 2.5 reductions lead to ∼130-36,000 mortalities per year avoided among the scenarios, with the largest health benefits observed in the ORC scenarios. Nationwide CO 2 emissions reduced <0.04% by DHSs but showed larger reductions using ORCs (1.9-7.4%). Coal fly-ash as material exchange in cement and brick production was assessed, and capacity exists to completely reutilize unused fly-ash toward cement and brick production in each of the scenarios.

Particulate oxidative potential may comprise a key health-relevant parameter of particulate matter (PM) toxicity. To identify biological perturbations associated with particulate oxidative potential and examine the underlying molecular mechanisms, we recruited 54 participants from two dormitories near and far from a congested highway in Atlanta, GA. Fine particulate matter oxidative potential ("FPMOP") levels at the dormitories were measured using dithiothreitol assay. Plasma and saliva samples were collected from participants four times for longitudinal high-resolution metabolic profiling. We conducted metabolome-wide association studies to identify metabolic signals with FPMOP. Leukotriene metabolism and galactose metabolism were top pathways associated with ≥5 FPMOP-related indicators in plasma, while vitamin E metabolism and leukotriene metabolism were found associated with most FPMOP indicators in saliva. We observed different patterns of perturbed pathways significantly associated with water-soluble and -insoluble FPMOPs, respectively. We confirmed five metabolites directly associated with FPMOP, including hypoxanthine, histidine, pyruvate, lactate/glyceraldehyde, and azelaic acid, which were implications of perturbations in acute inflammation, nucleic acid damage and repair, and energy perturbation. The unique metabolic signals were specific to FPMOP, but not PM mass, providing initial indication that FPMOP might constitute a more sensitive, health-relevant measure for elucidating etiologies related to PM 2.5 exposures.

A number of studies have found differing associations of disease outcomes with PM 2.5 components (or species) and sources (e.g., biomass burning, diesel vehicles and gasoline vehicles). Here, a unique method of fusing daily chemical transport model (Community Multiscale Air Quality Modeling) results with observations has been utilized to generate spatiotemporal fields of the concentrations of major gaseous pollutants (CO, NO 2 , NO x , O 3 , and SO 2 ), total PM 2.5 mass, and speciated PM 2.5 (including crustal elements) over North Carolina for 2002-2010. The fused results are then used in chemical mass balance source apportionment model, CMBGC-Iteration, which uses both gas constraint and particulate matter concentrations to quantify source impacts. The method, as applied to North Carolina, quantifies the impacts of ten source categories and provides estimates of source contributions to PM 2.5 concentrations. The ten source categories include both primary sources (diesel vehicles, gasoline vehicles, dust, biomass burning, coal-fired power plants and sea salt) and secondary components (ammonium sulfate, ammonium bisulfate, ammonium nitrate and secondary organic carbon). The results show a steady decrease in anthropogenic source impacts, especially from diesel vehicles and coal-fired power plants. Secondary pollutant components accounted for approximately 70% of PM 2.5 mass. This study demonstrates an ability to provide spatiotemporal fields of both PM components and source impacts using a chemical transport model fused with observation data, linked to a receptor-based source apportionment method, to develop spatiotemporal fields of multiple pollutants., Competing Interests: Declaration of Interest Statement Conflict of Interest The authors declare no conflict of interest.

Federal policy changes in the management of carbon emissions from power plants offer a potent real-world example for examining air-land-water interactions and their implications for coastal water quality. We integrate models of energy (Integrated Planning Model (IPM)), air quality (Community Multiscale Air Quality (CMAQ) and water quality (SPAtially Referenced Regression On Watershed attributes (SPARROW)) to investigate the potential water quality impacts of policy-driven changes in total nitrogen deposition in watersheds draining to US coastal areas. We estimate the combined effects of three recently proposed energy policy scenarios, population growth, and climate change. We decompose the combined effects into the roles of the individual components on the supply of riverine nitrogen for the entire US and eight coastal regions. We find that population growth is the most important driver of changes in coastal nitrogen flux. Energy policies play a minor role in offsetting the negative effects of population growth, although the effect varies by energy policy and region. The greatest population and policy effects are projected for the Gulf of Mexico. Given limited reductions in nitrogen emissions and deposition associated with energy policies, the net effect of policy and population changes is an increase in total nitrogen flux to all estuaries relative to the 2010 baseline. While population growth increases flux, and energy policies decrease flux in all regions, climate change can either increase or decrease flux depending on the region. That is because the relatively large individual effects of temperature and precipitation on watershed nitrogen processes work in opposing directions. The net result of the offsetting nature of individual climate processes varies in both magnitude and direction by coastal region. Further research is needed to sort out individual temperature and precipitation effects in different regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Gaseous and particulate chlorine species play an important role in modulating tropospheric oxidation capacity, aerosol water uptake, visibility degradation, and human health. The lack of recent global continental chlorine emissions has hindered modeling studies of the role of chlorine in the atmosphere. Here, we develop a comprehensive global emission inventory of gaseous HCl and particulate Cl - (pCl), including 35 sources categorized in six source sectors based on published up-to-date activity data and emission factors. These emissions are gridded at a spatial resolution of 0.1° × 0.1° for the years 1960 to 2014. The estimated emissions of HCl and pCl in 2014 are 2354 (1661-3201) and 2321 (930-3264) Gg Cl a -1 , respectively. Emissions of HCl are mostly from open waste burning (38%), open biomass burning (19%), energy (19%), and residential (13%) sectors, and the major sources classified by fuel type are combustion of waste (43%), biomass (32%), and coal (25%). Emissions of pCl are mostly from biofuel (29%) and open biomass burning processes (44%). The sectoral and spatial distributions of HCl and pCl emissions are very heterogeneous along the study period, and the temporal trends are mainly driven by the changes in emission factors, energy intensity, economy, and population.

Accurate spatiotemporal air pollution fields are essential for health impact and epidemiologic studies. There are an increasing number of studies that have combined observational data with spatiotemporally complete air pollution simulations. Land-use, speciated gaseous and particulate pollutant concentrations and chemical transport modeling are fused using a random forest approach to construct daily air quality fields for 12 pollutants (CO, NOx, NO 2 , SO 2 , O 3 , PM 2.5 , PM 10 , and PM 2.5 constituents: SO 4 2- , NO 3 - , NH 4 + , EC and OC) between 2005 and 2014 for the continental United States with little spatial or temporal bias. R 2 ranged from 0.45 to 0.96, depending upon pollutant. Additional analysis found that temporal R 2 ranged from 0.84 to 0.99 and spatial R 2 values ranged from 0.76 to 0.96 across species. Four-fold cross-validation was performed to assess the model's predictive power, and ranged from 0.40 for PM 10 to 0.94 for SO 4 with other pollutants falling within this range. Largest improvements were found for PM 10 which had substantial bias in the CMAQ fields that varied east-to-west; smallest improvements were for SO 4 which was already well simulated. The random forest model results to correct the simulation biases, while largely consistent year-to-year, did show slight variation due in part to changes in the distribution of monitors and changes in CMAQ simulation inputs.

Impacts of emissions from the Atlanta Hartsfield-Jackson Airport (ATL) on ozone (O 3 ), ultrafine particulates (UFPs), and fine particulate matter (PM 2.5 ) are evaluated using the Community Multiscale Air Quality (CMAQ) model and high-resolution satellite observations of NO 2 vertical column densities (VCDs) from TROPOMI. Two airport inventories are compared: an inventory using emissions where landing and take-off (LTO) processes are allocated to the surface (default) and a modified (3D) inventory that has LTO and cruise emissions vertically and horizontally distributed, accounting for aircraft climb and descend rates. The 3D scenario showed reduced bias and error between CMAQ and TROPOMI VCDs compared to the default scenario [i.e., normalized mean bias: -43%/-46% and root mean square error: 1.12/1.21 (1015 molecules/cm 2 )]. Close agreement of TROPOMI-derived observations to modeled NO 2 VCDs from two power plants with continuous emissions monitors was found. The net effect of aviation-related emissions was an increase in UFP (j mode in CMAQ), PM 2.5 (i + j mode), and O 3 concentrations by up to 6.5 × 10 2 particles/cm 3 (∼38%), 0.7 μg/m 3 (∼8%), and 2.7 ppb (∼4%), respectively. Overall, the results show (1) that the spatial allocation of airport emissions has notable effects on air quality modeling results and will be of further importance as airports become a larger part of the total urban emissions and (2) the applicability of high-resolution satellite retrievals to better understand emissions from facilities such as airports.

Modeling studies project that in the future surface waters in the northeast US will continue to recover from acidification over decades following reductions in atmospheric sulfur dioxide and nitrogen oxides emissions. However, these studies generally assume stationary climatic conditions over the simulation period and ignore the linkages between soil and surface water recovery from acid deposition and changing climate, despite fundamental impacts to watershed processes and comparable time scales for both phenomena. In this study, the integrated biogeochemical model PnET-BGC was applied to two montane forest watersheds in the Adirondack region of New York, USA to evaluate the recovery of surface waters from historical acidification in response to possible future changes in climate and atmospheric sulfur and nitrogen deposition. Statistically downscaled climate scenarios on average project warmer temperatures and greater precipitation for the Adirondack by the end of the century. Model simulations suggest under constant climate, acid-sensitive Buck Creek would gain 12.8 μeq L -1 of acid neutralizing capacity (ANC) by 2100 from large reductions in deposition, whereas acid insensitive Archer Creek is projected to gain 7.9 μeq L -1 of ANC. However, climate change could limit those improvements in acid-base status. Under climate change, a negative offset relative to the ANC increases with no climate change are projected for both streams by 2100. In acid-insensitive Archer Creek the negative offset (-8.5 μeq L -1 ) was large enough that ANC is projected to decrease by -0.6 μeq L -1 , whereas in acid-sensitive Buck Creek, the negative offset (-0.4 μeq L -1 ) resulted in a slight decline of the projected future ANC increase to 12.4 μeq L -1 . Calculated target loads for 2150 for both sites decreased when future climate change was considered in model simulations, which suggests further reductions in acid deposition may be necessary to restore ecosystem structure and function under a changing climate., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Ozone (O 3 ) isopleths describe the nonlinear responses of O 3 concentrations to changes in nitrogen oxides (NO X ) and volatile organic compounds (VOCs) and thus are pivotal to the determination of O 3 control requirements. In this study, we innovatively use the Community Multiscale Air Quality model with the high-order decoupled direct method (CMAQ-HDDM) to simulate O 3 pollution of China in 2017 and derive O 3 isopleths for individual cities. Our simulation covering the entire China Mainland suggests severe O 3 pollution as 97% of the residents experienced at least 1 day, in 2017, in excess of Chinese Level-II Ambient Air Quality Standards for O 3 as 160 μg·m -3 (81.5 ppbV equally). The O 3 responses to emissions of precursors vary widely across individual cities. Densely populated metropolitan areas such as Jing-Jin-Ji, Yangtze River Delta, and Pearl River Delta are following NO X -saturated regimes, where a small amount of NO X reduction increases O 3 . Ambient O 3 pollution in the eastern region generally is limited by VOCs, while in the west by NO X . The city-specific O 3 isopleths generated in this study are instrumental in forming hybrid and differentiated strategies for O 3 abatement in China.

Data from satellite instruments provide estimates of gas and particle levels relevant to human health, even pollutants invisible to the human eye. However, the successful interpretation of satellite data requires an understanding of how satellites relate to other data sources, as well as factors affecting their application to health challenges. Drawing from the expertise and experience of the 2016-2020 NASA HAQAST (Health and Air Quality Applied Sciences Team), we present a review of satellite data for air quality and health applications. We include a discussion of satellite data for epidemiological studies and health impact assessments, as well as the use of satellite data to evaluate air quality trends, support air quality regulation, characterize smoke from wildfires, and quantify emission sources. The primary advantage of satellite data compared to in situ measurements, e.g., from air quality monitoring stations, is their spatial coverage. Satellite data can reveal where pollution levels are highest around the world, how levels have changed over daily to decadal periods, and where pollutants are transported from urban to global scales. To date, air quality and health applications have primarily utilized satellite observations and satellite-derived products relevant to near-surface particulate matter <2.5 μm in diameter (PM 2.5 ) and nitrogen dioxide (NO 2 ). Health and air quality communities have grown increasingly engaged in the use of satellite data, and this trend is expected to continue. From health researchers to air quality managers, and from global applications to community impacts, satellite data are transforming the way air pollution exposure is evaluated.

Prescribed burning (PB) is a prominent source of PM 2.5 in the southeastern US and exposure to PB smoke is a health risk. As demand for burning increases and stricter controls are implemented for other anthropogenic sources, PB emissions tend to be responsible for an increasing fraction of PM 2.5 concentrations. Here, to quantify the effect of PB on air quality, low-cost sensors are used to measure PM 2.5 concentrations in Southwestern Georgia. The feasibility of using low-cost sensors as a supplemental measurement tool is evaluated by comparing them with reference instruments. A chemical transport model, CMAQ, is also used to simulate the contribution of PB to PM 2.5 concentrations. Simulated PM 2.5 concentrations are compared to observations from both low-cost sensors and reference monitors. Finally, a data fusion method is applied to generate hourly spatiotemporal exposure fields by fusing PM 2.5 concentrations from the CMAQ model and all observations. The results show that the severe impact of PB on local air quality and public health may be missed due to the dearth of regulatory monitoring sites. In Southwestern Georgia PM 2.5 concentrations are highly non-homogeneous and the spatial variation is not captured even with a 4-km horizontal resolution in model simulations. Low-cost PM sensors can improve the detection of PB impacts and provide useful spatial and temporal information for integration with air quality models. R 2 of regression with observations increases from an average of 0.09 to 0.40 when data fusion is applied to model simulation withholding the observations at the evaluation site. Adding observations from low-cost sensors reduces the underestimation of nighttime PM 2.5 concentrations and reproduces the peaks that are missed by the simulations. In the future, observations from a dense network of low-cost sensors could be fused with the model simulated PM 2.5 fields to provide better estimates of hourly exposures to smoke from PB. Implications : Prescribed burning emissions are a major cause of elevated PM 2.5 concentrations, posing a risk to human health. However, their impact cannot be quantified properly due to a dearth of regulatory monitoring sites in certain regions of the United States such as Southwestern Georgia. Low-cost PM sensors can be used as a supplemental measurement tool and provide useful spatial and temporal information for integration with air quality model simulations. In the future, data from a dense network of low-cost sensors could be fused with model simulated PM 2.5 fields to provide improved estimates of hourly exposures to smoke from prescribed burning.