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Ambient fine particulate matter (PM 2.5 ) is the world’s leading environmental health risk factor. Reducing the PM 2.5 disease burden requires specific strategies that target dominant sources across multiple spatial scales. We provide a contemporary and comprehensive evaluation of sector- and fuel-specific contributions to this disease burden across 21 regions, 204 countries, and 200 sub-national areas by integrating 24 global atmospheric chemistry-transport model sensitivity simulations, high-resolution satellite-derived PM 2.5 exposure estimates, and disease-specific concentration response relationships. Globally, 1.05 (95% Confidence Interval: 0.74–1.36) million deaths were avoidable in 2017 by eliminating fossil-fuel combustion (27.3% of the total PM 2.5 burden), with coal contributing to over half. Other dominant global sources included residential (0.74 [0.52–0.95] million deaths; 19.2%), industrial (0.45 [0.32–0.58] million deaths; 11.7%), and energy (0.39 [0.28–0.51] million deaths; 10.2%) sectors. Our results show that regions with large anthropogenic contributions generally had the highest attributable deaths, suggesting substantial health benefits from replacing traditional energy sources. Ambient fine particulate matter (PM 2.5 ) is one of the most important environmental health risk factors in many regions. Here, the authors present an assessment of PM 2.5 emission sources and the related health impacts across global to sub-national scales and find that over 1 million deaths were avoidable in 2017 by eliminating PM 2.5 mass associated with fossil fuel combustion emissions.

Air pollution is a growing global concern due to harmful constituents like potentially toxic metals (PTMs), which can attach to particles such as dust, soot, and secondary aerosols, increasing their toxicity. This study assessed the seasonal variation, source apportionment, meteorological patterns, and health risks associated with PTMs (V, Mn, Cd, Cr, Fe, Zn, Ni, As, Co, Cu, Pb) in PM₂.₅ over Ilorin, Nigeria. PM 2.5 data for 2019 were obtained from the SPARTAN network at the University of Ilorin and processed for analysis. Results showed that PTM concentrations—particularly Fe, Zn, Cr, Pb, and Co, were significantly higher during the dry season. Cu and Cd also contributed to observed seasonal variations. PMF showed that the sources of pollutant were crustal, industrial sources, secondary inorganic, and biomass burning. EF showed that Cu, Pb, As had values that were between 10 and 100 indicating that they were from both crustal and anthropogenic sources. Cd and Zn had values of 953.27 and 217.87 respectively, which were greater than 100 indicating that they were from industrial sources. Finally, V, Cr, Mn, Fe, Co, had values of 6.05, 1.97, 2.47, 1.00, and 5.28 respectively, which indicates that they were majorly from crustal sources. The Health risk assessment (non-cancer risk) via inhalation revealed a high hazard index (HI = 99.12), mainly from Fe (66.48) and Zn (31.76). Monte Carlo simulation for cancer risk (CR) indicated Cr and As as the highest contributors via inhalation (7.06E-05 and 2.84E-06), while Ni posed the greatest risk via dermal exposure (3.20E-05). These findings highlight significant health concerns associated with airborne PTMs and the need for targeted air quality management, particularly during the dry season.

Environmental contaminations by polycyclic aromatic hydrocarbons (PAHs) especially from incinerators occur subtly, and PAH contribution from this source is underestimated. However, as environmental PAH concentrations build up, this may be a serious concern around the incinerator vicinity due to the potential consequences of PAHs on ecosystems and human health. Thus, the contribution of selected (12) PAHs from the Obafemi Awolowo University Teaching Hospital medical waste incinerator (or source, HWI_0) was determined by sampling stack gas and ambient air around incinerator vicinity from June 2014 to May 2015. Results showed that the 12 PAH source (HWI_0) concentrations were in the range of NA (for phenanthrene, pyrene, anthracene, benz[e]acephenanthrylene, and indeno[2,1-b]chromene) to 10.9 ng/m 3 (pyrelene) and generally higher than the receptor points (hospital waste incinerators (HWIs)). The average total PAH concentrations per month at HWI_0 and the receptors—HWI_1, HWI_2, HWI_3, HWI_4 and HWI_5—were 73.0 ± 27.9, 60.4 ± 30.8, 42.5 ± 23.6, 38.7 ± 21.9, 35.0 ± 27.2, and 39.2 ± 22.9 ng/m 3 , respectively. These results and multivariate receptor model analysis indicated high correlations between source PAH contributions and the receptor points. The PAH concentrations in the dry season were higher than the wet season suggesting that hydrological condition affects ambient PAH concentrations. The average PAH concentrations in the HWIs as well as the cumulative exposure concentrations observed throughout the period are of major health concern because PAH concentrations detected are several times higher than both the European Union standard and the WHO guideline level.

Background: Local production of garri (cassava crisps) is associated with air pollution and consequently lung function abnormalities among garri processing workers. This study was aimed at describing lung function abnormalities among Nigerians engaged in cassava crisps (garri) processing. Methods: A total of 351 workers and 351 controls were recruited at garri factories in Ogbomoso, Nigeria by multistage random sampling technique. Lung functional abnormalities were defined according to standardised European Respiratory Society/American Thoracic Society guidelines. Data analysis was performed using the IBM SPSS statistics version 22.0. Results: The mean age of patients was similar to that of controls (41.7 ± 14.9 vs. 41.6 ± 14.7 yearsP = 0.960). Larger proportion (46.2%) of cassava crisps factory workers had abnormal ventilatory function parameters compared to 6.8% in controls (P < 0.001). The mean peak expiratory flow among garri factory workers was significantly lower than that of the controls; 268.25 ± 86.20 versus 349.04 ± 97.21 (L/min) (P < 0.001), likewise the mean forced vital capacity (FVC) (litres) and forced expiratory volume (FEV1) (litres) of garri factory workers and controls were significantly lower than those of the controls; 2.55 ± 1.07 versus 2.87 ± 0.79 (P < 0.001) and 2.00 ± 0.76 versus 2.41 ± 0.83 (P < 0.001) with FEV1/FVC ratio of 0.82 ± 0.16 versus 0.87 ± 0.06 (P < 0.001), respectively. The restrictive pattern of ventilatory functional abnormality was predominant among garri factory workers, 92 (26.2%). Sixty-two (17.7%) and 8 (2.3%) of garri factory workers had an obstructive and mixed pattern of ventilatory function abnormalities, respectively. Conclusion: Garri processing workers had significant ventilatory function impairment. Preventive strategies should be encouraged to reduce occupational hazards associated with garri processing in Nigeria.

Earth system models (ESMs) participating in the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) simulate various components of fine particulate matter (PM2.5) as major climate forcers. Yet the model performance for PM2.5 components remains little evaluated due in part to a lack of observational data. Here, we evaluate near-surface concentrations of PM2.5 and its five main components over China as simulated by 14 CMIP6 models, including organic carbon (OC; available in 14 models), black carbon (BC; 14 models), sulfate (14 models), nitrate (4 models), and ammonium (5 models). For this purpose, we collect observational data between 2000 and 2014 from a satellite-based dataset for total PM2.5 and from 2469 measurement records in the literature for PM2.5 components. Seven models output total PM2.5 concentrations, and they all underestimate the observed total PM2.5 over eastern China, with GFDL-ESM4 (-1.5 %) and MPI-ESM-1-2-HAM (-1.1 %) exhibiting the smallest biases averaged over the whole country. The other seven models, for which we recalculate total PM2.5 from the available component output, underestimate the total PM2.5 concentrations partly because of the missing model representations of nitrate and ammonium. Concentrations of the five individual components are underestimated in almost all models, except that sulfate is overestimated in MPI-ESM-1-2-HAM by 12.6 % and in MRI-ESM2-0 by 24.5 %. The underestimation is the largest for OC (by -71.2 % to -37.8 % across the 14 models) and the smallest for BC (-47.9 % to -12.1 %). The multi-model mean (MMM) reproduces the observed spatial pattern for OC (R = 0.51), sulfate (R = 0.57), nitrate (R = 0.70) and ammonium (R = 0.74) fairly well, yet the agreement is poorer for BC (R = 0.39). The varying performances of ESMs on total PM2.5 and its components have important implications for the modeled magnitude and spatial pattern of aerosol radiative forcing.

The handling of used medical face mask waste is of great environmental concern, particularly in the developing African countries. A common technique for disposing of these materials is through open burning; however, this approach raises issues of air pollution. Hence, this study determined the concentration of polychlorinated biphenyl compounds (PCBs) from the open burning of different disposable medical facemask materials. A health risk assessment was conducted to evaluate the potential health risks associated with human inhalation of emissions from the open burning of these materials, using various health risk indicators. The concentration distribution around the open incineration site was also modeled. Waste facemasks were combusted in the open reactor, and the emissions were sampled for PCBs using a filter-sorbent system. PCB analysis was done using GC-MS. Incremental Life Cancer Risk (ILCR), Inhalation Risk Assessment (IRA), and Hazard Quotient (HQ) were calculated to assess health risk. The results showed the Ʃ PCBs from different face mask materials range from 253.21 to 733.81 µg/m 3 , WHO-recommended surgical facemasks, and N95 Facemasks emit the highest concentration of PCBs. Daily inhalation exposure values for children range from 0.0037 to 0.012 µg TEQ kg − 1 day − 1 while IRA for adults ranges from 0.0016 to 0.0056 µg TEQ kg − 1 day − 1 . Most of the ILCR values obtained are higher than the WHO stipulated permissible limits, which indicate possible cancer risk from inhalation of the emission. Also, HQ values obtained are greater than 1, indicating associated noncarcinogenic risks. The dispersion model of Dioxin-like PCBs from the burning source of the facemask depicts the presence of considerable PCB concentrations within a 3 km perimeter of the burning site after one year. The study concluded that proper disposal methods should be implemented for the management of medical face masks, especially in developing countries in Africa.

The ongoing trade war between the United States and China is having profound impacts on the global economy. As recent studies have found substantial amounts of carbon dioxide and air pollution embedded in the global supply chains, the Sino-US trade war may also affect emissions and health burdens worldwide, which remains poorly understood. Here, we estimate the potential changes in gross domestic product (GDP), anthropogenic emissions and particulate matter (PM2.5) related premature deaths worldwide under two Sino-US trade war scenarios. We find that for the US and China, the trade war would reduce their GDP and, less significantly, emissions and mortality, suggesting that the trade war is not an effective means of environmental protection. The trade war would increase both GDP and mortality in many developing regions, because of their increased production of goods targeted in the Sino-US trade war. Surprisingly, Western Europe and Latin America and Caribbean would have higher GDP but lower emissions and mortality, an economic and environmental win-win outcome as a net result of the complex changes in the global supply chains. Neighbour regions of the US and China such as Canada, Japan and Korea would also have higher GDP but lower mortality, because of reduced atmospheric transboundary transport from the US and China overcompensating for increased local emissions of these neighbours. The complex consequences of the Sino-US trade war highlight the strong inter-regional and economic-environmental linkage in support of a global collaborative strategy to foster economic growth and environmental protection.

Seven scenarios were designed to study the national environmental benefits of ULE in coal-fired power plants (CPPs), ULE in industrial coal burning (ICB) and NH3 emission reduction by using the GEOS-Chem model. The results showed that although the CPPs have achieved the ULE transformation target, the PM2.5 concentration across the country has decreased by 4.8% (1.4 μg/m3). Due to the complex non-linear chemical competition mechanism among nitrate and sulfate, the average concentration of nitrate in the country has increased by 1.5% (0.1 μg/m3), which has reduced the environmental benefits of the power plant emission reduction. If the ULE technology is applied to the ICB to further reduce NOx and SO2, although the PM2.5 concentration can be reduced by 10.1% (2.9 μg/m3), the concentration of nitrate will increase by 2.7% (0.2 μg/m3). Based on the CPPs-ULE, NH3 emissions reduced by 30% and 50% can significantly reduce the concentration of ammonium and nitrate, so that the PM2.5 concentration is decreased by 11.5% (3.3 μg/m3) and 16.5% (4.7 μg/m3). Similarly, based on the CPPs-ICB-ULE, NH3 emissions can be reduced by 30% and 50% and the PM2.5 concentration reduced by 15.6% (4.4 μg/m3) and 20.3% (5.8 μg/m3). The CPPs and ICB use the ULE technology to reduce NOx and SO2, thereby reducing the concentration of ammonium and sulfate, causing the PM2.5 concentration to decline, and NH3 reduction is mainly achieved through reducing the concentration of ammonium and nitrate to reduce the concentration of PM2.5. In order to better reduce the concentration of PM2.5, NOx, SO2 and NH3 emission reduction control measures should be comprehensively considered in different regions of China. By comprehensively considering the economic cost and environmental benefits of ULE in ICB and NH3 emission reduction, an optimal haze control scheme can be determined.

Road dust is a principal source and depository of polycyclic aromatic hydrocarbons (PAHs) in many urban areas of the world. Hence, this study probed the spatial and seasonal pattern, sources, and related cancer health risks of PAHs in the road dusts sampled at ten traffic intersection (TIs) of a model African city. Mixed PAHs sources were ascertained using the diagnostic ratios and positive matrix factorization (PMF) model. The results showed fluctuations in mean concentrations from 36.51 to 43.04 µg/g. Three-ring PAHs were the most abundant PAHs with anthracene (Anth) ranging from 6.84 ± 1.99 to 9.26 ± 4.42 µg/g being the predominant pollutant in Ibadan. Benzo(k)Fluoranthene (BkF) which is a pointer of traffic emission was the most dominant among the seven carcinogenic PAHs considered, varying from 2.68 ± 0.43 to 4.59 ± 0.48 µg/g. Seasonal variation results showed that PAH concentrations were 20% higher during dry season than rainy season. The seven sources of PAHs identified by PMF model include the following: diesel vehicle exhausts, gasoline combustion, diesel combustion, coal tar combustion, gasoline vehicle exhausts, coal and wood (biomass) combustion, and emissions from unburnt fossil fuels. Employing the incremental lifetime cancer risk (ILCR) model, the city’s cancer risk of 5.96E-05 for children and 6.60E-05 for adults were more than the satisfactory risk baseline of ILCR ≤ 10 −6 and higher in adults than in Children.

Fine particulate matter (PM.sub.2.5) pollution is a severe problem in China. Research on the sources of Chinese PM.sub.2.5 pollution has focused on the contributions of China's domestic emissions. However, the impact of foreign anthropogenic emissions has typically been simplified or neglected, partly due to the perception that the short lifetime of PM.sub.2.5 (a few days) does not allow long-distance transport. Here we explore the role of foreign anthropogenic emissions in Chinese PM.sub.2.5 pollution in 2015 using the GEOS-Chem chemical transport model. We validate the model simulations with a comprehensive set of observations of PM.sub.2.5 and its composition, including sulfate, nitrate, ammonium, black carbon, and primary organic aerosols, over China and its surrounding regions. We find that 8 % of PM.sub.2.5 (5 µg m.sup.-3) and 19 % of nitrate (2.6 µg m.sup.-3) over eastern China in 2015 was contributed by foreign anthropogenic emissions. The contributions were the highest in January (6.9 µg m.sup.-3 PM.sub.2.5, with 68 % nitrate) and the lowest in July (2.7 µg m.sup.-3 PM.sub.2.5, with 11 % nitrate). Yet, only 30 % of such foreign contributions in January were through direct atmospheric transport. The majority (70 %) were instead through chemical interactions between foreign-transported aerosol precursors and China's domestic emissions of pollutants. Specifically, the transport of non-methane volatile organic compounds (NMVOCs) from foreign countries enhanced the atmospheric oxidizing capacity and facilitated the oxidation of Chinese nitrogen oxides (NO.sub.x) to form nitric acid (HNO.sub.3) over eastern China. The abundance of Chinese ammonia (NH.sub.3) further partitioned nearly all HNO.sub.3 gas to particulate nitrate, leading to considerable foreign contributions of nitrate and PM.sub.2.5 to eastern China. Over southwestern China, foreign anthropogenic emissions contributed 4.9 µg m.sup.-3 PM.sub.2.5 concentrations (18 % of total PM.sub.2.5 mass) to Yunnan Province, with 37 % as organics and 27 % as sulfate. Our findings suggest that foreign anthropogenic emissions play an important role in Chinese PM.sub.2.5 pollution because of direct aerosol transport and, more importantly, chemical interactions between transported pollutants and China's local emissions. Thus, foreign emission reductions will be very beneficial for improving Chinese air quality.