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Inhalation of atmospheric PM 2.5 can induce the generation of excessive reactive oxygen species (ROS) in human alveoli, triggering local and systemic inflammation, which can directly or indirectly result in respiratory and cardiovascular diseases. In this study, we assessed the oxidative potential (OP) of fresh and O 3 -aged PM 2.5 particles from various urban and rural emission sources using the dithiothreitol (DTT) method. Our results revealed variations in the OP of fresh PM 2.5 among different emission sources, with biomass burning sources exhibiting the highest OP, followed by industrial areas, vehicular emissions, cooking emissions, and suburban areas, respectively. Water-soluble organics and transition metals might potentially exert significant influence on particle OP. O 3 aging notably decreased the OP of PM 2.5 particles, possibly due to the oxidation of highly DTT-active components into low redox-active small molecules. Moreover, the evolution of OP in different PM 2.5 components, including methanol-soluble and insoluble fractions, exhibited distinct responses to O 3 aging for source-oriented PM 2.5. Additionally, differences in chemical composition between fresh and aged PM 2.5 were further elucidated through measurements of component-dependent hygroscopic behaviors and phase transitions. This study systematically delineates variances in the toxic potential of fresh and O 3 -aged PM 2.5 from various anthropogenic sources. The findings highlight the intrinsic compositional dependence of particle OP and provide essential insights for assessing the health effects of source-oriented PM 2.5 , as well as for formulating human health protection policies. [ABSTRACT FROM AUTHOR]

This study investigated the size-segregated carbonaceous components of particulate matter (PM), including ultrafine particles (UFP or PM0.1), across three distinct urban settings in Phnom Penh, Cambodia: an educational site (University of Health Sciences, UHS), an institutional site (Ministry of Environment, MoE), and a residential area near a landfill. A cascade impactor-type sampler equipped with an inertial filter was used to collect size-segregated particles down to UFPs. Carbonaceous species, including organic carbon (OC) and elemental carbon (EC), were analyzed using a thermal/optical carbon analyzer to determine their composition and ratios. The results indicated no significant differences in mass concentration between weekdays and weekends at all sites; however, PM profiles varied across the location. The UHS site displayed higher EC levels in UFP, with concentrations suggesting significant local vehicular emissions, underscored by a lower OC/EC ratio (2.39 ± 1.13) compared to other sites. In contrast, the landfill site exhibited higher OC components in finer particles, suggesting emissions from organic sources such as waste burning and cooking activities, evidenced by higher OC/EC ratios across all particle sizes (e.g., OC/EC ratio in UFP at 3.78 ± 0.98). The MoE site presented a balanced profile with moderate levels of both OC and EC, influenced by its proximity to natural dispersion factors like the Tonle Sap River. Additionally, air mass backward trajectory analysis integrated with hotspot data indicated transboundary influences, particularly from agricultural burning in surrounding provinces, including Vietnam. Therefore, both local and transboundary emissions influenced the PM levels in Phnom Penh city. [ABSTRACT FROM AUTHOR]

Carbon footprint assessment is important to combat global warming and promote sustainability. Globally, organizations committed to biodiversity conservation are essential for maintaining ecosystems and the people who inhabit them. Nonetheless, these organizations produce a carbon footprint due to their operating operations. Hence, this study aimed to assess the specific carbon footprint of the Ezemvelo KZN Wildlife (EKZNW) to improve its understanding of its environmental implications and encourage sustainable behaviors within its particular missions. Using the greenhouse gas protocol corporate accounting and reporting standard as a guide, the study methodology examines greenhouse gas emissions from direct (Scope 1) and indirect (Scopes 2 and 3) sources related to Ezemvelo wildlife activities over five years (2014/2015--2018/2019). The results show that 34,016.62 tons of carbon dioxide equivalent (tCO2e) are emitted on average each year. The majority of these emissions are caused by Scope 2 electricity consumption, which accounts for 23,475.82 tCO2e, and Scope 1 emissions, which account for 7,826.20 tCO2e. Furthermore, there was a noticeable difference in emissions between the reserves, with the Imfolozi Game Reserve having the highest emissions. The findings of this study direct EKZNW toward ecologically conscious behaviors by acting as a catalyst for educated decision-making. The insight gained paves the way for proactive steps to lower carbon emissions, coordinating conservation efforts with more general goals of sustainability and climate resilience.

Coal production enterprises at present are facing immediate urgency to reduce their high carbon emissions so as to meet the "dual carbon" targets. This study therefore analyzed their potential in carbon emission reduction from the perspective of their coal products, mining processes and emission types. Specifically, this study proposed pathways for 1)upgrading coal production equipments, including the application of advanced clean technologies, upgrading and retrofitting production equipments, and implementing energy efficiency management strategies; 2)technology updates for coal exploration, mining, beneficiation and monitoring; 3)upgrading new energy vehicles and intelligent platforms for logistics management, and improving energy-consuming equipments for personnel in mining areas, all targeting at the major factors causing high carbon emissions; 4)upgrading coal and gas co-capture technologies and carbon sequestration methods during coal mining and beneficiation processes, based on which specific suggestions are offered for coal production enterprises. A comprehensive pathway for carbon emission reduction is thus constructed for coal production enterprises to achieve carbon peak and carbon neutrality.

Assessing environmental exposure to pollution is a challenging task, and scientists often use distance-based or proximity indicators when field or modeled data are unavailable. Although buffers are commonly used to represent the impact of a pollution source on neighboring populations, they can result in high-exposure misclassification. Euclidean distance-based indicators offer a promising alternative, but practices vary significantly in the literature. In this study, we aimed to compare several distance-based indicators for multiple environmental contaminants in an industrial and urban area. At the population's grid cell resolution of 200 × 200 m, we compared the distance to the closest source, the average or median distance to all sources, or a restricted number of nearby sources for six types of sources (industries, railways, rail areas, roadways, road crossings, and agricultural patches) against environmental contamination data (PM10, NO2, and multimetallic contamination in lichens). Our findings revealed that the representativeness of contamination by indicators is significantly affected by the type and number of nearby sources considered. Specifically, we found that considering the distance to the nearest source or the average distance to all sources can lead to exposure misclassifications. The optimal correlation between distance indicators and pollutant levels was observed when considering 10–14 of the closest industrial sources, located within a 4.9- to 5.5-km radius. For rail areas, the optimal number was two to three sources within a 5.4- to 7.4-km radius. For main roads, intersections, and railways, the optimal number of sources varied depending on the pollutant, generally falling within a 3- to 9.4-km radius. Environmental contamination is influenced by the diversity of nearby sources, and considering only one source increases the risk of misclassification. Our results suggest that proximity models are still appropriate for study areas where the etiology of existing health effects is unclear, providing an exploratory analysis before more sophisticated research. [ABSTRACT FROM AUTHOR]

It has been demonstrated that benzene, toluene, and xylene are carcinogens. Its combined effects with other contaminants have the potential to harm several ecosystem components. Since most human benzene exposure takes place inside, it is important to understand how outdoor benzene emissions from traffic and industry affect interior concentrations. However, this area of study has not received enough attention to date. Herein, we examine the outdoor concentrations of benzene, toluene, and xylene (BTX) in a Steelpoort mining area. BTX pollutants were passively sampled on the first seven days of the month, from January to December 2021 using Radiello samplers. The effects of meteorological parameters such as temperature, relative humidity, wind speed, and solar radiation on BTX concentrations were also statistically tested. For all seasons, BTX concentrations were greater in the winter than in the summer with concentrations of 0.69 µg/m3, 2.97 µg/m3 and 0.80 µg/m3 for benzene, toluene and xylene, respectively. In addition, toluene was the most common BTX compound with the highest concentrations when compared to benzene and xylene. Benzene, toluene and xylene, had yearly average concentrations of 0.61 µg/m3, 1.48 µg/m3 and 0.64 µg/m3, respectively. The benzene and xylene concentrations were below international exposure limits (annual, 5 µg/m3 for benzene; weekly, 260 µg/m3 for toluene), as in comparison to the World Health Organization, as well as within South African exceedance limits. Both positive and negative correlations between BTX and meteorological parameters were demonstrated by statistical models. Temperature, wind speed, and relative humidity depicted a weak negative correlation with benzene of 0.003, 0.019 and 0.006, respectively. Toluene showed a positive correlation with wind speed (1.90) and relative humidity (0.041). Overall, the concentration of benzene is of major concern since it is an agent of cancer and it is there in the atmosphere. [ABSTRACT FROM AUTHOR]

This study conducts a spatio-temporal analysis of tropospheric nitrogen dioxide (NO2) and total carbon monoxide (CO) concentrations in the Punjab and Haryana regions of India and Pakistan, using datasets from the Sentinel 5-Precursor (S5P) satellite. These regions, marked by diverse economic growth factors including population expansion, power generation, transportation, and agricultural practices, face similar challenges in atmospheric pollution, particularly evident in major urban centers like Delhi and Lahore, identified as pollution hotspots. The study also spotlights pollution associated with power plants. In urban areas, tropospheric NO2 levels are predominantly elevated due to vehicular emissions, whereas residential activities mainly contribute to CO pollution. However, precisely attributing urban CO sources is complex due to its longer atmospheric residence time and intricate circulation patterns. Notably, the burning of rice crop residue in November significantly exacerbates winter pollution episodes and smog, showing a more pronounced correlation with total CO than with tropospheric NO2 levels. The temporal analysis indicates that the months from October to December witness peak pollution, contrasted with the relatively cleaner period during the monsoon months of July to September. The severe pollution in the OND quarter is attributed to factors such as variations in boundary layer height and depletion of OH radicals. Furthermore, the study highlights the positive impact of the COVID-19 lockdown on air quality, with a significant decrease in NO2 concentrations during April, 2020 (Delhi: 59%, Lahore: 58%). However, the reduction in total CO columns was less significant. The study also correlates lockdown stringency with tropospheric NO2 columns (R2: 0.37 for Delhi, 0.25 for Lahore, 0.22 for Rawalpindi/Islamabad), acknowledging the influence of various meteorological and atmospheric variables. The research highlights the significant impact of crop residue burning on winter pollution levels, particularly on total CO concentrations. The study also shows the notable effect of the COVID-19 lockdown on air quality, significantly reducing NO2 levels. Additionally, it explores the correlation between lockdown stringency and tropospheric NO2 columns, considering various meteorological factors. [ABSTRACT FROM AUTHOR]

This study aims to generate a satellite-based qualitative emission source characterization for the heavily polluted eastern part of China in the 2010–2016 time period. The applied source identification technique relies on satellite-based NOx and SO2 emission estimates by OMI, their SO2:NOx ratio, and the MIX anthropogenic emission inventory to distinguish emissions from different emission categories (urban, industrial, natural) and characterize the dominant source per 0.25° × 0.25° grid cell in East China. Overall, we find good agreement between the satellite- and emission inventory–based spatiotemporal distribution and characterization of the dominant emission sources in East China in 2010–2016. In 2010, the satellite measurements suggest an emission distribution less dominated by industrial areas, a somewhat larger role for urban/transportation areas and agricultural activities, and more natural emissions in the southern part compared to the bottom-up emission categorization. In 2016, more than half of the classified emission categories over East China have remained the same. At the same time, there is a notable increase of agricultural lands and decrease of areas dominated by industry/transportation in 2016, suggestive of an overall decrease in heavy air pollution in East China over the course of 7 years. This is likely attributed to the sustained efforts of the Chinese government to drastically improve the air quality, especially since 2013 when the National Air Pollution Prevention and Control Action Plan was enacted. However, signs of urban expansion (urbanization) and rural–urban migration ("Go West" motion) stemmed from China's rapid economic growth and labour demand are evident; escalating industrialization (even with cleaner means) and the urban population growth in East China resulted in stronger emissions from sources representing consumption and transportation which are strongly related to NO2 and PM10 pollution (rather than SO2) and are directly influenced by the population size. This resulted to a shift of the emissions from the east mainly to the north and northwest of East China. Overall, although the effectiveness of the Chinese environmental control policies has been successful, the air pollution problem remains an important concern. [ABSTRACT FROM AUTHOR]

Air pollution is a great threat to the sustainable development of the world; therefore, the improvement of air quality through the identification and apportionment of emission sources is a significant tool to reach sustainability. Single particle analysis, by means of a scanning electron microscope equipped with X-ray energy dispersive analysis (SEM-EDS), was used to identify the morphological and chemical properties of the PM10 particles in order to identify and quantify the main emission sources in three areas of Lecce, a city in the Apulia region of southern Italy. This type of characterization has not yet been performed for the Lecce site, but it is of particular importance to identify, based on the shape of the particles, the natural sources from the anthropogenic sources that are responsible for the serious health effects of the inhabitants. Three primary schools located in peripheral areas of the city were chosen for the sampling: "School 1" (A site), "School 2" (B site), and "School 3" (C site) to carry out a study of the air quality. The A site is characterized by a greater presence of calcium sulphates probably due both to construction activities present during sampling and to reactions between Ca particles and the sulfur present in the atmosphere. At the C site, there is a relative numerical abundance of different groups of particles that present, in the EDS spectrum, an enrichment in sulfur. At the B site, the number of particle groups is intermediate compared to that of the other two sites. With the source apportionment technique, ten emission sources were identified: combustion, soot, industry, soil, carbonates, sea salt, calcium sulfates, SIA, biological particles, and others. In PM10, the three sites are more affected by the soil source, with an effect greater than 60%. [ABSTRACT FROM AUTHOR]

Here, we present the results of a comprehensive study of air quality in two tunnels located in the city of Krakow, southern Poland. The study comprised three PM fractions of suspended particulate matter (PM1, PM2.5 and PM10) sampled during campaigns lasting from March 14 to April 24, 2016 and from June 28 to July 18, 2016, in the road tunnel and the tram tunnel, respectively. The collected samples had undergone comprehensive chemical, elemental and carbon isotope analyses. The results of these analyses gave the basis for better characterization of urban transport as a source of air pollution in the city. The concentrations of particulate matter varied, depending on the analysed PM fraction and the place of sampling. For the tram tunnel, the average concentrations were 53.2 µg·m−3 (PM1), 73.8 µg·m−3 (PM2.5), 96.5 µg·m−3 (PM10), to be compared with 44.2 µg·m−3, 137.7 µg·m−3, 221.5 µg·m−3, respectively, recorded in the road tunnel. The isotope-mass balance calculations carried out separately for the road and tram tunnel and for each PM fraction, revealed that 60 to 79% of carbon present in the samples collected in the road tunnel was associated with road transport, to be compared with 15–33% obtained in the tram tunnel. The second in importance were biogenic emissions (17–21% and 41–49% in the road and tram tunnel, respectively. Sixteen different polycyclic aromatic hydrocarbons (PAHs) have been identified in the analysed samples. As expected, much higher concentrations of PAHs were detected in the road tunnel when compared to the tram tunnel. Based on the analysed PAHs concentrations, health risk assessment was determined using 3 different types of indicators: carcinogenic equivalent (CEQ), mutagenic equivalent (MEQ) and toxic equivalent (TEQ). [ABSTRACT FROM AUTHOR]

Hybrid approaches combining machine learning with traditional inverse problem solution methods represent a promising direction for the further development of inverse modeling algorithms. The paper proposes an approach to emission source identification from measurement data for advection–diffusion–reaction models. The approach combines general-type source identification and post-processing refinement: first, emission source identification by measurement data is carried out by a sensitivity operator-based algorithm, and then refinement is done by incorporating a priori information about unknown sources. A general-type distributed emission source identified at the first stage is transformed into a localized source consisting of multiple point-wise sources. The second, refinement stage consists of two steps: point-wise source localization and emission rate estimation. Emission source localization is carried out using deep learning with convolutional neural networks. Training samples are generated using a sensitivity operator obtained at the source identification stage. The algorithm was tested in regional remote sensing emission source identification scenarios for the Lake Baikal region and was able to refine the emission source reconstruction results. Hence, the aggregates used in traditional inverse problem solution algorithms can be successfully applied within machine learning frameworks to produce hybrid algorithms. [ABSTRACT FROM AUTHOR]

Although numerous studies have been carried out to study haze formation in the North China Plain (NCP) and Northeastern Plain (NP), little is known about the chemical compositions and haze formations in Qinhuangdao city, which is located in the northeast edge of the NCP and adjacent to the NP. In this study, water‐soluble inorganic ions, organic carbon and elemental carbon (EC) were analysed offline during two haze periods from October 29 to November 7, 2021. The results showed that NO3− and organic matter (OM) accounted for 34.81% and 21.15% of total PM2.5 mass concentration, respectively, followed by NH4+ (14.06%) and SO42− (12.33%). The sulphur oxidation ratio and nitrogen oxidation ratio as well as OM/EC ratio on haze days were higher than those on non‐haze days, suggesting both high secondary inorganic and organic aerosol formation on haze days under high relative humidity. Source apportionment results showed that marine aerosols contributed small of total aerosol particle loads, while the combustion‐related sources were the most, possibly coal combustion, biomass burning and vehicle emissions. Air masses during haze periods mainly came from southwest and west directions in this case. Further calculated meteorological data of 2018–2021 showed high PM2.5 mass in Qinhuangdao were mainly affected by low‐speed southwest wind in autumn. The results highlighted the important role of long‐range transport of air pollutants from the NCP instead of the NP on haze formation in autumn in Qinhuangdao. [ABSTRACT FROM AUTHOR]

Abstract This study aimed to identify the factors causing NH3 emissions in the South Korean Peninsula and West Sea region. To analyze the trends of NH3 and other air pollutants, such as NOx, CO, and NR-PM1, we collected samples from six supersites across the peninsula, a roadside in Seoul, and the West Sea over different sampling periods, ranging from 1 month to 1 year. The highest NH3 concentrations were found at rural areas, ascribed to agricultural activities, particularly NH4NO3 decomposition at high summer temperatures. Areas with low population densities recorded the lowest NH3 concentrations, attributed to the lack of anthropogenic activities. A roadside field experiment confirmed the close link between ambient NH3 and vehicle emissions in urban regions by showing a strong correlation between CO and NOx concentrations and that of NH3. Moreover, we examined oceanic emissions near the eastern coast of South Korea in the West Sea. Long-range transportation studies confirmed that most of the pollutants (NH3, CO, and PM1) were transported by wind from the northeastern region of China. A maritime origin study showed that oceanic emissions and NH4NO3 decomposition in the atmosphere owing to high temperatures were the causing NH3 pollution. These findings provided valuable insights into the emission sources of NH3 in primary air pollutants in South Korea, highlighting the contributions of land-based and oceanic sources. Our study can help inform policymakers and stakeholders for developing effective regional air pollution control strategies.

An intensive field campaign was carried out from December 2022 to March 2023 at six different sites across five major cities (Xi'an, Baoji, Xianyang, Weinan, and Hancheng) in the Guanzhong Basin, China, covering most of the heating period there, which is characterized by high PM2.5 pollution levels. During the campaign, the mean PM2.5 concentrations at these sites exceeded the 24 h PM2.5 standard (75 μg m−3), except the site at Hancheng, with mean PM2.5 concentrations of 57.8 ± 32.3 μg m−3. The source apportionment of PM2.5 varied significantly across sites, with vehicle exhaust being the dominant source at urban sites located in Xi'an and Baoji, coal combustion at suburban sites in Hancheng, and comparable contribution from coal combustion and industrial emissions at suburban sites in Xianyang and Weinan. Compared with clean condition, the contribution of vehicle exhaust and secondary inorganic sources (SIs) were largely enhanced during heavy PM2.5 pollution periods, while the contribution from biomass burning (BB) and dust decreased significantly at all sites. Combined with an analysis of meteorological parameters, the study further found that higher contributions of SIs and heavy PM2.5 pollution were generally associated with higher relative humidity (RH). In addition, higher PM2.5 concentrations at suburban sites were related to lower wind speeds, which could be explained by the stagnant condition favoring the accumulation of local emissions as well as the formation of secondary pollutants. In contrast, at urban sites (e.g., Xianyang), higher PM2.5 concentrations were more associated with the strong influence of vehicle exhaust at slightly higher wind speeds. [ABSTRACT FROM AUTHOR]

In this study, we concurrently determined the combined ratio of black carbon (BC) and carbon monoxide (CO) in two distinct cities in eastern India: Jamshedpur (JSR) and Kharagpur (KGP). The investigation spanned from October 2019 to January 2020, revealing BC mass concentrations of 10.06 (± 1.59) µg m−3 in JSR and 5.49 (± 1.15) µg m−3 in KGP. Additionally, the average CO concentrations measured were approximately 913.63 (± 217.85) ppbv in JSR and 507.31 (± 125.06) ppbv in KGP. Analysis of GIOVANNI NASA satellite data highlighted elevated concentrations of BC and CO in the Indo-Gangetic Plain (IGP), the foothills of the central Himalayas, and the eastern region of India. Utilizing diagnostic ratio analysis to attribute the sources of BC, we found that wood-burning contributed more significantly to the BC levels in KGP compared to JSR. The higher overall aerosol concentration in JSR was attributed to the prevalence of numerous industries and heavy traffic. Pearson correlation analysis indicated substantial correlations between BC–CO and BC–PM2.5, with correlation coefficients of r2 = 0.65 and r2 > 0.96, respectively. These results underscore the need for significant changes to be implemented, such as transitioning to alternative appliances that do not rely on fossil fuels. By adopting cleaner and more sustainable energy sources, we can effectively mitigate the adverse impacts of BC, PM2.5, and CO emissions on air quality and public health. Air back-trajectory analysis unveiled the predominant northward transmission of pollution from northern India. Additionally, air masses originating from neighboring countries such as Pakistan, Nepal, Bangladesh, and Bhutan also contributed to the pollution levels. Health risk assessments revealed estimated non-cancerous particulate health risks (Npsc) ranging from 6.27 to 25.6 in JSR and 2.02 to 8.28 in KGP, emphasizing potential health implications associated with BC exposure in the two cities. [ABSTRACT FROM AUTHOR]

Black carbon (BC) particles produced by incomplete combustion of biomass and fossil fuels warm the atmosphere and decrease the reflectivity of snow and ice, hastening their melt. Although the significance of BC in Arctic climate change is widely acknowledged, observations on its deposition and sources are few. We present BC source types in a 300‐year (1700–2005) Svalbard ice core by analysis of particle‐bound organic compounds, radiocarbon, and trace elements. According to the radiocarbon results, 58% of the deposited elemental carbon (EC, thermal‐optical proxy of BC) is of non‐fossil origin throughout the record, while the organic compounds suggest a higher percentage (68%). The contribution of fossil fuels to EC is suggested to have been elevated between 1860 and 1920, particularly based on the organics and trace element data. A second increase in fossil fuel sources seems to have occurred near the end of the record: according to radiocarbon measurements between 1960 and 1990, while the organics and trace element data suggest that the contribution of fossil fuels has increased since the 1970s to the end of the record, along with observed increasing EC deposition. Modeled atmospheric transport between 1948 and 2004 shows that increasing EC deposition observed at the glacier during that period can be associated with increased atmospheric transport from Far East Asia. Further observational BC source data are essential to help target climate change mitigation efforts. The combination of robust radiocarbon with organic compound analyses requiring low sample amounts seems a promising approach for comprehensive Arctic BC source apportionment. Plain Language Summary: Black carbon (BC) is a fine particulate emission component formed in natural and anthropogenic combustion of biomass and fossil fuels. BC effectively warms the atmosphere, and when it is deposited on snow and ice, it hastens their melt. BC strongly amplifies Arctic climate change but information on its deposition variations and sources are still very scarce. We studied sources of BC in a Svalbard (high‐Arctic) ice core covering the years 1700–2005 by analysis of chemical compounds, radiocarbon and trace elements. We found that throughout the ice core, the contribution of biomass combustion to BC was higher (ca. 60%–70%) than that of fossil fuels. The contribution of fossil fuel sources to BC in the ice core was elevated in 1860–1920, and again at the end of the record starting in the 1960s–1970s. Atmospheric transport modeling shows that increasing BC deposition observed at the glacier since the 1970s was associated with airmasses arriving increasingly from Far East Asia. Further observations on Arctic BC sources are essential to inform decision makers on which BC emissions most affect Arctic climate change. Key Points: Non‐fossil sources have dominated (ca. 60%–70%) elemental carbon (EC) deposition in a Svalbard ice core between 1700 and 2005The contribution of fossil fuels to EC was highest between 1860 and 1920 and toward the end of the record starting in the 1960s or 1970sAtmospheric transport modeling indicates that observed increased EC deposition was associated with potential Asian sources in 1948–2004 [ABSTRACT FROM AUTHOR]

As efforts to mitigate soil and groundwater pollution intensify nationwide, the incidence of volatile organic compound (VOC) contaminated sites has risen significantly. These sites exhibit continuous release and dispersion of VOCs during and after remediation/control processes, thereby adversely affecting the local environment and residents. This issue has emerged as a prominent concern in contemporary society. This study takes a representative pesticide-contaminated site as the research subject. The pollutant levels, composition, spatiotemporal distribution, and source characteristics of VOCs in the ambient air environment from 2016 to 2021 were investigated by statistical analysis, Geographic Information System (GIS) spatial interpolation, Positive Matrix Factorization (PMF) model, and characteristic ratio source. The results showed that the average mass concentration proportions of the five types of pollutants are: benzene, toluene, ethylbenzene, and xylenes (BTEX) (29.73%) > alkanes (26.85%) > oxygenated hydrocarbons (21.96%) > halogenated hydrocarbons (19.12%) > sulfides (2.35%). M-/p-xylenes and toluene were the main contributing pollutants of BTEX and appeared frequently in the lists of top three pollutant in the contribution rates at various sites. The average concentration range of VOCs inside (EA1∼EA5) and outside the site (CK1∼CK4) were 810.71–1437.24 μg/m³, and 784.47–1358.16 μg/m³, respectively. The spatial distribution and variation trend in concentrations of halogenated hydrocarbons and alkanes were similar, with both being high in the middle of the site in 2017 and high in the south in 2018, and then sharply falling to a lower level in 2019. The source analysis results showed that the main contribution sources of environmental air varied over time. There were three types of emission sources for VOCs during the monitoring periods in 2016 and 2018. The maximum contributions to total volatile organic compounds (TVOCs) in 2016 and 2018 were volatile sources of characteristic pollutants within the site (45.6%) and volatile source of fuel (70.6%), respectively. This study provides scientific evidence for the environmental management, planning, and VOCs pollution control of pesticide-contaminated sites in China.

Particulate matter (PM) in the atmosphere is highly relevant due to its far-reaching implications. These tiny solid or liquid particles affect human health, causing respiratory and cardiovascular issues, and even premature death. PM also plays a role in climate change, as some particles contribute to warming, while others have cooling effects, impacting Earth's energy balance. Additionally, PM influences visibility, transportation safety, and ecosystems by depositing on land and water surfaces, altering soil and water quality. Recognizing and monitoring the emissions and sources of PMs by 4 subclasses, from PM2.5 to PM10, but also as TSP (total suspended particles) and individually as BC - black carbon is vital for effective air quality management and mitigating its multifaceted impacts on our environment and well-being. This paper presents an analysis of PMs emissions divided into the 4 classes presented above, for Romania, between 1990-2021, as given by the national report made according to the National Emission reduction Commitments Directive (NECD), which aims to reduce emissions of the main air pollutants. The emission data are presented by national emission sectors, from different industries to different transport types, and also from agricultural activities, and waste management. Relevant averages and trends are quantified and analysed as a reference for real-time data at city level, such that to assess the local pollution level and data accuracy as compared to the national reports. [ABSTRACT FROM AUTHOR]

Between 9 July and 19 August 2016, the air concentrations of 57 volatile organic compounds (VOCs) were measured in Shandong Province, eastern China. Seven sampling sites representing urban, coastal and background sites were selected for sampling. The measured data were employed to investigate the VOCs' characteristics, ozone formation potential, and main sources. During the sampling period, the concentrations of the VOCs ranged between 15.3 and 883 ppbv, with a mean of 139 ppbv. The most severely polluted city was Zibo (833 ppbv), followed by Jinan (33.5 ppbv) and Qingdao (32.8 ppbv). Propane was the most abundant species in all of the sampling sites, with a concentration range of 1.05–9.86 ppbv. Ethene, i-butane, 1-butene, cis-2-butene, n-butane, i-pentane, n-pentane, benzene and toluene were the predominant species in both the urban and coastal sites. Propylene equivalent concentrations (Pro-Equiv) and maximum incremental reactivity (MIR) were employed to assess the reactivity and contribution of each species to the photochemical ozone formation. The results showed that alkenes and aromatics were the most active species performing a key function in the ozone formation, accounting for 43.9–90.7% of the Pro-Equiv and 41.0–93% of the ozone formation potential (OFP). The ratios of ethylbenzene and m/p-xylene were calculated, and the results showed that local emissions were the main sources. Gasoline exhaust/fuel evaporation, industry process/solvent usage, diesel exhaust/petrochemical emission and coal burning were the dominant sources of VOCs in Shandong Province. [ABSTRACT FROM AUTHOR]

Low-cost sensors (LCS) have been increasingly deployed to monitor PM2.5 concentrations. More than 1500 LCS have been installed in Thailand to increase public awareness of air quality. However, performance of these sensors has not been systematically investigated. In this study, PM2.5 LCS were co-located next to a PM2.5 federal equivalent method (FEM) reference instrument at three Thai locations—in the north, center and northeast. We evaluated the performance of a PM2.5 LCS (PMS7003, Plantower) to understand the key factors affecting performance, including emission sources, relative humidity, temperature and PM2.5 concentration. Low PM concentration and high humidity levels had a significant impact on performance. Sensors in a high traffic emission area showed low correlation. The unadjusted PM2.5 LCS performance varied with locations. Errors were mainly observed at low concentrations. They significantly underestimated concentrations in congested urban environments. After calibration, accuracy was improved with multiple regression models. The performance of sensors only at Chiang Mai (CM) during the dry season and Ubon Ratchathani (URT) during the dry and wet seasons were acceptable with coefficient of variation: 5.8 ± 4.7–6.8 ± 5.0%, slope: 0.829–0.945, intercept: 1.12–5.49 µg/m3, R2: 0.880–0.934 and RMSE: 4.3–5.1 µg/m3. In the congested area in Bangkok (BKK), they underestimated concentrations of small particles. [ABSTRACT FROM AUTHOR]

This study aimed to identify the factors causing NH3 emissions in the South Korean Peninsula and West Sea region. To analyze the trends of NH3 and other air pollutants, such as NOx, CO, and NR-PM1, we collected samples from six supersites across the peninsula, a roadside in Seoul, and the West Sea over different sampling periods, ranging from 1 month to 1 year. The highest NH3 concentrations were found at rural areas, ascribed to agricultural activities, particularly NH4NO3 decomposition at high summer temperatures. Areas with low population densities recorded the lowest NH3 concentrations, attributed to the lack of anthropogenic activities. A roadside field experiment confirmed the close link between ambient NH3 and vehicle emissions in urban regions by showing a strong correlation between CO and NOx concentrations and that of NH3. Moreover, we examined oceanic emissions near the eastern coast of South Korea in the West Sea. Long-range transportation studies confirmed that most of the pollutants (NH3, CO, and PM1) were transported by wind from the northeastern region of China. A maritime origin study showed that oceanic emissions and NH4NO3 decomposition in the atmosphere owing to high temperatures were the causing NH3 pollution. These findings provided valuable insights into the emission sources of NH3 in primary air pollutants in South Korea, highlighting the contributions of land-based and oceanic sources. Our study can help inform policymakers and stakeholders for developing effective regional air pollution control strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cultural practices such as the Diwali celebration exacerbates air pollution. • Widespread use of firecrackers releases a large amount of atmospheric pollutants. • Elevated concentrations of PM2.5, black carbon, and PAHs recorded during Diwali. • Short-term release of high concentrations of particulate matter may spread Covid-19. • Airborne PM2.5, black carbon, and PAHs may serve as a carrier of the Covid-19 virus. Emissions of black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) from various anthropogenic activities are often reported, yet cultural practices such as the multi-day Diwali festival and its influences on the emissions of these compounds are often overlooked. Major activities during this festival include burning rows of oil-filled earthen lamps (diyas) and fireworks (bursting of crackers). A comprehensive field investigation was conducted to document the role of Diwali celebrations on the releases of BC and PAHs during the ongoing Covid pandemic. The results show that large-scale releases of BC and PAHs were observed on the first day of Diwali compared to the remaining four days. BC and PM 2.5 mass concentrations throughout the monitoring period ranged from 3.24 to 27.64 µg m−3 and 83.33 to 288.13 µg m−3, respectively. The source apportionment was performed based on the calculated backward trajectories. The results show that the contribution of fossil fuel emission at Adityapur (ADP), Sakchi (SAK), and Gamharia (GMA) was approximately 36.1 %, 34.4 %, and 55.56 %, while biomass burning contribution was approx. 56.9 %, 59.9 %, 41.67 %, respectively. The result showed that fossil fuel emissions were lower compared to biomass combustion during Diwali. Simultaneously, PAHs diagnostic ratio showed that vehicular discharge and coal burning significantly contributed to PAHs at these study sites. [ABSTRACT FROM AUTHOR]

Methane (CH4), the second-largest greenhouse gas in terms of radiative forcing, is on the rise in the Eastern Himalayan region (EHR), as indicated by multiple datasets (CAMS ~ 0.087 Tg Yr−1, EDGAR v4.3.2 ~ 0.11 Tg Yr−1, and RCP8.5 ~ 0.16 Tg Yr−1). We found that the CH4 trend over the EHR is stronger than the global trend due to increased emissions from anthropogenic sources. From 1990 to 2016, CH4 emissions from anthropogenic activities and wetlands increased by 20% and 10% over the EHR. The land-use land-cover (LULC) change reveals a loss of ~ 0.42% of forest and an increase of 0.018% of urban built-up, 0.098% total wetland, and 0.033% of water-bodies coverage from 2001 to 2018. Future projections show a twofold (32.7 Tg CH4 Yr−1) increase in CH4 emissions by 2050 and up to a threefold (~ 48.2 Tg CH4 Yr−1) by the year 2100 from the base year level (14.6 Tg CH4 Yr−1) in 2000. Ambient concentrations of CH4 measured in Dibrugarh and the CAMS reanalysis data set from March 2014 to February 2015 show the maximum in December (~ 4485 and ~ 1981 ppb, respectively), while the minimum concentrations in July (~ 1155 ppb and ~ 976 ppb). The calculated global/EHR RF due to the CH4 for 2006–2100 is higher (0.0093 Wm−2 Yr−1/0.0095 Wm−2 Yr−1) than the historical (0.0038 Wm−2 Yr−1/0.0037 Wm−2 Yr−1) during 1851–2005. The resultant land surface temperature increase induced solely by CH4 is higher over the EHR (~ 0.0062 °C Yr−1) than the global (~ 0.0036 °C Yr−1).Article Highlights: The decadal CH4 emissions and trends on the regional scale are stronger than the global scale. Anthropogenic source contribution to increasing CH4 emissions over the Eastern Himalaya Region is more than natural sources. CH4-induced radiative forcing and resultant temperature trends are stronger over EHR than the global trend. The increasing temperature trends during 1981-2019 decreases snow cover area and snow water equivalent, more substantially regionally than worldwide. The predicted global radiative forcing and temperature trends are higher than historical trends. [ABSTRACT FROM AUTHOR]

Critical source areas (CSAs) are the areas prone to generating runoff and are characterized by a high level of soil pollution. CSAs may accumulate and release soil pollutants emitted by primary emission sources (industrial and municipal enterprises) into the surface water during storm events. The aim of this study was to identify CSAs and their pollution sources and to assess the level of soil pollution in CSAs with polycyclic aromatic hydrocarbons (PAH) and trace metals (TM). CSAs were identified using a geospatial data model (GIS), and primary emission sources were identified using a positive matrix factorization (PMF) model. It was found that the soils of CSAs were characterized by higher pollution levels than soils outside the CSAs. Pollution levels were highly variable among the identified CSAs due to the different capacities of the plants located in those areas. Due to high variability of TM concentrations in preindustrial soils, the pollution level of PAHs and the pollution level of TMs in CSA soils did not correlate with each other. The PAH composition of bottom sediments was different from that of soils, whereas the TM compositions of the soils and bottom sediments were similar. It was proved that the main sources of PAHs and TMs in CSA soils were traffic emissions and central heating boilers. [ABSTRACT FROM AUTHOR]

Black carbon is commonly considered as a short-lived climate forcer, the relatively short lifetime of which can cause climatic effects at the regional level. The lack of mandatory reporting on black carbon emissions and a unified methodology for black carbon inventory leads to high uncertainty of existing estimates of black carbon emissions in Russia. The estimates of emissions from priority source categories are provided in the present paper. According to the estimates, averaged black carbon emissions for the period of 2010–2020 from intentional fuel combustion at anthropogenic sources in Russia, including fuel combustion at energy and industrial enterprises, small and domestic combustion, transport, hydrocarbon flaring, are t per year, and those from open combustion sources on non-forest lands are t per year. Emissions from forest fires have the greatest interannual variability and vary from to t of black carbon per year. [ABSTRACT FROM AUTHOR]

Carbonyl concentrations in indoor-outdoor air were measured at three urban sites in the Metropolitan Zone of Mexico Valley (MZMV) during the first period of confinements due to COVID-19; the exposure for people living in indoor environments was also assessed. Indoor and outdoor samples were simultaneously collected sequentially with Sep-Pack DNPH-Silica cartridges. Formaldehyde, acetaldehyde, acetone, propionaldehyde, butyraldehyde and acrolein were quantified according to the US-EPA TO-11A method. Acrolein and acetone were the most abundant carbonyls in indoor air, with average concentrations of 55.5 µg m−3 and 46.4 µg m−3, respectively, followed by formaldehyde (29.1 µg m−3), acetaldehyde (21.4 µg m−3) and butyraldehyde (7.31 µg m−3). Propionaldehyde was not detected. Acetone was the dominant carbonyl in outdoor samples with an average concentration of 8.4 µg m−3, followed by formaldehyde (2.8 µg m−3) and acetaldehyde (0.7 µg m−3). Butyraldehyde and acrolein were not detected in outdoor air. Indoor/outdoor (I/O) ratios showed that indoor sources prevail for most aldehydes. Statistical analysis of simple correlations showed that the measured carbonyls were influenced by the presence of indoor sources. The average cancer risk coefficients (LTCR) for formaldehyde and acetaldehyde and the non-cancer risk coefficients (HQ) for acrolein and formaldehyde were higher than the recommended limits, which should be a cause for public concern. [ABSTRACT FROM AUTHOR]

Air pollution is a global problem. In Europe, ambient air quality remains poor in many areas, particularly in urban ones. Air pollutants have a significantly adverse effect on human health and ecosystems. They are the main cause of many serious illnesses and thus contribute to increased mortality. This paper analyzes the air pollutant emissions in the last four years (2018-2021) in the Upper Silesian Region, which has one of the worst air qualities in Poland and in Europe in general, and the emissions in the Lublin Region in eastern Poland, which is considered as a clean region. In each of the above-mentioned regions, the areas with the highest air pollutant emissions were specified i.e. the Upper Silesian Agglomeration and the Lublin Agglomeration. The emission data for the following pollutants: particulate matter (PM10, PM2.5), benzo(a)pyrene (BaP), sulfur oxides (SOx) and nitrogen oxides (NOx) have been compared. The obtained results were also compared with the estimated average emissions in Poland. It was indicated that in both agglomerations the exposure to air pollutants was on similar levels, which were several times higher than in the remaining parts of the considered regions and the average values for Poland in general. In the Silesian Agglomeration, the exposure to PM10 was over 5 times higher than the average national exposure. The exposure to PM2.5 was almost 6 times higher, the exposure to BaP was about 5 times higher, while the exposure to SOx and NOx was 16 and 10 times higher than the national average, respectively. This is reflected in the increased number of premature deaths and the number of years of life lost due to the exposure to air pollution. Therefore, the actions aimed at limiting air pollutant emissions are urgent in the above-indicated areas. [ABSTRACT FROM AUTHOR]

Fluorine-containing greenhouse gases (F-GHGs) and ozone layer substances (ODS) are being monitored without a global commercial monitoring system. In this study, the existing commercial volatile organic compounds (VOCs) moni7 toring system is modified in hardware and optimized in methodology to provide high-precision monitoring of 33 types of ODS and F-GHGs in the atmosphere. Moreover, the system eliminates the issue of excessive costs and lengthy development cycles associated with special monitoring equipment. Pre-concentration can enhance the enrichment of low boiling point and low concentration components by increasing the injection volume, improving water removal efficiency, and improving adsorption capacity. It is significant to be noted that InertCap 624MS is a one-dimensional column, while GASPRO is a two-dimensional column. It is possible to separate 33 target compounds completely and stably by Heart-cut and TwinLine using dual-column separation and single-detector detection mode. Experimental findings indicate that this monitoring tech14 nology has an accuracy of 0.22~3.70%. To accurately observe the changing trend of atmospheric concentration and trace the emission sources over time, a background gas with a known concentration has been used as a standard gas, and background atmospheric samples with unknown concentrations have been quantitatively tested using a single-point external standard method. [ABSTRACT FROM AUTHOR]

Antimony (Sb) is a toxic heavy metal, and PM2.5‐bound Sb (SbPM2.5) in the air impacts human health via inhalation pathways. In this study, we analyzed multiyear measurements of ambient SbPM2.5 in Beijing to characterize its spatiotemporal distributions, identify main sources, and predict future trends. The results show that ambient SbPM2.5 has been decreasing with fluctuations from 2005 to 2012 and decreased rapidly after 2013, which was likely a result of the government's enhanced air pollution control plan that targeted main sources of industrial Sb. Across the city, average SbPM2.5 concentrations were relatively higher at nonemission locomotive traffic sampling sites and in densely populated areas (9.45–19.45 ng/m3) and lower in background areas (0.6–0.9 ng/m3). Regional‐scale emissions and local human activities both affected the spatial distributions of SbPM2.5. Notably, SbPM2.5 concentration increased by 58.3% from 2006 to 2013 in one suburban background area, indicating the changing emission distributions and intensities over the study period. A neural network model was developed and tested to predict future SbPM2.5 levels, results from which showed that with simulated massive reductions in coal supplies and a rapid boom in the waste incineration industry, SbPM2.5 concentration would vary in a smaller range (from 4.08 to 4.38 ng/m3) over the next decade as compared to the observed range during 2011–2018 (19.0–5.44 ng/m3). The impact of the continued expansion of the waste incineration industry on SbPM2.5 pollution needs to be considered in future emission control policies. Plain Language Summary: Long‐term exposure to antimony (Sb) and related compounds, such as through respiration of Sb containing atmospheric particles, can result in negative health impacts to human body. Knowledge of concentration levels and future trends of Sb in PM2.5 (SbPM2.5) especially in populated megacities is needed in assessing the potential risks of atmospheric Sb to human health. In this study, SbPM2.5 concentration data in Beijing over the past 15 years were aggregated to assess its past trends and predict its future levels. Benefited from the implementation of stringent air pollution control programs in this region, SbPM2.5 concentrations have been decreasing, but with fluctuations from 2005 to 2012, and at a faster rate after 2013. However, the decreasing trend will likely slowdown in the next decade due to the rapid development of the waste‐to‐energy conversion industry, which is an important source of atmospheric SbPM2.5 emission. Thus, future SbPM2.5 levels may still pose a threat to human health, especially to infants and children. Key Points: Characteristics of PM2.5‐bound antimony in Beijing have been summarized over 15 years and they predict future trendsThe aggressive reduction of antimony (Sb) pollution levels is mainly influenced by a comprehensive air pollution control program by the governmentThe Sb emissions from waste incineration are likely to replace coal combustion as the primary source in PM2.5 now and in the next decade [ABSTRACT FROM AUTHOR]