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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]

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]

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]

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]

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]

[Display omitted] • Total greenhouse gas emissions from China's national parks amount to about 6.79 million tonnes; • Greenhouse gas emissions mainly come from residential life and animal husbandry; • Greenhouse gas emissions exhibit spatial clustering; • Emission levels in identified hotspots exceed the national average. National parks serve as crucial carbon reservoirs and sinks, yet their capacity to mitigate carbon emissions faces significant challenges, highlighting the urgent need for robust greenhouse gas (GHG) control and reduction strategies. Existing studies have often lacked comprehensive, spatially detailed GHG emission inventories for national parks at a national scale, hindering targeted carbon management efforts. This study addresses this gap by conducting a uniform national-scale assessment of GHG emissions across China's five national parks in 2020, with a focus on spatial distribution and emission source characterization. Our findings reveal that these parks collectively emitted 6.79 million tonnes of GHGs, primarily carbon dioxide, with residential and animal husbandry activities being the dominant sources. Emission patterns displayed strong spatial coherence, with high-emission and low-emission areas clustering distinctly. Although most national parks exhibited per-unit area emissions below the national average, hotspots in the Three-River-Source National Park exceeded the national average by 1.78 times. This study underscores the critical role of emission mapping in formulating effective GHG mitigation strategies to bolster the carbon–neutral potential of national parks. [ABSTRACT FROM AUTHOR]

The widespread occurrence of liquid crystal monomers (LCMs) in the environment has raised concerns about their persistence, bioaccumulation, and toxicity (PBT). Here we review the lifecycle of environmental LCMs, focusing on their occurrences, emission sources, human exposure routes, and toxicity. Industrial emissions from Liquid Crystal Display (LCD) manufacturing and e-waste recycling are the primary point sources of LCMs. In addition, emissions from LCD products, air conditioning units, wastewater treatment plants, and landfills contribute to environmental occurrence of LCMs as secondary sources. Dietary routes were identified as the primary exposure pathways to humans. E-waste dismantling workers and infants/children are vulnerable populations to LCMs exposure. Exposure to LCMs has been shown to potentially induce oxidative stress, metabolic disorders, and endocrine disruption. Accumulation of LCMs in the brain and liver tissues of exposed animals highlights the need for toxicokinetic studies. [Display omitted] • Production and e-waste recycling industries are primary sources of LCMs emissions. • Wastewater treatment plants and landfills are sinks and secondary sources of LCMs. • Diet is a major route of LCMs exposure to the general population. • E-waste dismantling workers and infants/children are vulnerable to LCMs exposure. • LCMs can bioaccumulate in organisms and induce various toxicological effects. [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]

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]

Urbanization and industrialization are important transformations shaping the current statement of the society, enhancing significantly the combustion emissions which are threatening the global climate system, air quality, and human health. These emissions contain polycyclic aromatic hydrocarbons (PAHs) which are well known for their high toxicity. The present study is the first assessing the seasonal variation of 17 PAHs in size segregated fractions of atmospheric aerosol particles from a Romanian metropolitan area. In addition to sources apportionment and health risks, the potential role of PAHs on the atmospheric chemistry in the area was also addressed. Higher PAHs concentrations were determined in winter season, the highest values being quantified for benzo[b]fluoranthene, benzo[a]pyrene, and indeno[1,2,3-cd]pyrene. Each analyzed PAH exhibited a dominant peak in the accumulation mode (0.1–1.0 μm), with maxima at 381 nm. Gasoline combustion was identified as a significant contributor to the PAHs levels in the atmospheric aerosols from the area. Biomass-burning contributions were highlighted during the winter and autumn seasons. The positive matrix factorization (PMF) model apportioned four PAHs sources, as follows: vehicular (31%), mixed combustion (33%), biomass and wood burning (19%), and coal and natural gas combustion (18%) sources. Concentration-weighted trajectory (CWT) analysis method revealed clear contributions to PAHs abundances from local and regional air masses. Alveolar region of adults seems to have the highest susceptibility for PAHs deposition. Values exceeding acceptable limits for carcinogenic risk throughout the year are associated with benzo[a]pyrene, benzo[b]fluoranthene, indeno[1,2,3-cd]pyrene, benzo[a]anthracene etc. The present study can be considered as a reference in the region in order measures of mitigation and control for PAHs emission sources to be introduced. [Display omitted] • The highest PAHs concentrations were determined in the winter for BbF, BaP, and InP. • PAHs size distributions presented a dominant fine mode with maxima at 381 nm. • Four sources of quantified PAHs were apportioned by PMF analysis. • The highest deposition dose of PAHs was located in the alveolar region. • Cumulative CR of PAHs by inhalation exceeded the acceptable threshold in cold seasons. [ABSTRACT FROM AUTHOR]

A high-quality methane emission estimation in China's oil and gas sector is the basis of an effective mitigation strategy. Currently, the published emission data and studies of China's oil and gas sector only provide estimations of total emissions, which is not enough for good analysis of the trend and impact factors for the instruction of emission mitigation activities. The main problem is that published data for oil and gas infrastructure in China is incomplete, which makes it difficult to apply the conventional greenhouse gas inventory compiling method and the uncertainty estimation strategy. Therefore, this paper aims to develop a method to estimate infrastructure data using all available data, including partial data for the infrastructure, national production and consumption of oil and gas, and production and production capacity data of oil and gas enterprises, and then uses a Monte Carlo-based method to generate a source-based inventory and uncertainty analysis of methane emission for China's oil and gas industry from 1995 to 2018. We found that methane emission increased from 208.3 kt in 1995 to 1428.8 kt in 2018. Methane emission in 2018 has an uncertainty of about ±3%. Compared to former studies, our research found that the production stage of natural gas is the main contributor, which is further driven by the growth of natural gas production. The mitigation potential introduced by technology development on methane emission remains large. [ABSTRACT FROM AUTHOR]

South Africa is the dominant continental source region of CO2 fossil fuel emissions. This is a result of the strong dependence of its economy on fossil fuels. However, the observations of atmospheric CO2 in South Africa are inadequate. The country has the Global Atmospheric Watch (GAW) Cape Point station as the only site with long-term ambient CO2 monitoring record. In this study, satellite data retrieved from the Tropospheric Emission Spectrometer (TES) instrument on board the Aura satellite from Dec 2004 to Dec 2009 is used for the first time to quantify the spatial distribution of CO2 over South Africa, as well as to determine its annual variability at selected sites. The study found that the surface CO2 foot print in South Africa resembles the industrial CO2 emission sources spatial distribution, particularly during the summer and autumn. In winter and spring seasons the surface CO2 foot prints are spatially expanded as a result of contributions of emissions from biomass and domestic fossil fuel combustion. The surface levels of CO2 at the study areas have been increasing during the period of the analysis. [ABSTRACT FROM AUTHOR]

Noncombustible air fresheners are indoor air emission sources of concern. The associated health risks should be better understood. Based on 15 products (4 sprays, 6 passive diffusers, and 5 active diffusers), the health risk assessment (HRA) approach was applied to a national use survey in France and to concentrations measured in an experimental house. The targeted substances included volatile organic compounds (VOCs), carbonyls, and fine particles (PM2.5). Mean‐use and reasonable worst‐case generic scenarios were designed. No situation of concern occurred regarding chronic exposure associated with the mean use. Under the reasonable worst‐case scenarios, the chronic risk could exceed selected health reference standards, mainly for acrolein (average inhaled concentration (AIC) up to 3.5 µg/m3), benzene (AIC up to 4 µg/m3), and limonene (AIC up to 8 mg/m3). The acute exposure, defined as a 1‐h exposure, could exceed selected health standards, primarily for acrolein (up to 23 µg/m3) and formaldehyde (up to approximately 370 µg/m3). Furthermore, the 1‐h average PM2.5 concentration, including ultrafine particles, could exceed 100 µg/m3, typically for sprays. These results suggest that the highest exposures should be reduced and, as such, that the emissions of the highest‐emissivity products should be lowered. [ABSTRACT FROM AUTHOR]

Black carbon (BC) along with PM2.5 (fine particular matters) plays an important role in the assessment health effect of human beings. Winter season campaign measurements carried out for BC concentrations by using 7 different wavelengths such as 370, 470, 520, 590, 660, 880, and 950 nm, handy aethalometer (AE-33, Magee Scientific, USA), at two different locations i.e., National Institute of Technology, Jamshedpur (NIT J) and Sakchi, Jamshedpur (SAK J), in eastern India. During the study period, the mass concentration of BC varies from 4.19 µgm−3 to 15.36 µgm−3, with an average mean of 8.88 ± 2.40 µgm−3 in NIT J and SAK J, the mass concentration of BC varies from 6.3 µgm−3 to 13.48 µgm−3, with an average mean of 10.29 ± 1.58 µgm−3. However, the concentration of PM2.5 varies from 102.98 µgm−3to 198.21 µgm−3, with an average mean of 155.82 ± 29.98 µgm−3 in NIT J and SAK J, the concentration of PM2.5 varies from 110.83 µgm−3 to 207.65 µgm−3, with an average mean of 169.14 ± 22.40 µgm−3. It was reported that SAK J has a higher BC concentration compared to NIT J. This was due to heavy traffic load and dense population in SAK J. Backward Trajectories were seen that the airborne particulate matter came from differerajeshnt directions. According to the diagnostic ratio analysis of BC, it was observed that most of the BC mass concentrations come from fossil-fuel (69.70%) followed by wood-burning (30.30%) in a particular place. The overall health risk assessment of BC concentration observed during the study period was 26.70, 13.95, 24.95 and 51.32 at NIT J as well as 32.07, 16.72, 29.95 and 61.87 at SAK J, the passive cigarettes comparable concerning the risk of CVM, LC, LBW, and PLEDSC, respectively. [ABSTRACT FROM AUTHOR]

The escalating levels of aerosols have emerged as a significant concern for climate extremes in the Southeast Asian regions, particularly accentuated during El Nino Years. In this study, we utilized a combination of atmospheric measurements and modeling to investigate the seasonal and geographical distribution of PM 2.5 mass concentrations and its primary contributors across Thailand during La Nina (2017) and El Nino (2019) years. Our findings revealed the highest daily mean surface PM 2.5 mass concentration during the summer season across most regions, followed by winter, and the lowest levels during the rainy season. Notably, a significant shift in daily mean PM 2.5 mass was observed from 2017 to 2019 across all seasons, with a pronounced increase of 70.9% over northern Thailand during the summer, attributed to heightened biomass burning (BB) contributions. In terms of source attribution for PM 2.5 mass, the primary contributors in 2017 were BB at 34.3%, followed by anthropogenic emissions (AE) at 32.4%, and natural emissions (NE) at 30.1%. However, in 2019, the BB contribution surged to 47.4% nationwide. During El Nino years, BB played a significant role in shaping concentrations during summer and winter, while NE dominated the rainy season. An important implication of our findings is the significant potential for reducing daily and annual mean PM 2.5 mass levels throughout Thailand by effectively reducing BB emissions. [Display omitted] • Aerosol increases in Southeast Asia, notably during El Niño Years. • Summer season shows the highest PM 2.5 levels in various regions, followed by winter. • PM 2.5 levels surged by 70.9% in northern Thailand during the summer (2017–2019). • In 2017, main PM 2.5 sources: biomass burning (34.3%) and human activities (32.4%). • Reducing biomass burning can significantly lower PM 2.5 levels across Thailand. [ABSTRACT FROM AUTHOR]

• The heavy haze episodes formation in autumn was related with the increase of secondary organic aerosols and NH 4. • The contribution of POC and NH 4 + were significant during the evolution of pollution periods in wintertime. • The local and short-distance air mass transportation have significant impact. To study the pollution features and underlying mechanism of PM 2.5 in Luoyang, a typical developing urban site in the central plain of China, 303 PM 2.5 samples were collected from April 16 to December 29, 2015 to analyze the elements, water soluble inorganic ions, organic carbon and elemental carbon. The annual mean concentration of PM 2.5 was 142.3 μg/m3, and 75% of the daily PM 2.5 concentrations exceeded the 75 μg/m3. The secondary inorganic ions, organic matter and mineral dust were the most abundant species, accounting for 39.6%, 19.2% and 9.3% of the total mass concentration, respectively. But the major chemical components showed clear seasonal dependence. SO 4 2− was most abundant specie in spring and summer, which related to intensive photochemical reaction under high O 3 concentration. In contrast, the secondary organic carbon and ammonium while primary organic carbon and ammonium significantly contributed to haze formation in autumn and winter, respectively. This indicated that the collaboration effect of secondary inorganic aerosols and carbonaceous matters result in heavy haze in autumn and winter. Six main sources were identified by positive matrix factorization model: industrial emission, combustion sources, traffic emission, mineral dust, oil combustion and secondary sulfate, with the annual contribution of 24%, 20%, 24%, 4%, 5% and 23%, respectively. The potential source contribution function analysis pointed that the contribution of the local and short-range regional transportation had significant impact. This result highlighted that local primary carbonaceous and precursor of secondary carbonaceous mitigation would be key to reduce PM 2.5 and O 3 during heavy haze episodes in winter and autumn. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbonaceous aerosols have a significant impact on global climate and human health. Controlling carbonaceous aerosol pollution is a considerable challenge due to the complex sources and the unintelligible secondary formation processes. The 14th National Games of the People's Republic of China were successfully held in Xi'an in 2021, which imposed strict emission controls on air pollution sources for the whole society, providing an experimental opportunity to study the effects of air pollution control measures on carbonaceous aerosols. Based on a combination of atmospheric observation studies and the Weather Research and Forecasting model coupled with online chemistry (WRF-Chem) simulations, we explore the impact of air pollution control on carbonaceous aerosol pollution characteristics, sources, and formation mechanisms. After removing the meteorological conditions, the anthropogenic abatement measures significantly improve regional ambient air quality with the air quality index reduced by 25 % and carbonaceous aerosol concentrations reduced by 30 %. These improvements are mainly attributed to the effective control of primary sources, resulting in the concentrations of primary organic carbon (POC) decreased by 33 %, while only a 22 % decrease in secondary organic carbon (SOC) concentrations. According to the source analysis, carbonaceous aerosols in the control period are mainly from secondary formation and biomass burning. The emission reductions weaken the titration effect of air pollutants on atmospheric oxidants and intensify the near-ground columnar UV radiation, thus promoting the generation of atmospheric oxidants. Consequently, air pollution control changes the main pathway of SOC formation from aqueous-phase reactions to atmospheric oxidation reactions, resulting in a poor control effect on SOC. The aging of organic carbon from the biomass burning source after long-distance transport also contributes significantly to the SOC concentrations. Our results confirm the effectiveness in air pollution controls on carbonaceous aerosol pollution and also highlight that the control of SOC precursors needs to be further optimized to reduce atmospheric oxidation. [Display omitted] • Control makes the decrease in POC concentration more significant than SOC. • Air pollution controls changes the SOC formation main pathway, leading to ineffective SOC control. • The SOC formation changes from aqueous-phase reactions to atmospheric oxidation reactions during the control period. [ABSTRACT FROM AUTHOR]

Siloxanes are organo-silicon compounds containing Si-O-Si linkages and methyl branches. Depending on the structure, siloxanes can be divided into cyclic and linear compounds. Methyl siloxanes with small and medium molecular weights (molecular weights less than 500 g mol−1), are volatile under normal conditions, and hence are referred to as volatile methyl siloxanes (VMSs). VMSs are additive ingredients in many products such as plastics, rubber, personal care products, and household items. This review provides information on the distribution of VMSs in consumer products, indoor air and dust, and their implications for human exposure. VMSs have been used in personal care products and household items at concentrations on the order of hundreds to thousands of micrograms per gram which are the main sources of contamination in the indoor environments. VMSs have been found widely in indoor air and dust. A significant correlation existed between VMS concentrations in indoor air and dust. Among typical VMSs, dodecamethylcylcopentasiloxane (D5) is the major compound found in indoor environments. The human exposure doses to VMSs through dermal absorption, dust ingestion, and inhalation were compiled; Inhalation is a dominant pathway of exposure to VMSs, especially in indoor environments of occupational settings like hair salons. The human exposure doses were higher in children than in adults. Unlabelled Image • Using PCPs containing VMSs is the main released source into the indoor environments. • A significant correlation existed between VMS concentrations in indoor air and dust. • Specific occupational settings contain elevated levels of VMSs in air and dust. • Inhalation is the major exposure pathway to VMSs in indoor environments. [ABSTRACT FROM AUTHOR]

Abstract Mercury (Hg) emissions from stone coal that formed from marine lower organisms in the late Proterozoic and early Paleozoic have not been paid much attention in China. In this research, Hg concentrations in different fueled coals (stone coal, humic coal) and charcoal that derived from wood and paired slags, atmospheric Hg emissions and atmospheric Hg levels were studied in Shaanxi province, China. The average Hg concentration in stone coal produced in Da-Ba-Shan mountain areas in Southern Shaanxi was 539.4 μg·kg−1, about 15 and 38 times higher than that of humic coal (36.0 μg·kg−1) and charcoal (14.2 μg·kg−1), respectively. Atmospheric Hg emission usually lasted for 2–3 h after fueling stone coal, with the majority of Hg emitted during the first 1 h. 95.5–99.4% of Hg in the fuel would be lost into the atmosphere for three types of fuels. Mercury emission factor (MEF) of stone coal was 40–120 times higher than those of humic coal and charcoal based on heat value. Average atmospheric Hg concentration at 0.5 m above the stove could reach 1600–2000 ng·m−3 if burning stone coal, which exceeded the standards for residential ambient air (200–300 ng·m−3) by 5–10 times and also was nearly two orders of magnitude higher than that of burning humic coal (20–60 ng·m−3). Health risk would be a concern for local residents who depend on stone coal for cooking and heating but without any control measures of flue gas. In Shaanxi province alone, Hg emission through domestic combustion of stone coal was estimated to be 1.34 Mg in 2011. Higher mercury emission amounts are possible in southern China where stone coal has been intensively used. Total mercury emissions from this source category need to be further investigated on the national scale. Highlights • Mercury concentration is 15–38 times higher in stone coal than other domestic humic coal and charcoal. • Mercury emission factor base on heat value is 40–120 times higher from stone coal than other fueled coal and charcoal. • Mercury is mainly released during the first 1 h of stone coal burning and up to 22 μg/m3 of Hg0 is found in indoor air. • Annually mercury emission from stone coal burning in Shaanxi province was estimated to be 1.34 Mg in 2011. [ABSTRACT FROM AUTHOR]

Abstract Polycyclic aromatic hydrocarbons (PAHs) were analyzed in road and aerial dust to assess their concentration, composition profile, distribution, emission sources, and potential human health risks. Sixteen priority PAHs and Benzo [ e ]pyrene (BeP) were analyzed in 13 aerial dust samples from Jalalabad, and 78 road dust samples from Kabul and Jalalabad cities, Afghanistan. The mean concentration of ∑17PAHs in road dust from Kabul and Jalalabad were 427 μg kg−1 and 288 μg kg−1, respectively whereas ∑17PAHs in aerial dust from Jalalabad averaged 200 μg kg−1. Fluoranthene (Flu), Chrysene (Chr), Benzo [ b ]fluoranthene (BbF), Benzo [ k ]fluoranthene (BkF) and BeP were major individual PAH species. The composition patterns of the PAHs were dominated by 5-6-ring PAHs (51% in road dust from Kabul; 44% in road dust from Jalalabad; and 44% in aerial dust) followed by 4-ring and 2-3-ring PAHs. Source apportionment of the road dust PAHs by the molecular diagnostic ratios (MDR) and principal component analysis (PCA), indicated signatures of PAHs sources (including vehicular exhaust, coal/wood combustion and oil spill). The Benzo [ a ]pyrene (BaP) toxicity equivalent values (BaP eq 17PAHs) for road dust were 75 μg kg−1 (Kabul) and 36 μg kg−1 (Jalalabad); and 35 μg kg−1 for aerial dust (Jalalabad). BaP and Dibenz [ a,h ]anthracene (DahA) together contributed > 50% of the BaP eq associated cancer risk. All incremental lifetime cancer risk (ILCR) due to human exposure to road and aerial dust PAHs were in the order of 10−7, which is one-fold lower than the threshold (10−6). The noncancerous risk (Hazard Index < 1) on exposure to dust was also negligible for both subpopulations. Highlights • Aerial and road dust samples were collected from Kabul and Jalalabad cities. • Total 17PAHs concentrations were higher in road dust than aerial dusts. • High molecular PAHs were higher in road and aerial dusts than low molecular PAHs. • BaP and DahA together contributed >50% of the BaP eq associated cancer risk. • The estimated ILCR from exposure to dust was negligible for children and adults. [ABSTRACT FROM AUTHOR]

Abstract I am often reminded of the famous saying of Goethe: "Vedi Napoli e poi muori! - See Naples and die!". Sadly, Naples is now confronted with a number of serious, ongoing problems with a need to alleviate pressure on the worsening environment. One serious problem facing the environment is the presence of the potentially hazardous persistent organic pollutants (POPs), although few systematic studies at regional scale have been conducted. In this study, samples of soil, air, and bulk deposition were collected in Naples metropolitan area (NMA) to characterize the status of POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The results obtained showed that most of these compounds are pervasive in all the studied environmental matrices, especially in some hotspot areas, such as the Bagnoli Brownfield Site and the infamous "Triangle of the Death", where unwanted ecological risk conditions for PAHs and Endosulfan were determined, respectively. The interactional complexity between urban and the surrounding rural areas was also confirmed, as is the role that urban areas play in the migration and transformation process of POPs. High urban-rural gradients for atmospheric PAHs and PCBs were observed in the NMA, and the urban areas were identified as the emission source of these contaminants. Similarly, the OCP residues, historically originated from the nearby agricultural regions, experience long-term soil re-emission and continuously influence the connected urban environment via atmospheric transport processes. Graphical abstract Unlabelled Image Highlights • Presents systemic data on POP concentrations in a multimedia environment. • Urban areas were identified as the emission source of PAHs and PCBs. • Validates long-term soil re-emission of the OCP residues. • Identifies ongoing effects of "hotspots" on surrounding areas via atmospheric transport. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) sources differ in urban environments and may show spatiotemporal distinct patterns for varying particle aerodynamic diameters (D P). We here assess such patterns using high-resolution PM ≤10 μm data recorded with a cargo bike along a 14 km route through urban, suburban, and rural areas in Mainz (Germany). The measurements conducted twice a day between May and August 2021 reveal decreasing particle number concentration (PNC) with increasing D P including ∼6000 times higher particle numbers at D P 0.22–0.25 μm compared to D P 4–5 μm. Total mass concentration is bi-modally distributed and dominated by particles <0.3 μm and from 3 to 5 μm representing 36 and 22% of the entire air load, respectively. PM concentrations in Mainz are significantly higher in the morning than in the afternoon, and PM 1 and PM 10 are 13 and 31% higher in urban compared to surrounding suburban and rural areas. The high-resolution measurements also revealed 30% higher PM concentrations at D P 3–5 μm in the urban compared to the rural sectors, which is indicative for road dust, brake and tyre abrasion as the main source. D P distribution in rural hotspots is generally shifted toward larger particles >3 μm, most likely related to natural dust from agricultural fields. These findings show that high-resolution PM profiles can skillfully be recorded using bikes as mobile platform to identify spatial pollution patterns and attribute D P spectra to particular emission sources. • PM 1 and PM 10 are significantly higher in the morning than in the afternoon. • PM 1 and PM 10 are 13 and 31% higher in urban compared to surrounding rural areas. • Particle numbers decrease significantly with increasing diameter along the track. • Total mass is bi-modally distributed and dominated by particles <0.3 μm and 3–5 μm. • Mass diameter distributions indicate traffic as main emission at urban hotspots. [ABSTRACT FROM AUTHOR]

Abstract To identify the critical factors impacting the number concentration of particles with the aerodynamic diameters less than 2.5 μm (PNC 2.5), the continuous measurement of PNC 2.5 , chemical components in PM 2.5 , gaseous pollutants and meteorological conditions were conducted at an urban site in Tianjin in June 2015. Results indicated that the average PNC 2.5 was 2839 ± 2430 d N /dlog D p 1/cm3 during the campaign. Compared to other meteorological parameters, the relative humidity (RH) had the strongest relationship with PNC 2.5 , with a Pearson's correlation coefficient of 0.53, and RH larger than 30% influenced strongly PNC 2.5. The important influence of secondary reactions on PNC 2.5 was inferred due to higher correlation coefficients between PNC 2.5 and SO 4 2 −, NO 3 −, NH 4 + (r = 0.78–0.89; p < 0.01) and between PNC 2.5 and ratios that represent the conversion of nitrogen and sulfur oxides to particulate matter (r = 0.42–0.49; p < 0.01). Under specific RH conditions, there were even stronger correlations between PNC 2.5 and NO 3 −, SO 4 2 −, NH 4 +, while those between PNC 2.5 and EC, OC were relatively weak, especially when RH exceeded 50%. Principal component analysis (PCA) and Pearson's correlation analysis indicated that secondary sources, vehicle emission and coal combustion might be major contributors to PNC 2.5. Backward trajectory and potential source contribution function (PSCF) analysis suggested that the transport of air masses originated from these regions around Tianjin (Liaoning, Hebei, Shandong and Jiangsu) influenced critically PNC 2.5. The north of Jiangsu, the west of Shandong, and the east of Hebei were distinguished as major potential source-areas of PNC 2.5 by PSCF model. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract To investigate chemical characteristics and sources of humic-like substances (HULIS) in the background region of Southwest China, daily PM 2.5 samples were collected on Weizhou Island from 14 March 2015 to 14 April 2015. Water soluble inorganic ions, organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), HULIS, oxalate, levoglucosan and mannosan were analyzed. Average concentration of PM 2.5 was 32.5 ± 12.6 μg/m3 with SO 4 2−, OC and NH 4 + as the three most abundant components. Average concentration of HULIS was 5.00 ± 2.21 μg/m3 with daily values ranged from 1.46 to 10.36μg/m3. The carbon content of HULIS (HULIS-C) contributed 35.6% ± 7.2% of OC and 76.8% ± 12.9% of WSOC, indicating HULIS-C as one of the most important species in OC and WSOC in this region. The concentration of HULIS correlated well with those of non-sea salt (nss) K+, levoglucosan, oxalate, OC, EC, WSOC, SOC and WSOC/OC, suggesting dominant source factors from both biomass burning and secondary aerosol formation. Contributions from crust and sea salt source factors to HULIS were minimal as indicated by its poor correlation with nss-Ca2+, Mg2+ and Na+. Research flight observations showed increasing biomass-burning indicators with increasing altitude, likely due to aerosols produced from biomass burning in Southeast Asia, which were then uplifted by deep convection to the middle troposphere and transported to this area. This hypothesis was supported by negative correlations between HULIS and sea level pressure when high-altitude air masses were transported from the Southeast Asian. Air mass backward trajectory analysis suggested Southeast Asian as the dominant source region for HULIS on Weizhou Island. Graphical abstract Image 1 Highlights • HULIS was firstly investigated in Weizhou Island. • The concentration of HULIS was significantly high in Weizhou Island as a remote site. • Biomass burning and secondary formation are two sources of HULIS in Weizhou Island. • The highest frequency of air mass reaching this area was from southwest. • Interregional transport had great impacts on HULIS and PM 2.5 chemical species. [ABSTRACT FROM AUTHOR]

Abstract Volatile organic compounds (VOCs) are a kind of important precursors for ozone photochemical formation. In this study, VOCs were measured from November 5th, 2013 to January 6th, 2014 at the Second Jinshan Industrial Area, Shanghai, China. The results showed that the measured VOCs were dominated by alkanes (41.8%), followed by aromatics (20.1%), alkenes (17.9%), and halo-hydrocarbons (12.5%). The daily trend of the VOC concentration showed a bimodal feature due to the rush-hour traffic in the morning and at nightfall. Based on the VOC concentration, a receptor model of Positive Matrix Factorization (PMF) coupled with the information related to VOC sources was applied to identify the major VOC emissions. The result showed five major VOC sources: solvent use and industrial processes were responsible for about 30% of the ambient VOCs, followed by rubber chemical industrial emissions (23%), refinery and petrochemical industrial emissions (21%), fuel evaporations (13%) and vehicular emissions (13%). The contribution of generalized industrial emissions was about 74% and significantly higher than that made by vehicle exhaust. Using a propylene-equivalent method, alkenes displayed the highest concentration, followed by aromatics and alkanes. Based on a maximum incremental reactivity (MIR) method, the average hourly ozone formation potential (OFP) of VOCs is 220.49 ppbv. The most significant source for ozone chemical formation was identified to be rubber chemical industrial emissions, following one by vehicular emission. The data shown herein may provide useful information to develop effective VOC pollution control strategies in industrialized area. Graphical abstract Source profiles (percentage of species total) resolved from Positive Matrix Factorization (PMF). Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Continuous observation of isoprene, α-pinene and β-pinene was carried out in a typical urban area of Beijing from March 2014 to February 2015, using an AirmoVOC online analyzer. Based on the analysis of the ambient level and variation characteristics of isoprene, α-pinene and β-pinene, the chemical reactivity was studied, and their sources were identified. Results showed that the concentrations of isoprene, α-pinene and β-pinene in the urban area of Beijing were lower than those in richly vegetated areas; the concentrations of isoprene were at a moderate level compared with those of previous studies of Beijing. Concentrations of isoprene, α-pinene and β-pinene showed different seasonal, monthly, daily and diurnal variations, and all of the three species showed higher level at night than those in the daytime as a whole, the variations of isoprene, α-pinene and β-pinene mainly influenced by emission of sources, photochemical reaction, and meteorological parameters. Isoprene was the largest contributor to the total OFP values than α-pinene and β-pinene. α-Pinene was the largest contributor to the total SOAFP values than isoprene and β-pinene in autumn, while isoprene was the largest one in other seasons. Isoprene, α-pinene and β-pinene were derived mainly from biological sources; and α-pinene level were also affected by industrial sources. To reduce the concentrations of isoprene, α-pinene and β-pinene, it is necessary to scientifically select urban green plant species, and more strict control measures should be taken to reduce the emission of α-pinene from industrial sources, such as artificial flavors and resins synthesis processes. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Brown carbon (BrC), a carbonaceous aerosol which absorbs solar radiation over a broad range of wavelengths, is beginning to be seen as an important contributor to global warming. BrC absorbs both inorganic and organic pollutants, leading to serious effects on human health. We review the fundamental features of BrC, including its sources, chemical composition, optical properties and radiative forcing effects. We detail the importance of including photochemical processes related to BrC in the GEOS-Chem transport model for the estimation of aerosol radiative forcing. Calculation methods for BrC emission factors are examined, including the problems and limitations of current measurement methods. We provide some insight into existing publications and recommend areas for future research, such as further investigations into the reaction mechanisms of the aging of secondary BrC, calculations of the emission factors for BrC from different sources, the absorption of large and long-lived BrC molecules and the construction of an enhanced model for the simulation of radiative forcing. This review will improve our understanding of the climatic and environmental effects of BrC. [ABSTRACT FROM AUTHOR]

This paper presents the first attempt to investigate the emission source control of the Middle Reaches of Yangtze River Urban Agglomerations (MRYRUA), one of the national urban agglomerations in China. An emission inventory of the MRYRUA was developed as inputs to the CAMx model based on county-level activity data obtained by full-coverage investigation and source-based spatial surrogates. A classification technology method for priority control of atmospheric emission sources was introduced and applied in the MRYRUA for the evaluation of the emission sources control on the region-scale and city-scale, respectively. The results demonstrated that the emission sources in the Hefei-centered urban agglomerations contributed the biggest on the mean PM 2.5 concentrations of the MRYRUA and should be taken the priority to control. The emission sources in the Ma'anshan city, Xiangtan city, Hefei city and Wuhan city were the bigger contributors on the mean PM 2.5 concentrations of the MRYRUA among the cities and should be taken the priority to control. In generally, emission sources in cities along the Yangtze River and the tributary should be given the special attention for the regional air quality target attainments. This study can give an understanding of Chinese emissions and provide a valuable preference to policy makers for finding effective mitigation measures and control strategies for reducing national and regional air pollution in China. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds considered as pollutants of high priority due to their carcinogenic potential. PAH can appear in water, soil or in the atmosphere as adsorbed on particulate material or in gas phase. An increased number of studies on atmospheric PAH in urban areas have been published in the last decade, especially in the last years. Anthropogenic sources are frequently mentioned to be responsible for the increased concentration of PAHs in the atmosphere of urban areas, which at the same time seems to depend on meteorological parameters. This research is focused on compiling information on PAH levels in Latin America and their relationship with typical meteorological variables from seasonal and tropical countries. Brazil is the country with the most number of bibliographies about this topic, followed by Argentina, Chile and Mexico. Scarce information was found for Colombia and Venezuela and none for the rest of Latin American countries. The majority of studies checked have evaluated the climatological parameters in relationship with the PAH concentration and their distribution, finding that it affects meaningfully their levels. The monitor campaigns in Brazil have been developed mainly in the southern cities, where PAHs are strongly influenced by the seasons and their proximity to the South Pole. Tropical countries such as Venezuela and Colombia showed moderate variation of PAH concentration through months. The main influential parameters are precipitation and direction/speed winds. [ABSTRACT FROM AUTHOR]

An in-depth understanding of urban road-deposited MPs is important for the accurate prediction of the risk posed by MPs in different exposure scenarios. This study provides new insights into the intrinsic/extrinsic factors in terms of the variability of concentration and species in urban road-deposited MPs. The study results confirmed that a considerable abundance of road-deposited MPs can be identified with the average concentration ranging from 0.33 to 3.64 g m-2. Land use types and sediment particle size are the important factors that contribute to MPs abundance. The majority of detected MPs including polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET) are mainly derived from anthropogenic activities in commercial and residential land uses while rubber MP particles in urban road surfaces are mainly derived from tyre wear. The significant correlation (p < 0.05) between MPs and fine dust particles (< 150 µm) indicated the high affinity of small dust particles for MPs. The risk scores from MPs varied greatly from 10 to 11,000 among the study sites, which indicated the significant spatial variation of potential environmental risks posed by road-deposited MPs. The hotspots of risks posed by MPs were in areas with a high fraction of industrial, commercial and residential land uses. Specifically, the highest risk from MPs was found in mixed industrial and residential areas. [Display omitted] • Land use and particle size are the crucial factors for road-deposited MPs abundance. • Particles < 75 µm show stronger correlation with MPs concentration than MPs species. • Mixed industrial and residential land use has the highest risk posed by MPs. [ABSTRACT FROM AUTHOR]

Indoor air quality is vital to the health and comfort of people who live inside a controlled ecological life support system (CELSS) built for long-term space explorations. Here we measured aromatic hydrocarbons to assess their sources and health risks during a 4-person-180-day integrated experiment inside a CELSS with four cabins for growing crops, vegetables and fruits and other two cabins for working, accommodations and resources management. During the experiment, the average concentrations of benzene, ethylbenzene, m,p -xylenes and o -xylene were found to decrease exponentially from 7.91 ± 3.72, 37.2 ± 35.2, 100.8 ± 111.7 and 46.8 ± 44.1 μg/m 3 to 0.39 ± 0.34, 1.4 ± 0.5, 2.8 ± 0.7 and 2.1 ± 0.9 μg/m 3 , with half-lives of 25.3, 44.8, 44.7 and 69.3 days, respectively. Toluene to benzene ratios indicated emission from construction materials or furniture to be a dominant source for toluene, and concentrations of toluene fluctuated during the experiment largely due to the changing sorption by growing plants. The cancer and no-cancer risks based on exposure pattern of the crews were insignificant in the end of the experiment. This study also suggested that using low-emitting materials/furniture, growing plants and purifying air actively would all help to lower hazardous air pollutants inside CELSS. Broadly, the results would benefit not only the development of safe and comfort life support systems for space exploration but also the understanding of interactions between human and the total environment in closed systems. [ABSTRACT FROM AUTHOR]

Despite the importance of domestic wastewater, the contribution of greywater to both alkylphenol and phthalate pollution is not yet well documented. Likewise, the detailed emissions of phthalates and alkylphenols by greywater have been insufficiently studied, this work aims to fill this gap. The levels of four phthalates (DEP, DnBP, BBP and DEHP) and two alkylphenols (nonylphenol isomers and octylphenol) were quantified in six different types of greywater, namely that from washing machines, manual dishwashing, dishwashers, bathroom water (from showers and sinks) and floor cleaning. This paper presents the methodology used to characterize all sources of greywater and provides their levels of contamination. The highest concentrations were found in greywater produced by the washing machine and floor cleaning, while washing machine and shower greywater have the highest phthalate and alkylphenol loads because of the volume associated with these two sources of greywater. [ABSTRACT FROM AUTHOR]

This paper includes the results of chemical composition of bulk deposition samples collected simultaneously at urban (Poznań city) and forest (Jeziory) sites in central Poland, between April 2013 and October 2014. Rainwater samples were analyzed for trace elements (As, Zn, Ni, Pb, Cu, Cr, Cd) and physicochemical parameters. Overall, three metals, i.e. Zn, Pb and Cu were the most abundant anthropogenic constituents of rainwater samples from both locations. In Poznań city, the rainwater concentrations of trace elements did not differ significantly between spring and summer. However, they were elevated and more variable during the cold season (fall and winter), suggesting strong contribution from local high-temperature processes related to coal combustion (commercial and residential sector). In contrast to the urban site, relatively low variability in concentrations was found for Cu, Ni, Zn at the forest site, where direct impact of emission from vehicle traffic and coal-fired combustion (power plants) was much lower. The bulk deposition fluxes of Ni, As, Pb and Zn at this site exhibited a clear trend, with higher values during the cold season (fall and winter) than in spring and summer. At the urban site, the sums of total bulk deposition fluxes of Zn, Cu, Pb, Ni, As, Cr, Cd were as follows: 8460.4, 4209.2, 2247.4, 1882.1, 606.6, 281.6 and 31.4 μg m − 2 . In addition, during the winter season, a significantly higher deposition fluxes of Cu and Zn were observed for rain (on average 103.8 and 129.4 μg m − 2 , respectively) as compared to snow (19.7 μg Cu m − 2 and 54.1 μg Zn m − 2 ). This suggests that different deposition pattern of trace elements for rain, mixed and snow was probably the effect of several factors: precipitation type, changes in emission and favorable meteorological situation during rain events. [ABSTRACT FROM AUTHOR]

A study of spatial variability of PM10 elemental components was conducted in Terni city (Central Italy), situated in an intramountain depression characterized by the presence of several particulate matter emission sources. The meteorological conditions of the Terni basin limit the dispersion and enhance the accumulation of atmospheric pollutants. Thanks to the utilization of new smart samplers, used for the first time and working in parallel at 23 sampling sites, spatially resolved data were obtained. Localizations of the samplers were chosen in order to evaluate the impact of different local PM10 sources. Chemical composition of the samples was determined in combination with a chemical fractioning procedure that allowed us to discriminate water-soluble and residual fractions of analyzed elements in which proved to be a valuable approach for increasing selectivity of elements as source tracers. Spatial variability of elements underlined the contribution of local emission sources and the different dispersion capacity of each element. The city of Terni resulted to be an ideal area to test and validate a new experimental method for the acquisition of spatially resolved data providing the possibility to properly evaluate the spatial variability of PM10 and its chemical components. [ABSTRACT FROM AUTHOR]

Background and Objective: Polycyclic aromatic hydrocarbons (PAHs) are a group of organic pollutants that are mostly generated during the incomplete combustion. The main objective of this study was to characterize potential sources of PAHs in Tehran. Materials and Methods:, Samples of PM10 were collected at 10 monitoring stations belonging to Tehran Air Quality Control Company (AQCC) and transferred to laboratory for analysis. Besides, a SKC Flite 2 Air Sampling Pump (SKC, USA) equipped with a sampling head and PM10 size-selective inlet was used at four stations to compare the results obtained by collecting AQCC monitors (AQCCMs) tapes with the standard sampling procedures for assessing the interchangeability of two field sampling methods. The principal component analysis (PCA) and diagnostic ratios were applied to identify emission sources and source contribution. Results: The average diagnostic ratios of phenanthrene (Phe)/ (Phe+anthracene (Ant)), benzo(a)anthracene (BaA)/ (BaA+chrysene (Chry)), fluorantene(Flu)/ (Flu+pyrene (Py)), and indeno(1,2,3cd) pyrene (IcP)/(IcP+benzo(ghi)perylene (BghiP)) in samples were 0.79, 0.52, 0.43 and 0.38, respectively. These ratios showed that the combustion, especially fossil fuels and motor vehicles, was the main sources of PAHs emission in Tehran. The results of PCA analysis also indicated that 49, 29 and 22% of PAHs sources in Tehran atmosphere were attributed to gasoline-driven vehicles, diesel vehicles and other sources, respectively. Conclusion: According to the results, the combustion, especially fossil fuel and motor vehicle, was the main sources of PAHs emission in Tehran. [ABSTRACT FROM AUTHOR]

Alternaria spores are a common component of the bioaerosol. Many Alternaria species are plant pathogens, and their conidia are catalogued as important aeroallergens. Several aerobiological studies showing a strong relationship between concentrations of airborne spore and meteorological parameters have consequently been developed. However, the Alternaria airborne load variation has not been thoroughly investigated because it is difficult to assess their sources, as they are a very common and widely established phytopathogen. The objective of this study is to estimate the impact of vegetation and land uses as potential sources on airborne spore load and to know their influence, particularly, in cases of long-medium distance transport. The daily airborne spore concentration was studied over a 5-year period in León and Valladolid, two localities of Castilla y León (Spain), with differences in their bioclimatic and land use aspects. Moreover, the land use analysis carried out within a 30 km radius of each monitoring station was combined with air mass data in order to search for potential emission sources. The results showed a great spatial variation between the two areas, which are relatively close to each other. The fact that the spore concentrations recorded in Valladolid were higher than those in León was owing to prevailing winds originating from large areas covered by cereal crops, especially during the harvest period. However, the prevailing winds in León came from areas dominated by forest and shrubland, which explains the low airborne spore load, since the main Alternaria sources were the grasslands located next to the trap. Furthermore, the risk days in this location presented an unusual wind direction. This study reveals the importance of land cover and wind speed and direction data for establishing potential airborne routes of spore transport in order to improve the Alternaria forecasting models. The importance of conducting Alternaria aerobiological studies at a local level is also highlighted. [Display omitted] • There is a great spatial variation in Alternaria airborne load between nearby areas. • The analysis of land use around each trap is crucial to explain spore variation. • High frequencies of low wind speeds from Alternaria sources cause high spore levels. • Cereal crops and grasslands are the most important Alternaria emission sources. • Harvest season with favorable spore transport conditions is the period of greatest risk. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are an important group of compounds because of their role in atmospheric chemistry and the risk they pose to human health and ecosystem. Therefore, the interest in determining VOCs in the atmosphere has increased over the last few decades to understand their emission, distribution, and sources. Considering the expanding urbanization and increasing use of fuels, very limited data of VOCs in India is available. This paper describes the chemical analysis of 12 light VOCs in 144 ambient air samples collected from three different sites near Raipur, India during a period of April, 2006-March, 2007 in order to understand their temporal and spatial distributions. This data has provided some important insights into the VOC profile, for the first time, of an industrial area in India. The annual average concentrations of all 12 VOCs in our study ranged from 43.2 to 160.4 μg m (mean: 95.6 ± 31.0). The annual average concentration of individual VOCs in Raipur region ranged from 3.4 μg m for xylenes to 18.3 μg m for n-butane. n-Butane, i-butane, and propane were the three most abundant pollutants among all of the VOCs measured. The observed concentrations of these compounds in Raipur region were comparable to other Asian cities with some exceptions. The levels of total VOCs showed seasonal variations with a statistically significant winter maximum and lower values during summer and monsoon ranging from 55.9 ± 9.9 μg/m in August to 144.5 ± 15.5 μg/m in January. Sources of these VOCs have been described using species ratios and correlation studies. [ABSTRACT FROM AUTHOR]

This article investigated the major air pollutants and its spatial and seasonal distribution in 74 Chinese cities. Factor analysis and Cluster analysis are employed to indentify major factors of air pollutants. The following results are obtained (1) major factors are obtained in spring, summer, autumn, and winter. The first factor in spring includes NO 2 , PM10, CO, and PM2.5; the first factor in summer and autumn includes PM10, PM2.5, CO and SO 2 ; in winter, the first factor includes NO 2 , PM10, PM2.5, and SO 2 . (2) In spring, cities of cluster 5 are the severest polluted by emission sources of SO 2 , CO, PM10, and PM2.5; the emission sources of O 3 would significantly influence the air quality in cities of cluster 2; the emission sources of NO 2 could significantly influence the air quality in cities of cluster 3 and cluster 5. (3) In summer, cities of cluster 5 are the severest polluted by automotive emissions and coal flue gas. Cities of cluster 1 are the lightest polluted. Cities of cluster 3 and cluster 2 are polluted by emission sources of SO 2 and O 3 . (4) In Autumn, cities of cluster 3 and 4 are the severest polluted by the emission sources of SO 2 , CO, PM10, and PM2.5; the emission sources of NO 2 would significantly influence the air quality in cities of cluster 5; the emission sources of O 3 could significantly influence the air quality in cities of cluster 1 and cluster 4. (5) In winter, cities of cluster 5 are the severest polluted by the emission sources of SO 2 , CO, PM10, PM2.5, and CO; the emission sources of O 3 could significantly influence the air quality in cities of cluster 1 and cluster 5. [ABSTRACT FROM AUTHOR]

Background and Objective: The present study was carried out to determine the amount and ionic characterization of TSP and PM10 aimed at identifying the potential emission sources of particulates in the ambient air of Tabriz. Materials and Methods: TSP and PM10 samples were collected by two high volume samplers during September 2013 to August 2014. Water-soluble ions in particulate matter were extracted using ultrasonic method and were identified by ion chromatography. Using Stata12 software, linear regression analysis was performed between the ions to determination of the major ionic component of the particulates. In addition, in order to identify the potential emission sources of PM10, the rotation varimax model was used. Results: Total measured water-soluble ions in TSP and PM10 of the urban sampling site were 20.33±20.77 and 16.04±14.08 µg/m3, respectively. Among all detected ions, sulfate (8.69±5.79 µg/m3) and nitrate (8.47±7.9 µg/m3) were the dominant constituents followed by calcium and sodium. Conclusion: The modeling results revealed that the soils of surrounding ground together with secondary PM and also resuspension of PM from polluted soil account for 80 percent of PM10 mass. [ABSTRACT FROM AUTHOR]