Asian Journal of Atmospheric Environment最新文献

In this study, major chemical components of PM_2.5 including nitrate, sulfate, organic carbon (OC), and elemental carbon (EC) were measured in Chuncheon, South Korea in May–June, 2021. Average PM_2.5 concentration was 16.4±9.7 µg m⁻³, and OC was the largest contributor of PM_2.5 mass concentration. High concentration episodes (HCEs), defined when PM_2.5 concentration exceeded 30 µg m⁻³, were caused by Asian dust, secondary inorganic aerosol (SIA) formation, and primary OC emission. NH₄⁺ was determined to be a limiting factor for SIA formation based on neutralization ratio. There was statistically significant correlation between n-alkanes and PM_2.5, and odd alkanes including C27, C29, and C31, which are generally emitted from biogenic sources, were abundant species, suggesting the importance of natural sources over fossil fuel combustion. Polycyclic aromatic hydrocarbons (PAHs) concentrations were significantly lower than those measured at the same sampling site in 2014–2015. Based on the diagnostic ratios of PAHs, vehicular emission, rather than solid fuel emission, were significant for PAHs. Detailed characterization of chemical composition of PM_2.5 reported in this study can be of great help in establishing an appropriate abatement policy to reduce PM_2.5 concentrations.

In this work, two single particle analytical techniques such as a quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), called low-Z particle EPMA, and attenuated total reflectance Fourier transform-Infrared (ATR-FTIR) imaging were applied in combination for the characterization and distinction of six standard asbestos and one non-asbestos Mg-silicate minerals of micrometer size. Asbestos fibers have been reported as a natural carcinogen which causes some serious illness like mesothelioma, asbestosis, and lung cancer. Atmospheric aerosols are heterogeneous mixtures and airborne asbestos fibers would be present due to their extensive industrial uses for various purposes. The fibers could also be airborne from natural and anthropogenic sources. As different asbestos fibers have different carcinogenic properties, it is important to determine different types of individual asbestos and non-asbestos Mg-silicate mineral particles and their sources for the public health management. In our previous works, the speciation of individual aerosol particles was performed by the combined use of the two single-particle analytical techniques, which demonstrated that the combined use of the two analytical techniques is powerful for detailed characterization of externally heterogeneous aerosol particle samples and has great potential for characterization of atmospheric aerosols. In this work, it is demonstrated that the identification and differentiation of asbestiform and non-asbestiform Mg-silicate mineral particles is clearly performed using the two single particle analytical techniques in combination than using either technique individually. Especially, anthophyllite and talc can be differentiated using this analytical approach, which has not been easy up until now.

According to the 2018 National Air Pollutant Emissions Inventory (NEI), air pollutant emissions in the Republic of Korea comprised 808,801 tons of CO, 1,153,265 tons of NO_X, 300,979 tons of SO_X, 617,481 tons of TSP, 232,993 tons of PM₁₀, 98,388 tons of PM_2.5, 15,562 tons of black carbon (BC), 1,035,636 tons of VOCs, and 315,975 tons of NH₃. As for national emission contributions to primary PM_2.5 and PM precursors (NO_X, SO_X, VOCs, and NH₃), major source categories were the road sector for NO_X, the industry sector for SO_X and PM_2.5, and the everyday activities and others sector for VOCs and NH₃. In the case of emissions by region, the largest amount of NO_X was emitted from the Seoul Metropolitan Areas (SMA; Seoul, Incheon, and Gyeonggi-do, hereafter SMA) and the largest amounts of SO_X, PM_2.5, VOCs, and NH₃ were from the Yeongnam region. A 3D chemical transport modeling system was used to examine the uncertainty of the national air pollutant emissions based on the National Emission and Air Quality Assessment System (NEAS). Air quality was simulated using CAPSS 2018, and the simulation data were compared with observed concentrations to examine the uncertainties of the current emissions. These data show that emissions from five si (cities) (Pohang, Yeosu, Gwangyang, Dangjin, and Ulsan) need to be improved. Most of all, it is necessary to examine the emissions from places of business that use anthracite, which is the major PM_2.5 emission source, as fuel in these areas.

This study aims to assess the particulate matter (PM₁, PM_2.5, PM₁₀) and black carbon (BC) in the Korea Train eXpress (KTX) cabin during train running, and the personal exposure of PM_2.5 for the female/male passengers who use the KTX 20 days a month to commute. Intensive measurements were made on the day when the outside ambient PM concentration was much higher than usual. To compare with the PM concentration in the subway cabin, a measurement was also performed in some sections of the Seoul Metro subway (from Namyoung Station (hereafter referred to as the “Sta.”) to Jonggak Sta.). The amount of PM_2.5 exposure

was calculated for the male/female passengers who regularly board the KTX. The

, which is the amount of PM_2.5 exposure when moving by car in the same section, was also calculated. The PM concentration in the KTX cabin elevated and fallen off at train staying and train running, respectively. The PM_2.5 concentrations inside KTX cabin at the stop station exhibited a remarkable positive correlation with those of outdoor. Compared to the PM concentration measured in the cabin of Seoul Metro subway, PM₁, PM_2.5, and PM₁₀ in the KTX passenger cabin were 74.9%, 73.3%, and 62.7% of those in the cabin of Seoul Metro subway, respectively. The PM_2.5 exposure amount (exposure PM_2.5 (μg)) when moving the same section using the KTX and passenger cars was calculated, and as a result, the exposure PM_2.5 (μg) for both male and female were 5.7 times lower in the KTX than that in car. The mapping result of BC concentration drawn on the KTX line from Iksan Sta. to Gwang-myeong Sta. shows that it fluctuated greatly for each service section or stop station.

The livestock industry is a major source of atmospheric volatile organic compounds(VOCs), but details on these emissions are not well documented in Japan. In particular, it remains unclear how the rearing method affects the emissions of VOCs from livestock, which originate primarily from feces and urine. Here we aimed to estimate the amounts of VOCs emitted from the feces and urine of tethered Holstein dairy cattle in a cattle shed in Japan. Dimethyl sulfide and acetone accounted for about 60% of the total VOCs emitted from feces, followed by formaldehyde and acetaldehyde. Also, dimethyl sulfide and acetone were the dominant VOCs emitted from urine, accounting for 90% of the total VOCs. The VOCs from manure were considered to be emitted between the excretion and removal of the manure during the cleaning of the shed. As a result of analyzing images from three cameras installed in the shed, the average time between excretion and cleaning during the daytime (8:00 am–5:00 pm) was 80 min for feces and urine, whereas at night (5:00 pm–7:00 am), the average time between excretion and cleaning was 480 min. Based on the above findings, the emissions of VOCs in the interval between excretion and cleaning of the shed were estimated. As a result, the emissions of VOCs from feces and urine per head of cattle in the shed were estimated to be 1.75 and 1.52 g day⁻¹, respectively. Furthermore, contribution of VOCs emitted from manure to odor activity value (OAV) and hydroxyl radical reactivity (OHR) were also estimated. Volatile fatty acids and sulfur compounds emitted from feces estimated to have high contribution to OAV, whereas aldehydes contributed mainly for OHR from manure.

A comprehensive analysis of pollutant’s trend and their measurement techniques are crucial for evaluating the air quality, and thereby helpful in formulating better control policies. In this report, we summarise ground based PM_2.5 and PM₁₀ data report in India (2015–2019). The important points discussed here are: (i) review of the ground-based data of PM_2.5 and PM₁₀ and the techniques used, (ii) mapping of the data over India with spatial and temporal distribution so that better understanding on PM pollution level can be made, (iii) identifying the technological gaps in measurement of PM concentration in India, and (iv) evaluation of MERRA-2’s (Modern-Era Retrospective Analysis for Research and Applications, Version 2) simulation of PM_2.5 against surface measurements in India to better understand biases for spatial and seasonal distribution, and then (v) suggestions for better PM measurement protocols, policies and metrological aspects for both measurement and control policies. It is observed that the amount of ground data on ambient monitoring of fine PM is insufficient and has several inconsistencies which require adequate attention. In India, not much work has been done on developing certified reference materials, traceable standards and calibration facility for particulate matter measurement which is a crucial step to ensure quality checks. Further, the comparison of MERRA-2 and ground PM_2.5 concentrations revealed huge discrepancies with underestimating PM_2.5 measurements in highly polluted regions like the Indo-Gangetic plain, especially during winter when pollution load was high. Better PM_2.5 agreement was found in summer and monsoon season, based on performance statistics explained in this paper. Inconsistencies between MERRA-2 and ground PM_2.5 are partly due to few limitations in MERRA-2 reanalysis method which are discussed in this paper, apart from several issues in ground-based observation. The aim of this review and comparison is to highlight such issues and give more attention to the importance of data quality assurance for effective air quality management. The present study may be helpful for the researchers in evaluating and choosing appropriate reanalysis products for their future studies.

Cyclone sampling devices have been helpful in assessing the toxic effects of fine particulate matter (PM_2.5). The particle collection efficiency of sampling devices is critical. This study investigated the effect of cyclone size on particle size, chemical composition, and particle toxicity. Three cyclones with different inner diameters (12–68 mm) were tested for penetration using an aerodynamic particle sizer, fluorescent polystyrene latex, and a differential mobility analyzer. The elemental and water-soluble ion compositions of the particles collected by different cyclones were compared. An evaluation of the particles’ toxicity was conducted by comparing the results of dithiothreitol (DTT), limulus amebocyte lysate (LAL), and cell exposure assays. The experimental evaluation showed a 50% cut-size of the cyclones between 0.17–0.28, 0.34–0.36, and 0.70 μm for the small, medium, and large cyclones, respectively. To collect PM_2.5 and evaluate separation performance in the real environment, the small and large cyclones were selected according to the particle penetration and flow rate. A comparison of chemical composition and enrichment factor values found that the particles in the small cyclone samples contained smaller and more anthropogenic sources than those in the large cyclone samples. The oxidative potential (OP) measured by the DTT assay of the samples collected using the small and large cyclones differed across sampling periods and associated with the transition metals. The viability of human epithelial A549 cells after exposure to the collected particles using the cyclones was different across sampling periods and associated with OP. The endotoxin concentrations measured in the LAL assay were found only in the large cyclone samples; they affected the estimated level of cytokine based on IL(interleukin)-6 release from human leukemia monocytic (THP-1) cells derived macro-phage-like cells. Regardless of the size, the cyclone techniques used in this study to collect aerosol particles would be a powerful tool for a detailed evaluation of particle toxicity.

In Japan, the achievement rate of environmental standards for air pollution has been improving in recent years, but for photochemical oxidants, including ozone, improvement are required. In this study, we investigated trends in ozone counter-measures in the United States and Europe from the State Implementation Plan (SIP) and National Air Pollution Control Program (NAPCP) and examined whether there are any points recommended in Japan. The United States and Europe have different policies on environmental standards for air pollution and ozone control. In the United States, states that do not meet the environmental standards for ozone concentration are required to develop an SIP to attain the standards. There was an urgent need to find a cost-effective approach to addressing the ozone problem, and forest control measures were one of the possibilities. In Europe, the European Union has set “target values” for ozone and NAPCP does not mention forest control measures or ozone sensitivity regimes. The main focus in Europe is on the win-win solution of reducing emissions of air pollutants at the same time as greenhouse gases. Japan should consider a framework including setting feasible step-by-step goals to attain the desired standards. As ozone is greatly affected by advection, wide-regional measures against ozone precursors and prediction of the future precursor reduction and concentration are required. The preparation of an emissions inventory and estimated reduction amount is prerequisites as basic data for simulation. To achieve this, cooperation between national, local and private research institutes is crucial. Since the international community has agreed to prioritize greenhouse gas counter-measures, Japan could consider a win-win solution for both ozone and greenhouse gas reduction.

The present study was conducted in Lucknow city to assess the impact of firecracker burning during Diwali, from 2 November 2021–6 November 2021 including the pre and post-Diwali days. The concentrations of PM₁₀, PM_2.5, SO₂, NO₂, CO, O₃, benzene and toluene, were monitored from the Central Pollution Control Board site on an hourly basis. The Air Quality Index was also recorded for PM₁₀, PM_2.5, SO₂ and NO₂. A questionnaire survey was done with 51 doctors to know the reported complaints post-Diwali. On Diwali night the PM_2.5 value reached 262 µg m⁻³ around 22:00 hours and the maximum value (900 µg m⁻³) was obtained on 5 November, reported from the Central School monitoring station. From Gomti Nagar highest PM_2.5 value obtained on Diwali day was 538 µg m⁻³ at 23:00 hours reaching 519 µg m⁻³ post-Diwali. Areas belonging to the old part of the city witnessed higher variations as PM_2.5 crossed 900 µg m⁻³, in Lalbagh and Talkatora areas. The multivariate analysis showed that on Diwali night there was an increase of 204, 386, 344 and 341 in the PM_2.5 concentration reported from Gomtinagar, Central School, Talkatora and Lalbagh stations, showing that firecracker burning resulted in a significant increase in air pollution. The Toluene/Benzene ratio was mostly more than 1 indicating that toluene and benzene may be emitted from other sources as well including the mobile sources. Around 50–75% rise was seen in the number of patients post-Diwali. 57.1% of the reported cases had respiratory issues, followed by allergic reactions. The data obtained from Lalbagh, Talkatora and Central School showed that although the values remained high, a decreasing trend was seen in the AQI compared to previous years which is a good sign and may be attributed to public awareness and the ongoing pandemic making people conscious.

The objective of this study was to analyze the temporal and spatial characteristics of fine particulate matters by using huge hourly datasets of PM_2.5, including chemical information monitored at the 6 national intensive monitoring sites (NIMSs) from 2013 to 2018 in Korea. Hourly PM_2.5 raw datasets were obtained from the National Institute of Environmental Research (NIER) in Korea. Monitoring sites included urban, rural/agricultural, industrial, and marine environments. Since the PM_2.5 concentration steadily decreased nationwide, each species concentration also decreased in general. One of key reasons for decreasing PM_2.5 might be explained by the implementation of domestic fine dust reduction policies and external influences such as PM_2.5 concentration reduction in China. It was observed that 45.0% of all datasets for 6 years were classified as good condition. The average sum of 14 elements over all sites in 2018 was calculated to be 501.5 ng/m³, and its mass ratio for PM_2.5 (21.9 μg/m³) was 2.30%. The inorganic elements were generally higher in industrial/urban areas than in agricultural areas. In addition, the average TC (total carbon) over all 6 sites was 28.3% of PM_2.5 with the range of 23.6% to 31.4%. The TC in small urban areas was much higher than that in marine areas or even that in large, populated urban area/industrial areas. It seemed that the latter areas were better controlled than the former area in terms of combustion activities of fossil fuels. It is suggested that these results could be play an important role as important basic data to manage ambient air quality and establish effective emission reduction strategies in each region.