Asian Journal of Atmospheric Environment最新文献

Atmospheric aerosols, including primary aerosols emitted directly into the atmosphere and secondary aerosols generated in the atmosphere from various chemically complex particles, cause a variety of environmental problems such as climate change, photochemical smog formation, and a decrease in incoming solar radiation. Therefore, it is important to understand the causes of aerosol particles and their impact on human society. In particular, particle size is an important indicator of lung penetration depth, aerosol transport, and optical properties. Hence, we mathematically estimated the airborne particle size distributions of each chemical component by collecting aerosol samples from the atmosphere using two types of cyclone samplers, large and small cyclone samplers. This study’s findings also suggest that calculated changes in particle size distribution can reflect changes in particle sources. The higher resolution of the continuous functions will enable the detection of the subtle changes in particle size distributions of each chemical component, which is helpful to understand the temporal changes in the chemical properties of the airborne aerosol particles.

Exhausts or emission from industries/automobiles/indoor appliances is one of the most prominent sources of air pollution. Innumerable noxious gases have been identified and been recurrently treated through various technologies from past many decades. Cumulative studies suggest that air pollutants affect the respiratory and cardiovascular systems along with the central nervous system, may it be directly or indirectly. In particular, acquaintances to such air pollutants in early life can lead to developmental delays and may stunt neurological development. This review presents the recent technologies that have been tested at the laboratory level as well as in situ utilizing one of the abundantly available industrial wastes, i.e. red mud. Unlike the conventional expensive catalysts, red mud provides a cheaper alternative in the treatment of toxic exhaust gases from various sources. Furthermore, the review identifies the gap through which experts from other disciplines can explore the employment of red mud in the comprehensive spectrum of pollution control.

The chemical characteristics of particulate matters collected from 53 schools in 2019 through 2022 were closely investigated to determine the main sources of classroom PM_2.5. On average, indoor PM_2.5 measured during class hours distributed from 3.3 μg/m³ to 45.97 μg/m³, and it consisted of 45% of ions, 33% of carbons, 17% of metals and others. The average indoor-to-outdoor ratio (I/O) of PM_2.5 was 0.73. Values for I/O ranged from 0.6 to 0.91 for inorganic elements; 0.3 to 0.8 for ions; 0.50 to 2.69 for elemental carbons (EC), and 0.52 to 8.50 for organic carbons (OC). The linear correlation of indoor EC with concentrations of K⁺ and NO₃⁻ indicates that the contribution of combustion-related sources to classroom PM_2.5 is significant in roadside schools. The findings from this study should help establish construction guidelines for urban schools near high-traffic areas.

The Observation-Constrained Atmospheric BOX model (OCABOX) was used to analyze the formation of secondary inorganic PM species in the Seoul Metropolitan Area (SMA), South Korea. The measurement data of the ionic components of PM_2.5 and their gaseous precursors made at the Olympic Park ground site (37.53°N, 127.12°E) during the Korea-United States Air Quality field campaign were used to run OCABOX in observation-based mode and compare the simulation results. The use of the HNO₃ concentrations measured at a marine background site as the boundary conditions appeared to increase the accuracy of the model prediction of HNO₃ and particulate NO₃⁻ concentrations. For the primary precursors emitted considerably throughout the SMA, such as NO_x and NH₃, using the data measured inside the SMA as the boundary conditions could lead to more accurate predictions. OCABOX was shown to be a reliable tool to analyze the formation of secondary inorganic aerosol in the SMA if used with appropriate regional background concentrations and observation-based constraints

A study on monitoring PM_2.5 concentrations at an underground subway station using light scattering and beta attenuation methods was conducted. Six optical particle counters (OPCs), which were representative of the light scattering method and had 16 size channels, were installed at different sampling sites in the waiting room and platforms to compare PM_2.5 concentrations, determine PM_2.5 /PM₁₀ ratios, and characterize the size distribution based on particle number. In terms of the beta attenuation method, a beta-ray attenuation monitor (BAM) was set up at the platform to compare it with OPCs for one month. It was found that 1h-average PM_2.5 concentrations varied at different sampling sites depending on PM composition, while 24h-average PM_2.5 concentrations were independent of the sampling sites. There was a significant difference between the means of 1h-average PM_2.5 concentrations observed by the BAM and OPC when PM_2.5 contributed to less than 50% or higher than 80% of PM₁₀. In contrast, the 24h-average PM_2.5 concentrations observed by the BAM and OPC showed the same patterns as each other with an insignificant difference. Therefore, an OPC can be used to monitor the 24h-average PM_2.5 concentration in an underground subway station. However, the use of OPC to measure the 1h-average PM_2.5 concentration should consider PM composition and other factors. In addition, more frequent calibration is needed on a regular basis.

The preparation of eco-friendly carbon-rich (biochar) materials by thermal pyrolysis of waste biomass has been recognized as one of the most economical and effective strategies for gas purification in recent years. Through control of synthesis and activation methods, the surface features and catalytic sites in biochar can be engineered for diverse heterogeneous catalytic reactions. Nonetheless, its commercial utilization in air pollution control has yet been limited to a large extent because of (i) the shortage of databases related to the actual catalytic performance of biochar and (ii) the complexity involved in industrial upscaling. Herein, the merits and demerits of biomass-to-biochar catalyst conversion are discussed, along with the factors to consider in the synthesis stage for enhancing catalytic activities toward air purification applications. This paper also offers an in-depth evaluation of the techno-economic and environmental aspects of biochar-based catalysts and their catalytic reactions for air pollution control and energy production. Lastly, a contemporary perspective is offered to help develop novel biochar-based catalysts for real-world applications in air purification fields.

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.