Air Quality Variation in Wuhan, Daegu, and Tokyo during the Explosive Outbreak of COVID-19 and Its Health Effects.

This study was designed to assess the variation of the air quality actually measured from the air pollution monitoring stations (AQMS) in three cities (Wuhan, Daegu, and Tokyo), in Asian countries experiencing the explosive outbreak of COVID-19, in a short period of time. In addition, we made a new attempt to calculate the reduced (μg) at the bronchiolar (Br.) and alveolar-interstitial (AI) regions of the 10-year-old children after the city lockdown/self-reflection of each city.

Measurements of major VOCs released into the closed cabin environment of different automobiles under various engine and ventilation scenarios.

Volatile organic compounds (VOCs) in automobile cabins were measured quantitatively to describe their emission characteristics in relation to various idling scenarios using three used automobiles (compact, intermediate sedan, and large sedan) under three different idling conditions ([1] cold engine off and ventilation off, [2] exterior air ventilation with idling warm engine, and [3] internal air recirculation with idling warm engine). The ambient air outside the vehicle was also analyzed as a reference. A total of 24 VOCs (with six functional groups) were selected as target compounds.

Ambient particulate matter in a central urban area of Seoul, Korea.

The concentrations of PM2.5 and PM10 were monitored at a central urban area of Yongsan (YS), Seoul, Korea during 2013. The daily average concentrations of both PM2.

An investigation into the relationship between the major chemical components of particulate matter in urban air.

Particulate matter (PM) generally comprises such chemical components as inorganic ions, organic carbon (OC), elemental carbon (EC), and metals. In terms of environmental studies, these major chemical components of particulate matter (MCP) are important in understanding PM distribution, behaviors and source apportionment. In this study, the MCP fractions of total suspended particles (TSP) were measured at an urban residential area in Seoul, Korea from February to December in 2009.

A novel approach to identifying the elemental composition of individual residue particles retained in single snow crystals.

This study was carried out to describe the chemical characteristics of individual residual particles in hexagonal snow crystals, which can provide a clue to the aerosol removal mechanism during snowfall. In the present study, to collect snow crystal individually and to identify the elemental composition of individual residues retained in a hexagonal crystal, an orchestration of the replication technique and micro-particle induced X-ray emission (micro-PIXE) analysis was carried out. Information concerning the elemental compositions and their abundance in the snow crystals showed a severe crystal-to-crystal fluctuation.

Volatile Organic Compounds in Ambient Air at Four Residential Locations in Seoul, Korea.

To investigate the environmental behavior of volatile organic compounds (VOCs) in urban areas, their concentrations were measured at four urban monitoring sites (namely, N, S, E, and W) in Seoul, Korea (February to December 2009). A total of 27 compounds were quantified that consist of four chemical groups: aromatic (AR), halogenated aromatic, halogenated paraffin, and halogenated olefin. Results were evaluated by focusing on these four functional groups just mentioned and their summation term as total VOC (TVOC) along with several individual species (mainly AR species, that is, benzene, toluene, ethylbenzene, and xylene).

An analysis of long-term changes in airborne toxic metals in South Korea's two largest cities from 1991 to 2004.

Background, Aim, And Scope: Investigations on the temporal variabilities of metals generally show that the concentration levels of many harmful metals in air have been continuously decreasing around the world including North America and Western Europe. However, an excursion from such trends has been expected and demonstrated from E. Asia due to the major source contribution from China.

Analysis for chemical characterization of atmospheric aerosols application of X-ray microprobe system and double thin film method.

The X-ray microprobe system was applied to ultra trace characterization of single Kosa aerosols and non-Kosa aerosols simultaneously collected at Yasaka, Japan and TaeAnn, Korea. We demonstrated remarkable mass increase of heavy metals as well as soil components in individual particles during the Kosa event compared with the non-Kosa period at Yasaka. Backward trajectory analysis suggested that the Kosa samples were in the mixing state of mineral components and anthropogenic heavy elements.

Elemental distribution in individual rain droplets determined by a combination of the replication method and the synchrotoron radiation X-ray fluorescence microprobe technique.

The main objective of the present study is to specify the chemical properties of individual rain droplets. For this purpose, we have combined the collodion replication method and the SR-XRF microprobe technique. The dry residual materials retained in a single rain droplet, which correspond to the former cloud condensation nuclei and the scavenged particles during droplet falling, were successively reconstructed by the multiple elemental maps using SR-XRF microprobe analytical system.