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In this study, the impact of long-range transport, one of the factors contributing to the presence of PM2.5, was examined, and an analysis of marker compounds associated with its long-range transport was conducted. Aerosol optical depth, wind field, CO/CO2 back-trajectory analysis, and satellite observation results were performed to determine PM2.5, volatile organic compound (VOC), CO, CO2, SO2, O3, NO, NO2, and NH3 levels at an orchard located in Jeollabuk-do, Republic of Korea. The characteristic of long-range transport at the observation area was evaluated during the research period. The concentrations for long-range transport based on concentration changes in gaseous materials and composition changes in PM2.5 were analyzed. A back-trajectory analysis for the ratio of CO to CO2 with satellite observation results was used to identify long-range transport. Furthermore, the proportionality between the ratio of 1,2-dichloroethane to naphthalene in VOCs and the quantity of precursor compounds linked to long-range transport were observed. [ABSTRACT FROM AUTHOR]

A dynamic multimedia model (POPsLTEA) for an East Asia region was developed and evaluated to quantitatively assess how climate change (CC) alters the environmental fate and transport dynamics of 16 polycyclic aromatic hydrocarbons (PAHs) in air, water, soil, and sediment. To cover the entire model domain (25°N–50°N and 98°E–148°E) where China, Japan, and South and North Koreas are of primary concern, a total of 5000 main cells of 50 km × 50 km size were used while 1008 cells of a finer spatial resolution (12.5 km × 12.5 km) was nested for South Korea (33°N–38°N and 126°E–132°E). Most of the predicted concentrations agreed with the observed values within one order of magnitude with a tendency of overestimation for air and sediment. Prediction of the atmospheric concentration was statistically significant in both coincidence and association, suggesting the model's potential to successfully predict the fate and transport of the PAHs as influenced by CC. An example study of benzo( a )pyrene demonstrates that direction and strength of the CC influence on the pollution levels vary with the location and environmental media. As compared to the five year period of 2011 to 2015, the changes across the model domain in the annual geometric mean concentration over the years of 2021 through 2100 were predicted to range from 88% to 304%, from 84% to 109%, from 32% to 362%, and from 49% to 303%, in air, soil, surface water, and sea water, respectively, under the scenario of RCP8.5. [ABSTRACT FROM AUTHOR]

Abstract: This study used the Community Multi-scale Air Quality modeling system associated with emission and meteorological datasets to conduct a one-year Particulate Matter (PM) simulation in East Asia. The performance of the PM simulation results was evaluated against observed data using high-spatial resolution monitoring data from Taiwan (e.g., concentration of PM and its compositions and precursors), Air Pollution Index-derived data in 82 cities of China, and satellite-derived surface PM2.5 concentrations. Based on error analysis of two indicators (overall bias and gross error), the validity of model performance is demonstrated. Daily comparison results at the various stations (cities) in 2007 indicate that the simulations at Taiwan's monitoring stations were superior to those in cities in China. Overall, the PM10 and PM2.5 concentrations in Taiwan were underestimated by 11 and 10%, respectively, whereas the simulated PM10 concentrations in six regions of China showed significant differences, with the simulation overall bias ranging between −55 and 52%. There are two primary reasons for the large differences in model performance between Taiwan and China. First, the grid resolution for China was coarser than that for Taiwan because of the limitation of emission data resolution in the Regional Emission Inventory in Asia (REAS). Second, the spatial distribution and magnitude of emissions in the REAS might be incorrect in some regions, particularly in the domain boundary areas of China. In addition to the relatively good emission database for Taiwan, the reasonable emission estimates for the central areas of China may be partially responsible for better model performance of PM in Taiwan. [Copyright &y& Elsevier]

Two elevated fine particulate mass concentration events were observed in a span of a week in northern Philippines on March of 2017. Results from chemical characterization, lidar observation, and model simulations of particulate matter show the high aerosol concentration events to be caused by long range transport (LRT) of anthropogenic pollutants from northern East Asia at the surface and biomass burning emission from Indochina aloft. In this study, we investigated the transport path of these LRT aerosols and estimated their direct radiative forcing. A strong Siberian high and a confluent flow induced by a continental high over the main Asian continent and a cyclonic circulation over the south of Japan produced a strong northerly wind that carried pollutants from northern East Asia to northern Philippines. At the same time, strong westerlies 2–4 km aloft carried biomass burning emissions from Indochina, which also had an impact on ground concentration. Mass extinction efficiency of LRT aerosols was estimated to be in the range of 2.06–6.44 m2g-1 with a mean value of 4.32 ± 1.32 m2g−1. In addition, we calculated the direct radiative forcing effect under clear sky condition and found that the transported aerosols had a mean net negative forcing (cooling) effect of −50.80 ± 12.38 Wm−2 and −11.98 ± 3.96 Wm−2 on surface and at the top of the atmosphere, respectively. Such pollutant transport during wintertime cold surges had been shown to reduce local surface pollutants in northern China. Consequently, its impacts shift to downwind regions as far as the Philippines. As winter cold surge frequency increases due to the warming arctic, more LRT events may be expected as a result of climate change. • Spring-time aerosol transport pattern from East Asia to the Philippines. • Biomass burning emissions from Indochina observed in northern Philippines. • Conceptual flow of long-range transport of aerosols during spring. • Transport of aerosols has cooling effect in the region. [ABSTRACT FROM AUTHOR]