Influences of the Long-Range Transport of Biomass-Burning Pollutants on Surface Air Quality during 7-SEAS Field Campaigns

Abstract

The transport of aerosols relies primarily upon air flow for conveyance; however, the air flow pattern is dominated by large-scale circulation conditions. One mission of the 2013 7-SEAS/BASELInE (Seven SouthEast Asian Studies/Biomassburning Aerosols & Stratocumulus Environment: Lifecycles and Interactions Experiment) was to capture/confirm the downwind effect on the surface air quality due to the long-range transport of Southeast Asia biomass-burning (SEA BB) pollutants. This phenomenon was first discovered during the 2010 Dongsha experiment and directly observed by a lidar system at Hengchun in southern Taiwan during 7-SEAS/BASELInE. Through three-dimensional structural analysis, it was found that the sinking motion behind the upper-level active short wave trough is the major mechanism that enhances subsidence along the cold surge leading edge. In turn, the enhanced subsidence could bring the long-range transport of the SEA BB pollutants down to the surface. Furthermore, the HYSPLIT backward air trajectories helped identify the SEA BB pollutants in the mid-troposphere, while the fine-resolution WRF model simulation combined with dual-polarization lidar observations demonstrated the evolution of the brought-down aerosols process. An additional significant finding of this study is that the upper-level ridge-trough short wave within 20°-35°N was very active during spring 2013, highlighting the inter-annual variability of the long-range transport of SEA BB pollutants.

Study on the impact of three Asian industrial regions on PM<sub>2.5</sub> in Taiwan and the process analysis during transport

“…The simulated proportions of Na + and Cl − in PM 2.5 at position 3 and position 4 were higher than those at position 1 and position 2. The higher sea salt due to a stronger wind speed is expected because the Taiwan Strait was a wind tunnel between the Central Mountain Range in Taiwan and the Wuyi Mountains in the Fujian province (Lin et al, 2012). In addition, the simulated proportions of nitrate in PM 2.5 at BQ, ZM, and CY were higher than those over position 1-4, which should be caused by the local pollution.…”

Study the impact of three Asian industrial regions on PM<sub>2.5</sub> in Taiwan and the process analysis during transport

“…It is known that the EAH events mainly occur in winter (Chuang et al, 2008a;Wang et al, 2016). Although the high PM2.5 events in Taiwan caused by the EAH during spring period sometimes was enhanced by the Southeast Asian biomass burning aerosol (Yen et al, 2013;Chuang et al, 2016;Lin et al, 2017), the latter would implicitly complicate the transport of EAH…”

Enhanced Receptor Modeling Using Expanded Equations with Parametric Variables for Secondary Components of PM2.5

“…2015; Stein et al, 2015). Twenty-four-hour back trajectories were computed using meteorological data from the Weather Research and Forecasting (WRF) model simulation with a 1-km grid spacing (Skamarock and Klemp, 2008;Lin et al, 2017). The initial meteorological condition was from ds083.3 NCEP GDAS/FNL 0.25 Degree Global Tropospheric Analyses and Forecast Grids (DOI:…”