Atmospheric PM2.5 near an Urban-Industrial Complex during Air-pollution Episodes with Various Meteorological Conditions

Abstract

This study investigates the atmospheric fine particulate matter (PM 2.5 ) issue caused by the multi-effect of complicated sources, terrain, and meteorology at Southern Taiwan. Three sampling stations represent an urban, a rural, and a coastal sites near an urban-industrial complex. The atmospheric PM 2.5 were measured during a pollution episode from November to February, when the reference samples were collected in April. The sample was collected with a constant-flow sampler with the Federal Reference Method performance. After determining the PM 2.5 mass, their chemical compositions of ions, metals, and carbons were analyzed for the different properties caused by the multi-factors. The chemical mass balance (CMB) model was employed to evaluate the emission contributions. Additionally, an inverse trajectory model is used to analyze the pollutant transport and support the CMB results. The air-pollution episodes occurred within the winter to spring. The PM2.5 were composed of 51-69% ions, 18-31% carbonaceous species, and 1.5-3.0% metals. The SO 4 2-, NH 4 + , and NO 3contributed 92-96% of the ions. Most of the organic/elemental carbon ratios were low, suggesting more primary carbon emissions. The metal contents were minor and dominated by Fe and Zn. The CMB model indicated the PM 2.5 were dominated by 24% secondary SO 4 2-, 14.7% traffics, 8.3% petrochemical emissions, 6.8% soil dust, and 4.5% sintering plant emission. For non-episode days, the PM 2.5 were contributed by 34.9% traffics, 30% the secondary SO 4 2-, 10.3% secondary NO 3 -, and 6.8% soil dust. Nevertheless, the frequent sea-land breeze might lead to more powerful wind eddies and bring the primary PM 2.5 and the aerosol precursors from the emission areas. Consequently, the uncontrollable meteorological changings would lead to the pollution issues at the lowly convective area. Therefore, the averaging emissions of the PM 2.5 and precursors should be lowered; meanwhile, the rapid controls of the primary emissions are suggested when the high-level PM 2.5 are forecasted.

Do the Street Sweeping and Washing Work for Reducing the Near-ground Levels of Fine Particulate Matter and Related Pollutants?

“…The PQ200 particulate samplers (BGI, Boston, MA) was used to collect the PM2.5 on both Teflon membrane and quartz fiber filter papers at each station. After sampling on Teflon filter membrane, put it into a plastic bottle cleaned ultrasonically with deionized water after precision weighing, then inject 10-ml deionized water and seal the bottle cap tightly, and treat it with ultrasonic extraction for 90 minutes to extract watersoluble ions on Teflon filter paper (Lin et al, 2022). After extraction, pour the extraction solution into a 10-mL syringe, the particles in the sample were removed by filtration with a 0.45 mm membrane.…”

Impact of Ship Emissions on Air Quality in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA): With a Particular Focus on the Role of Onshore Wind

“…The dispersion of air pollutants in coastal regions could be affected by a combination of multiple factors, such as the topographic and meteorological conditions [17][18][19][20]. Among them, winds, as an important meteorological factor in coastal areas [21][22][23][24], can significantly affect the dispersion and transportation of pollutants emitted from ships. Onshore winds can drive pollutants to be transported inland, whereas offshore winds can transport pollutants to the sea [22,25].…”