Fujung Tsai

High wintertime particulate matter pollution over an offshore island (Kinmen) off southeastern China: An overview

Both the Yangtze River Delta (YRD) and the Pearl River Delta (PRD), the two most rapidly developing areas in eastern China, have suffered from serious air pollution, and thus, numerous investigations were devoted to studying these problems. Other areas in eastern China have received less attention despite similar rapid development in their industries and economy. In this study, we analyzed air‐quality data from Kinmen Island (24°27′26′′N, 118°19′36′′E) located off Fujian Province and between the two above‐mentioned deltas. Our results clearly show that the study area is experiencing serious air quality deterioration. Particularly, high levels of suspended particulate matter (PM) were observed during winter, when the northeasterly monsoon prevails. For example, concentrations of wintertime PM10 (particles ≤ 10 mm in diameter) frequently exceeded 100 mg/m3 in the last three years. In addition to the air‐quality data analysis, aerosol samples were collected between 22 November 2007 and 6 March 2008 and subjected to chemical analyses of various species. Our findings show that the three principal PM components include organic, mineral, and sulfate species with moderate to minor fractions of nitrate, sea salt, elemental carbon, and trace metal oxides. The high PM levels observed over the island may be partly attributed to the transport from a mixed‐type industrial area located ∼40 km northeast of Kinmen. Our study could partially fill the air quality data gap between the YRD and PRD regions, and highlight the alarming fact that air pollution has gradually expanded along eastern China’s coastal zone.

Effects of acidic processing, transport history, and dust and sea salt loadings on the dissolution of iron from Asian dust

[1] Aerosol particles collected over the East China Sea (ECS) were analyzed for water-soluble Fe (Fe s ), total Fe (Fe T ), and other chemical species. Eight samples were classified as high Asian dust (HAD) on the basis of total Al concentrations >1500 ng/m 3 . Comparisons with low Asian dust (LAD) samples showed that unlike Fe T or most other substances, the percentage of Fe T soluble in deionized water (%Fe s ) was lower in the HAD samples. The %Fe s in the HAD samples varied with transport pattern and air mass history. As the difference in Fe s concentrations between HAD and LAD is relatively small and HAD occurs several days each year, the supply of Fe s through dry deposition to the surface ocean may be less sporadic than previously thought. Soluble Fe correlated with non-sea-salt sulfate, water-soluble organic carbon, and nitrate, possibly because of an anthropogenic, relatively soluble, form of Fe or enhanced dissolution caused by reactions with anthropogenic acids. Sea salt loadings evidently have a negative effect on %Fe s , presumably due to buffering effects of the salts. Dust concentrations and %Fe s followed an inverse power law relationship with a moderate correlation, suggesting that the %Fe s may be increased by acid processing during transport as dust loadings gradually decrease.

Case study of the Asian dust and pollutant event in spring 2006: Source, transport, and contribution to Taiwan

Surface measurements and a regional dust model were used to analyze the source, transport, and contribution of a dust event transporting with aerosol pollutant over Taiwan from 16 to 19 March, 2006. During the event, the hourly aerosol concentrations reached close to 400 μg m(-3) in northern Taiwan, and approximately 300 μg m(-3) in other areas of the island. Trajectory and regional dust models show that the dust event originated in eastern Mongolia and northern China, and the dust layer can descend from 2 to 3 km in the source area to below 1.5 km over Taiwan. On the other hand, model results show that pollution was transported near the surface from coastal China to Taiwan. During this dust event, polluted aerosol was first observed over northern Taiwan right after a frontal passage, and the concentration was strongly enhanced following the passage of the light rainfall 12h later. The descent of dusty air from the free troposphere lagged the arrival of polluted air by 7h, and was partially mixed with polluted aerosol when the transport decelerated over Taiwan. During the event, dust particles accounted for up to 60% of observed particulate matter less than 10 μm (PM10) over Taiwan, but decreased to less than 35% for particulate matter less than 2.5 μm (PM2.5) over most areas of the island. On the other hand, the long-range transport of non-dust aerosols, mainly anthropogenic pollutants, accounted for close to 30% of observed PM10 concentration in northern and western Taiwan prior to dust arrival, and the contribution of PM2.5 increased to close to 40% over the same areas. Local emission of aerosols accounted for less than 25% of PM10 concentrations in northern Taiwan, but was about 60% for PM2.5 in central and southern Taiwan because these areas are less influenced by long-range transport.