Asian Dust Storm and Their Impact on the Air Quality of Taiwan

Abstract

Measurements of aerosols (PM1O) and other air pollutants at stations of the air quality monitoring network of Taiwan Environmental Protection Administration (EPA) from 1993 to 2000 are analyzed to evaluate the impact of Asian dust storm events on the air quality of Taiwan. Enhancements of PM10 at Yangming mountain station in northern Taiwan as well as coastal stations to the north and northeast turn out to be the key indicators in identifying unambiguously the major Asian dust storm events and to estimate the impact of these events on the PM10 over Taiwan. Our analysis shows that the major increases of PM10 at Yangming station occur in March, April, and May. They are clearly associated with the Asian dust storm events. On a yearly basis, the impact ranges from about 3% in southwestern cities to about 12% for Yangming station. On the monthly basis, the enhancements can be as large as 150% for a clean station such as Hengchun hear the southern tip of Taiwan. Although the major component of the observed PM10 enhancements is mineral dust, we estimate that sulfate and nitrate ions contribute to about one quarter of the enhancements. The corresponding enhancements for other air pollutants (i.e. CO, O3, NO2, and SO2) can be identified only occasionally because of high ambient values, large variability in concentrations, and other reasons.