Influence of long-range transport dust particles on local air quality: A case study on Asian dust episodes in Taipei during the spring of 2002

In the spring of 2002, an intensive field measurement campaign was conducted to investigate the impact of Asian dust transport on local air quality in Taipei, Taiwan. The mass concentration, size distribution and chemical composition of the atmospheric aerosols were measured. Air quality data collected by the Taiwan EPA during this period were also analyzed. It was found that the content of crustal elements in aerosols could drastically increase on the arrival of air masses transported from the desert areas in Northwestern China and Mongolia. Time series analysis of aerosol measurements, air quality data, and meteorological conditions identified six Asian dust transport episodes occurring in the spring of 2002. In order to apportion the ambient aerosol burden between local and long-range sources, nitrogen oxides (NOX) was chosen as a local pollution tracer and a simplified algorithm based on the NOX and PM10 correlation was proposed. It was estimated that long-range transported aerosols contributed as much as 87% to the PM10 in Taipei on Feb. 11, the most intense dust event in 2002. A weak event that occurred on Mar. 23 contributed 35 % to the PM10 - Our results indicate that the air quality impact due to Asian transport dust is still important even during weak dust events.