Spatial variations of airborne particles in metropolitan Taipei.

During the summer and fall of 1991, total (TSP) and PM10 measurements were conducted at several sites simultaneously to evaluate the spatial variation of particle pollution in Taipei. Eighty-four samples were obtained from high-, medium- and low-polluted areas of the city. PM10 levels on roadside, sidewalk and covered walkways near a main road were 527.8 micrograms/m3, 466 micrograms/m3 and 477 micrograms/m3, respectively; the concentrations were not significantly different horizontally away from the emission sources. The PM10 concentrations on the second, seventh and 14th floors of a building were 305.31 micrograms/m3, 178.3 micrograms/m3 and 168.7 g/m3, respectively; the highest was on the second floor, but concentrations did not diminish from the seventh to the 14th floor. In addition, PM10 concentrations on the main street, side street and alley of an area were 155.3 micrograms/m3, 267.7 micrograms/m3 and 167.1 micrograms/m3, respectively; the highest concentration appeared on the side street. Furthermore, high fractions of PM10 in TSP mass were 90%, 84% and 79% for the high-, medium- and low-polluted areas. The percentages that exceed the US PM10 standard of 150 micrograms/m3 for the high- and medium-polluted areas were 100% and 71% and their exceedance was substantial. Therefore actions to mitigate the emission sources need to be fortified.