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 μg/m³, 466 μg/m³ and 477 μg/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 μg/m³, 178.3 μg/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 μg/m³, 267.7 μg/m³ and 167.1 μg/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 μg/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.