Concentrations of nano and related ambient air pollutants at a traffic sampling site

Abstract

A micro-orifice uniform deposit impactor (MOUDI) and a nano-MOUDI were used to measure the atmospheric coarse (PM2.5- 10), fine (PM2.5), ultrafine (PM0.056 - 1) and nano (< 0.056 μm) particle concentrations and size distributions at a traffic sampling site in winter in central Taiwan, from November 2004 to January 2005. Concentrations of metallic elements (Fe, Mg, Cr, Zn, Pb, Cu) and major ion (SO2-4; NO-3; NH+4) in particles of various sizes (nano, ultrafine, fine and coarse) were measured. Ambient air particulates generally exhibited a bimodal size distribution in the range 0.056-10 mm. The results show that the concentrations followed the order, Fe-Mg-Cr-Zn-Pb-Cu in PM10, fine, ultrafine and nano-sized particles. Moreover, the data showed that the average metallic elements Fe and Zn have similar concentration distributions: the concentration decreased as the particle size fell in the nano size range.