Determination of mercury in size-segregated ambient particulate matter using CVAAS

Abstract

Particulate matter-bound mercury (Hg) was investigated in 13 particle size fractions of ambient particulate matter (PM). PM was sampled with the use of a thirteen-stage cascade impactor, in 3-day continuous sampling periods, at an urban background site from January to December 2013. The Hg content of PM was determined by means of cold-vapor atomic absorption spectrometry (CVAAS, MA-2 analyzer, Nippon Instr. Co.) in thermolysed samples. The limits of detection and quantification for the applied analytical method were 0.094 and 0.283ng, respectively. The method performance was checked by determining Hg content of two kinds of reference material with certified Hg content (the mean standard recoveries were 90% and 96%).The yearly concentrations of Hgp (total PM-bound Hg), PM10-, PM2.5-, PM1-, and PM0.1-bound Hg were 66, 64, 54, 43, and 4 pg m−3, respectively. About 97% of the Hgp mass was in PM10, 83% was in PM2.5, 66% was in PM1, and only 6% was in PM0.1.The Hgp mass size distribution was unimodal in the winter and in the whole 2013year and trimodal in the summer. The absolute maxima of the distribution density functions (main modes) occurred in 0.4–0.65μm for the year, 0.4–0.65μm for the winter, and 0.65–1μm for the summer. The two remaining maxima for the summer distribution were in 2.5–4.4μm and 6.8–10μm.