Instrumental neutron activation analysis of extractable organohalogens in PM2.5 and PM10 in Beijing, China

PM2.5 and PM10 samples were simultaneously collected monthly at a downtown site in Beijing from May 2002 to April 2003 and analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction method for the concentrations and distributions of extractable organohalogens (EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and organoiodinated compounds (EOI). The concentrations of EOCl, EOBr and EOI were 10.5–79.2 ng/m3, ND-8.2 ng/m3 and 1.6–8.2 ng/m3 in PM2.5, respectively, and 37.0–73.3 ng/m3, 1.6–12.8 ng/m3 and 1.6–8.5 ng/m3 in PM10, respectively, which were increasing in the order of EOCl≫EOBr∼EOI. EOCl accounted for 73–88% and 69–91% of EOX in PM2.5 and PM10, respectively, which showed that EOCl was the major component of the organohalogens. There was a significant difference of EOCl concentrations in PM2.5 and PM10 in different seasons, which suggested that the concentrations of EOCl in the atmosphere were significantly affected by the meteorologic conditions and anthropogenic activities.