Characterization of atmospheric organic and elemental carbon of PM2.5 in a typical semi-arid area of northeastern China

In the spring of 2006, daily particulate matter (PM2.5) aerosol samples were collected in Tongyu, a semi-arid area in northeastern China. The concentrations of organic carbon (OC) and elemental carbon (EC) were determined with a thermal/optical carbon analyzer in the filter samples. The average concentrations of OC and EC in PM2.5 were 14.1 ?? 8.7 and 2.0 ?? 1.3 ?gg/m3, respectively. A good correlation between OC and EC was observed during the spring season, suggesting that they might be derived from similar sources. The correlation between OC and K+ was high (R = 0.74), and the K+/OC ratio, as detDepartment of Civil and Environmental Engineerin