Distribution of atmospheric particulate inorganic nitrogen in different weather conditions in the heating period in Qingdao

Abstract

The atmospheric aerosol samples were collected before and in the heating period during October 2007-April 2008 in Qingdao coastal region, and inorganic nitrogen components were analyzed using IC (Ion Chromatography). The results showed that the concentration of aerosol particles and particulate inorganic nitrogen components (NH+4, NO-3) were increased from 137.41 μg/m3, 2.48 μg/m3, 6.95 μg/m3before to 250.34 μg/m3, 4.43 μg/m3, 10.28 μg/m3in the heating period respectively. The concentrations of TSP (total suspended particles) and inorganic nitrogen in Qingdao were influenced by different weather conditions. The average concentration of TSP was 181.34 μg/m3in sunny days during heating period, increased by 32.0% than before. But the nitrate and ammonium showed a value of 5.56 and 1.86 μg/m3in sunny days, lower than that before heating, which mainly came from secondary aerosols. The average concentrations of TSP, nitrate and ammonium increased were 1-2 times higher in foggy days in heating period due to lower temperature, high humidity and accumulation of pollutants. The concentrations of TSP, nitrate and ammonium decreased in strong winds and temperature drop weather. The size distribution of aerosol particles and inorganic nitrogen, were influenced clearly by heating soot and ash. The size distribution of nitrate showed double peaks with a higher peak in accumulation mode (0.43-0.65 μm) and a lower one in coarse mode (3.3-4.7 μm) before heating, and the peak in the 'accumulation mode' shifted to 0.65-1.1 μm during heating period. NH+4-N, a major inorganic nitrogen component in the particulate matter, showed single peak in the "accumulation mode".