Measurement on the Atmospheric SO_2, NO_x, CO and O_3 concentrations in Beijing

The purpose of this study is to investigate the atmospheric pollution and its variation characteristics in Beijing, China. Continuous monitoring in the urban area from August 2004 to July 2005 was carried out. The characteristics of concentrations of air pollutants (SO2, NOx, O3 and CO) were analyzed, comparing the variation in different seasons. The results showed that diurnal variation of SO2 concentrations shows a very clear cycle with two peaks, one appears at about 07:00 in the morning and the other is at 23:00 in the evening. The magnitude of concentration of SO2 is obviously higher during the heating period than during the period without heating. The concentration of SO2 during the heating period is over three times as high as the one during the period without heating. The concentrations of NOx and CO appear peaks in the morning and evening respectively. The highest concentrations of NOx, and CO are about 130×10-9 and 3 300×10-9 volume ratio respectively. The diurnal and seasonal variations of the concentrations of NO are obvious, however the variations of NO2 concentrations are not pronounced. The concentration of O3 is higher in summer than in winter, and the diurnal variations show one peak often appear at about 14:00-15:00 in the early afternoon.