| Applying of passive sampler which is a cheap and simple method, the concentrations of SO2, NO2, O3and NH3 were monitored in ten stations as network in Beijing-Tianjin-Hebei area from Dec. 2007 to investigate the concentration level and change of contaminants as well as the compound pollution in this region. Passive sampler method was fully evaluated to check the applicability in the area and the concentration and spatial distribution of pollutants were studied in this paper. The evaluation results indicate that passive sampler method can be used for long term sampling and the frequency was settled as one month. The coefficients of variation of parallel samplers of SO2, NO2, O3 and NH3 were 6.4%, 7.1%, 4.2% and 3.9% respectively which can represent the good stability of this method. The concentrations monitored by passive sampler had good consistency with the monthly average concentrations calculated from active monitoring. The correlation coefficients of SO2, NO2 and O3 were 0.91, 0.88 and 0.93, slopes of fitted curve were 1.25, 0.98 and 0.93 and average relative standard deviation were 23.3%, 14.9% and 8.5% respectively which indicated that passive sampler can basically meet the atmospheric sampling requirement. Short-term monitoring of NH3 also indicated that results of passive sampler and active monitoring were comparable. Passive sampler is proven to be a reliable atmospheric monitoring method and can be used in regional pollution investigation. In the summer of 2008, average concentrations which were monitored by passive sampler calculated from 10 observation stations of SO2, NO2, O3 and NH3 were (12.3±6.3)×10-9, (13.2±7.0)×10-9, (40.5±9.5)×10-9 and (24.0±13.7)×10-9 respectively in Beijing-Tianjin-Hebei area. The concentrations of SO2 and NO2 were relatively higher in city sites and concentrations of NH3 were higher in agricultural sites. The pollution of SO2, NO2 and NH3 are obviously influenced by local emission. The concentrations of O3 were about 40×10-9in most area around Beijing and Tianjin except background station Xinglong and showed regional pollution characteristic. |
