济南市春季大气颗粒物污染研究

Study on atmospheric particle pollution of Jinan in the spring of 2005

对济南市2005年春季大气颗粒物中PM10、PM2.5和细颗粒物中的黑碳气溶胶的浓度水平、时间分布和日变化进行了观测,并结合气象资料对变化特征进行综合分析,探讨了PM10、PM2.5和黑碳的相对含量以及对能见度的影响等.研究结果表明,PM10和PM2.5平均浓度分别为242.5μg·m-3和109.4μg·m-3,与我国空气质量二级标准PM10日均值150μg·m-3和美国国家空气质量PM2.5日均标准65μg·m-3相比,超标率分别达到80.77%和84.61%,污染较严重;监测期间PM2.5/PM10的平均值为0.456.在PM2.5中,黑碳气溶胶平均质量浓度为5.39μg·m-3,占PM2.5的5.06%,日浓度变化呈双峰型.在监测时间内,污染物浓度与温度无明显的相关性;与相对湿度呈弱正相关;与风速呈明显的负相关关系.降水对PM10、PM2.5和黑碳的清除作用较为显著.PM10、PM2.5和黑碳浓度与能见度均呈负相关,相关系数(r)分别为-0.633、-0.695和-0.704,细颗粒物是影响能见度的主要因素.

The concentration, temporal distribution and diurnal variation of PMl0 and PM2.5 and the concentration of black carbon in fine particles were measured during the spring of 2005 in Jinan. The average concentrations of PM10 and PM2.5 were 242.5 μg·m^-3 and 109.4μg·m^-3, respectively. According to China National Ambient Air Quality Standard Class Ⅱ for PM10 of 150 μg·m^-3 and EPA＇s Standard for PM2.5 of 65 μg·m^-3, Jinan air exceeded the standards for PM10 80.77% of the time and for PM2.5 84.61% of the time indicating very serious atmospheric pollution in the city. The average concentration of black carbon in PM2.5 was 5.39 μg·m^-3 and the diurnal variation of black carbon shows two peaks. The mass fraction of PM2.5 in PM10 was 45.6% and the mass fraction of black carbon in PM2.5 was 5.06%. A further statistical analysis, together with meteorological parameters, indicated that the concentration of particles was positively correlated with the relative humidity （RH） and significantly negatively correlated with the wind velocity, but not obviously correlated with the temperature. Rain plays an important role in the cleanup of aerosols. The correlation coefficients of PM10, PM2.5 and BC with visibility were -0.633, -0. 695 and -0.704, respectively, and the fine particles had a much more conspicuous effect on the decrease of visibility than coarse particles.