天津市PM10, PM2.5和PM1连续在线观测分析

利用2010年9月1日─11月30日在中国气象局天津大气边界层观测站采集的ρ(PM10),ρ(PM2.5)和ρ(PM1)数据,分析了观测期间可吸入颗粒物的统计特征,结合同期气象观测资料,分析了典型天气条件下ρ(PM10),ρ(PM2.5)和ρ(PM1)的日变化特征及与风速、风向的关系.结果表明:观测期间,ρ(PM10)日均值有超过12的天数超过《国家环境空气质量标准》(GB 3095─1996)二级标准限值;ρ(PM2.5)有63 d超过美国国家环境保护局(US EPA)1997标准限值,超标率高达76.8%;不同天气条件下,ρ(PM10),ρ(PM2.5)和ρ(PM1)日变化特征明显,三者一般在大雾或扬沙浮尘天气条件下出现高值,有降水过程时出现低值;可吸入颗粒物以粗粒子(PM2.5～10)和PM1为主,PM2.5～10,PM1～2.5和PM1主要分布在风速小于3 m/s,风向为225°～280°和70°～110°范围内;风速大于3 m/s时,ρ(PM2.5～10)和ρ(PM1～2.5)有所增加.ρ(PM10),ρ(PM2.5)和ρ(PM1)未出现周末效应,但存在明显的周内变化.

Continuous Online Observation Analysis of Mass Concentrations of PM10, PM2.5 and PM1 in Tianjin City

The statistical characteristics of inhalable particles were determined based on mass concentration data of PM10,PM2.5 and PM1 observed in the atmospheric boundary layer station of the Chinese Meteorological Administration in Tianjin during September 1 to November 30,2010.Daily variations of ρ(PM10),ρ(PM2.5) and ρ(PM1) were analyzed separately in typical synoptic conditions combined with meteorological data during the same period.Relationships were determined between mass concentration of different sized particulate matter and wind speed and direction.The results show that the daily average of ρ(PM10) was above the second standard of the national air quality standards for more than half of the days during the observation period.ρ(PM2.5) was above the US EPA 1997 standard for 63 days,accounting for 76.8% of the time.Diurnal variations of ρ(PM10),ρ(PM2.5) and ρ(PM1) were obviously different among different weather conditions: largest in the dense fog or blowing sand dust condition,and lowest in the precipitation condition.Coarse particles PM2.5-10(diameter 2.5-10 μm) and PM1 were the main components of the inhalable particles in Tianjin.The mass concentrations of PM2.5-10,PM1-2.5 and PM1 mainly accumulated when the wind speed was less than 3 m s and the wind direction was 225°-280° and 70°-110°.When the wind speed exceeded 3 m s,ρ(PM2.5-10) and ρ(PM1-2.5) increased to some extent.The air pollutants varied greatly during the week,but no "weekend effect" was observed.