Han Tingting, Liu Xingang, Zhang Yuanhang, Qu Yu, Zeng Limin, Hu Min, Zhu Tong
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
J Environ Sci (China). 2015 May 1;31:51-60. doi: 10.1016/j.jes.2014.08.026. Epub 2015 Mar 3.
A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility<l0 km and RH (relative humidity)<90%. Four haze episodes, which accounted for ~60% of the time during the whole campaign, were characterized by increases of SNA (sulfate, nitrate, and ammonium) and SOA (secondary organic aerosol) concentrations. The average values with standard deviation of SO4(2-), NO3-, NH4+ and SOA were 49.8 (±31.6), 31.4 (±22.3), 25.8 (±16.6) and 8.9 (±4.1)μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO4(2-), NO3-, NH4+, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about 27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR (sulfur oxidation ratio) and NOR (nitrogen oxidation ratio) increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO4(2-) and NO2 to NO3-, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing.
2006年8月18日至9月8日在中国北京进行了一项野外实验。雾霾天被定义为能见度<10公里且相对湿度（RH）<90%。四个雾霾时段占整个观测期间约60%的时间，其特征是硫酸盐、硝酸盐和铵（SNA）以及二次有机气溶胶（SOA）浓度增加。在雾霾时段，SO4(2-)、NO3-、NH4+和SOA的平均值及标准差分别为49.8（±31.6）、31.4（±22.3）、25.8（±16.6）和8.9（±4.1）μg/m3，分别是非雾霾天的4.3、3.4、4.1和1.7倍。在非雾霾天，SO4(2-)、NO3-、NH4+和SOA分别占PM10总质量浓度的15.8%、8.8%、7.3%和6.0%。在雾霾天，SNA各物种对PM10的贡献分别升至约27.2%、15.9%和13.9%，而SOA的贡献保持在同一水平，略有下降至约4.9%。观测到的SNA和SOA质量浓度随PM10质量浓度的增加而增加，然而，SNA的增加速率比SOA快得多。硫氧化率（SOR）和氮氧化率（NOR）从非雾霾天到雾霾天增加，并随相对湿度的增加而增加。高浓度的气溶胶和水汽有利于SO2向SO4(2-)以及NO2向NO3-的转化，这加速了气溶胶的积累并导致北京雾霾的形成。
