传输指数在合肥市重污染过程中的应用分析

Application of transport index for heavy air pollution in Hefei during winter in 2015

利用潜在源区贡献法计算了合肥市2015年冬季传输指数,并基于传输指数和PM_(2.5)浓度将合肥市的重污染过程划分为3类,同时对各类重污染过程进行气象成因分析.结果表明:污染物传输型重污染过程的传输指数明显增大且PM_(2.5)浓度急剧增大;污染物积累型重污染过程的传输指数无明显增大且PM_(2.5)浓度逐渐增大;污染物暴发性排放型重污染过程的传输指数无明显增大但PM_(2.5)浓度急剧增大.污染物传输型重污染过程主要是高压南下迫使北方重污染气团输送引起的;污染物积累型重污染过程主要是静稳的天气形势导致污染物堆积造成的;污染物爆发性排放型重污染过程是由污染物暴发性排放而无法及时扩散引起的.

In this study, the transport index was calculated with PSCF for heavy air pollution in Hefei during winter in 2015. Based on the transport index and PM2.5 concentration, the heavy air pollution events were classified into three types, i.e. ＂transport type＂, ＂accumulation type＂, and ＂explosion type＂. Results showed that for ＂transport type＂, the transport index and PM2.5 concentration increased rapidly. However, gradual increase of PM2.5 concentration and no significant increase in the transport index were observed in ＂ accumulation type＂. In comparison, PM2.5 concentration increased dramatically without significant increase in the transport index for ＂explosion type＂. The meteorological conditions played an important role for all types of heavy air pollution. The northern high-pressure center brought the polluted air into Hefei and induced ＂transport type＂ heavy pollution. The ＂accmrtulation type＂ heavy pollution was associated with the poor horizontal and vertical diffusion conditions due to the stability of atmosphere. The ＂explosion type＂ heavy pollution was mainly triggered by sudden massive emissions of pollutants together with the unfavorable atmospheric diffusion and dilution conditions.