河源市空气质量首要污染物特征及其与气象条件的关系

Characteristics of primary pollutants of air quality and their relationships with meteorological conditions in Heyuan

基于2017—2019年河源市空气质量数据,分析了河源市首要污染物的年际变化特征,同时利用2019年东埔国控站点的首要污染物与气象要素进行了相关性分析,并以典型污染日为案例,分析了气象条件对污染过程的影响。结果表明:2017—2019年细颗粒物(PM_(2.5))污染日比重大幅度降低,以臭氧(O_(3))为首要污染物的污染日逐年增加,污染形式逐渐从颗粒物污染向臭氧污染发生转变。O_(3)浓度与温度和湿度分别呈正负相关关系,高浓度O_(3)主要出现在(20—30℃,25%—55%)阈值之间,在吹西北偏北风时O_(3)浓度也较高。PM_(2.5)和PM_(10)与湿度也呈负相关关系,温度与湿度组合在(8—13℃,40%—55%)范围内时两者容易同时出现高值;在夏季PM_(2.5)和PM_(10)还与温度具有较强的正相关关系,这意味着高温情况下河源有出现颗粒物与O_(3)复合污染的可能。河源市典型污染日具有风速较小局部扩散不利的特征,低温低湿条件下容易出现PM_(2.5)污染,且主要受到区域的传输影响;而高温低湿条件下容易发生O_(3)污染,且较高的前体物浓度容易加剧O_(3)的本地污染。

Based on the air quality monitoring data in Heyuan from 2017 to 2019,the interannual variation of primary air pollutants was analyzed in this study.The correlation analysis between the concentrations of primary air pollutants and meteorological conditions was conducted using the data at the Dongpu national observational station in 2019,and the impact of the meteorological conditions on typical air pollution events was also explored.The results showed that the proportion of polluted days with fine particle matter(PM_(2.5))as the primary air pollutant decreases significantly,and the polluted days with ozone(O_(3))as the primary air pollutant increase,which means the particulate matter pollution gradually transfers to ozone pollution in Heyuan.O_(3)concentrations are positively correlated with temperature and negatively correlated with humidity.High concentrations of O_(3)mainly concentrate within the thresholds(20-30℃,25%-55%),and also occur under north-northwesterly winds.PM_(2.5)and PM_(10)concentrations are negatively correlated with humidity and tend to have high values when temperature and humidity are within the ranges of 8-13℃and 40%-50%,respectively.In summer,PM_(2.5)and PM_(10)show a strong positive correlation with temperature,which means the combined PM and ozone pollution is possible to occur under high-temperature conditions in Heyuan.The typical pollution days in Heyuan are characterized by weak winds and unfavorable local dispersion conditions.PM pollution tends to occur under low temperature and low humidity conditions and is mainly affected by regional transport.O_(3)pollution tends to occur under high temperature and low humidity conditions and can be exacerbated in the presence of high precursor concentrations.