宜昌地区大气污染特征及气象影响分析

Characteristics and Meteorological Factors of Air Pollution in Yichang City

为探讨宜昌市主要大气污染变化的气象成因,利用2016~2020年气象与环境监测资料,对宜昌污染物变化特征及关键气象因素进行了分析,结果表明:①宜昌市主要污染物为PM_(2.5)、PM_(10)和O_(3),除2019年受频繁弱冷空气和伏秋连旱影响、污染加重外,空气质量整体变好。②颗粒物浓度与平均气温整体负相关,O_(3)浓度与平均气温正相关,15~17℃时,易出现PM_(2.5)-O_(3)复合污染。③相对湿度50%~80%时,与PM_(10)和O_(3)浓度负相关,与PM_(2.5)浓度正相关;80%以上时,受西南暖湿气流增湿减压及冷空气水平输入影响,颗粒物浓度波动上升,接近饱和时陡增。④降水对PM_(2.5)的正清除率占比与降水量相关性最好,PM_(10)浓度与降水量相关性最强。⑤风速增加有利于颗粒物浓度下降,但平均风速3.3~3.7 m/s时,粉尘被风带起,颗粒物浓度增大;平均风速大于2.1 m/s时,风对O_(3)扩散稀释作用为主。

Meteorological and environmental monitoring data were used to analyze relationship between major air pollutants and meteorological factors in Yichang City from 2016~2020.The results showed that:①The main air pollutants in Yichang City were PM_(2.5),PM_(10) and O_(3).The air quality had been improved except for 2019,because of frequent weak cold air and continuous drought.②Average temperature had positive correlation between O_(3) concentration.Average temperature had negative correlation with particulate matter.At 15~17℃,the weak cold air was active and the temperature fluctuated greatly and induced PM_(2.5)-O_(3) compound pollution.③When the relative humidity was 50%~80%,it was positively correlated with PM_(2.5),and negatively correlated with PM_(10) and O_(3) concentration.Affected by warm and humid air flow and cold air,the particle concentration fluctuated and increased sharply near saturation.④The proportion of positive scavenging rate of PM_(2.5) had the best correlation with precipitation,and the correlation between PM_(10) concentration and precipitation was the strongest.⑤Wind speed was negatively correlated with PM_(2.5) and PM_(10) concentrations,but the correlation was positive when the average wind speed was 3.3~3.7 m/s.Wind speed was positively correlated with O_(3) concentrations,but the correlation was negative when the average wind speed was above 2.1 m/s.