摘要
依据2001-2012年的空气污染指数(API)日报数据,从月(或季、年)平均和空气污染等级2个角度出发,研究西北5省5城市(西宁、兰州、银川、西安和乌鲁木齐)API和空气污染状况比例的变化特征和趋势分析,统计结果表明:(1)5城市空气质量等级以Ⅱ级良为主,首要污染物以可吸入颗粒物为主。在年、季节、采暖期和非采暖期API值有趋于同步的下降变化趋势,污染(优良)天数呈现明显的下降(上升)趋势,大气污染呈现一定的"区域化"的特征。(2)5城市API指数变化规律有明显的时间和空间差异。从多年API年均值来看,西安、兰州和乌鲁木齐较高,银川和西宁相对较低,且乌鲁木齐、兰州和西宁空气质量状况不稳定,而西安和银川变化相对比较平缓。5城市的年变化也呈现不同的变化特征,总体上夏秋季空气质量明显好于冬春季。(3)5城市谱峰区间逐渐向低浓度范围偏移且天数逐渐增加,高浓度事件逐渐减少,各城市向低浓度转变的年份不完全一致。
From the views of monthly mean and air pollution level, the variation characteristics and trend of API and pollution proportion of five cities(Xining, Lanzhou, Yinchuan, Xi′an and Urumqi)are researched based on the daily air pollution index(API) during 2001 to 2012. The results show as follows:(1)Air quality levels in five cities were rated level Ⅱ. The primary pollutants is inhalable particles. API show a decrease trend in inter-annual, seasonal, heating period and non-heating period, the days of pollution also show obvious decline trend. Air pollution present'regionalization'characteristics.(2)API index have obvious difference in temporal and spatial scale. Air quality in Xi′an, Lanzhou and Urumqi is higher than air quality in Yinchuan and Xining from annual average of API analysis. Air quality is stable in Xi′an and Yinchuan but fluctuating in Urumqi, Lanzhou and Xining. Annual API appear different characteristic in five cities but air quality is better in summer than winter and spring.(3)Peak identification of API reveal that API skewed to low concentration and the number of days increased. High concentrations of API events reduce gradually. The year that API changed to low concentration is not same in each city.
出处
《环境科学与技术》
CAS
CSCD
北大核心
2014年第S2期183-189,共7页
Environmental Science & Technology
基金
国家自然科学基金地区科学基金项目(41161009
41165008)
