拉萨市环境空气中NO2变化特征分析

选取用长光程差分光谱法监测的拉萨市2000年7月-2004年6月环境空气质量监测数据,分析了NO₂变化特征.结果表明:目前拉萨市ρ(NO₂)在<环境空气质量标准>(GB3095-1996)一级标准之内,但呈逐渐上升趋势.拉萨市ρ(NO₂)月均值呈明显的"U"字型分布规律,即1月和年末10-12月高,其他时间低;每年10月至次年1月,ρ(NO₂)月均值超过年均值,月均最高值均出现在12月;每日在8:00-12:00,20:00-24:00有2个高峰值区.汽车尾气、当地居民生活中的燃烧过程是目前拉萨市NO₂的主要产生源,特殊边界层气象条件影响拉萨市环境空气中ρ(NO₂)的变化规律. 

Recent Atmospheric NO2 Concentration Dynamics of Lhasa City

The variability of NO_2 mass concentration in the air of Lhasa city was analyzed based on the automatically monitoring data from July 2000 to June 2004.It was shown that the NO_2 mass concentration in the air of Lhasa city remained below the first degree according to the Standard of Ambient Air Quality(GB3095-1996),but was increasing in recent years.The seasonal variation of NO_2 mass concentration in the air was that it was higher in the winter(October to January) than in the other months,the highest NO_2 mass concentration emerged in December,and the monthly average of NO_2 mass concentration from October to the next January exceeded the year's mean.The monthly average NO_2 mass concentration showed a typical "U" shape.And daily variation showed two peaks of NO_2 mass concentration in the time period of from 8:00 to 12:00 and from 20:00 to 24:00.The car emission and fuel burning in daily life were the main sources of NO_2 around the Lhasa city at present in terms of human devotion,and the special weather condition in the aerosphere was another factor that affected the variability of NO_2 mass concentration in the city.