杭州灰霾现象与环境空气质量的差异比较

对2006-2010年颗粒物浓度和灰霾进行分析,比较灰霾天数与颗粒物浓度超标状况,并设立多个颗粒物评价指标进行筛选,结果表明,近5年来杭州灰霾频繁出现,灰霾频率平均为41.9%,依据目前环境空气质量评价体系进行的评价表明主城区环境空气质量优良率平均为84.7%,,超标率仅15.3%,与灰霾频率相差悬殊。增加新修改的国家环境空气质量标准(征求意见稿)中PM2.5日均浓度(参考限值)为指标进行评价,超标率为33.3%,,比原评价体系有较大幅度的改善,但仍有一定的差距。考虑到灰霾现象出现的短期性,再增加PM2.5最大小时浓度作为新指标。在选取0.100 mg/m3、0.150 mg/m3、0.200 mg/m3三个参考值作为增加指标时,以0.150 mg/m3作为最大小时浓度限值指标时,超标率为39.2%,与灰霾频率基本一致。

Difference of Haze Phenomenon and Ambient Air Quality in Hangzhou

Based on air quality monitoring data and haze data in Hangzhou from 2006-2010,nonattainment situations between concentration of particulate matter with haze were compared.Several evaluation parameters about particles were selected.Results showed that haze frequently occurred in recent 5 years,which was about 41.9% annually.But nonattainment rate of API for current ambient air quality assessment was about 15.3% every year,which was wide gap difference with haze frequency.According to newly revised national ambient air quality standards,the reference limit value of PM2.5 diurnal average concentration was 0.075 mg/m3.Nonattainment rate of PM2.5 concentration was 33.3%,which were still bigger difference with frequency of haze even if it was improved upon one of PM10.Due to short term occurrence of haze phenomenon,hourly peak PM2.5 concentrations were chosen as the reference limit value,which were above 0.100 mg/m3,0.150 mg/m3,0.200 mg/m3 respectively.When the limit value was chosen as 0.150 mg/m3,nonattainment rate was kept consistent with the frequency of haze.