秸秆焚烧对哈尔滨空气质量的影响研究

Analysis on effect of straw burning on air quality in Harbin

对2015—2016年哈尔滨重污染天气的分布特征与规律进行分析,依据黑龙江省近10年主要作物秸秆产量、草谷比、焚烧比例和排放因子估算秸秆焚烧对PM2.5贡献量,并结合后向轨迹模型从气象要素、火点分布等方面分析哈尔滨重污染天气的成因。结果表明,哈尔滨2015—2016年重污染天数49d,重污染率6.7%,优良天数515d,优良率70.5%,秋冬重污染天数占重污染总天数的79.6%;2006—2015年黑龙江省秸秆露天焚烧总量18 944.49万t,PM2.5排放总量163.00万t,其中玉米、稻谷、豆类PM2.5排放量最高,分别占PM2.5总排放量的60.73%、23.13%、9.09%;10—11月为秸秆焚烧期,该时段风速小湿度低,稳定的气象条件不利于污染物扩散和颗粒物沉降,是造成污染物累积从而导致重污染天气的重要原因;当地及周边农业种植区秸秆焚烧是造成哈尔滨2015年、2016年10—11月重污染天气的主要原因,且秸秆焚烧对城市空气质量的影响具有数天的滞后现象。

The distribution characteristics and pattern of heavy pollution weather in Harbin during 2015 to 2016 were analyzed.According to the crop straw yield,grass valley ratio,burning ratio and emission factor of the main crops in Heilongjiang province,the emission factor method was used to estimate the contribution of straw burning on PM 2.5.Combined with the backward trajectory model from the aspects of meteorological elements,the fire distribution of heavy pollution weather of Harbin was analyzed.The results showed that from 2015 to 2016,the number of heavy pollution days was 49 d,the heavy pollution frequency was 6.7%,the excellent days were 515 d,the excellent rate was 70.5%,and the days of heavy pollution in autumn and winter accounted for 79.6%of the total heavy pollution days.In the 10 years from 2006 to 2015,the total amount of outdoor burning of straw in Heilongjiang province was 189 444.9 thousand tons,and the total PM 2.5 emissions was 1 630.0 thousand tons,corn,rice,and beans was top three contributor of PM 2.5 emissions,which account for 60.73%,23.13%and 9.09%of total PM 2.5 emissions.During the October to November,straw burning period,low wind speed and low humidity,and stable meteorological conditions were not conducive to pollutant diffusion and particle deposition,which caused the pollutants accumulation and leads to the heavy pollution of weather.The straw burning in local and surrounding agricultural planting area of Harbin were the main causes of heavy pollution in Harbin,however,impact of straw burning on urban air quality would had several days of hysteresis.