某燃煤电厂周边区域空气中亚微米颗粒物的粒径分布特征

Characterization of the submicrometer particle size distribution around a coal-fired power plant zone

为研究某燃煤电厂周边区域中亚微米颗粒物的分布特征,于2017年11、12月份使用静电低压冲击器对电厂下风向不同距离处大气中亚微米颗粒物进行了实时测量。结果表明:采样点中亚微米颗粒物以核模态(<20nm)粒子数浓度占亚微米颗粒物的50%以上,超细颗粒物(<100 nm)是电厂周边亚微米颗粒物中的主要成分。电厂西南方向(下风向)14 km处核模态、爱根核模态(20~100 nm)及积聚模态(100~1 000 nm)粒子数浓度均高于对照点,日均值分别为138 364、8 803、4 450 cm^(-3)。不同距离处各模态粒子数浓度日变化特征存在较大差异。电厂西南方向的6、9、12、14 km处核模态粒子数浓度均在17:00左右达到峰值,其中14 km处的爱根核模态和积聚模态粒子数浓度峰值均出现在17:00,电厂东北方向3 km处的对照点的核模态粒子数浓度呈现"双峰型"日变化特征,峰值出现在9:00和17:00;位于电厂污染物最大落地地面浓度距离处左右的14 km处亚微米颗粒物的主要来源于电厂的烟气排放。

A real-time measurement and analysis of the submicrometer particle size distribution was conducted using the electronic low pressure impactor in different distances down the wind of a coal-fired power plant from november to december,2017.The results showed that the largest number concentration of the submicron particles in these sampling site from the power plant were nucleation mode(<20 nm),which made up 50%number concentration of the submicron particles.It’s clear that ultrafine particles(<100 nm)were the fundamental part of the submicron particle in the atmospheric environment around the coal-fired power plant.The averaged number concentration of nucleation mode,aitken mode(20-100 nm),accumulation mode(100-1 000 nm)at 14 km south east(downwind)of the coal-fired power plant were higher than the background site,which were 138 364,8 803,and 4 450 cm-3,respectively.Number concentration of mode particle in different distance from the power plant has obvious diurnal variation.Nucleation mode particle number concentration at 6,9,12,and 14 km south east of the coal-fired power plant showed a trend,the highest number concentration of particles emerged at 17:00 when the number concentration at background site showed“double peak”trend change,the highest number concentration of particles emerged at 9:00 when the second number concentration at 17:00.The main atmospheric submicron particle resource of the 14 km was coal-fired power plant emission,which was the nearest place to the maximum pollutant concentration distance around it.