灰霾天气下煤矿区气溶胶单颗粒特征

Individual particle characterization of aerosol in mining area under hazy weather

采用带能谱的透射电镜(TEM-EDX)分析煤矿区城市大气PM_(10)的类型和成分,并重点分析矿物颗粒的酸化机理及其在大气化学中的作用.结果表明:PM_(10)主要包括矿物颗粒、烟尘集合体、燃煤飞灰、碳质颗粒以及一些混合颗粒等.其中,矿物颗粒共有4种类型:原生不规则矿物,以粘上、碳酸盐为主,主要来源于地壳;核-壳结构矿物,为原生矿物与酸性气体反应的产物;规则矿物,以大气中直接结晶析出的K_2SO_4和CaSO_4为主;球形矿物,主要为表面覆盖一层水膜的(NH_4)_2SO_4.二次反应生成的矿物颗粒,不仅受SO_2和NO_x排放量的影响,还与PM_(10)的化学组成以及空气湿度有关.

Particulate matter 〈10um of coal-industrial city was studied under transmission electron microscopy equipped with X-my energy-dispersion spectroscopy, and emphasis was placed on PMlo acidification mechanism as well as its effect on atmospheric chemistry. Particulate matter was composed of mineral particles, soot, fly ash, Carbon-rich particles, as well as some mixed particles. Mineral particles can be divided into 4 types： a） irregular particles, dominated by clay and carbonate, which are of crustal origin; b） coated particles, product of heterogeneous reaction of crustal minerals with acidic gas; c） regular particles, mainly directly precipitating from atmosphere as K2SO4 and CaSO4; d） spherical particles, （NH4） 2SO4 particles coated by a moisture film. The formation of secondly mineral particles was not only influenced by SO2 and NOx emission, but also associated with chemical composition of particulate matter and the atmospheric relative humidity.