北京市冬季室内空气PM_(10)微观形貌及粒度分布

Microscopic morphology and size distribution of indoor air PM_(10) in Beijing City in winter

探讨了北京市吸烟和非吸烟4户家庭室内外空气可吸入颗粒物(PM10)的质量浓度变化规律,利用高分辨场发射扫描电镜(FESEM)和图像分析技术研究了室内PM10的微观形貌特征及粒径分布特点.结果表明,吸烟室内PM10浓度一般高于非吸烟室内;室内PM10一般由烟尘集合体、燃煤飞灰、矿物颗粒、生物质颗粒及未知颗粒共5种颗粒物组成.吸烟和非吸烟室内PM10的粒径-般小于2.5μm,呈双峰分布.其中在吸烟室内,烟尘集合体和未知颗粒等的贡献比较大,而非吸烟室内PM10的数量-粒度分布也为双峰分布,烟尘集合体、燃煤飞灰的贡献比较大.吸烟和非吸烟室内PM10的体积-粒度分布均为单峰分布,并且集中在2.5-10μm范围.其中吸烟室内的烟尘集合体,矿物颗粒物占优势.而非吸烟的室内矿物颗粒占优势.虽然矿物颗粒对粒度粒径的贡献较小,但对体积的贡献比较大.

Indoor inhalable particles (PM10) mass concentrations in 4 smoker's and non-smoker's homes of Beijing City was discussed, and microscopic characteristics and size distribution of PM10 was investigated by high resolution Field Emission Scanning Electron Microscopy (FESEM) and image analysis technologies. The PM10 concentrations in smoker's homes were usually higher than those of non-smoker's. Indoor PM10 could be divided into 5 major categories, including soot aggregates, fly ash, mineral, biological and unresolved particles. Most PM10 particles were in the size range of <2.5 um displaying a bimodal number-size distribution. Soot aggregates and unresolved particles made a great contribution to PM10 number in smoker's homes, while soot aggregates and fly ash dominated the non-smoker's homes. In contrast, volume-size distribution of PM10 in both smoker's and non-smoker's homes exhibited a unimodal pattern with the peak in 2.5~10um range. By volume, mineral particles were major components of PM10 in smoker's homes and mineral particles were also typical in non-smoker's homes. Though mineral particles were insignificant in number, they normally have a considerable contribution to PM10 volume.