中文摘要：

采用傅里叶变换衰减全反射红外光谱法（ATR-FTIR）研究北京西北城区灰霾天气下PM_（2.5）中有机官能团（R-OH羟基、R-CH脂肪族碳氢基、R-CO-羰基、R-NO2硝基官能团）和无机离子（NH_4~＋、SO_4~（2-）、NO_3~-）的变化规律.结果表明,PM_（2.5）中无机离子（NH_4~＋、SO_4~（2-）、NO_3~-）的ATR-FTIR吸收峰值高于有机官能团（R-CH,R-CO-,R-NO_2,R-OH）的峰值;有机官能团R-CH的吸收峰峰值高于R-CO-和R-NO_2官能团的吸收峰,R-OH官能团的吸收峰峰值最低.灰霾天PM_（2.5）中各有机官能团和无机离子的ATR-FTIR吸收峰值明显高于非灰霾天.说明灰霾天气下PM_（2.5）中这些官能团及无机离子的质量浓度均高于非灰霾天.灰霾天PM_（2.5）中无机离子（NH_4~＋、SO_4~（2-）、NO_3~-）质量浓度高于有机官能团（R-CH,R-CO-,R-NO_2,R-OH）的质量浓度,且有机官能团以R-CH为主,R-CO-,R-NO_2次之,R-OH最少.

英文摘要：

An Attenuated Total Reflectance-Fourier Transform Infrared （ART-FTIR） spectroscopy was used to measure the functional groups （R-NO2, R-CO-, R-CH and R-OH） and inorganic ions （SO42-, NO3- and NH4＋） in PM2.5 collected in the northwest of Beijing during haze days. The absorption peaks of inorganic ions （NH4＋, SO42- and NO3-） were higher than those of functional groups （R-NO2, R-CO-, R-CH and R-OH）, the absorption peak of R-CH was higher than those of R-NO2 and R-CO-, and the absorption peak of R-OH was lowest. The absorption peaks of these functional groups and inorganic ions of the PM2.5 in haze days were higher than those in the non-haze days, indicating that the mass concentrations of these functional groups and inorganic ions in haze days were higher than those in the non-haze days. During haze days, the mass concentrations of the inorganic ions （NH4＋, SO42- and NO3-） were higher than those of functional groups （R-NO2, R-CO-, R-CH and R-OH）, the mass concentration of R-CH was higher than those of R-NO2 and R-CO-, and the mass concentration of R-OH was lowest.