广州市大气PM2.5中多环芳烃的现状及分布情况

目的 了解广州市大气PM_2.5中多环芳烃在不同时间、不同地区内的分布特征。 方法 于2018年在广州市越秀区(市区),从化区(农村)和番禺区(市郊)采集PM_2.5有效样品252份,用高效液相色谱法测定样品中16种多环芳烃的浓度,以分析不同地区、不同时间及季节间的分布特征和变化趋势。结果 广州市大气PM_2.5中16种多环芳烃均有检出,但质量浓度处于较低水平,年均值为(4.907±3.642)ng/m³。PM_2.5及多环芳烃的质量浓度呈现明显的季节性波动,表现为冬春季较高,夏秋季较低,不同季节差异有统计学意义(F=3.624～72.439,均P<0.05)。市区为(54.321±35.106)μg/m³,农村地区为(46.298±25.933)μg/m³,市郊PM_2.5的质量浓度为(51.821±30.033)μg/m³,差异无统计学意义(F=1.513,P>0.05),多环芳烃中萘、苯并a]芘、二苯并a,h]蒽、茚并1,2,3-cd]芘的污染水平在不同地区之间差异有统计学意义(F=4.428～6.422,P<0.05),农村高于市区和市郊。结论 广州市大气PM_2.5中多环芳烃污染水平较低,呈现明显的季节性波动和城乡差别。

Current status and distribution of polycyclic aromatic hydrocarbons in atmospheric PM2.5 in Guangzhou City

Objectives To understand the characteristics of temporal and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in atmospheric PM_2.5 in Guangzhou City. Methods A total of 252 effective PM_2.5 samples were collected in Yuexiu District (urban area), Conghua District (rural area) and Fanyu District (suburb) of Guangzhou City in 2018. High-performance liquid chromatography was used to detect the concentration of 16 kinds of PAHs in the samples, and spatial, temporal and seasonal distribution characteristics and variation trends of the PAHs were analyzed. Results Sixteen kinds of PAHs in atmospheric PM_2.5 in Guangzhou City were detected, but the mass concentration of the PAHs was at a lower level, with the annual average being (4.907±3.642)ng/m³. The mass concentration ofPM_2.5 and the PAHs exhibited an obvious seasonal fluctuation, was higher in winter and spring but lower in summer and autumn, showing statistically significant differences among different seasons (F=3.624-72.439, all P<0.05). The concentration of PM_2.5 in urban, rural and suburban areas was (54.321±35.106) μg/m³, (46.298±25.933)μg/m³ and (51.821±30.033) μg/m³, respectively, without statistically significant difference (F=1.513, all P>0.05). The pollution status of naphthalene, benzo a] pyrene, dibenzo a, h] anthracene, indeno 1,2,3-cd] pyrene among different areas showed statistically significant differences (F=4.428-6.422, all P<0.05), and the pollution level was higher in rural area than in urban and suburban areas. Conclusion The pollution levels of the PAHs in atmospheric PM_2.5 in Guangzhou City are lower, showing obviously seasonal variation and urban-rural disparity.