2016~2020年石家庄市大气PM2.5化学成分变化趋势及健康风险评估

目的 分析石家庄市大气细颗粒物(PM_2.5)化学成分的变化趋势和季节分布特征,评估其对人群的潜在健康风险。 方法 以石家庄市环境空气质量监测点2 km范围内两所小学的教学楼楼顶作为采样点,于2016年1月至2020年12月的每月10~16日采集PM_2.5样品共840份,并分别采用离子色谱仪、电感耦合等离子体质谱仪和气相色谱-质谱联用仪检测PM_2.5中水溶性无机离子(WSIIs)、金属及类金属和多环芳烃(PAHs)的含量,并依据《化学物质环境健康风险评估技术指南》(WS/T777-2021)评估其对人群的健康风险。 结果 石家庄市2016~2020年PM_2.5年均浓度呈逐年下降趋势,但仍超过标准限值(35 μg/m³),整体呈现出冬秋季高于夏春季的特点。WSIIs在PM_2.5中含量最高,除硝酸根离子(NO₃^-)外其余WSIIs浓度基本呈现出逐渐下降趋势,并表现出与PM_2.5相似的季节分布特征;金属与类金属元素铝(Al)、铅(Pb)、锰(Mn)在PM_2.5中含量较高,除Al和Mn外,其他元素在5年间基本呈下降趋势,但铬(Cr)浓度仍远高于标准限值,多数元素表现出冬季较高的季节分布特征;16种PAHs总年均浓度呈现出自2016年逐渐上升、2018年后逐渐下降的趋势,多数单体表现出秋冬季浓度较高的季节分布特征。风险评估结果显示,砷(As)、Cr和PAHs在不同年份和季节中均存在一定的致癌风险(CR>1.0×10^-6),同时,PAHs也存在较高的非致癌风险(HQ>1)。 结论 近年来石家庄市空气质量虽然有所好转,但形势依然严峻,PM_2.5中部分成分在目前接触水平下仍存在一定的致癌和非致癌风险,应继续加强监测和风险评估。

Trend and health risk assessment of chemical components in atmospheric PM2.5 in Shijiazhuang City from 2016 to 2020

Objective To analyze the trend and seasonal distribution characteristics of chemical components in fine particulate matter(PM_2.5)in Shijiazhuang City, and to evaluate their potential health risks. Methods A total of 840 PM_2.5 samples were collected from the roofs of teaching buildings of two primary schools within 2 km of the ambient air quality monitoring point in Shijiazhuang City from January 2016 to December 2020. The components of water-soluble inorganic ions(WSIIs), metals and metallic elements, polycyclic aromatic hydrocarbons(PAHs)in PM_2.5 were detected by ion chromatography, inductively coupled plasma mass spectrometry and gas chromatography-mass spectrometry, respectively, and the health risk assessment was carried out through Technical Guide for Environmental Health Risk Assessment of Chemical Exposure(WS/T777-2021). Results The average annual concentration of PM_2.5 from 2016 to 2020 showed a downward trend year by year, but still exceeded the standard limit(35 μg/m³), and it was higher in winter and autumn than in summer and spring. WSIIs had the highest content in PM_2.5; the concentration of all ions basically showed a trend of gradual decline except for nitrate ion(NO₃^-), and showed seasonal distribution characteristics similar to PM_2.5. Metals and metallic elements aluminum(Al), lead(Pb), manganese(Mn)in PM_2.5 content was high, others showed a downward trend in 5 years basically except for Al and Mn, but the concentration of chromium(Cr)was still well above the standard limit, and most elements were higher in winter. The total annual concentration of 16 PAHs showed a gradual upward trend since 2016 and gradual decline after 2018, with the characteristics of higher concentrations in autumn and winter. The health risk assessment results showed that arsenic(As), Cr, and PAHs had carcinogenic risk in different years and seasons(CR>1.0×10^-6), and PAHs had a higher risk of non-carcinogenicity(HQ>1). Conclusion In recent years, the air quality in Shijiazhuang has improved, but the situation is still serious. Some components in PM_2.5 still exists a certain risk of carcinogenic and non-carcinogenic in the current level of exposure, and the monitoring and health risk assessment should be strengthened.