2019年元旦前后石家庄市重污染过程PM2.5污染特征及来源解析

2018年12月30日至2019年1月15日石家庄市发生了连续的灰霾天气，出现12个重污染天，首要污染物均为PM_2.5.本文从污染演变、时空分布、组分分析、污染来源和气象因素等多方面展开分析探讨污染成因.结果表明，PM_2.5主要成分为二次无机离子（65.4%），主要来源为燃煤（24.4%）和工业工艺源（23.7%）.随污染加剧SO₄^2-占比和二次无机源贡献均大幅增加.先后受来自偏南-东南和偏西-西南方向低空气团及特殊地形、静稳高湿、近地逆温等不利气象条件影响，燃煤、工业和机动车尾气等一次源产生的污染物在太行山前快速积累，气态污染物二次转化和颗粒物吸湿增长推高PM_2.5，硫酸盐暴发式增长加剧污染发生.建议重污染应急响应期间在确保各项减排措施落实到位情况下，加强二次无机组分前体物SO₂、NO_x及NH₃排放源的管控，并重点关注SO₂排放源（散煤等），同时加强市区东北方向新乐、无极、深泽、晋州和行唐区县大气排放源管理，减少局地传输影响.

Analysis of Pollution Characteristics and Sources of PM2.5 During Heavy Pollution in Shijiazhuang City Around New Year's Day 2019

We report on successive haze weather that occurred in Shijiazhuang City, China, from December 30, 2018 to January 15, 2019. There were 12 days of heavy atmospheric pollution during this period, which primarily involved aerosol fine particulate matter (PM_2.5). This study analyzes the causes of the pollution using component analysis and by assessing pollution evolution, spatial and temporal distributions of PM_2.5, pollution sources, and meteorological factors. The results showed that PM_2.5 was mainly composed of secondary inorganic ions (65.4%) that were mainly sourced from coal combustion (24.4%) and industrial sources (23.7%). The contributions of sulfate and secondary inorganic sources increased significantly with increasing pollution. Pollution was affected by unfavorable meteorological conditions (e.g., a low air mass) and by the particular local terrain, static stability, high humidity, and near-ground reverse temperatures from the south-southeast and west-southwest directions. Contaminants from primary sources including coal combustion, industry, and motor vehicle exhausts accumulated quickly in front of the Taihang Mountains. Secondary transformation of gaseous pollutants and increasing moisture absorption of particulate matter increased PM_2.5 concentrations. Sulfate explosion also increased pollution. We recommend that as part of emergency responses to heavy pollution events, emissions reduction measures should be implemented to strengthen the control of SO₂, NO_x, and NH₃ emission sources of secondary inorganic precursors, especially SO₂ emission sources (i.e., coal etc.). We further propose a strengthen of the management of atmospheric emission sources in Xinle, Wuji, Shenze, Jinzhou, and Xingtang counties in the northeast of the city to reduce the impact of local transmission.