2020年1月内蒙古河套地区重污染过程溯源分析
- Traceability analysis of heavy pollution process in Hetao area of Inner Mongolia in January 2020
- 基金项目：国家自然科学基金项目（面上项目，重点项目，重大项目）,省级自然科学基金，一流学科科研专项项目
- 摘要：2020年1月内蒙古河套区域出现连续性、高强度的重污染过程，重污染天数占比为2015年以来最强，本文利用污染特征雷达图、气流后向轨迹聚类、潜在源区贡献（PSCF）和浓度权重轨迹分析（CWT）等方法对本次过程进行溯源分析，结果表明：（1）本次河套地区持续性重污染过程呈典型的区域同步变化特征，其中呼和浩特市重度及以上污染占比最大，其次为包头市和巴彦淖尔市。（2）即使存在疫情管控的污染减排，重污染期间常规大气污染物与过去5年同期相比仍呈四升（PM2.5、PM10、CO、NO2）两降（SO2、O3）的变化趋势，结合污染物雷达特征图判断主要污染源来自PM2.5，污染过程为偏二次型。（3）气象条件和地形是本次重污染过程的主导因素，大气呈静稳形势，高湿度有利于颗粒物吸湿和二次颗粒物的生成，低风速不利于污染物的扩散，造成持续污染天气，阴山山脉以南和蒙古高原以北的低海拔地区是污染最严重的区域，配合有利气象条件促进污染物的进一步聚集。（4）呼和浩特市激光雷达特征进一步表明首要污染物为PM2.5，结合50和600m高度气流后向轨迹聚类、PSCF和CWT分析可见，本次河套重污染过程区域传输作用显著，污染物主要来自本地生成和区域相互传输。
- Abstract：A continuous and high-intensity heavy pollution process occurred in the Hetao area of Inner Mongolia in January 2020 which was the highest proportion of heavy pollution days since 2015,.By using methods like pollution characteristic radar map, backward trajectory clustering of airflow,PSCF and CWT to conduct traceability analysis on the long-term heavy pollution process. The results show that:(1)The sustained and heavy pollution process in the Hetao area of Inner Mongolia showed typical regional synchronous changes. Hohhot city was the highest proportion of severe and above pollution, followed by Baotou city and Bayannur city.(2) Even though there was pollution reduction through epidemic control measures during this period, the pollution was still severe, the conventional air pollutants showed a trend of four liters (PM2.5, PM10, CO, NO2) and two decreases (SO2, O3) compared to the same period in the past five years.Based on the Pollutant characteristic radar chart the main source of pollution during the severe pollution period came from PM2.5 and the pollution process was more secondary.(3)Meteorological conditions and terrain are the dominant factors in the heavy pollution process.The atmosphere is in a stable and calm weather pattern,the high humidity environment is conducive to the absorption of particulate matter and the generation of secondary particles leading to the accumulation of pollutants and continuous pollution weather. The low altitude areas south of the Yinshan Mountains and north of the Mongolian Plateau are the most severely polluted with low altitude and favorable meteorological conditions promoting further accumulation of pollutants.(4) The laser radar characteristics of Hohhot city indicate that the primary pollutant was PM2.5. Combined with the clustering analysis of the backward trajectory of airflow at 50m and 600m heights potential source contribution factors and concentration weight trajectory analysis there is a significant regional transmission effect of heavy pollution weather processes in the Hetao area, pollutants mainly come from local generation and regional transmission.
