基于气象分型的大气环境允许排放量测算方法

Research on atmospheric environmental capacity accounting method based on classification of meteorological conditions

本文提出一种基于气象条件分型的城市大气环境允许排放量测算方法,该方法基于环境空气质量和颗粒物组分数据,对气象条件进行分污染天气类型的二次转化规律研究,并确定不同天气类型下的迁移扩散系数.基于扩散理论,建立了污染物排放强度、不同天气类型迁移扩散系数和目标控制浓度之间的关系,在特定区域排放布局和排放方式基本不变的前提下,测算不同天气类型达空气质量标准下的一次PM_(2.5),PM_(10),NO_(x)和SO_(2)的允许排放量.以沧州市为例,结合空气质量从优到严重污染程度将对应气象要素依次划分为7种天气类型,测算7种天气类型达空气质量目标下的主要污染物允许排放量.基于2018年基准年的排放量,在天气类型7最不利气象条件下,沧州市一次PM_(2.5),PM_(10),NO_(x)和SO_(2)排放量削减率应分别在82.62%,81.17%,75.05%和74.54%以上,才能达到空气质量标准.结果表明,不利气象条件下大气环境允许排放量很小,需要更大力度减少污染物排放,才能避免发生重污染天气.

Research on atmospheric environmental capacity accounting method based on specific meteorological conditions,especially during heavy pollution episodes has become a hot topic in recent years.An accounting method was proposed in this paper,which studied the classification of annual meteorological conditions to explore the migration and transformation coefficients under different meteorological conditions.The relationship among emission amount,meteorological conditions and constraints of multiple pollutants concentrations was established,and the permitted-emission amount for primary PM_(2.5),PM_(10),SO_(2) and NO_(x) were measured,under the premise that the way and layout of emission was not variable.This method was applied to quantify the atmospheric environmental capacity under 7 typical meteorological conditions in the city of Cangzhou.The results showed that,taken 2018 as the basic year,the proportion of emission reduction for primary PM_(2.5),PM_(10),NO_(x) and SO_(2) under most adverse meteorological conditions were at least 82.62%,81.17%,75.05%and 74.54%,respectively.It was obvious that the environmental capacity under adverse meteorological conditions was far less than that under the normal diffusion conditions.Therefore,greater efforts should be made to reduce pollutants emission under adverse meteorological conditions,in order to prevent heavy pollution episodes.