新版全球空气质量指南对南通市空气质量达标影响分析

Influence of the new global air quality guidelines on Nantong's air quality attainment

基于南通市2018—2022年大气国控点监测数据,根据国家标准方法,分别采用国家《空气质量标准》(GB3095—2012)二级标准、世界卫生组织《全球空气质量指导值》(2005版)、《全球空气质量指导值》(2021版)(以下分别简称国标二级、AQG2005、AQG2021)限值浓度对空气质量进行评价。结果显示近五年来,南通市空气质量总体向好,优良天数比率呈波动上升趋势,除O_(3)年均浓度上升、日均浓度达标比率下降外,其余5项指标年均浓度逐年下降,日均浓度达标比率逐年上升。使用国标二级评价时,2022年优良天数比率达88.2%,PM_(2.5)、PM_(10)、O_(3)日均浓度达标率分别达97%、99.4%、84.1%,其余三项指标达标率100%。使用AQG2021评价对SO_(2)产生正影响、CO无明显影响,其余指标较使用AQG2005、国标二级评价时明显下降。为进一步提升空气质量,需设置更高要求的空气质量管理目标,建议南通市PM_(2.5)、PM_(10)年、日指标可参考AQG2021IT-3过渡期目标,NO_(2)年、日指标可分别在AQG 2021 IT-3和指导值之间、IT-2和指导值之间取合适的限值,O_(3)仍需以国标二级为参考。

Based on the monitoring data of the national air control point in Nantong from 2018 to 2022,according to the method of China's national standards,the national standard level 2,AQG2005 and AQG2021 limit concentrations were used to evaluate the air quality.The results showed that in the past five years,the air quality in Nantong was generally good,the ratio of good days showed a fluctuating upward trend.The average annual concentration of the other five indicators decreased year by year,and the average daily concentration compliance ratio increased year by year,except for the increase of the average annual concentration of O_(3) and the decrease of O_(3) average daily concentration compliance ratio.When using the national standard second-level evaluation,the rate of excellent days in 2022 reached 88.2%,the compliance rate of average daily concentration of PM_(2.5),PM_(10) and O_(3) reached 97%,99.4% and 84.1%,respectively,and the remaining three indicators reached 100%.When using AQG2021,the SO_(2) had a positive impact,while CO had no significant impact,and the remaining indicators were significantly reduced compared with the evaluation using AQG2005 and national standards level 2.In order to further improve air quality,more demanding air quality management objectives need to be set.It is suggested that the annual and daily indicators of PM_(2.5) and PM_(10) in Nantong City can refer to the transitional target of AQG2021IT-3,and the annual and daily indicators of NO_(2) can take appropriate limits between AQG2021IT-3 and the guideline value,and between IT-2 and the guideline value,respectively.O_(3) still needs to take the second-level national standard as a reference.