General discussion: Urban air quality; Meteorological influences and air quality trends
General discussion: Urban air quality; Meteorological influences and air quality trends
复制标题
一般性讨论：城市空气质量；
DOI：
10.1039/d1fd90014e
复制
发表时间：
2021
影响因子：
3.4
通讯作者：
Bloss W
中科院分区：
文献类型：
--
作者：
Bloss W
陈颖开始对余建振论文的讨论：感谢余教授的出色工作。我正在考虑如何计算出由于气象变化和封锁导致的地表浓度降低的比例。据推测，二月比一月温暖，行星边界层（PBL）可能更高，这也会稀释污染物？也许2019年2月和1月的差异可以给我们一些提示？于建振回应：我们同意，从广义上讲，气象条件对PM2.5有影响。 5污染物浓度。为了定性研究天气条件的影响，我们对气团返回轨迹进行了聚类分析，在2020年1月1日至2月9日的实地观测期间生成了四个聚类（本文的图1）。我们论文的 3.1 节提供了详细的描述。在星团 2 和其他三个星团之间观察到了星团范围内的温度差异，其中星团 2 显示出明显较低的温度（图 2 中的第 7 个图），这与其起源一致，因为它来自北部大陆地区（图 1）。另一方面，2月初与1月份的整体温差并不明显。比较锁定之前和锁定期间同一气团中的污染物表明，无论气团类型如何，锁定期间氮氧化物明显较低，而氧气明显较高。另一方面，PM2.5的差异。封锁之前和封锁期间的 PM2.5 值在不同集群之间存在差异，反映出影响 PM2.5 的复杂因素（例如排放、气象和化学）之间存在更高的相互作用。 5 及其主要组成部分。需要进行 3D 空气质量建模调查，以定量确定由于气象因素或封锁引起的排放/化学物质导致浓度降低的比例。
Ying Chen opened the discussion of the paper by Jian Zhen Yu: Thanks for the very nice work, Professor Yu. I am thinking about how we could gure out the proportion of surface concentration reductions attributed to meteorological change and lockdown. Presumably, February is warmer than January and planetary boundary layer (PBL) could be higher and that dilutes the pollutants as well? Maybe the difference between February and January in 2019 could give us some hints?Jian Zhen Yu responded: We agree that broadly speaking, meteorological conditions play a role in affecting PM2. 5 pollutant concentrations. To qualitatively examine the impact of the synoptic weather conditions, we did cluster analysis of air mass back trajectories, which generated four clusters for the eld observation period of 1 January to 9 February 2020 (Fig. 1 in our paper). Section 3.1 of our paper provides a detailed description. The cluster-wide difference in temperature was observed between cluster 2 and the other three clusters, with cluster 2 showing signi cantly lower temperatures (7th plot in Fig. 2), in accordance with its origin as it comes from the northern continental area (Fig. 1). On the other hand, the overall temperature difference between early February and January was not distinct. Comparison of pollutants in the same air mass cluster for before and during lockdown periods shows NOx was notably lower while O3 was notably higher during lockdown, regardless of air mass cluster types. On the other hand, the difference in PM2. 5 before and during lockdown varied among different clusters, re ecting the higher interplay in complex factors (eg, emissions, meteorology, and chemistry) that impact PM2. 5 and its major components. A 3D air quality modelling investigation will be needed to quantitatively ascertain the proportion of concentration reduction due to meteorological factors or emissions/chemistry arising from lockdown.