Department of Biochemistry and Molecular Biology, School of Medicine, Complutense University of Madrid, Spain.
Department of Biochemistry and Molecular Biology, School of Medicine, Complutense University of Madrid, Spain.
Environ Res. 2021 Apr;195:110863. doi: 10.1016/j.envres.2021.110863. Epub 2021 Feb 17.
Previous studies described the presence of SARS-CoV-2 in outdoor air particulate matter (PM) in urban areas of northern Italy and USA. The city of Madrid was heavily affected by COVID-19 during March-June 2020. Also, this city usually displays high concentrations of PM under several atmospheric situations. This is mandatory to assess the presence of viral RNA in PM, as an indicator of epidemic recurrence. Our study was aimed at investigating the presence of SARS-CoV-2 RNA in outdoor air samples (on PM10, PM2.5 and PM1).
Six samples of PM10, PM2.5 and PM1 were collected between the May 4th and 22nd 2020 in Madrid, on quartz fiber filters by using MCV high volume samplers (30 m h flow) with three inlets (Digitel DHA-80) for sampling PM10, PM2.5 and PM1. RNA extraction and amplification was performed according to the protocol recently set by Setti et al.2020c in Italy. Up to three highly specific molecular marker genes (N1, N2, and RP) were used to test the presence of SARS-CoV-2 RNA.
After RNA extraction and expression measurements of N1, N2 and RP genes from all the collected filters, no presence of SARS-CoV-2 RNA was observed. Control tests to exclude false positive results were successfully accomplished.
No presence of SARS-CoV-2 in quartz fiber filters samplers for PM10, PM2.5 and PM1 fractions was observed in our study carried out in Madrid during the month of May 2020. Nevertheless, the absence of viral genomes could be due to different factors including: limited social interactions and economic activities resulting in reduced circulation of the coronavirus, lower daily PM concentration in outdoor air, as well as to meteorological stability and higher temperature that characterize spring season. Further research should be carried out during winter, in presence of higher viral circulation and daily PM exceedances.
先前的研究描述了 SARS-CoV-2 存在于意大利北部和美国城市的户外空气颗粒物（PM）中。马德里市在 2020 年 3 月至 6 月期间受到 COVID-19 的严重影响。此外，该市在几种大气情况下通常显示出高浓度的 PM。这对于评估 PM 中病毒 RNA 的存在是必要的，因为这是疫情复发的一个指标。我们的研究旨在调查 SARS-CoV-2 RNA 是否存在于户外空气样本中（PM10、PM2.5 和 PM1 上）。
2020 年 5 月 4 日至 22 日，在马德里使用 MCV 大容量采样器（30 m h 流量）通过三个入口（Digitel DHA-80）收集了 6 个 PM10、PM2.5 和 PM1 的石英纤维过滤器样品，用于采集 PM10、PM2.5 和 PM1。根据 Setti 等人最近在意大利制定的方案进行 RNA 提取和扩增。使用了多达三个高度特异性的分子标记基因（N1、N2 和 RP）来测试 SARS-CoV-2 RNA 的存在。
从所有收集的过滤器中提取 RNA 并测量 N1、N2 和 RP 基因的表达后，未观察到 SARS-CoV-2 RNA 的存在。成功完成了排除假阳性结果的对照测试。
在我们 2020 年 5 月在马德里进行的研究中，未在 PM10、PM2.5 和 PM1 分馏石英纤维过滤器采样器中观察到 SARS-CoV-2 的存在。然而，病毒基因组的缺失可能是由于以下不同因素造成的：社交互动和经济活动减少导致冠状病毒循环减少，户外空气中每日 PM 浓度较低，以及春季的气象稳定和较高温度。应在冬季进行进一步研究，此时病毒循环和每日 PM 超标较高。
