In September 2020, the World Meteorological Organization (WMO) Research Board set up an interdisciplinary and international Task Team to respond to the challenge of providing timely decision support and relevant knowledge on meteorological and air quality (MAQ) factors affecting the sever acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (the virus that causes COVID-19) pandemic. The aims of the Task Team are: to provide decision makers and the public with a rapid summary of the state of knowledge regarding potential MAQ influences on SARS-CoV-2/COVID-19; to offer general technical guidance for researchers and service providers who wish to consider MAQ data in their analyses, estimates, predictions and projections of COVID-19 risks.

This report presents a summary of key findings to date, as informed by peer-reviewed literature. It is motivated both by the global relevance of the subject and by the staggering number of papers and preprints currently available, which emphasizes the need for careful review and communication of the state of the science.

We note that the report adopts a number of constraints. First, it considers only peer-reviewed papers (not preprints) that were published by the first week of January 2021. Second, the report focuses on outdoor MAQ conditions. Links between outdoor and indoor environments are considered, but the report does not address details of indoor air circulation or climate control. Third, this report was written just as the existence of new strains of SARS-CoV-2 were recognized. As such, there was no peer-reviewed literature to consider regarding the influence of MAQ on transmission of the new strains, or on severity of infections caused by these new strains. We also emphasize that the report is not a formal systematic review; it is a summary of the overall state of the literature.