coronavirus transmissions have occurred indoors, but experts say that wearing a mask outside is justified because there is still a risk of infection.The likelihood of catching the virus increases at events where people stand near each other and talk for long periods of time, such as parties or election campaign rallies.Relative riskSince the start of the pandemic, studies have described cases of infection in restaurants, houses, factories, offices, conferences, trains and planes.One study published in April identified a single case of transmission outdoors, between two Chinese villagers, out of more than 7,000 studies.In an analysis of 25,000 cases, which has not yet been independently reviewed, six percent of cases were linked to.