https://www.scientificamerican.com/article/tear-gassing-protesters-during-an-infectious-outbreak-is-a-recipe-for-disaster/

In nationwide demonstrations sparked by the killing of George Floyd in police custody, protesters have been frequently pepper-sprayed or enveloped in clouds of tear gas. These crowd-control weapons are rarely lethal, but in the middle of the coronavirus pandemic, there are strong calls for police to stop using these chemical irritants because they can damage the body in ways that can spread the coronavirus and increase the severity of COVID-19.

Even before the coronavirus pandemic, some experts said additional research was needed on the risks of tear gas—an umbrella term for several chemical “riot-control agents” used by law enforcement. It’s known that the chemicals can have both immediate and long-term health effects.