- “Let’s Clear The Air On COVID” – The White House
(https://www.whitehouse.gov/ostp/news-updates/2022/03/23/lets-clear-the-air-on-covid/) - “The virus is an airborne threat, the C.D.C. acknowledges.” – New York Times (https://www.nytimes.com/2021/05/07/health/coronavirus-airborne-threat.html)
- “Carbon dioxide levels reflect COVID-19 risk” – Science Daily (https://www.sciencedaily.com/releases/2021/04/210407143809.htm)