It has been more than 4 million years since CO2 levels were as high as today. 

Studies have shown that pollution makes respiratory infections worse. In fact, according to the Environmental Protection Agency, “The combination of experimental and epidemiologic studies has provided evidence of a relationship between short-term (daily) exposures to particle pollution and several respiratory-related effects, including elevated morbidity, higher frequency of emergency department visits and hospital admissions, as well as excess mortality.”

According to a 2022 Lancet report on pollution and health, “pollution was responsible for 9 million premature deaths in 2015, making it the world’s largest environmental risk factor for disease and premature death.”