Air pollution

Air pollution is the "presence of contaminants or pollutant substances in the air (air pollutants) that interfere with human health or welfare, or produce other harmful environmental effects. The substances may include gases; particulate matter; or volatile organic chemicals"

Health effects
An observational study in the United States found a "decrease of 10 µg per cubic meter in the concentration of fine particulate matter was associated with an estimated increase in mean (±SE) life expectancy of 0.61±0.20 year." With the exception of exercise and smoking cessation, the health benefit of reduction in pollution is estimated to be greater than most primary prevention efforts in health care such as infant vaccines, mammography and Papanicolaou smears.