environmental air pollution

ambient air pollution

According to the WHO, 99% of the global population lives in places where air quality exceeds 2021 WHO guidelines for mean outdoor air pollution for PM10 or PM2.5.

sources of ambient air pollution are principally

• Internal combustion engines

• Power generation

• Domestic biomass and coal burning

• In some places, wind-blown dust and wildfire smoke may be significant, but episodic

• Fossil fuels may cause about 65% of deaths attribute to air pollution globally

global ambient air pollution and mortality

Ambient air pollution leads to ~6% more deaths in the most polluted than in the least polluted cities. PM2.5 shows greater effect than PM10 for a given increase in concentration. Higher temperatures lead to more deaths.

WHO estimates for causes of premature deaths from outdoor air pollution in 2019

• 45.7% heart disease

• 22% stroke

• 14.2% acute lower respiratory infections e.g. tuberculosis

• 13.6% chronic obstructive pulmonary disease (COPD) - emphysema and bronchitis

• 4.6% lung and throat cancers

PM2.5

PM2.5 is especially harmful because of very large surface area exposed to alveoli; gases including nitrogen oxides may be very significant too.

mechanisms may include

• Greater coagulability of blood

• Constriction and inflammation of blood vessels

• Disturbances of heart functions

COPD

COPD global incidence and mortality 2019

High incidence in many countries, smoking being most important cause in wealthy countries.

COPD mortality is disproportionately high relative to incidence in poorer counties.

overview of airborne particulates - affected populations