Table 1.

Sources and health effects of our four pollutants.

Source: WHO (2018)

Pollutant	Sources	Health effects
Nitrogen Dioxide (NO${}_2$)	Combustion processes, mainly for power generation, heating and motor vehicles	Respiratory difficulties, reduced lung function
Sulphur Dioxide (SO${}_2$)	The burning of sulphur-containing fossil fuels, mainly from power generation, domestic heating and transport	Respiratory difficulties, irritation of the eyes
Coarse Particulate Matter (PM10)	Road transport and the burning of fuels for industrial, commercial and domestic uses	Respiratory difficulties and cardiovascular disease
Carbon Monoxide (CO)	Incomplete burning of fossil fuels in transport and industrial processes	Cardiovascular disease