Table 1.

Major air pollutants.

Pollutants	Sources	Effects	Release
Particulate matter (PM)	Indoor: cooking using BMF, cigarette smoking Outdoor: natural dusts, vehicles exhaust, industrial activities, constructions.	PM can reduce visibility and cause a variety of respiratory problems. PM has also been linked to cancer and other systemic diseases.	Direct and formed in air
Nitrogen oxides (NOx)	BMF Combustion, vehicles exhaust, industrial activities, power plants. Nitride is the product of nitrogen oxide photochemical reaction.	NOx can make individuals vulnerable to respiratory infections, lung disease, and possibly cancer. It contributes to the brownish haze seen over congested areas and to acid rain.	Direct
Ozone (O3)	BMF Combustion, vehicles exhaust, industrial activities (photochemical reaction between nitrogen oxides and reactive hydrocarbons).	Ozone can cause irritation of airways, and cause airway hyperresponsiveness and bronchospasm. Repeated exposure can cause permanent lung damage.	Formed in air under sunlight
Carbon monoxide (CO)	BMF incomplete combustion, wood burning, cigarette smoking, vehicles exhaust, industrial activities, forest fire.	CO interferes with the oxygenation of hemoglobin CO can cause death in high concentration.	Direct
Sulfur dioxide	BMF Combustion, coal-burning power plants, volcanic gas.	SO2 easily dissolves in water and forms an acid which contributes to acid rain.	Direct

Abbreviation: BMF: biomass fuels.