Air pollution is a major environmental health problem affecting both developed and developing countries. Concern focuses not only on ambient air quality in cities but also on indoor air quality in the home and workplace. Levels of air pollution in Asian cities regularly exceed World Health Organization (WHO) guidelines with smoke, dust and particles double the world average. Pollutants emissions have direct and indirect effects (e.g. acidification, eutrophication, ground-level ozone) on air quality with a wide range of impacts on human health, ecosystems, agriculture and materials.

In 2001 the total number of deaths was estimated to be approximately 56.55 million. Approximately 2.5 million deaths per year are the result of exposure to particulate matter (WHO, 2002). Indoor smoke from solid fuels in developing countries represents 65 per cent of these 2.5 million deaths and is the major cause of excess deaths due to air pollution world-wide. Ischaemic heart disease, acute lower respiratory infections, chronic obstructive pulmonary disease and perinatal conditions are the main causes leading to death, with air pollution being one of the contributing causes of these diseases.

Many people are vulnerable to the adverse effects of air pollutants because they are highly exposed to pollutants and/or have increased sensitivity to exposure (e.g., children, the fetus, older people or the sick). The world’s poorest people suffer most from adverse environmental conditions and are exposed to high levels of indoor as well as ambient air pollution. Most of the poor, especially in the less developed countries, live and work in rural areas and at the margins of expanding urban centres.

Air pollution has an effect on visibility and has long been a significant source of damage to non-living materials. Air pollution has contributed to the corrosion of metals, cracking of rubber, soiling and eroding of building surfaces, deterioration of works of art, and fading of dyed materials. Injury to vegetation has been one of the earliest signs of air pollution, for example due to the effects of SO2 emitted from smelters, and fluoride gases. The effects of air pollutants on vegetation, crops, and forests include visible symptoms such as identifiable changes in the colour of the leaf. Subtle effects do not result in visible injury measured in terms of plant growth, reproduction, yield and effects on populations and communities of plants (SEI, 2008)