- Particulatesare tiny pieces of solids and tiny droplets of liquids floating in the air.
- Moreparticulates are found in urban areas than in rural areas. The concentration of particulates in urban areas is around 10-40 pg/m^3, compared to less than 10 pg/m^3 in rural area.
Sources of Particulates
- Vehicle exhaustswhich produce very fine particulates. About 80% of fine particulates in urban areas are from vehicle exhausts.
- Burningof refuse, cigarettes and fuel such as coal which produces both fine and coarse particulates.
- Construction, miningand quarrying with these activities produce coarse particulates.
- Plants and moulds, also generate coarse particulates.
- Particulates can cause health problems. Coarser particulatesare usually filtered out by the nose and throat, but finer particulates less than 10 pm in diameter can enter the
- PM10 could causeor make worse problems like asthma, bronchitis, lung cancer and heart disease.
- Pollutants, such as nitrogen oxides, sulphur oxidesand hydrocarbons, come from burning fossil fuels.
- When these pollutantscome into contact with sunlight, the UV light causes them to break down into harmful chemicals which form photochemical smog.
- Photochemical smog is a problemin many cities including Los Angeles, Beijing, Mexico City and Barcelona.
- It’s more common in places with hotand sunny climates because there’s more sunlight.
- These locations often have a temperature inversion, which keeps the pollutants at ground level.
- Photochemical smog is linked to health problems, such as breathing difficulties, respiratory disordersand