Particulates Pollutants are the minute solid particles or liquid droplets in air. These are present in vehicle emission, smoke particles from fires, dust particles and ash from industries. Particulate in the atmosphere may be viable or non- viable.
The viable particulates e.g., bacteria 🦠, fungi, moulds, algae etc., are minute living organisms that are dispersed in the atmosphere. Human beings are allergic to some of the fungi found in air.
They can also cause plant diseases.
Non- viable particulates may be classified according to their nature and size as follows:
- Smoke particulates consists of solid or mixture of solid and liquid particles formed during combustion of organic matter. Examples are cigarette smoke from burning of fossil fuels fuel, garbage and dry leaves oil smoke etc.
- Dust is composed of fine solid particles (over 1um in diameter), produced during crushing grinding and attribution of solid materials, Sand from sand blasting, saw dust from wood work, pulverized coal, cement and fly ash from factories, dust storms etc., are some particulate emission.
- Mists are produced by particles of spray liquids and by condensation of vapours in air. Examples are by sulhuric acid mist and herbicides and insecticides that miss their targets and travel through air and from mists.
- Fumes are generally obtained by the condensation of vapours during sublimation, distillation, boliling and several other chemical reactions . Generally, organic solvents metals and metallic oxides form fume particles.
The effect of particulate pollutants are largely dependent such as dust, fumes, mist etc., are dangerous for human health. Particulate pollutants bigger than 5 microns are likely to lodge in the nasel passage, whereas particles of about 1.0 mucron enter into lungs easily.
Lead used to be a major air pollutants emitted by vehicles. Leaded petrol used to be the primary source of air-borne lead emission in Indian cities. This problem has now been overcome by using unleaded petrol in most of the cities in India.
Lead interferes with the development and maturation of red blood cells.
