(N/A) Particulate pollutants are minute solid particles or liquid droplets suspended in the air. These are present in vehicle emissions,smoke from fires,dust,and industrial ash. There are two main types of particulates in the atmosphere:
$a$. Viable
$b$. Non-viable
$a$. Viable Particulates: These include minute living organisms like bacteria,fungi,moulds,and algae that are dispersed in the atmosphere. Some fungi found in the air can cause allergies in humans and diseases in plants.
$b$. Non-viable Particulates: These are classified based on their nature and size:
$i$. Smoke: Consists of solid or a mixture of solid and liquid particles formed during the combustion of organic matter,such as cigarette smoke,smoke from fossil fuels,garbage,and dry leaves.
$ii$. Dust: Composed of fine solid particles produced during the crushing,grinding,and attrition of solid materials,such as sand from sandblasting,sawdust,pulverized coal,cement,and fly ash.
$iii$. Mists: Produced by particles of spray liquids and the condensation of vapours in the air,such as sulphuric acid mist,herbicides,and insecticides.
$iv$. Fumes: Generally obtained by the condensation of vapours during sublimation,distillation,boiling,and various chemical reactions,such as those involving organic solvents,metals,and metallic oxides.