JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III AIR POLLUTION AND CONTROL Previous Question Paper (July - 2023 - R16)

Air pollution is defined as the presence in the outdoor atmosphere of one or more contaminants, such as dust, fumes, gas, mist, odor, smoke, or vapor, in quantities, of characteristics, and of a duration such as to be injurious to human, plant, or animal life, or to property, or which unreasonably interfere with the comfortable enjoyment of life and property.

The salient terms are:

• Contaminants: Substances (particulate or gaseous) that alter the natural composition of the atmosphere.
• Injurious/Interference: The threshold at which these substances cause adverse health effects, ecological damage, or economic loss, distinguishing pollution from mere presence.
• Duration: The persistence of the pollutant in the atmosphere, which determines the extent of exposure and subsequent impact.

Primary pollutants are emitted directly into the atmosphere from identifiable sources, such as industrial stacks or vehicle exhausts. In contrast, secondary pollutants are not emitted directly; they are formed in the atmosphere through chemical or photochemical reactions between primary pollutants and other atmospheric components.

Examples of primary pollutants include:

• Carbon monoxide (CO)
• Sulfur dioxide (SO₂)

Examples of secondary pollutants include:

• Ground-level ozone (O₃)
• Peroxyacetyl nitrate (PAN)