$(a)$ Explain how does burning of fossil fuels cause air pollution?
$(b)$ Justify "Dust is a pollutant".

(N/A) Burning of fossil fuels releases gases such as $CO$, $CO_2$, $SO_2$, $NO_2$, and unburnt carbon particles or hydrocarbons, commonly known as suspended particulate matter.
$(i)$ The presence of $CO_2$ in large quantities leads to global warming.
$(ii)$ The presence of $SO_2$ and $NO_2$ in large quantities causes acid rain, which damages crops and buildings made of marble.
$(b)$ Dust is considered a pollutant because:
$(i)$ It reduces visibility and acts as condensation nuclei for water vapor, leading to the formation of smog.
$(ii)$ Inhalation of dust-laden air increases the incidence of respiratory allergies, lung cancer, and cardiovascular diseases.