Question

The $UV$ radiation from sun cause reaction that produces

• A. carbon monoxide
• B. sulphur dioxide
• C. ozone
• D. fluorides

Answer 1

Answer: (C)

Ozone is formed in the atmosphere through chemical reaction involving pollutants like $(S{O}_2,N{O}_2$ etc $)$ on absorption of UV radiation.
$NOx+$ Hydrocarbon $\stackrel{\text{ UV radiation }}{\to }\underset{\text{(Photo chemical smog)}}{PAN+O_3}$
This gas is a serious pollutant lower down in the trophosphere as it is highly reactive gas which causes oxidation of a number of macro molecules within a biological system. It produces free radicals, which have been implecated in a number of ozone induced pulmonary or extra pulmonary damage and these free radicals can also damage DNA molecules and cause carcinogenesis.
Carbon monoxide accounts for about $52\%$ of total air pollution. It is a colourless, odourless gas. Its main source is automobile exhausts. Metallergical operation, domestic combustion of coal, dried organic matter and fuel gases etc.
Sulphur dioxide is the second most important pollutant of the atmosphere. Most of the atmospheric $S{O}_2$ comes from burning of organic matter, fossil fuels and from industrial units processing sulphur bearing ores. Prolonged intake of fluoride containing water stiffens the bone joints, particularly of spinal cord and gets accumulated in bone and outward bending of legs from the kneesknock-knee syndrome.