Question

The term brown air is used for
(A) Acid fumes
(B) Photochemical smog
(C) Sulphurous smog
(D) Industrial smog

Answer 1

Hint: Brown air is also known as photochemical smog. Photochemical smog is a mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds react to sunlight, creating a brown haze above cities. It tends to occur more often in summer, because that is when we have the most sunlight.

Complete answer:
Photochemical smog which is mainly composed of ozone, Peroxyacetyl nitrate and nitrogen oxide, is also known as brown air where solar radiation is intense.
Ground level ozone constitutes one of the major components of photochemical smog, so called because of the photochemical reaction of air pollutants such as nitrogen oxides and volatile organic compounds with ultraviolet light or sunlight. Thus, the ozone levels vary strongly with season and the highest levels.
Photochemical smog is formed when sunlight interacts with certain chemicals in the atmosphere. Ozone is the main component in this type of air pollution. Ozone in the stratosphere protects us against harmful ultraviolet radiation, but on the ground, it is hazardous to human health.
So, the correct answer is (2) photochemical smog.

Note:
We can control photochemical smog by getting regular tune-ups, changing oil on schedule, and inflating tires to the proper level can improve gas mileage and reduce emissions. Fuel up during the cooler hours of the day and night or early morning. This prevents gas fumes from heating up and producing ozone. Avoid products that release high levels of volatile organic compounds.