Question

In almost all Indian metropolitan cities like Delhi, the major atmospheric pollutant(s) is/are
a. Suspended particulate matter (SPM)
b. Oxides of Sulphur
c. Carbon dioxide and Carbon monoxide
d. Oxides of nitrogen

Answer 1

Air pollution is caused by the substances which are present in large amounts in the air and are harmful to our health as well as the biodiversity. They are a major cause of global warming. They can be present in the form of gases, biological molecules, or particulates. These pose threats especially in the metropolitan cities of India.

Complete answer:
- Suspended particulate matter is known by many names such as atmospheric aerosol particles, particulate matter, etc.
- These are microscopic solid or liquid particles that are suspended in the air.
- The source of these particles can be manmade or natural.
- They have an adverse effect on the environment and lead to a variety of respiratory problems.
- There are different types of atmospheric particles such as suspended particulate matter; inhalable coarse particles; thoracic and respirable particles; designated PM10; fine particles, ultrafine particles designated PM2.5; and soot.
- The composition of aerosols particles depends on their sources.
- Wind-blown mineral dust is made from mineral oxides.
- The second-largest contributor is Sea salt and consists of Sodium chloride from sea spray. In addition, they may contain organic compounds, which influence their chemistry.
- The oxidation of primary gases such as sulfur and nitrogen oxides into sulfuric acid (liquid) and nitric acid (gaseous) are considered secondary particles.

Hence, the correct answer is option (A).

Note: The change in climate is due to the increasing effect of global warming.
- Greenhouse gases pose a major threat to the ozone layer.
- The aerosol affects the environment in three ways- directly, semi directly, or indirectly.
- It affects human health along with vegetation. These are considered as Group 1 Carcinogens by WHO.