The question asks to identify the index widely used in India for communicating air pollution levels and associated health risks to the public. We need to evaluate each option based on its relevance to air quality monitoring and public communication in India.
Correct Option: A) Air Quality Index (AQI)
Catalytic converters fitted in the exhaust systems of vehicles mainly help reduce air pollution by converting harmful gases like CO and NOx into:
Ozone and chlorine gas
Pure oxygen and hydrogen gas
Methane and ammonia
Less harmful gases such as CO2, N2, and water vapour
The question asks about the function of catalytic converters in vehicles. Catalytic converters are designed to reduce harmful emissions from internal combustion engines by facilitating chemical reactions that convert toxic gases into less harmful substances before they are released into the atmosphere.
D) Less harmful gases such as \(\text{CO}_2\), \(\text{N}_2\), and water vapour. This option accurately describes the products of the catalytic conversion process, which transforms highly toxic gases like CO and NOx into relatively benign substances.
The question asks to identify a cleaner fuel alternative to petrol and diesel, specifically one promoted for public transport in Indian cities to reduce vehicular air pollution. We need to evaluate each option based on its environmental impact and common usage in public transport in India.
Correct Option: C) Compressed Natural Gas (CNG) — CNG is known for its cleaner combustion compared to petrol and diesel, emitting fewer pollutants such as particulate matter, carbon monoxide, and nitrogen oxides. It has been a cornerstone of air pollution control strategies for public transport in major Indian cities.
The question asks for the approximate natural (unpolluted) concentration of carbon dioxide in the atmosphere by volume. This requires knowledge of the typical composition of Earth's atmosphere.
Correct Option: B) 0.03% by volume. This figure represents the approximate natural concentration of carbon dioxide in the Earth's atmosphere before the industrial revolution led to a significant increase in its levels.
The question asks about the primary environmental impact of Volatile Organic Compounds (VOCs) released from common sources. We need to identify which atmospheric phenomenon is directly caused or significantly contributed to by VOCs.
Correct Option: D) Photochemical smog and ground-level ozone
Volatile Organic Compounds (VOCs) are key precursors in the atmospheric reactions that lead to the formation of photochemical smog. In the presence of sunlight, VOCs react with nitrogen oxides (\(\text{NO}_x\)) to produce ground-level ozone (\(\text{O}_3\)) and other harmful secondary pollutants that constitute smog. This process is a major environmental concern, particularly in urban areas.
The question asks to identify which of the given options is classified as a particulate pollutant rather than a gaseous air pollutant. We need to understand the difference between gaseous and particulate pollutants.
Correct Option: A) Smoke is a particulate pollutant, consisting of tiny solid and liquid particles suspended in the air, along with gases. It is not primarily classified as a gaseous pollutant.