Question 25 from UPSC CSE 2016 - Environment

Question

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index?
1. Carbon dioxide
2. Carbon monoxide
3. Nitrogen dioxide
4. Sulfur dioxide
5. Methane
Select the correct answer using the code given below.

IASCODEX · Accepted Answer

Correct Option: B. 2, 3, and 4 only

Strategy: Identify the standard pollutants in the National Air Quality Index (AQI) from a given list of gases. The selection is based on whether the gas has direct, local health impacts, as this is the focus of the AQI. Include **Carbon monoxide**, **Nitrogen dioxide**, and **Sulfur dioxide**. Exclude **Carbon dioxide** and **Methane** as they are primarily greenhouse gases with global climate effects, not direct local pollutants.

Key Info: The Air Quality Index (AQI) is a tool for effectively communicating air quality status to people. In India, the National AQI was launched in 2014 by the Ministry of Environment, Forest and Climate Change. It integrates measurements of various pollutants into a single number and color-coded category.

*   **AQI Categories**: There are six AQI categories: Good, Satisfactory, Moderately polluted, Poor, Very Poor, and Severe.

*   **Pollutants Monitored for AQI Calculation**: The National AQI considers eight key pollutants for which short-term (up to 24-hourly averaging period) National Ambient Air Quality Standards (NAAQS) are prescribed. These are:
    *   **Particulate Matter (PM2.5)**
    *   **Particulate Matter (PM10)**
    *   **Nitrogen Dioxide (NO2)**
    *   **Sulfur Dioxide (SO2)**
    *   **Carbon Monoxide (CO)**
    *   **Ozone (O3)**
    *   **Ammonia (NH3)**
    *   **Lead (Pb)**

*   **Carbon dioxide (CO2)**: While a significant atmospheric gas and a primary greenhouse gas, CO2 is not typically included in the standard AQI calculation because its direct health impacts are generally not acute at ambient levels, and its primary concern is climate change rather than local air quality in the context of AQI.

*   **Methane (CH4)**: Similar to CO2, methane is a potent greenhouse gas but is not one of the eight pollutants considered in India's National AQI for assessing local air quality.

IASCODEX · Answer

Option A: 1, 2, and 3 only

IASCODEX · Answer

Option C: 1, 4, and 5 only

IASCODEX · Answer

Option D: 1, 2, 3, 4, and 5

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index? Carbon dioxide Carbon monoxide Nitrogen dioxide Sulfur dioxide Methane Select the correct answer using the code given below.

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index?

Carbon dioxide

Carbon monoxide

Nitrogen dioxide

Sulfur dioxide

Methane
Select the correct answer using the code given below.