question_answer

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index? (IAS Prelims 2016)

1. Carbon dioxide

2. Carbon monoxide

3. Nitrogen dioxide

4. Sulfur dioxide

5. Methane

Select the correct answer using the code given below.

A)  1, 2 and 3 only

B)  2, 3 and 4 only

C)  1, 4 and 5 only

D)  1, 2, 3, 4 and 5

Correct Answer: B

Solution :

(i) The API level is based on the level of 6 atmospheric pollutants, namely sulfur dioxide, nitrogen dioxide, suspended particulates smaller than 10 in aerodynamic diameter (PM10), suspended particulates smaller than 2.5 in aerodynamic diameter (PM2.5), carbon monoxide (CO), and ozone  measured at the monitoring stations throughout. So by elimination we are left with option ?b?. Ref: Thehindu newspaper/ April 9, 2015; http: //www. thehindu. com/opinion/blogs/blog-datadelve/article7083985.ece