This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment, Subject name: Social & Preventive Medicine
All are indicators of Air pollution except: 
Select and explain. 
A. Soiling index, B. McArdle's index, C. Suspended paicle count, D. So2 concentration
B: McArdle's index
Answer: B: McArdle's index 
Explanation: Indicators of air pollution: Co2, Co So2 , No2 Air pollution index Soiling index Coefficient of Haze SPM - Best chemical indicator of air pollution - S02. - Best biological indicator of air pollution - Lichens. McArdle's index It is an index of thermal comfo. Max P4SR (Predictable 4 hour sweat rate): <4.5lit/4hours. Beyond this death of person is imminent.