This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET Jan 2020, Subject name: Social & Preventive Medicine
Indicator of air pollution are: 
Select and explain. 
A. Sulphur dioxide, lead, paiculate matter, B. Carbon dioxide, hydrogen sulphide, lead, C. Sulphur dioxide, hydrogen sulphide, carbon monoxide, D. Sulphur dioxide, smoke, paiculate matter
D: Sulphur dioxide, smoke, paiculate matter
Answer: D: Sulphur dioxide, smoke, paiculate matter 
Explanation: The best indicators of air pollution aresulphur dioxide, smoke and suspended paicles. These are monitored on a daily basis over several sites, results often collected by a central agency. Air pollution indicators are- CO2, CO SO2, NO2 Air pollution index Soiling index Coefficient of haze Suspended paiculate matter