This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Air, Light, Sound, Housing, Radiation, Waste Disposal, Subject name: Social & Preventive Medicine
[{'content': 'Soiling index is used for Quaity assessment of:- \nSelect and explain. \nA. Water, B. Air, C. Soil, D. Noise', 'role': 'user'}, {'content': 'Answer: B \nExplanation: AIR POLLUTION INDICATORS; CO2, CO, SO2, NO2, Air pollution index Soiling index Coefficient of haze SPM Overall best air pollution indicator/ Overall best chemical indicator is SO2. Best biological indicator of air pollution - LICHENS. Air pollution monitoring - CPCB.(Central pollution control board)', 'role': 'assistant'}]