question_answer 13)

  According to the Central Pollution Control Board, particles that are responsible for causing great harm to human health are of diameter (a) 2.50 micrometers                                                      (b) 5.00 micrometers (c) 10.00 micrometers                                                    (d) 7.5 micrometers

Answer:

                  (a) Particulate air pollutant like soot, flyash, dust of various types, pollens, spores, fur. hair, etc., can be differentiated as settable (10m or more) and suspended, (less than10) particulate matter pollutant. Their effect (on the environment) depends on the size of particles. According to CPCB ,particulate matter of 2.5 m or less in diameter are responsible for causing great harm to human health. The particular matter of 2.5 or less in size are inhaled deep into the respiratory tract (up to lungs) and causes respiratory problems and may even lead to death.