Q.
Consider a box model for an airshed over a city and assume that the initial concentration of a pollutant is zero and that the air entering the box is clean. If the length of the box is 10 km and the wind speed along the length of the box is 5 m/s, what is the time taken for the pollutant concentration to reach ~ 95% of its final value ?
[A] 1 h 40 minutes
[B] 1 h 7 minutes
[C] 33 minutes 20 seconds
[D] 2 h 13 minutes 20 seconds
Answer & Explanation
Answer: 1 h 40 minutes