Q. There are 20,000 vehicles operating in a city with an average annual travel of 12,000 km per vehicle. The NOx emission rate is 2.0 g/km per vehicle. The total annual release of NOx will be
(A) 4,80,000 kg (B) 4,800 kg (C) 480 kg (D) 48 kg
Ans: 4,80,000 kg
Sol:
Total Annual Emission = Average Annual daily emission per vehicle × Number of Vehicle
Average Annual daily emission per vehicle = Emission per km of travel × Distance traveled (in km)
∴ Total Annual Emission = Number of vehicles × Distance travelled × Rate of emission
Calculation:
Total Annual Emission = Number of vehicles × Distance traveled × Rate of emission
∴ Total Annual Emission = 20000 × 12000 × 2 × 10-3 (kg) = 480000 kg