Question

3. Using the given conversion factors, calculate the residence time of methane in an atmospheric condition where the steady state influx concentration is 1.75 ppv and the total release of methane from all sources is 550 million tons per year [2000lbs- ton, 2.2 lbs-1 kg, average molecular weight of air molecules is 29 g/mol, total mass of the atmosphere = 5.27 x 10' kg ] {Hint: Residence time= [steady- state amount of substance in the reservoir][rate of inflow to (or outflow from) reservoir]^

Answer 1

As per the given question: Steady-state amount of substance in reservoir (total mass of the atmosphere)- 5.27x1018 Rate of inflow to (or outflow from) reservoir Total release ofmethane (CH4) in 1 day As given in the hint that steady state amount of substance in the reservoir rate of inflow to (or outflow from reservoir Resi dence time- We know that 1 Ton 2000 Kg Total release of methane from all sources is 550 milion tons per year Therefore, Total release of CH, in 1 day - 550x10x 2000 365 Kg 550x10x2 365 Kg -3.01x10Kg/day Thus, Resi dence time- Steady state amount of substance in the reservoir Rate of inflow to (or outflow from) reservoir state 5.27x1013 Kg Resi dence time- 3.01x10 Kg/day Residence time -1.75x101 day