micro- scale urban or regional or synoptic or local scale mesoscale global scale 100yr long-lived CFC's species N20 CH4 10yr inter-hemispheric mixing time 1yr RESIDENCE TIME - SO2 intra-hemispheric mixing time boundary layer mixing time 1 day CH3CCI3 -CH3 Br moderately long- .CO lived species Aerosols Trop og H20 H2O2 .NO DMS CH6 CH3 shorl-lived species CH,02 HO2 .NO, 1hr 100s 1s 1m 10m 100m 1km 10km 100km 1000km 10.000km SPATIAL SCALE OF VARIABILITY Chemical Engineering Homework Problem: Ammonia (NH3), nitrous oxide (N20) and methane (CH4) comprise 1 x 10-8, 3 x 10-5, and 7 x 10-5 % by mass of the Earth's atmosphere, respectively. If the effluxes of these chemicals from the atmosphere are 5 x 10^10, 1 x 10^10, and 4 x 10^11 kg a-1, respectively, what are the residence times of NH3, N20, and CH4 in the atmosphere? (Mass of the Earth's atmosphere = 5 x 10^18kg.) =