Lecture 11

Question 1

Dry deposition

Answer 1

Removal of substituents from atmosphere by direct transfer. No water or ice

Question 2

Wet deposition

Answer 2

Removal process in which gases & particles are dissolved or entrapped in water

Question 3

The importance of [NOx]

Answer 3

peroxy radicals react rapidly w NO
HO2 + NO –> OH + NO2
but if NOx is low HO2 & CH3O2 (peroxy) are consumed
HO2 + HO2 –> H2O2 + O2
and
CH3O2 + HO2 –> CH3OOH + O2

Photolysis of NO2 is most important process in ozone production
CO + 2O2 + hv –> CO2 + O3 + KE/heat

Question 4

Sources of NOx

Answer 4

microbes in soil, lightning, biomass burning

Question 5

what is PAN

Answer 5

reservoir species for NOx that can extend the lifetime of NOx & provide a source when others are absent

CH3CO.O2 + NO2 <—> CH3CO.O2NO2

reaction is shifted right at lower temp

Question 6

Oxidation of alkanes

Answer 6

Important for ozone production
OH + CH4 –> CH3 + H2O
R + O2 –> RO2
RO2 + NO –> RO + NO2

Question 7

Oxidation of alkenes

Answer 7

ethene & propene
OH + C2H4 –> C2H4OH
OH + CH3ChCh2 –> Ch3ChCh2OH