NRES 351 exam 1 (tropospheric precipitation)

Species of N that contribute to acidity

-NH3: biogenic & volatilization
-NOX: stratosphere, atmospheric oxidation of NH3, lighting, biogenic, biomass combustion, fossil fuel combustion

Species of S that contribute to acidity

So42-: sea salt & dust
Reduced sulfur: biogenic & DMS
Partially oxidized S: volcanoes & fossil fuel combustion

Formation of nitric acid (day)

1. Oxidation of nitric oxide by O3 to form NO2 radical & O2
2. Oxidation of nitrogen dioxide by OH radical to form HNO3

Formation of nitric acid (night)

1. Oxidation of NO2 by O3 to form NO3 radical
2. Formation of HNO3 either by hydrogen abstraction or N2O5

Formation of sulfuric acid

1. Production of thionyl radicals
2. Oxidation of thionyl radicals
3. Oxidation of sulphur dioxide by homogenous/heterogenous rxns to form H2SO4

Homogenous oxidation of S

So2 + OH radical --> HOSO2 radical + M
HOSO2 + O2 + M --> HOO + SO3 + M
SO3 + H2O --> H2SO4

Heterogenous oxidation of S

SO2(g) --> SO2 (aq)
SO2 (aq) + 2H2O --> HSO3- + H3O+
-HSO3- + H2O2 --> HOOSO2 + H2O
HOOSO2- + H3O+ --> H2SO4 + H2O
-HSO3- + O3 --> SO$2- + H3O+ + O2

Removal process for nitric & sulfuric acid

CaCo3
NH3