Everyday Life and Chemistry - Essentials of Chemical Education - page 230

8.2.15 Air: Example “Smog”

In inverted atmospheric conditions, a warm air layer is lying on the cold air above
ground like a cover: these air layers do not allow the diffusion of gases like sulfur
dioxide, nitrogen oxides, and carbon monoxide into higher regions of the
atmosphere. There is also solid dust that cannot escape and creates “smog” - a
word combining smoke and fog. Gases and dust are considerably polluting the air
and consequently the breathing. Nitrogen oxides are mainly produced by the
reaction of air in hot automotive engines operating at high speed:

N 2 ð g Þþ O 2 ð g Þ! 2NO (g) ; 2NO (g) þ O 2 ð g Þ! 2NO 2 ð g ; brown Þ RR

In the catalytic convertor of a car, finely dispersed platinum crystals on the
ceramic body function as catalyst material, reducing nitrogen oxides and oxidizing
carbon monoxide:

NO ð g Þþ CO ð g Þ! 1 = 2N 2 ð g Þþ CO 2 ð g Þ RR

8.2.16 Water: Example “Sterilizing Drinking Water”

To sterilize drinking water, one uses chlorine or ozone - in both cases “nascent”
O atoms {O} are able to oxidize the organic impurities:

2H þ ð 2Cl ð Cl 2 ð g Þþ H 2 O ! aq Þþ aq Þþf O g RR

O 3 ð aq Þ! O 2 ð aq Þþf O g RR

8.2.17 Soil: Example “Soil Acidification”

Acid deposition is caused by industry and by car emissions into the air: droplets of
hydrochloric acid, sulfuric acid, or nitric acid solution occur causing acidification of
the soil after rain. On the one hand, this causes fine roots to be damaged and
carbonates from mineral nutrients to be dissolved and washed out. On the other
hand, Al 3+ ions that are fixed and harmless in solid aluminum salts are set free and
able to damage the roots of trees and plants:

3H þ ð Al 3 þ ð

Al ð OH Þ 3 (s) þ aq Þ! aq Þþ 3H 2 O ABR