Air Pollution One Page AP Review

From natural sources such as dust, forest, fires, and geological processes

Humans add air pollutants through burning of Fossil Fuels, erosion of land, factory emissions

-  Major outdoor air pollutants

-Carbon oxides (CO, CO₂)

-Nitrogen oxides (NO, NO₂, N₂O)

-Sulfur oxides (SO₂, SO₃)

-Suspended Particulate Matter 

-Solids (dust, soot, lead, nitrate and sulfate salts)

-Liquids (sulfuric acid, PCBs, pesticides, dioxins

-Photochemical Oxidants (ozone)

-VOCs (Hydrocarbons like methane & benzene from incomplete combustion)

-Hazardous Air Pollutants 

-Cause cancer, birth defects, nervous system damage

-HAPs: benzene, formaldehyde, chloroform, lead, radioactive)

- Primary pollutants: directly put in troposphere 

• Examples:

• CO₂ & NO_x gases from car exhaust

• Ash produced from burning coal

• SO₂ gas from volcanoes or burning coal

- Secondary pollutants: when primary pollutants react with air to form new pollutants

Ex:  Acid Rain

-Sulfur based from coal: SO₂ + H₂O → H₂SO₄ (ACID RAIN)

-Nitrogen based from cars NO₂ + H₂0  →  2HNO₃  (ACID RAIN)

-leads to acid deposition in soil and rocks (Al) and acidification of water

Ex:  Photochemical Smog (ozone in the troposphere… BAD): 

-From car emissions: VOC + NOx + heat + light → OZONE (resp. irritant)

-Smog:

-Photochemical smog = orange smog and associated with car emissions: ozone!

-Industrial Smog = grey smog (soot)

-Due to burning large amounts of coal (China) … SO₂… ACID RAIN

Thermal Inversions

-warm air covers cool air and no movement occurs forming a “blanket”…. Traps pollution!

-big problem in cities (worsened in mountainous areas)

Technologies for Removal of Air Pollution
          -Baghouse filter – remove very fine particulates
          -Cyclone collector – particulate removal; cheap! Like a Dyson vacuum cleaner
          -Electrostatic precipitator – removal of particulates based on charge separation
          -Wet Scrubber - removes particulates and gases such as SOx; goes through mist of liquid chemicals (water)
          -Catalytic converter (on cars) – transform toxic pollutants into less harmful forms  (CAA 1973) 

Natural Factors that Reduce Air Pollution
-rain and snow
-salty spray from the ocean
-winds

Indoor Air Pollution

-Cigarette smoke:  Lung cancer!  Also creates CO, CO₂, sulfur and particulates

-CO (reduces O₂ in your blood): burning fireplaces, car emissions, cig smoke

-formaldehyde: “new” smell from building materials, carpet; dizziness

-radon-222: trapped in radioactive uranium rocks; carcinogen

-asbestos and fine particulates: fire retardants in old homes; carcinogen

Clean Air Acts: 1973 (NAAQS: set 6 criterion air pollutants: CO, NO2, SO2, particulates, Ozone, Lead)

1990 (SO2 cap and trade program)