Atmospheric Pollution Notes

Atmospheric Pollution: Learning Objectives and Essential Knowledge Statements

Sources and Effects of Air Pollutants

  • Coal Combustion: Releases air pollutants:
    • Carbon dioxide (CO_2)
    • Sulfur dioxide (SO_2)
    • Toxic metals
    • Particulates
  • Combustion of Fossil Fuels: Releases nitrogen oxides (NO_x) into the atmosphere.
    • Leads to ozone production (O_3)
    • Formation of photochemical smog
    • Conversion to nitric acid (HNO_3), causing acid rain
    • Other pollutants include:
      • Carbon monoxide (CO)
      • Hydrocarbons
      • Particulate matter
  • Sulfur Dioxide Release: Burning of fossil fuels, mainly diesel, affects air quality.
  • Clean Air Act & EPA: Regulated lead use, especially in fuels, which significantly decreased atmospheric lead.
  • Primary vs. Secondary Pollutants:
    • Air pollutants can be primary or secondary.

Photochemical Smog: Causes, Effects, and Reduction Methods

  • Formation:
    • Nitrogen oxides (NO_x) and volatile organic hydrocarbons (VOCs) react with heat and sunlight to produce pollutants.
  • Environmental Factors:
    • Many factors affect photochemical smog formation.
  • Nitrogen Oxide Production:
    • Produced early in the day.
  • Ozone Concentrations:
    • Peak in the afternoon.
    • Higher in the summer due to chemical reactions between oxygen and sunlight.
  • Volatile Organic Compounds (VOCs):
    • Evaporate or sublimate at room temperature (e.g., formaldehyde, gasoline).
    • Trees are a natural source of VOCs.
  • Urban Areas:
    • Photochemical smog often forms due to the large number of motor vehicles.
  • Reduction Methods:
    • Reducing nitrogen oxide and VOCs.
  • Harm to Human Health:
    • Respiratory problems
    • Eye irritation

Thermal Inversion and Pollution

  • Definition:
    • The normal temperature gradient is altered; air temperature at the Earth’s surface is cooler than air at higher altitudes.
  • Trapping Pollution:
    • Traps pollution close to the ground, especially smog and particulates.

Natural Sources of CO_2 and Particulates

  • Carbon Dioxide:
    • Respiration
    • Decomposition
    • Volcanic eruptions
  • Particulate Matter:
    • Variety of natural sources.

Indoor Air Pollutants

  • Carbon Monoxide (CO):
    • Classified as an asphyxiant.
  • Particulates:
    • Asbestos
    • Dust
    • Smoke
  • Sources:
    • Natural sources
    • Human-made sources
    • Combustion
  • Common Natural Source Indoor Air Pollutants:
    • Radon
    • Mold
    • Dust
  • Common Human-Made Indoor Air Pollutants:
    • Insulation
    • VOCs from furniture, paneling, and carpets
    • Formaldehyde from building materials, furniture, upholstery, and carpeting
    • Lead from paints
  • Common Combustion Air Pollutants:
    • Carbon monoxide
    • Nitrogen oxides
    • Sulfur dioxide
    • Particulates
    • Tobacco smoke
  • Radon-222:
    • Naturally occurring radioactive gas.
    • Produced by the decay of uranium.
    • Found in some rocks and soils.

Effects of Indoor Air Pollutants

  • Radon Gas Infiltration:
    • Moves up through the soil.
    • Enters homes via the basement or cracks in walls/foundation.
    • Dissolved in groundwater that enters homes through a well.
  • Exposure to Radon Gas:
    • Radon-induced lung cancer.
    • Second leading cause of lung cancer in America.

Reducing Air Pollutants at the Source

  • Methods:
    • Regulatory practices
    • Conservation practices
    • Alternative fuels
  • Vapor Recovery Nozzle:
    • Air pollution control device on gasoline pumps.
    • Prevents fumes from escaping into the atmosphere.
  • Catalytic Converter:
    • Air pollution control device for internal combustion engines.
    • Converts pollutants (CO, NOx, hydrocarbons) into less harmful molecules (CO2, N2, O2, H_2O).
  • Wet and Dry Scrubbers:
    • Air pollution control devices.
    • Remove particulates and/or gases from industrial exhaust streams.
  • Coal Burning Power Plants:
    • Methods to reduce air pollution: scrubbers and electrostatic precipitators.

Acid Deposition

  • Cause:
    • Nitrogen oxides and sulfur oxides from anthropogenic and natural sources.
  • Nitric Oxides:
    • From motor vehicles and coal-burning power plants.
  • Sulfur Dioxides:
    • From coal-burning power plants.

Effects of Acid Deposition on the Environment

  • Affected Communities:
    • Mainly downwind from coal-burning power plants.
  • Effects:
    • Acidification of soils and bodies of water.
    • Corrosion of human-made structures.
  • Regional Differences:
    • Soils and bedrock affect the impact of acid deposition.
    • Limestone bedrock can neutralize the effect of acid rain on lakes and ponds.

Human Activities Resulting in Noise Pollution and Its Effects

  • Noise Pollution:
    • Sound at levels high enough to cause physiological stress and hearing loss.
  • Sources in Urban Areas:
    • Transportation
    • Construction
    • Domestic and industrial activity
  • Effects on Animals:
    • Stress
    • Masking of sounds used to communicate or hunt
    • Damaged hearing
    • Changes to migratory routes