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