AP Environmental Science - Air, Aquatic, & Terrestrial Pollution

Point and Nonpoint Source Pollutants

  • Point Source Pollution:
    • Defined as pollutants that enter the environment from a single, easily identifiable source.
    • Examples:
    • Emissions from a smokestack of a coal power plant, which releases pollutants like CO2, NOx, SOx, and PM.
    • Oil spills involving hydrocarbons and benzene.
    • Wastewater discharge from a factory.
  • Nonpoint Source Pollution:
    • Pollutants that originate from multiple diffuse sources, making it harder to trace back to a single source.
    • Examples:
    • Urban runoff from streets that carries motor oil, fertilizers, and debris into waterways.
    • Agricultural runoff that carries pesticides and nutrients from farmland.

Air Pollution

  • Sources and Types of Air Pollution:
    • Primary Pollutants:
    • Emitted directly from sources (e.g., CO2, SO2, NOx, PM).
    • Secondary Pollutants:
    • Formed when primary pollutants react in the atmosphere (e.g., ozone, acid rain).
  • Health Effects:
    • Respiratory irritants leading to conditions like asthma and bronchitis.
    • Formation of smog and acid precipitation which can harm human and ecosystem health.
  • Key Air Pollutants Listed by the Clean Air Act:
    • Six criteria pollutants: Carbon Monoxide (CO), Lead (Pb), Nitrogen Dioxides (NOx), Ozone (O3), Particulate Matter (PM), and Sulfur Dioxide (SO2).

Thermal Pollution

  • Concept: Refers to the degradation of water quality due to changes in water temperature caused by human activities.
  • Causes:
    • Power plants using water for cooling and returning warmer water back to aquatic ecosystems.
  • Effects:
    • Decreased dissolved oxygen (DO) levels, affecting aquatic life.
  • Thermal Inversion:
    • An atmospheric condition where cooler air is trapped under warmer air, preventing pollutant dispersion and increasing health risks.

Sewage Treatment

  • Steps in Sewage Treatment:
    • Primary Treatment: Physical removal of large debris through filtration.
    • Secondary Treatment: Biological breakdown of organic matter using bacteria.
    • Tertiary Treatment: Advanced chemical treatment to further reduce pollutant levels.
  • Challenges:
    • Combined sewage and stormwater systems can overflow during heavy rains, discharging untreated sewage into water bodies, leading to pollution and health risks.

Human Impact on Pollution

  • Pollution's Effects on Health and Environment:
    • Contributes to loss of biodiversity and health issues in humans and wildlife (respiratory diseases, waterborne diseases).
    • Increases in water temperate and acidity affect aquatic life negatively (e.g., coral bleaching due to thermal pollution).
  • Regulatory Frameworks:
    • Laws such as the Clean Air Act aim to limit emissions and protect public health and the environment through established air quality standards.