AIR POLLUTION



IMPORTANT FACTORS:

  • Identity of the substance

  • Concentration

  • Duration of exposure

  • Location

  • Environmental conditions

  • Characteristics of the exposed population

  • Toxicity or hazard

  • Resulting health or environmental effects


CONTAMINANTS vs POLLUTANTS

  • Contaminants

    • Substance or agent that is present where it is not desired or expected, or that alters the normal composition of a medium.

  • Pollutants

    • A contaminant that, under relevant conditions, contributes to undesirable effects or risks to human health, welfare property, ecosystems, or other environmental resources.


WHY CONCENTRATION MATTERS?

  • A substance may exist naturally in the atmosphere without automatically creating an air pollution problem.

  • Question should not be: Is this substance present?

  • Bu rather: At what concentration, for how long, where, and with what consequences?


SOURCES OF AIR POLLUTION

  • Natural Sources

    • Volcanic eruptions

    • Wildfires

    • Windblown dust

    • Sea spray

    • Biological activity

    • Decomposition

    • Natural emission from vegetation

  • Anthropogenic Sources

    • Transportation

    • Power generation

    • Industrial processes

    • Fuel combustion

    • Construction

    • Agricultutre

    • Waste management

  • Stationary

    • Sources located at a fixed location.

    • Example:

      • Power plants

      • Industrial boilers

      • Furnaces

      • Cement plants

      • Chemical manufacturing plants