1 / 18

Air Pollution

Air Pollution. A thick layer of smoke and haze over Santiago, Chile. Chapter 10 review. In equatorial regions, the intertropical convergence zone (ITCZ) is a boundary where air rises in response to the convergence of of the northeast trades and the southeast trades

drury
Download Presentation

Air Pollution

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Air Pollution A thick layer of smoke and haze over Santiago, Chile

  2. Chapter 10 review • In equatorial regions, the intertropical convergence zone (ITCZ) is a boundary where air rises in response to the convergence of of the northeast trades and the southeast trades • The polar front is a zone of low pressure where storms often form. It separates the mild westerlies of the middle latitudes from the cold, polar easterlies of the high latitudes • In the Northern Hemisphere, the major global pressure systems and winds belts shift northward in summer and southward in winter • The two major semipermanent subtropical highs that influence the weather of North America are the Pacific high off the west coast and the Bermuda high off the southeast coast • The northward movement of the Pacific high in summer tends to keep summer weather along the west coast of North America relatively dry

  3. Chapter 10 review • Jet streams exist where strong winds become concentrated in narrow bands. The polar front jet stream is associated with the polar front and meanders in a wavy, west-to-east pattern… • The subtropical jet stream is found on the poleward side of the Hadley cell, between 20 and 30 deg latitude. • Winds blowing over the surface of the water drive the major ocean currents. The direction of the current varies with depth (Ekman spiral). • The net transport of water is at right angles to the surface wind • Where winds and Ekman transport drive water away from a coastline, cold, nutrient-rich water upwells to replace it (upwelling).

  4. A brief history of air pollution • Early humans: “smoke problems” in poorly ventilated caves • Middle ages: use of coal as a heating fuel • Industrialization, London disasters (1873,1911,1952) • Smog = smoke + fog (smoke + fog?) • Air pollution in the US • The “Smoky City”? • The Donora disaster (1948) • Most polluted cities (American Lung Association 2004) • Los Angeles, Visalia, Bakersfield, Fresno, Pittsburgh, Detroit, Atlanta, Cleveland, … • The Clean Air Act (1970), updated 1977 and 1990 • Federal government can set emission standards… • … regardless of the cost (Supreme Court, 2001) Pittsburgh, PA

  5. Indoor Air Pollution • Cooking and heating with solid fuels on open fires or traditional stoves results in high levels of indoor air pollution (IAP). • The World Health Organisation estimated in 2002 that IAP is responsible for around 1.6 million deaths per year, due to respiratory infections, lung diseases and lung cancer

  6. Types and sources of air pollution • Air pollutants: airborne substances (solids, liquids or gases) that occur in concentrations high enough to threaten the health of people and animals, harm vegetation and structures, or toxify a given environment • Primary: enter the atmosphere directly • Secondary: form when a chemical reaction occurs between a primary pollutant and another atmospheric component • Natural sources: dust, soot, volcanic ashes, salt particles, forest fires • Human caused sources: • Fixed sources: industrial plants, home/office buildings. • Mobile sources: motor vehicles, ships, aircraft. • Human caused sources (alternative classification) • Industrial • Personal

  7. Primary pollutants and their sources • The primary pollutants fall into 5 groups (will discuss each one in turn) • Transportation accounts for ~50% of the air pollution in the US

  8. Principal Air Pollutants - I • Particulate matter (aerosols): solid particles or liquid droplets small enough to remain suspended in the air (soot, dust, smoke, pollen, asbestos fibers, arsenic, sulfuric acid, pesticides, metals, …) • Reduces visibility (haze) • Removed from the atmosphere by rain and snow (condensation/ice nuclei) • The smaller the particles, the higher the health risk • PM-10: less than 10 micrometers • PM-2.5: less than 2.5 micrometers

  9. Principal Air Pollutants - II • Carbon Monoxide (CO): colorless, odorless, poisonous gas which forms during incomplete combustion of carbon fuels (car engine, furnace). • causes suffocation (hemoglobin prefers CO to O2) • roll down car windows when stuck in a snowstorm and engine running • install CO detectors in the house • removed from the atmosphere by soil microorganisms • Sulfur dioxide (SO2): colorless gas resulting from the burning of sulfur-containing fossil-fuels • Human sources: power plants, heaters, smelters, petroleum refineries, paper mills. • Natural sources: volcanic eruptions, ocean spray • Can damage crops: causes bleached marks on lettuce/spinage leaves • Can aggravate respiratory problems (asthma, bronchitis…)

  10. Principal Air Pollutants - III • Volatile Organic Compounds (VOCs): organic compounds, mainly hydrocarbons • Methane – occurs naturally • Benzene, formaldehyde, chlorofluorocarbons • Some are carcinogens (cancer-causing agents) • In the presence of sunlight some will react with nitrogen to produce secondary pollutants • Nitrogen oxides (NO2, NO) • Concentrated in urban environments (~10-100 times) • React with water vapor to produce nitric acid HNO3 (acid rain, see Chapter 1) • Primary sources: vehicles, power plants, waste disposal

  11. Number of unhealthful days

  12. Air Quality Index • Tracks five pollutants: CO, SO2, NO2, particulate matter, O3. • If pollutant value equals the air quality standard -> 100%

  13. Health-related maps

  14. Indoor Air Pollutants • Radon: colorless, odorless, radioactive gas. • Results from Uranium decays in the soil and rock • Seeps through cracks and accumulates in the house near the floor (it is very heavy) • Decays to Polonium which attaches to dust particles and can be inhaled in the lungs • Polonium decays damage the lung tissue • Test for radon when you buy a house! • The Environmental Protection Agency recommends radon mitigation if the radon concentration exceeds 4 pCi/L

  15. Indoor Air Pollutants • Formaldehyde: colorless, pungent-smelling gas used to manufacture building materials and insulation • Asbestos: mineral fiber once used in insulation and as a fire retardant • Lead: from chipping or peeling lead paint (before 1978) • Carbon monoxide (CO): needs to be checked if you have a furnace or fireplace – install detectors. • Legionnaire's Disease: caused by waterborne bacterium • Molds and allergens: result from • moisture-induced growth of mold colonies • animal dander or plant pollen • Tobacco smoke (ban smoking indoors)

More Related