ES unit 16

• South Asian Brown Cloud


  Massive air pollution problem in South Asia
• Causes of South Asian Brown Cloud


  • The South Asian Brown Cloud is primarily caused by a combination of vehicle emissions, industrial pollution, biomass burning, and agricultural practices, leading to the accumulation of aerosols and pollutants in the atmosphere.
• Chemical composition of South Asian Brown Cloud


  The South Asian Brown Cloud is composed of a mixture of pollutants including black carbon, sulfates, nitrates, organic aerosols, and dust particles suspended in the atmosphere.
• South Asian Brown Cloud affects west coast of the United States
• China and India need stricter air pollution standards
• Troposphere


  Innermost layer of the atmosphere that supports life

  
• Density and atmospheric pressure decrease with altitude
• Troposphere


  • 75-80% of the earth's air mass
  • Closest to the earth's surface
  • Involved in chemical cycling
  • Rising and falling air currents: weather and climate

  
• South Asian Brown Clouds


  Causing gradual melting of Himalayan glaciers
• Particles in South Asian Brown Clouds

  Absorb sunlight and warm air above the glaciers
• Particles in South Asian Brown Clouds

  Reflect some sunlight back to space
• South Asian Brown Clouds


  Overall cooling effect on earth's atmosphere
• Stratosphere


  Similar composition to the troposphere, with less water and containing the ozone layer

  
• Ozone layer


  Filters 95% of harmful UV radiation, allowing life to exist on land

  
• Air pollution


  Concentrations high enough to harm human health or alter climate
• Natural sources of air pollution


  • Dust blown by wind
  • Pollutants from wildfires and volcanoes
  • Volatile organics released by plants

  
• Human sources of air pollution


  • Stationary sources: power plants and industrial facilities
  • Mobile sources: motor vehicles

  
• Some pollutants in the atmosphere combine to form other pollutants

  
• Primary pollutants are emitted directly into the air, while secondary pollutants are formed from reactions of primary pollutants

  
• Air quality is improving in developed countries, but less-developed countries face big air pollution problems
• Burning fossil fuels


  Adds CO2 and O3 to troposphere, leading to global warming and altering climates
• Using nitrogen fertilizers and burning fossil fuels


  Releases NO, NO2, N2O, and NH3 into troposphere, producing acid rain
• Refining petroleum and burning fossil fuels


  Releases SO2 and toxic heavy metals (Pb, Cd, and As) into troposphere
• Criteria air pollutants monitored by EPA

  • Nitrogen Dioxide: NO2
  • Ozone: ground level O3
  • Carbon monoxide: CO
  • Lead: Pb
  • Particulate Matter: PM10 (PM 2.5)
  • Sulfur Dioxide: SO2

  
• Volatile Organic Compounds (VOCs)


  Organic compounds that evaporate easily, usually aromatic
• Carbon Monoxide (CO)


  Colorless, odorless gas that is heavier than air and makes up 0.0036% of the atmosphere
• Carbon Monoxide (CO)


  Binds tighter to hemoglobin than oxygen, affecting mental functions and visual acuity
• 60-95% of carbon monoxide emissions come from auto exhaust
• Nitrogen Oxides (NOx)


  Nitrogen oxides (NO) and nitric acid (HNO3), which contribute to acid deposition and photochemical smog
• Nitrogen Dioxide (NO2)


  Reddish brown gas that is a strong oxidizing agent and forms nitric acid in the air
• Nitrogen Dioxide (NO2)


  Causes acid rain, lung and heart problems, decreased visibility, and suppresses plant growth
• Sulfur Dioxide (SO2)


  Colorless gas with an irritating odor that produces acid rain (H2SO4)
• Sulfur Dioxide (SO2)


  Causes breathing difficulties, eutrophication, and is an indicator for lichen and moss
• Suspended Particulate Matter (PM10)


  Particles suspended in air that are less than 10 micrometers in size
• Suspended Particulate Matter (PM10)


  Causes lung damage and can be mutagenic, carcinogenic, and teratogenic
• Ozone


  Colorless, unpleasant odor gas that is a major part of photochemical smog

  
• Ozone


  Lung irritant that damages plants, rubber, fabric, and eyes
• Volatile Organic Compounds (VOCs)


  Organic compounds that evaporate easily, usually aromatic, and are eye/respiratory irritants, carcinogenic, and can damage plants and the climate
• Lead (Pb)


  Grayish metal that accumulates in tissue and affects the kidneys, liver, and nervous system, especially in children
• Chemical reactions form major outdoor air pollutants