Unit 7

• Primary Pollutants


  Directly emitted from sources, such as NO2 (Nitrogen Dioxide) from car emissions
• Secondary Pollutants


  Formed through chemical reactions in the atmosphere, such as O3 (Ozone) from NO2 and sunlight
• Key Pollutants and Their Abbreviations

  • Sulfur Oxide (SOx)
  • Nitrogen Oxide (NOx)
  • Carbon Dioxide (CO2)
  • Toxic Metals
  • Particulate Matter (PM)
• Sulfur Oxides (SOx)


  Released from burning fossil fuels, mainly from power plants and coal burning
• Nitrogen Oxides (NOx)


  Released from burning fossil fuels, mainly from power plants and cars
• Carbon Dioxide (CO2)


  Naturally occurring, but also released from human activities, contributing to climate change
• Toxic Metals


  Released from combustion of coal, including Lead and Mercury
• Particulate Matter (PM)


  Released from combustion of coal, wood, and other sources
• The Clean Air Act is a United States federal law that regulates six major air pollutants
• The Clean Air Act helps regulate lead in gasoline
• Photochemical Smog


  Smog formed when NOx chemicals react with sunlight and volatile organic compounds (VOCs) in the atmosphere
• Sources of VOCs


  • Gasoline
  • Formaldehyde
  • Varnishes
  • Paint
  • Nail polish
  • Perfume
  • Natural sources like tree sap
• Photochemical Smog Formation


  1. NOx chemicals are released in the morning, mainly from traffic

  2. Ozone is created through reaction with sunlight

  3. When VOCs are present, smog is formed
• Photochemical Smog Reaction


  1. NO2+sunlight→NO+O

  2. O+O2→O3

  3. O3+NO→O2+NO2
• VOCs can hijack the reaction, preventing the second formula from taking place, leading to smog formation
• Thermal Inversion


  Warm air above, cool air below, trapping pollution near the surface
• Thermal inversions can cause devastating health effects, as seen in the Great Smog of London in 1952
• Acid Deposition


  Both wet and dry deposition, including acid rain and particulate acid falling from the atmosphere
• Causes of Acid Deposition

  1. Nitrogen oxides and sulfur oxides released into the atmosphere

  2. Mix with water vapor to form nitric acid and sulfuric acid, contributing to acid deposition
• Acid deposition is a serious environmental issue, affecting both human health and the environment
• Effects of Acid Deposition on the Environment


  • Irritates skin, lungs, and eyes
  • Acidifies soils and water bodies, lowering their pH levels
  • Damages trees and forests
  • Reacts with marble and other materials, damaging ancient structures and buildings
• Effects of Acid Deposition on Human Health


  • Irritates skin, lungs, and eyes
  • Can cause respiratory problems
• Acid deposition can leach toxic metals from the ground, including mercury, into the environment
• Neutralization by Limestone


  Limestone, a basic substance, can help neutralize acid deposition by reacting with the acidic compounds
• Indoor Air Pollutants


  • Radon
  • Mold and dust particulates
  • Asbestos
  • Volatile Organic Compounds (VOCs)
  • Lead and paint
• Radon


  A radioactive material that occurs naturally in the ground
• Volatile Organic Compounds (VOCs)


  Found in furniture, carpets, and paint, causing lung and eye irritation
• Combustion Sources of Indoor Air Pollutants

  • Carbon monoxide (CO)
  • NOx and SOx chemicals
  • Particulate matter
• Reduction of Indoor Air Pollutants

  1. Use of radon-resistant construction materials

  2. Proper ventilation to reduce VOCs and other pollutants

  3. Regular cleaning and dusting to reduce particulates
• Noise Pollution


  High levels of noise that cause harm to humans and the environment
• Effects of Noise Pollution on Humans

  • Hearing loss
  • Anxiety and stress
  • Poor concentration and sleep disturbance
• Effects of Noise Pollution on the Environment

  • Alteration of animal behavior
  • Disruption of communication and mating habits
  • Impact on echolocation in animals
• Sources of Noise Pollution

  • Urban transportation
  • Construction activity
  • Domestic activity (e.g. loud stereos)
  • Industrial activity
  • Boat motor noise and offshore drilling
• Catalytic Converters


  Components of vehicles that burn fossil fuels, designed to reduce NOx and CO emissions
• Vapor Recovery Nozzles


  Found on gasoline pumps, capturing fumes before they're released into the atmosphere
• Scrubbers and Electrostatic Precipitators

  Equipment used in industrial settings, such as coal-fired power plants, to remove particulates from emissions
• Reducing fossil fuel use in general can help decrease air pollutants
• Regulatory methods, such as the Clean Air Act in the USA, help regulate air pollutants and keep them out of the atmosphere