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ENVS 1000 – Problems: Air Pollution – Outdoor

Environmental Problem: Air Pollution - Outdoor

• Focus on outdoor air pollution, its characteristics, sources, and solutions.

What are the Characteristics of the Earth’s Atmosphere?

• Thin Layer of Gases: Surrounds Earth and is crucial for life.

• Absorption of Radiation: Regulates climate by absorbing solar radiation.

• Transport of Essential Elements: Recycles water, nutrients, and contaminants across the globe.

• Impact of Human Activity: Human activities change the composition of atmospheric gases, contributing to pollution.

Layers of the Atmosphere

• Tropospheric Ozone: Considered harmful ("bad") as it occurs at ground level, contributing to health issues.

• Stratospheric Ozone: Considered beneficial ("good") as it protects against harmful UV radiation from the sun.

Composition of the Atmosphere

• Key Components: Include nitrogen, oxygen, argon, and trace gases, which are vital for ecological stability.

What is Outdoor Air Pollution?

Types of Air Pollutants

• Primary Pollutants: Directly harmful substances such as soot and carbon dioxide (CO2).

• Secondary Pollutants: Result from reactions between primary pollutants and atmospheric components (e.g., ozone and sulfuric acid).

Sources of Air Pollution

• Mobile Sources: Vehicles and transportation.

• Stationary Sources: Power plants and industrial facilities.

• Point Sources: Specific locations discharging large quantities of pollutants, like factories.

• Non-point Sources: Diffused sources comprising many smaller emitters, such as automobiles.

Natural Sources of Outdoor Air Pollution

• Dust Storms: Millions of tons of dust carried by strong winds, exacerbated by unsustainable farming and grazing practices.

• Volcanic Eruptions: Release particulate matter, sulfur dioxide, and other gases into the atmosphere.

• Natural Fires: Produce soot and gases, often exacerbated by human activities like deforestation and climate change.

Criteria Air Contaminants for Outdoor Air

• Key Pollutants:

  • Sulfur Dioxide (SO2)

  • Nitrogen Dioxide (NO2)

  • Ammonia (NH3)

  • Particulate Matter (PM)

  • Lead (Pb)

  • Carbon Monoxide (CO)

  • Tropospheric (Ground-Level) Ozone (O3)

  • Volatile Organic Compounds (VOCs)

Specific Pollutants and Their Hazards

1. Sulfur Dioxide (SO2):

   • Colorless gas with strong odor from coal emissions; can lead to acid rain.

2. Nitrogen Gases:

   • Nitrogen Dioxide (NO2): Reactive, foul-smelling gas from combustion processes; contributes to smog and acid rain.

3. Ammonia (NH3):

   • Emitted primarily from agricultural practices.

4. Particulate Matter:

   • Suspended solid or liquid particles; damaging when inhaled, from natural and human activities.

5. Lead:

   • Bioaccumulates and affects the nervous system; previously used in gasoline.

6. Carbon Monoxide (CO):

   • Colorless, odorless gas from incomplete fuel combustion; poses risks even at low concentrations.

7. Tropospheric Ozone (O3):

   • Harmful secondary pollutant formed from reactions under sunlight; contributes to smog.

8. Volatile Organic Compounds (VOCs):

   • Diverse pollutants predominantly from vehicle exhaust that have significant health impacts.

Types of Outdoor Air Pollution

• Smog:

  • Industrial (Gray Air) Smog: Produced by heavy industries; reduced in developed countries but remains a risk in developing regions.

  • Photochemical Smog: Result of sunlight-driven chemical reactions; commonly associated with urban areas.

Increasing Trends in Outdoor Pollution

• Outdoor air pollution is escalating due to industrial activities and lax emissions regulations.

• Developing nations are experiencing severe pollution; for example, many cities in China exceed safety thresholds, contributing to global health crises.

What are Solutions to Outdoor Air Pollution?

• Government Action: Extensive monitoring and regulations can improve air quality.

• Successful Emission Reductions: Despite population and economic growth, total emissions of monitored pollutants have successfully declined in some areas.

Summary

• The menu of air pollution problems includes understanding the characteristics and sources of air pollutants as well as identifying viable solutions.

Questions and Contact

• For further inquiries, students can contact instructor Mary Olaveson via the Canvas inbox or arrange an appointment.