_Unit 7 Smedes APES Note Slides (22-23)

Introduction to Air Pollution

• Overview

  • Slides created by Jordan Dischinger-Smedes - Free resources for AP Environmental Science.

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Suggested Skill: Experimental Modifications

• Skill 4.E

  • Explain modifications to an experimental procedure that will alter results.

Learning Objectives and Essential Knowledge

Objective: Identify Sources and Effects of Air Pollutants

• STB-2.A

  • STB-2.A.1: Coal combustion releases pollutants:

    • Carbon dioxide (CO2)

    • Sulfur dioxide (SO2)

    • Toxic metals (e.g., mercury, arsenic)

    • Particulates

  • STB-2.A.2: Combustion of fossil fuels releases:

    • Nitrogen oxides (NO & NO2) - leads to photochemical smog and acid rain.

    • Other pollutants include carbon monoxide (CO) and particulates.

  • STB-2.A.3: Air quality affected by sulfur dioxide from burning diesel fuels.

  • STB-2.A.4: Clean Air Act reduced atmospheric lead levels, particularly from fuels.

  • STB-2.A.5: Distinction between primary (direct emissions) and secondary (transformation of primary pollutants) pollutants.

Basics of Air Pollution

• Key Pollutants

  • Coal combustion impacts: respiratory irritants, smog, acid precipitation.

  • Combustion of fossil fuels (FF) and biomass leads to:

    • SO2, nitrogen oxides (NOx), carbon monoxide (CO), particulate matter (PM).

  • Clean Air Act identifies six criteria air pollutants requiring regulation by the EPA.

Air Pollutants vs. Greenhouse Gases

• CO2 Distinctions

  • Not a criteria pollutant under Clean Air Act despite EPA’s ability to regulate it post-2007 SC ruling.

  • CO2 does not directly impair air quality or human health from a toxicity standpoint but has environmental impacts due to greenhouse effect.

Impact of Coal Combustion

• Coal as a Power Source

  • Accounts for ~35% of global electricity production.

  • Releases various pollutants including:

    • CO, CO2, SO2, NOx, toxic metals, PM.

  • Major impacts of SO2:

    • Respiratory irritant, worsens asthma, forms sulfurous smog, and acid precipitation.

Nitrogen Oxides (NOx)

• Release Sources

  • Produced from combustion processes, especially fossil fuels and biomass.

    • Forms when nitrogen in the atmosphere combines with oxygen.

    • Contributes to ozone formation and acid rain.

EPA Regulations on Lead

• Lead Phaseout

  • Lead was common in gasoline but phased out by EPA in 1974.

  • Vehicles made post-1974 require catalytic converters, reducing NOx, CO, and hydrocarbon emissions.

Primary vs. Secondary Air Pollutants

• Definitions

  • Primary pollutants: emitted directly (e.g., CO, NOx).

  • Secondary pollutants: formed from reactions in sunlight, water, and O2 (e.g., tropospheric ozone).

Photochemical Smog

Formation of Photochemical Smog

• Learning Objective: Causes and Effects

  • Produced through reactions of NOx and VOCs under sunlight.

  • Formation occurs more prominently in urban areas.

Environmental Factors

• Key Influencers: direct sunlight, heat, and urban traffic contribute to higher levels of photochemical smog, especially in the afternoon.

Health Impacts

• Human Risks

  • Causes respiratory issues, eye irritation, and other health problems.

Thermal Inversion

Concept and Effects

• Definition

  • The normal temperature gradient is altered, trapping pollutants close to the ground. Impacts include:

Pollution Concentration

• Human Health

  • Increased respiratory problems and economic impacts due to lower tourism and photosynthesis inhibition.

Natural Sources of CO2 and PM

Natural Contributions

• CO2 Origins

  • Releases from respiration, decomposition, volcanic eruptions.

  • Particulate matter from pollen, sea salt, and forest fires.

Indoor Air Pollutants

Types of Pollutants

• Common Pollutants

  • Carbon monoxide, asbestos, dust, radon, VOCs.

  • Sources range from combustion, materials used in construction, to human activity.

Health Implications

• Lead Effects

  • Damages nervous systems, particularly in children. Measures to reduce exposure involve replacing lead-based paints and pipes.

Reduction of Air Pollutants

Mitigation Strategies

• Objective: Explaining Reduction Methods

  • Include regulatory practices, alternative fuels, and conservation practices.

  • Use of technologies like catalytic converters, vapor recovery nozzles, and scrubbers.

EPA Initiatives

• Clean Air Act Policies

  • Allows for regulation of emissions and establishes standards to improve air quality.

Acid Rain

Formation and Sources

• Cause

  • Formed from NOx and SO2 emissions. These originate mainly from vehicle emissions and coal-burning power plants.

Effects

• Environmental Impact

  • Acidification of soil and water bodies, corrosion of structures, and regional ecological effects.

Noise Pollution

Urban Noise Sources

• Key Contributors

  • Construction, transportation, industrial activity often exceed sound levels that can cause stress and health issues.

Wildlife Effects

• Impact on Ecology

  • Noise pollution has physiological effects on animals and can disrupt communication, breeding, and migration.