Air Pollution Notes

Introduction to Air Pollution

Definition of Air Pollutants: Specific molecules or particles that contribute to air pollution rather than the concept of pollution itself.
Clean Air Act (1970): Law identifying 6 criteria air pollutants for which the EPA must set limits, monitor, and enforce.

SO2 - Sulfur Dioxide:
- Source: Coal combustion.
- Effects: Respiratory irritant, contributes to smog and acid precipitation.
NOx - Nitrogen Oxides (NO and NO2):
- Source: Combustion of fossil fuels, especially gasoline.
- Effects: Contributes to photochemical smog and acid precipitation.
O3 - Ozone (Tropospheric):
- Formation: Photochemical oxidation of NO2.
- Effects: Respiratory irritant, damages plant growth.
CO - Carbon Monoxide:
- Source: Incomplete combustion of carbon-based fuels.
- Effects: Lethal to humans in high concentrations.
PM - Particulate Matter:
- Source: Fossil fuel and biomass combustion.
- Effects: Respiratory irritant, contributes to smog.
Pb - Lead:
- Source: Metal production, waste incineration.
- Effects: Neurotoxic, harmful to brain development.

CO2: Not a criterion pollutant under the Clean Air Act, does not directly impact air quality or human health though it has environmental implications due to global warming.
Focus for FRQ (Free Response Question) scoring in APES should remain on: SO2, NOx, O3, PM.

Releases significant amounts of air pollutants including: CO, CO2, SO2, NOx, and toxic metals (e.g., mercury, arsenic).
Impacts of SO2: Can cause respiratory issues, create sulfur aerosols, and lead to acid precipitation.

Created from combustion processes, leading to respiratory issues and contributing to ozone formation and acid precipitation.

Lead was previously a common gasoline additive phased out commencing in 1974, known for neurotoxic effects.
Vehicles from 1974 onward must have catalytic converters to reduce NOx, CO, and hydrocarbon emissions.

Primary Pollutants: Emitted directly from sources such as vehicles or natural events.
Secondary Pollutants: Formed from the transformation of primary pollutants in the atmosphere, often exacerbated by sunlight; includes ozone and various acids.

Precursors: NO2 and VOCs (Volatile Organic Compounds) are essential for smog formation.
Formation Mechanism: NO2 gets broken down by sunlight; ozone forms when free oxygen binds to O2.
Environmental Impact: Causes respiratory irritation and damages plant growth.

A phenomenon where cooler air is trapped beneath a layer of warmer air, leading to pollution accumulation at lower altitudes. This can exacerbate respiratory illness and reduce tourism.

Formation: UV radiation splits oxygen molecules, creating ozone (O3).
Depletion Sources: CFCs and natural phenomena like polar stratospheric clouds contribute to ozone layer thinning.

Montreal Protocol (1987): International agreement to phase out CFCs in favor of less harmful substances.

Common sources include: forest fires, vehicle emissions, industrial outputs, and power plants.

Engagement in public transport, using renewable sources, conserving electricity, and decreasing vehicle emissions are effective strategies.

The Clean Air Act allows for regulation and monitoring of air pollutant levels.
Pollution Credits System: Allows companies exceeding emission limits to buy credits from firms that have reduced emissions below standards.
CAFE Standards: Set mileage standards for vehicles to reduce emissions.

Use of technologies such as catalytic converters, wet/dry scrubbers, electrostatic precipitators to reduce pollutants at their sources.

Caused primarily by NOx and SO2 emissions, leading to environmental degradation such as soil and water acidification.
Mitigation strategies involve reducing emissions and applying natural buffers like limestone to affected areas.