APES Unit 7/9

EPA role in mitigating air pollution

The EPA monitors, sets limits, and enforces limits for air pollutants under the Clean Air Act.

6 criteria air pollutants

Sulfur dioxide, nitrogen oxides, particulate matter, carbon monoxide, tropospheric ozone, and lead.

EPA role in emissions reduction

Enforces Clean Air Act limits and sets standards for vehicle and factory emissions.

EPA removal of lead from gasoline

Set guidelines and phased out lead in gasoline, reducing atmospheric lead levels.

Photochemical smog formation

NO2 + sunlight → NO + O; O + O2 → O3; VOCs react with NO to form oxidants, preventing O3 breakdown and causing smog buildup.

Pollutants in photochemical smog

NO, VOCs, and O3.

Conditions for photochemical smog

Sunlight, warm temperatures, high VOCs, traffic emissions, and afternoon ozone buildup.

Normal vs inversion temperature gradient

Normal: warm at surface, cooler with altitude; Inversion: cool air trapped at surface, preventing pollutant dispersion.

Anthropogenic CO2 sources

Fossil fuel combustion and biomass burning.

Natural CO2 sources

Decomposition, wildfires, and cellular respiration.

Anthropogenic PM sources

Factories, vehicle exhaust, and construction.

Natural PM sources

Dust, wildfires, volcanoes, pollen, and spores.

Measuring CO2

Ice cores and ppm (parts per million).

Measuring PM

Categorized by size: PM10, PM2.5, etc.

Health impacts of PM

Asthma, bronchitis, and respiratory issues.

Lead (sources, impacts, reduction)

Sources: paint, pipes; Impact: neurotoxin; Reduction: remove paint, replace pipes.

Dust and mold

Sources: dust movement, damp areas; Impact: respiratory issues; Reduction: clean and fix moisture.

Radon gas

Sources: uranium decay; Impact: lung cancer; Reduction: seal cracks, ventilate, water treatment.

VOCs

Sources: chemicals, cleaners; Impact: lung/eye irritation; Reduction: ventilation, fewer new materials.

Carbon monoxide (CO)

Sources: incomplete combustion; Impact: asphyxiation; Reduction: ventilation, CO detectors.

Asbestos

Sources: old insulation; Impact: lung disease; Reduction: professional removal.

Indoor PM

Sources: smoke, dust; Impact: respiratory issues; Reduction: clean, ventilate, avoid smoking.

CAFE standards and pollution credits

CAFE improves fuel efficiency; pollution credits allow companies to trade emission allowances.

Vapor recovery nozzles and catalytic converters

Capture VOCs at gas stations; convert harmful gases into less harmful ones.

Crushed limestone & fluidized bed combustion

Reduce SO2 and NOx emissions by improving combustion and chemical reactions.

Dry/wet scrubbers

Remove pollutants using chemicals and/or water droplets.

Baghouse filters & electrostatic precipitators

Trap or electrically remove particulate matter from emissions.

Reducing acid rain

Use scrubbers and add limestone to neutralize acidity.

Acid rain formation

NOx and SO2 + H2O + O2 → nitric and sulfuric acids, releasing H+ ions.

Effects of acid rain

Increases metal toxicity, harms plants, and kills aquatic life.

Noise pollution (aquatic)

Disrupts communication and migration of marine animals.

Noise pollution (terrestrial

Interferes with predator/prey detection and mating.

Stratospheric ozone importance

Blocks harmful UV radiation, preventing mutations and skin cancer.

Ozone formation and breakdown

O2 split by UV → O; O + O2 → O3; reverse reactions break ozone down.

CFCs and ozone depletion

Chlorine radicals break down ozone repeatedly into O2.

Montreal Protocol

Global agreement to phase out CFCs.

CFC substitutes

HCFCs (still harmful), HFCs (no chlorine but GHG), HFOs (lower impact).

Greenhouse effect

Infrared radiation trapped and re-radiated, warming Earth.

Role of clouds and albedo

Clouds reflect sunlight (cooling); albedo changes affect warming.

Positive feedback loops

Melting ice lowers albedo; permafrost releases methane, increasing warming.

Greenhouse gases and sources

CO2 (fossil fuels), CH4 (agriculture), N2O (soils), CFCs (refrigerants), H2O (evaporation).

Vegetation and climate change

Carbon sequestration removes CO2 from atmosphere.

Greatest warming impact

Polar regions due to albedo changes.

Mitigating climate change

Shift to renewable energy and reduce fossil fuel use.

Coral reef importance

Support high biodiversity in ocean ecosystems.

Ocean warming impacts

Thermal stress, bleaching, and coral death.

Ocean acidification impacts

Reduces calcium carbonate formation for coral skeletons.

Sedimentation impacts

Smothers corals and blocks sunlight.

Ocean acidification cause

CO2 + H2O → carbonic acid → releases H+, reducing carbonate availability.

Impact of lower ocean pH

Weakens shells, harms organisms, disrupts ecosystems.