Air Pollution

Local Air Pollution

vehicle exhaust in cities, indoor air pollutants

Regional Air Pollution

smog that spreads across metropolitan areas

Continental Air Pollution

acid rain transported from industrial regions

Global Air Pollution

greenhouse gases and ozone depletion that circulate globally

Primary Pollutants

Emitted directly from identifiable sources (e.g., Carbon monoxide, Sulfur dioxide)

Secondary Pollutants

Formed in the atmosphere by chemical reactions (e.g., tropospheric Ozone, sulfuric acid)

Carbon monoxide

A primary pollutant; one of the 6 criteria pollutants

Tropospheric Ozone

A secondary pollutant; one of the 6 criteria pollutants

Six Criteria Air Pollutants

Carbon monoxide, Particulate matter, Lead, Sulfur dioxide, Nitrogen dioxide, Ozone

NAAQS

National Ambient Air Quality Standard, limits concentration levels of criteria pollutants

Lead Primary Source

Historically from leaded gasoline, industrial smelting

Lead Main Impact

Neurotoxin; damages brain development in children

Lead Success Story

90%+ reduction since phasing out leaded fuel

Sulfur Oxides Source

Burning of coal and oil; industrial processes

Sulfur Oxides Impact

Forms sulfuric acid leading to acid rain

Sulfur Oxides Solution

Flue-gas desulfurization (scrubbers), cleaner fuels

Nitrogen Oxides Source

Combustion engines, power plants, vehicle exhaust

Nitrogen Oxides Impact

Precursor to ozone and photochemical smog

Nitrogen Oxides Solution

Vehicle emissions controls, catalytic converters

Tropospheric Ozone Source

Secondary pollutant formed from Nitrogen oxides + VOCs in sunlight

Tropospheric Ozone Impact

Respiratory irritant, reduces crop yields, damages materials

Photochemical Smog Formation

Nitrogen oxides and VOCs react with UV light to produce Ozone, which creates smog

Conditions for Smog

Warm, sunny days; light winds; temperature inversions

Indoor Air Quality Problem

Can be 2–5 times more polluted than outdoor air due to poor ventilation

Radon Indoor Source

Natural radioactive gas seeping from soil

Radon Health Effect

Lung cancer

Carbon monoxide Indoor Source

Gas stoves, heaters, tobacco smoke

Carbon monoxide Prevention

Carbon monoxide detectors, proper appliance maintenance

Formaldehyde Indoor Source

Building materials, furniture, fabrics

Asbestos Health Effect

Lung cancer, mesothelioma

VOCs (Indoor Source)

Paints, cleaning agents

Clean Air Act (CAA) Overview

Enacted 1970; regulates emissions and improves public health

CAA Success Measurement

Significant reductions (e.g., Carbon monoxide down 82%, Lead down 90%)

Remaining CAA Concerns

Urban ozone and Particulate matter 2.