8.3 Urban air pollution

Objective notes

11 learning objectives

8.3.1Urban air pollutants

• NOx, sulfur dioxide, carbon monoxide, particulate matter

• PM2.5 (≤2.5 µm), PM10 (≤10 µm)

8.3.2Primary pollutant sources

• Natural: forest fires, dust, volcanic eruptions

• Anthropogenic: burning for clearance, fossil fuels, construction dust

8.3.3Fossil fuel combustion

• Most common urban air pollutants

• Primary: PM2.5, PM10, CO, SO₂

• Secondary: tropospheric ozone

8.3.4Management strategies

• Public transportation, cycling infrastructure, trees

• Green walls, catalytic converters, pedestrianized areas

8.3.5Acid rain formation

• NOx + SO₂ react with water and oxygen

• Produces nitric and sulfuric acid

8.3.6Acid rain impacts

• Terrestrial: soil leaching, toxification, foliage damage

• Freshwater: toxicity, impacts on fish/invertebrates

• Buildings: corrosion of marble, limestone, steel

• Human health: tissue damage, lung inflammation

8.3.7Acid rain management

• Alter human activity (alternative energy)

• Control at release (scrubbers, catalytic converters)

• Restore damaged systems (healthcare, lake treatment)

8.3.8(HL)—Photochemical smog

• Sunlight acts on primary pollutants → secondary pollutants

• Primary: NOx, VOCs

• Secondary: PANs, tropospheric ozone

8.3.9(HL)—Smog intensification factors

• Meteorological: abundant insolation, reduced wind, temperature inversion

• Topographical: mountains, high buildings

8.3.10(HL)—Tropospheric ozone direct impacts

• Biological: plant damage, eye irritation, respiratory illnesses

• Physical: fabric and rubber damage

8.3.11(HL)—Tropospheric ozone indirect impacts

• Societal costs, lost economic output

• Healthcare system impacts, reduced workforce

• Disproportionate impact on poorer communities