outdoor air pollution 7.1

1. Carbon Monoxide (CO)

• Colorless, odorless gas from incomplete combustion.

• Sources: Vehicle exhaust, indoor stoves (kerosene/wood).

• Health Effects: Interferes with oxygen uptake → asphyxiation, harms fetal development.

2. Lead

• Sources: Refineries, smelters, battery/steel industries.

• Gasoline: Phased out since 1974; damages catalytic converters.

• Health Effects: Neurotoxicant → brain/kidney damage, lower IQ, anemia.

3. Particulate Matter (PM10 vs. PM2.5)

• PM10: Dust, pollen, mold (≥10μm); causes respiratory irritation.

• PM2.5: Combustion particles (<2.5μm); reaches lungs → bronchitis, lung cancer risk.

4. Nitrogen Oxides (NOx)

• Reddish-brown reactive gas from fossil fuel/biomass combustion.

• Converts between NO & NO2 with sunlight.

• Health: Respiratory irritant.

• Environment: Forms tropospheric ozone, acid rain.

5. Photochemical Smog

• Formed by: Sunlight + NOx + VOCs

• O3 forms, can’t convert back at night if VOCs are present.

• More smog: High temp, sunlight, vehicle/VOC emissions, urban areas.

6. Ozone (Tropospheric)

• Secondary pollutant formed from NOx + VOCs + sunlight.

• Health: Irritates eyes/throat, worsens asthma.

• Environment: Damages plants, reduces photosynthesis, increases temps.

• Solution: Reduce fossil fuel use.

7. Sulfur Dioxide (SO2)

• Colorless gas from coal, diesel, and sulfur-containing processes.

• Health: Respiratory irritation, worsens asthma.

• Environment: Forms acid rain, blocks sunlight, creates grey smog.

8. Acid Rain

• Formed by: NOx + SO2 + O2 + H2O → Nitric & Sulfuric Acid

• Acid dissociates in water → harmful ions (H⁺, sulfate, nitrate).