IP Chemistry Upper Sec 12: Maintaining Air Quality

For Integrated Programme students: Your current school materials, teacher instructions, and assessment scope take precedence because IP topic sequence and depth vary by school. This is an Eclat IP guide, not the O-Level / SEC G3 exam-track guide.

The core idea is simple: Air-quality questions link pollutant, source, harm, and control.

Use it as a working check: Keep carbon monoxide toxicity, acid rain, particulates, greenhouse gases, and ozone roles separate. Name the control method that fits the pollutant.

Then go one layer deeper: Example: catalytic converters reduce nitrogen oxides and oxidise carbon monoxide, while limestone slurry helps remove sulfur dioxide from flue gases.

How this chapter applies

• Eclat core: air composition, pollutant sources, health and environmental effects, catalytic converters, flue-gas desulfurisation, ozone, the carbon cycle, greenhouse gases, and climate effects form the main route.
• School-sensitive extension: particulate-control devices, radical mechanisms for ozone depletion, local PSI interpretation, and wider climate chemistry should be used only where the current school teaches or supplies them.
• 2027 national comparison: K324 Topic C12 covers the named atmospheric pollutants, redox removal in catalytic converters, calcium carbonate in acid-rain mitigation and flue-gas desulfurisation, ozone-layer depletion, the carbon cycle, and greenhouse-gas effects.
• Check your school: pollutant lists, required equations, local data sources, and the depth of climate evaluation can differ. Use the current school materials and question data.
• Exam-track route: use the separate O-Level and SEC G3 Chemistry notes for K324 topic ownership.

What you must know

• Dry air composition: ~78% nitrogen, 21% oxygen, ~1% argon, ~0.04% carbon dioxide.
• Pollutants and sources: carbon monoxide (incomplete combustion), sulfur dioxide (burning sulfur fuels/volcanoes), nitrogen oxides (vehicle engines/lightning), unburnt hydrocarbons (engines), methane (decomposition, agriculture), ozone (secondary pollutant).
• Effects: CO is toxic (binds haemoglobin), SO₂/NOₓ → acid rain damaging lungs/buildings/aquatic life, particulates worsen respiratory issues, tropospheric ozone irritates lungs; greenhouse gases trap heat.
• Controls: catalytic converters (oxidise CO/HC, reduce NOₓ), limestone/calcium carbonate to neutralise acidic gases (flue gas desulfurisation), low-sulfur fuels, better combustion/engine tuning.
• Carbon cycle: photosynthesis removes