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S6 Geography: Urban Climate and Air Pollution (Paper 3 (challenge))
S6 Geography: Urban Climate and Air Pollution (Paper 3 (challenge))
Paper 3 (challenge): ten questions on urban climate and air pollution with worked numbers, answers and one line notes.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S6 Geography: Urban Climate and Air Pollution |
| Level | S6 |
02 Questions (10 items)
- FoundationHow is heat island intensity defined?
- FoundationHow does a cool roof (high albedo) reduce heat?
- FoundationWhat usually happens to night-time temperature as the sky view factor falls?
- IntermediateWhen planning a ventilation corridor, how should it align with the prevailing wind?
- IntermediateWhat does a temperature inversion do to pollutants?
- IntermediateWhat else is needed for vehicle nitrogen oxides to form ozone?
- ChallengeThe urban station reads 32.4 degrees and the rural station 27.6. What is the heat island intensity?
- ChallengeA district has 400000 residents and 60 hectares of green space. How many square metres of green space per person?
- ChallengePM10 measures 80 micrograms per cubic metre and PM2.5 accounts for sixty percent. What is the PM2.5 concentration?
- Error redoError clinic: cutting industrial emissions alone will certainly solve air pollution. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | The air temperature difference between the city and the countryside, usually the night-time maximum | Only comparing the two places at the same moment gives a meaningful figure. |
| 2 | It reflects more shortwave radiation, so the building absorbs less heat | The higher the albedo, the less is absorbed and the slower the daytime heating. |
| 3 | It rises, because longwave radiation escapes to the sky less easily | A street hemmed in by tall buildings sees little sky, so it cools slowly at night. |
| 4 | Roughly parallel, so the wind enters the city smoothly | A corridor perpendicular to the prevailing wind, or lined with tower blocks, loses most of its effect. |
| 5 | It suppresses vertical mixing, so pollutants accumulate near the ground | Cooler, heavier air sits below, so pollutants cannot rise and disperse. |
| 6 | Sunlight and volatile organic compounds | That is why photochemical smog is common on sunny afternoons. |
| 7 | 4.8 degrees | 32.4 minus 27.6 gives 4.8. |
| 8 | 1.5 square metres | 60 hectares is 600000 square metres, which divided by 400000 people gives 1.5. |
| 9 | 48 micrograms per cubic metre | 80 multiplied by 0.6 gives 48. |
| 10 | Vehicle emissions and regional transport matter just as much, so cuts must be city-wide and regional | Roadside pollutants come mainly from vehicles, and regional transport also affects Hong Kong. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
For urban climate questions, decide first whether the answer is a temperature difference or a percentage: subtract for a difference, and divide the change by the original value then multiply by one hundred for a percentage. For air questions, remember that smaller particles reach deeper into the lungs, and ozone needs sunlight and nitrogen oxides.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
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