Question

How has population growth in the United Kingdom contributed to air pollution over time?

Population growth caused farmers to use more fertilizers to increase production.


Population growth caused an increase in automobile traffic in the country's cities.


Population growth caused the government to open protected areas for development.


Population growth has increased industrial demand for power from nuclear energy plants.

Answer 1

Correct choices: 1 and 2 are meaningful ways population growth has increased air pollution; 4 is not; 3 is only an occasional/indirect factor.

Short explanations:
- Farmers using more fertiliser (1): intensification to feed a larger population raises use of nitrogen fertilisers. That releases ammonia (NH3) and nitrous oxide (N2O) to the atmosphere and contributes to secondary particulate formation (ammonium aerosols) and to greenhouse gases — so it can increase air pollution.
- More automobile traffic in cities (2): urban population growth and car ownership raise emissions of NOx, CO, volatile organic compounds and particulates, and contribute to urban smog and ozone formation — a major historical contributor in the UK.
- Opening protected areas for development (3): while population pressure can drive development into greenbelt/protected land in some cases, UK planning policies have often limited this; where it happens it can locally increase emissions, but it is not a general primary pathway for national air pollution.
- Increased demand for power from nuclear plants (4): nuclear power produces no combustion emissions, so expanding nuclear generation does not increase air pollution (and can reduce emissions from fossil-fuel plants).