system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why does coal pollute much more than oil?
gpt
1. Coal has more impurities so burning it releases worse chemicals
2. Unless there is a spill, collecting coal is has worse effect on environment than drilling oil.
3. Oil is used mainly in vehicles, while coal is used almost exclusively to produce electricity, which is a much larger industry.