AP Environmental Science / Unit 7: Atmospheric Pollution
7.2 Photochemical Smog
Notes
Forms when $NO_x$ and VOCs react with sunlight, making tropospheric ozone.
- Worst on hot, sunny days in cities with lots of traffic.
- Ozone peaks in the afternoon after morning traffic.
Practice
Photochemical smog needs:
Sunlight drives the reactions.
Ozone near the ground:
Good up high, bad nearby.
Smog is usually worst:
Takes time and sunlight to form.
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