7–10% of the AP exam. 9 key topics. 4 common errors analyzed.
Unit 7 (Atmospheric Pollution) addresses environmental systems and human impacts. FRQs in this unit typically ask you to identify problems, propose specific solutions, and explain environmental consequences.
These are the most frequently penalized mistakes on AP exam FRQs and MCQs. Review each before your next practice session.
Confusing tropospheric ozone (a harmful secondary pollutant and component of smog, formed at ground level) with stratospheric ozone (a beneficial shield against UV radiation) — location determines whether ozone is harmful or protective
Describing acid deposition as only 'acid rain' when it also includes acid fog, acid snow, and dry acid deposition — using the umbrella term 'acid deposition' is more accurate and scores better on FRQs
Omitting the thermal inversion mechanism: students state that inversions trap pollution but fail to explain that a warm air layer above cooler surface air prevents the vertical mixing that normally disperses pollutants upward
Misidentifying which pollutants are primary vs. secondary — tropospheric ozone is commonly misclassified as primary when it is in fact a secondary pollutant formed from photochemical reactions between primary emissions
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