The sources, chemistry, and human health effects of air pollution. Photochemical smog, thermal inversions, atmospheric CO2 and particulates, indoor air pollutants, acid rain, and noise pollution — plus the strategies used to reduce them.
Eight topics from the College Board CED, in order.
Topic 7.1
Introduction to Air Pollution
Primary pollutants (emitted directly) vs. secondary pollutants (formed through chemical reactions in the atmosphere).
Topic 7.2
Photochemical Smog
How sunlight reacts with vehicle emissions (NOx and VOCs) to form ground-level ozone and smog.
Topic 7.3
Thermal Inversion
A weather condition that traps a layer of cool air (and pollution) beneath a layer of warmer air, worsening air quality.
Topic 7.4
Atmospheric CO2 & Particulates
Sources of rising CO2 and particulate matter (PM2.5, PM10), and their effects on climate and respiratory health.
Topic 7.5
Indoor Air Pollutants
Radon, carbon monoxide, asbestos, and other pollutants that can accumulate at harmful levels indoors.
Topic 7.6
Reduction of Air Pollutants
Catalytic converters, scrubbers, and regulations like the Clean Air Act that reduce pollutant emissions.
Topic 7.7
Acid Rain
How sulfur dioxide and nitrogen oxides combine with atmospheric water to lower the pH of precipitation, damaging ecosystems.
Topic 7.8
Noise Pollution
Excessive or disruptive sound levels and their effects on human health and wildlife behavior.
About Unit 7
Unit 7 turns to pollution of the atmosphere — the chemistry behind smog, acid rain, and particulate pollution, and the weather and geography that can trap pollutants near the ground. You'll also cover indoor air quality, a College Board favorite, and the regulatory tools used to clean up the air we breathe.
This unit is roughly 7–10% of the AP Environmental Science exam and takes about 8–10 class periods. Expect chemistry-flavored questions about the reactions behind smog and acid rain, alongside conceptual questions about sources and health effects.
The College Board ties Unit 7 to a single Big Idea:
Big Idea: STB
Sustainability — air pollution sources, health effects, and strategies to reduce them