Exercises: Smog, Acid Rain and Air Pollution Control

Name the two primary pollutants that react in sunlight to form photochemical smog, and name the key secondary pollutant that results.

Which two pollutants emitted by burning fossil fuels are the main causes of acid rain? State the approximate pH of normal, unpolluted rain.

Identify the device used in coal power plants to remove sulfur dioxide from exhaust gases and the device used to remove particulates.

Los Angeles often has severe smog. Explain how a thermal inversion traps pollutants near the ground, and why the city's mountains and sunny, car-heavy conditions make it worse.

Rain in a lake region in the northeastern U.S. has a pH of 4.6, while normal rain has a pH of about 5.6.

(a) By what factor is the rain more acidic than normal rain? Remember that each pH unit is a tenfold change.

(b) Explain two effects of acid deposition on forests or lakes.

Compare two ways to reduce air pollution from a coal-fired power plant: (a) switching to low-sulfur coal and (b) installing a scrubber. Explain how each lowers emissions and name one limitation of each.

The table shows average daily ozone and nitrogen oxide (NOx) levels in a large city on a summer weekday.

(a) Explain why NOx peaks in the morning.

(b) Explain why ozone peaks in early afternoon rather than at the morning rush hour.

(c) Propose two strategies, one technological and one policy-based, to reduce peak ozone, and explain how each works.

A state is considering a rule that requires all coal plants to install scrubbers and catalytic converters on diesel trucks. Plant owners say it will raise electricity prices by 4%.

(a) Describe how each technology reduces a pollutant that causes acid rain or smog.

(b) Explain how lowering SO₂ and NOx would help forests and lakes downwind of the state.

(c) Evaluate the rule, considering costs, health benefits, and the fact that pollution crosses state lines.