7.6 Reduction of Air Pollutants

Legislation and Regulation

The Clean Air Act (1970) set national standards to reduce air pollution in the US, regulating emissions from industry and vehicles. It established National Ambient Air Quality Standards (NAAQS) for criteria pollutants. International agreements like the Montreal Protocol targeted ozone-depleting substances (CFCs), successfully reducing stratospheric ozone loss.

Technological Solutions

Scrubbers remove sulfur dioxide and particulates from smokestack emissions using liquid or chemical sprays. Catalytic converters in vehicles convert harmful gases (CO, NOx, hydrocarbons) into less harmful ones (CO2, N2, H2O). Electrostatic precipitators use charged plates to capture particulate matter before it exits a chimney.

Alternative Practices

Switching to low-sulfur coal or renewable energy reduces SO2 and particulate emissions. Improving fuel efficiency and using electric vehicles cuts vehicle emissions. Carpooling, public transit, and smart urban planning reduce overall vehicle miles traveled, lowering smog and greenhouse gas output.

Key terms

Clean Air Act

1970 US law establishing NAAQS and regulating emissions of major air pollutants from industry and vehicles.

Scrubber

Device that sprays liquid/chemicals into smokestack emissions to remove SO2 and particulates.

Catalytic converter

Vehicle device that converts CO, NOx, and hydrocarbons into CO2, N2, and H2O.

Electrostatic precipitator

Uses charged plates to attract and remove particulate matter from exhaust before release.

Montreal Protocol

1987 international treaty that phased out CFCs and successfully reduced ozone depletion.

Try an AP-style question

What does a wet scrubber remove from smokestack gases?

1. Sulfur dioxide
2. Carbon dioxide
3. Radon
4. Ozone