In this module, we have seen that the best approach for decreasing air pollution emissions is by avoiding them in the first place. This can be done by choosing fuels that contain fewer impurities or by increasing the efficiency of operations. After these options have been considered and implemented, a number of pollution control technologies are available to prevent pollutants from entering the air. The baghouse filter physically removes particles and the electrostatic precipitator uses an electrical charge to attract and remove pollutant particles. The scrubber literally scrubs the exhaust stream with water droplets, creating a sludge that can be collected and removed. Innovative techniques for reducing pollution include putting a price on the right to emit certain pollutants and allowing pollution permits bought and sold on the free market to bring down emissions in the most cost-
Module 48 AP® Review Questions
1. Which method is used to reduce nitrogen oxide emissions?
Installation of catalytic converters
Increased temperature of combustion
The addition of oxygen to combustion processes
The use of fluidized bed combustion
The use of calcium carbonate to absorb the emissions
2. Which is NOT used to prevent the emission of particulate matter?
Gravitational settling
Fabric filters
Electrostatic precipitators
Catalytic converters
Scrubbers
3. Which pollution control method was proposed by an amendment to the Clean Air Act?
Allowing tolls to limit the use of automobiles
A market for sulfur emissions
The regulation of radon emissions
The use of catalytic converters
Chemicals developed to prevent the formation of ozone
4. If carbon monoxide emissions decreased from 145 million tons annually to 80 million tons annually, by what percentage have emissions been reduced?
41 percent
45 percent
47 percent
52 percent
55 percent