Until we reduce air pollution, acid rain will continue to be a problem. Activities to resolve this problem include cleaning up the smokestacks and exhaust pipes that pour pollutants into the air, finding alternative sources of energy, repairing the damage already done by acid rain, and conserving our resources.

There are several ways to reduce the amount of sulfur entering the air. One way is to wash the sulfur out of the coal before it is burned. Another is to wash the sulfur out of the smoke before it goes up to the smokestacks. Scrubbers remove sulfur from the smoke by spraying a mixture of water and powdered limestone into the smokestack. The mixture traps the sulfur before it can escape into the air above.

Scientists and engineers are also discovering new ways to burn fossil fuels that produce much lower amounts of pollution.

Nitrogen oxides from burning coal and from vehicles also contribute to acid rain. Vehicles give off nitrogen oxides and other pollutants in their exhaust fumes. Devices such as catalytic converters reduce the pollution from those exhaust fumes. All new cars sold in the United States are required to have catalytic converters.

There are problems with using hydroelectric and nuclear power. Hydroelectric plants require a constant source of water. Because rainfall is not always predictable, hydroelectric plants are not as reliable as those using coal or oil. Hydroelectric plants can also harm the environment. Thousands of acres of land often have to be flooded to create a reservoir, a holding place for the great amounts of water needed to power these plants. Sometimes the land that would be flooded is home to rare types of plants or animals. Nuclear power plants produce electricity cheaply. But the nuclear waste they leave remains dangerous for thousands of years.

Scientists are looking at other energy sources, such as windmills and solar energy, using the power of the sun itself. In several states, there are modern windmills like airplane propellors that make energy from the wind. In other places, wind power pumps water from the ground. In Arizona and New Mexico, solar energy is at work making electric power. Each of these sources has drawbacks as well. Windmills and solar panels are reliable only where it is windy or sunny most of the time.

All sources of energy have benefits and limitations, including the cost of producing the energy. All of these factors must be weighed when deciding which energy source to use.

Liming is expensive and the effects are only temporary. As long as acid rain continues to fall, limestone must be reapplied or the water will become acidic again. Liming may be the only way to make sure that life in acid lakes or streams survives until the amount of acid rain falling on the surrounding land can be reduced.

Each person who turns off the lights when no one is using them and uses energy-saving appliances reduces the amount of electricity a power plant has to produce. When less power needs to be produced, pollution from power plants decreases. Car-pooling, using public transportation, and walking reduce the pollutants that come from vehicles. The sum total of all these individual actions can be very great indeed.

The more informed people are about acid rain and other environmental problems, the more they can do to make the earth a cleaner, healthier place.