Cars, factories, and electricity make our lives easier, but they also produce gasses and chemicals that pollute the air.
Polluted air is bad for people to breathe, and it can harm animals, trees, and plants.
And it doesn't just blow away the pollution can return to earth as acid rain. Scientists are trying to think of ways to keep our air cleaner. Turn out the lights Many power plants make electricity by burning fossil fuels, such as coal and oil, and that creates air pollution. When you leave a room, turn out the lights. Less electricity will be used, less coal will get burned, and less pollution will be released into the air.