XI. Fill in each blank with a word from the box.
controlled
deaths
negative
matter
pollutants
emit
Air pollution is the addition of gases, chemicals, and particle (1) pollutants into the atmosphere. Air
pollution primarily comes from burning fossil fuels such as natural gas, petroleum, and coal. A study has listed
air pollution as the cause of four percent of the (2) deaths in the United States.
Humans are the main cause of air pollution. Industry, including (3) give and power plants, burn
large quantities of fuel. (4)
coal and petroleum releases sulfur oxides and nitrogen oxide into
the air. Airplanes, boats, and cars burn petroleum, releasing carbon monoxide and carbon dioxide. The waste
in landfills releases methane. Sulfur oxides, carbon monoxide and carbon dioxide, and methane all have a very
(5)
effect on air quality. These (6)
can also contribute to the greenhouse
effect.
burning
factories
carbon
Some air pollution is not directly caused by humans: for example, animals (7)
dioxide when they breathe, and volcanoes release sulfur oxide. However, most air pollution is linked directly