Have you ever noticed smog over a big city?
Then you’ve actually seen outdoor air pollution.
Some outdoor air pollution is invisible to us, of course, but it can still affect our lives.
Many factors play a role in outdoor air quality. Natural things like volcanic eruptions, wildfires, wind currents, and trees can affect it. Some human activities add pollutants into the air. Think of factories and power plants pumping out smoke and chemicals, and tractors on farms blowing up dust clouds.
When we breathe in pollutants, they can create health problems — or make existing health problems worse. For example, they may trigger symptoms of asthma, or cause other kinds of breathing problems. Some polluters can cause more problems for some people than for others. Air pollution can also cause heart disease and cancer.
Some content courtesy of the National Library of Medicine.