The quality of the air you breathe can affect your health and the
health of other organisms near your home. Clean air laws passed
in 1970 and 1990 have helped improve air quality in many regions
of the United States. By investigating your community's air quality,
you can determine how changes in the laws have affected the air
you breathe. You also can investigate methods people have used to
help make air cleaner and healthier.
The air quality index tells you how clean the air is and whether
is will affect your health. Some areas of the United States experience
more air quality problems than others. Form a hypothesis about how
weather conditions affect the air quality index.