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(KSL News) The government says our air is a lot cleaner than it was 30 years ago.
One of the reason is because of a crackdown on factories and car emissions.
But, the American Lung Association reports nearly half of all Americans still live in areas with unhealthy air. Health experts say it's not just our lungs we need to worry about. Smog also can affect the blood system and cause heart attacks.
The Lung Association and environmentalists want the Environmental Protection Agency to create tougher standards for ozone smog.