Smog: Why stricter rules are so important

The proposed EPA limits on ozone don't go far enough—here's how you can help

Flickr/Steven Buss

  • Nearly40%of Americans live in areas with unhealthy levels of smog pollution

What is smog?
Across many major cities, a hazy brown soup of pollution hangs over the skyline, especially in the warmer months. This is smog, known more specifically as ground-level ozone.

Smog is formed when industrial emissions from power plants, factories, cars, and other sources react with heat and sunlight in the atmosphere.

Why is it harmful?
When inhaled, smog irritates our airways, increasing our risk of serious heart and lung diseases. These health risks are why many cities monitor smog levels. On a high ozone-alert day, for example, your eyes and throat may burn, and you may cough and wheeze.

Is anyone trying to fix it?
Every five years the U.S. Environmental Protection Agency reviews air quality standards in light of any new medical evidence, and makes updates, if appropriate.

A 2015 review lowered the nation’s air quality standard for smog pollution from 75 parts per billion (ppb) to 70 ppb.

While this change is an improvement, it falls short of what’s needed to safeguard public health. Strong scientific evidence shows hundreds of thousands of asthma attacks and numerous deaths annually at smog pollution levels lower than 70 ppb.

For this reason, we’ll continue to urge the EPA to issue stronger standards that protect our kids, older adults, people active outdoors and all Americans at risk.

The science on ozone’s health effects is rock solid.

Elena Craft Senior Health Scientist

The air quality standard falls short of what is necessary to safeguard our health.

Vickie Patton EDF General Counsel

Clean air policy resources

EDF seeks to safeguard human health by reducing air pollution and other environmental threats.

Media contact

  • Sharyn Stein
    (202) 572-3396 (office)
    (202) 905-5718 (cell)

How can you help?

By signing up to support our clean air work, you can be part of a better way. We’ll send you alerts and let you know when your help is needed most. (Read our privacy policy.)