Air Quality Guide for Ozone

Ground-level ozone is one of our nation's most common air pollutants. Use the chart below to help reduce your exposure
and protect your health. Visit AirNow.govfor your local air quality forecast (www.airnow.gov).

Air Quality
Index

Who Needs to
be Concerned?

What Should 1 Do?

Good
(0-50)

It's a great day to be active outside.

Moderate
(51-100)

Some people who may be
unusually sensitive to ozone.

Unusually sensitive people: Consider making outdoor
activities shorter and less intense. Watch for symptoms
such as coughing or shortness of breath. These are signs
to take it easier.

Everyone else: It's a good day to be active outside.

Unhealthy for
Sensitive Groups
(101-150)

Sensitive groups include people
with lung disease such as
asthma, older adults, children
and teenagers, and people who
are active outdoors.

Sensitive groups: Make outdoor activities shorter and
less intense. Take more breaks. Watch for symptoms such
as coughing or shortness of breath. Plan outdoor
activities in the morning when ozone is lower.

People with asthma: Follow your asthma action plan and
keep quick-relief medicine handy.

Everyone else: Consider making outdoor activities
shorter and less intense.

Unhealthy
(151-200)

Everyone

Sensitive groups: Do not do long or intense outdoor
activities. Schedule outdoor activities in the morning
when ozone is lower. Consider moving activities indoors.

People with asthma: Follow your asthma action plan and
keep quick-relief medicine handy.

Everyone else: Reduce long or intense outdoor activity.
Take more breaks, do less intense activities. Schedule
outdoor activities in the morning when ozone is lower.

Very Unhealthy
(201-300)

Everyone

Sensitive groups: Avoid all physical activity outdoors. Move
activities indoors* or reschedule to when air quality will be
better. People with asthma: Follow your asthma action
plan and keep quick-relief medicine handy.

Everyone else: Avoid long or intense outdoor exertion.
Schedule outdoor activities in the morning when ozone is
lower. Consider moving activities indoors.*

Hazardous
(301-500)

Everyone

Everyone: Avoid all physical activity outdoors.*

People with asthma: Follow your asthma action plan and
keep quick-relief medicine handy.

*Note: If you don't have an air conditioner, staying inside with the windows closed may be dangerous in extremely hot
weather. If you are hot, go someplace with air conditioning or check with your local government to find out if cooling
centers are available in your community.


-------
Key Facts to Know About Ozone:

•	Ozone in the air we breathe can cause serious health problems, including breathing difficulty, asthma attacks, lung
damage, and even death from lung disease.

•	Ozone forms in sunlight, usually on hot summer days. Ozone is worse in the afternoon and early evening, so plan
outdoor activities for the morning.

•	You can reduce your exposure to ozone and still get exercise! Use AirNow's (www.airnow.gov) current Air Quality
Index (AQI) information and forecasts to plan your outdoor activities.

What is ozone?

Ozone is a colorless gas that can be good or bad,
depending on where it is. Ozone up high in the
stratosphere forms the ozone layer, which shields the
earth from the sun's ultraviolet rays. But ozone at ground
level, where we breathe, can harm human health.
Ground-level ozone forms when two types of pollutants,
volatile organic compounds and nitrogen oxides, react in
sunlight. These pollutants come from sources such as
vehicles, industries, power plants, and products such as
solvents and paints.

Why is ozone a problem?

Ozone can cause health problems, including coughing,

breathing difficulty, and lung damage.

Exposure to ozone can make the lungs more susceptible to

infection, aggravate lung diseases, increase the frequency

of asthma attacks, and increase the risk of death from lung

disease.

Do I need to be concerned?

Even healthy adults can experience ozone's harmful
effects, but some people may be at greater risk. They
include:

How can I protect myself?

Use the Air Quality Index (AQI) to plan outdoor activities

when ozone levels are lower. Check AirNow.gov, download
the free AirNow app, or install the free AirNow widget on your
website.

Find the app (https://www.airnow.gov/airnow-mobile-app/)
Find the widget (https://www.airnow.gov/aqi-widgets/)

Stay healthy: exercise, eat a balanced diet, and keep asthma
under control with your asthma action plan.

When you see that the AQI is unhealthy, take simple steps to
reduce your exposure:

•	Choose a less intense activity.

•	Shorten or take more breaks during outdoor activity.

•	Reschedule activities to the morning or to another day.

•	Move your activity inside where ozone levels are usually
lower.

Can I help reduce ozone?

Yes! Here are a few tips.

Drive less: bike or walk, carpool, or use public
transportation.

•	People with lung disease such as asthma.

•	Children, including teenagers, because their lungs
are still developing, and they breathe more air per
pound of body weight than adults.

•	Older adults.

•	People who are active outdoors, including outdoor
workers.

United States
Environmental Protectio
mI	Agency

Office of Air Quality and Radiation
EPA-452/F-23-001
www.airnow.gov
February 2023

Turn off lights and devices that you are not using.

Keep your vehicle engine tuned, and don't let your
engine idle.

Inflate tires to the recommended pressure.

When refueling, stop when the pump shuts off. Avoid
spilling fuel and tighten your gas cap.

Use low-VOC paint and cleaning products; seal and
store them so they can't evaporate.

Watch for Ozone Action Days in your area.


-------