What to Do at Today’s AQI: Practical Advice by AQI Level

At a glance

What matters most

01
Use the AQI category, the pollutant driving it and the activity you plan to do; one headline number is not a personal medical assessment.
02
The most direct ways to lower dose are usually spending less time in polluted air, reducing strenuous outdoor activity and choosing cleaner indoor air when it is available.
03
Children, older adults and people with heart or lung disease may be affected at lower AQI levels and should use their own care plan and local public-health advice.
04
A well-fitting particulate respirator can reduce particle exposure, but fit matters and particle filters do not protect against every gas or indoor hazard.

Start with the reading you actually have

AQI is a short-term health communication tool, not a diagnosis. Before changing plans, check whether the number is current or forecast, which AQI system produced it, and which pollutant is driving the result. AQI.news labels its headline city reading as US AQI; the same number on another service may use a different scale, location or averaging period.

Then match the decision to the exposure. A short walk, a long run beside traffic, outdoor work and opening windows for hours do not carry the same dose. If you have symptoms or a clinician-provided asthma, heart or lung-disease action plan, follow that plan rather than relying on a general table.

A practical guide for each US AQI category

US AQI	For most people	For sensitive groups
0–50 · Good	Usual outdoor activity is generally appropriate.	Usual activity is generally appropriate.
51–100 · Moderate	Usual activity is generally appropriate; people who are unusually sensitive can watch for symptoms.	Consider reducing unusually long or hard outdoor activity if it causes symptoms.
101–150 · Unhealthy for Sensitive Groups	Normal daily activity is generally possible; consider making sustained, strenuous outdoor activity shorter or less intense.	Reduce prolonged or heavy outdoor exertion; choose a cleaner time or indoor option when practical.
151–200 · Unhealthy	Reduce prolonged or heavy outdoor exertion; consider an indoor alternative for demanding activity.	Avoid prolonged or heavy outdoor exertion where possible; use cleaner indoor air for exercise and recovery.
201–300 · Very Unhealthy	Avoid prolonged or heavy outdoor exertion and move nonessential activity indoors when possible.	Avoid outdoor exertion where possible; limit time outside and follow local health advice.
301–500 · Hazardous	Avoid outdoor exertion and limit nonessential time outside; follow official local instructions.	Stay in cleaner indoor air where possible and follow local public-health or clinical guidance.

Choose the action that fits your day

The goal is exposure reduction, not perfect avoidance. Indoor air is not automatically clean: cooking, smoke, combustion and other sources can raise pollution even when windows are shut. A cleaner indoor option works best when outdoor pollution is reduced at entry and indoor sources are also controlled. Air quality and exercise guidance can help you adapt a workout without giving up movement altogether, while air quality and children guidance focuses on families and schools.

Situation	A practical adjustment when AQI rises
Exercise outdoors	Move a long or intense session indoors, make it shorter or easier, and avoid routes beside heavy traffic.
Walking, cycling or commuting	Reduce time on busy roads when practical; choose a less exposed route, enclosed transport or a different travel time.
Children and school	Check the current category before prolonged, vigorous outdoor play; use the school or local authority’s policy where one exists.
Windows and ventilation	When outdoor particle pollution is high, avoid unnecessary open-window ventilation; still address urgent indoor hazards such as combustion fumes.
At home or work	Reduce indoor particle sources, use properly maintained filtration where available, and create a cleaner-air room during severe episodes.

Where respirators and air cleaning fit

For particle pollution such as PM2.5, a properly selected and well-fitting particulate respirator can reduce what reaches the wearer. Fit is essential: gaps around the face can substantially reduce protection. N95, FFP2 and similar filtering facepieces are designed for particles; they are not a universal solution for gases, oxygen-deficient spaces or every workplace hazard.

At home, the first priorities are removing or reducing indoor sources and managing outdoor air entry. A suitably sized, maintained particle air cleaner can complement those steps, but it does not remove every gas or make a hazardous situation safe. Use certified smoke and carbon-monoxide alarms for those hazards rather than relying on an AQI app or particle monitor.

When general AQI guidance is not enough

Get urgent medical help for severe trouble breathing, chest pain, blue or grey lips or face, confusion, fainting, or other emergency symptoms. For worsening asthma, COPD or heart symptoms, follow your clinician’s action plan and seek medical advice as appropriate.

During wildfire smoke, dust storms, industrial releases or official air-quality emergencies, local authorities may issue instructions that are more specific than this guide. Those local instructions take priority because they reflect the event, pollutant mix and services available where you are.

Frequently asked questions

Should I cancel exercise when AQI is above 100?

Not automatically. At US AQI 101–150, people in sensitive groups should reduce prolonged or heavy outdoor exertion, while others can consider a shorter, easier or indoor session. As AQI rises, indoor exercise becomes the more practical choice. Symptoms, the pollutant and your route also matter.

Should I close my windows when AQI is high?

If outdoor particle pollution is high, reducing unnecessary open-window ventilation can limit entry of outdoor particles. But do not ignore indoor hazards: cooking fumes, gas appliances, smoke and carbon monoxide need source control, appropriate exhaust and certified alarms.

Does an N95 protect me from high AQI?

A genuine, well-fitting N95 can reduce exposure to airborne particles such as PM2.5. It does not remove all gases or make every situation safe, and gaps at the face reduce protection. It is one layer alongside reducing time and intensity of exposure and using cleaner indoor air.

Who is in a sensitive group for AQI guidance?

Sensitive groups can include people with heart or lung disease, people with asthma, children, older adults and people who are active outdoors. Susceptibility varies by pollutant and individual health, so personal clinical advice takes priority.

Primary sources

This reference was prepared from the following primary public-health and regulatory sources:

What to Do at Today’s AQI: A Practical Air-Quality Guide