When air quality is poor, changing the session can be more useful than changing running gear. Start with the current public-health advice for your location, the forecast and your own health circumstances. A familiar route or a clear-looking sky does not establish that the air is suitable for a hard run.
Check the source and the scale
Use the environmental or public-health agency responsible for your area. Read the location, observation time, pollutant and accompanying activity advice. A saved screenshot can be out of date by the time the group meets. Do not transfer a numerical threshold from one country's index to another without checking what each scale means.
In the United States, AirNow explains the Air Quality Index. Its guide to using current and forecast air quality helps distinguish a forecast for planning from conditions reported during the day. Elsewhere, follow the equivalent local service and its health advice.
Keep a practical alternative ready
A club organiser can publish a fallback before conditions deteriorate: postpone, cancel or move to an appropriate indoor activity. State who makes the decision and when participants will hear. Avoid requiring members to disclose a diagnosis to opt out. People can have different reasons for following more cautious advice.
Changing an intense session to a shorter or easier outing is not a universal solution for every air-quality category. Follow the agency's activity guidance, including advice for sensitive groups. For smoke, consult AirNow's smoke guidance. Choose an indoor alternative with suitable air quality rather than assuming any building provides protection.
Equipment cannot certify the conditions
An ordinary running top does not make polluted air safe to breathe. Do not treat a mask marketing claim or a watch display as permission to ignore health advice. A route app is not a personal exposure assessment. Anyone managing asthma or another relevant condition should use their agreed care plan and discuss exercise questions with their clinician.
Communicate the decision
Update the meeting details, tell participants whether there will be a replacement session, and remove ambiguity about attendance. Use the club-session brief builder to record the fallback. This guide is a planning checklist, not a local pollution forecast or medical clearance to run.