The Air Quality Index — or AQI — is an estimate of air pollution levels, including particles and ozone. The higher those levels, the greater the health risks.

Think of the colors as a yardstick for health risks

The AQI is divided into levels to help people know when safety precautions are necessary. Few health effects are expected in the green (good) or yellow (moderate) zones. When the AQI reaches 101 (orange), the air is unhealthy for sensitive groups, including those with respiratory or heart disease, the elderly and children. At 151 (red) or higher, the air is unhealthy for everyone, even those with no prior health concerns. The likelihood of health problems is higher in the very unhealthy (purple) zone. Beyond that (the maroon or emergency zone) is when air quality conditions are the worst and the highest precautions are essential.

Those with chronic health conditions should closely watch their symptoms. Those with lung disease like asthma and COPD should especially monitor shortness of breath. Call your doctor if symptoms worsen. If they do get worse and don’t respond to your usual medication, don’t delay in seeking urgent or emergency care.

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