How to Read Air Quality Index (AQI) And Determine If It’s Safe To Go Outside

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View Sacramento’s current Air Quality Index now.

The Air Quality Index (AQI) is an index for reporting daily air quality. It tells you how clean or polluted the outdoor air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air.

The Environmental Protection Agency calculates the AQI for five major air pollutants regulated by the Clean Air Act:

  • ground-level ozone
  • particle pollution (also known as particulate matter)
  • carbon monoxide
  • sulfur dioxide
  • nitrogen dioxide

Understanding the AQI

The purpose of the AQI is to help you understand what local air quality means to your health. To make it easier to understand, the AQI is divided into six categories. Each category corresponds to a different level of health concern.

The six levels of health concern and what they mean are:

  • Good - AQI is 0 to 50. Air quality is considered satisfactory, and air pollution poses little or no risk.
  • Moderate – AQI is 51 to 100. Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people. For example, people who are unusually sensitive to ozone may experience respiratory symptoms.
  • Unhealthy for Sensitive Groups – AQI is 101 to 150. Although general public is not likely to be affected at this AQI range, people with lung disease, older adults and children are at a greater risk from exposure to ozone, whereas persons with heart and lung disease, older adults and children are at greater risk from the presence of particles in the air.
  • Unhealthy – AQI is 151 to 200. Everyone may begin to experience some adverse health effects, and members of the sensitive groups may experience more serious effects.
  • Very Unhealthy – AQI is 201 to 300. This would trigger a health alert signifying that everyone may experience more serious health effects.
  • Hazardous – AQI greater than 300. This would trigger a health warnings of emergency conditions. The entire population is more likely to be affected.

The Sacramento County has recommended that Sacramento County School Districts minimize smoke exposure for students when smoke is seen or smelled by staying inside with windows and doors closed. Until air quality improves, the Public Health Officer continues to recommend that schools cancel outdoor recesses, outdoor activities and outdoor physical education (P.E.).

Download tips for children and smoke from the Sac Metro Air District that it developed with Counties and local air districts.