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Understanding AQI Categories in Under 5 Minutes

June 18, 2026 · The Clime Team
Understanding AQI Categories in Under 5 Minutes

The Air Quality Index (AQI) is a standardized system used to communicate the quality of air in a specific area and its potential health impacts. Understanding AQI categories is essential for making informed decisions about outdoor activities and health precautions.

What Are the AQI Categories?

The AQI is divided into six color-coded categories, each representing a different level of health concern:

  • Good (0–50): Air quality is satisfactory, posing little or no risk.
  • Moderate (51–100): Air quality is acceptable; however, there may be a risk for some individuals sensitive to air pollution.
  • Unhealthy for Sensitive Groups (101–150): Sensitive individuals, such as children, older adults, and those with respiratory conditions, may experience health effects.
  • Unhealthy (151–200): Everyone may begin to experience health effects; sensitive groups may experience more serious effects.
  • Very Unhealthy (201–300): Health alert: everyone may experience more serious health effects.
  • Hazardous (301 and higher): Health warning of emergency conditions: everyone is more likely to be affected.

These categories help individuals understand the potential health risks associated with current air quality levels. (airnow.gov)

How Is the AQI Calculated?

The AQI is calculated based on measurements of key air pollutants, including:

  • Ground-level ozone
  • Particulate matter (PM2.5 and PM10)
  • Carbon monoxide
  • Sulfur dioxide
  • Nitrogen dioxide

Each pollutant has specific breakpoints that translate its concentration into AQI values, which are then categorized into the six levels mentioned above. (airnow.gov)

Why Is Understanding AQI Important?

Being aware of AQI levels is crucial for protecting your health, especially if you belong to sensitive groups. High AQI levels can lead to respiratory issues, cardiovascular problems, and other health concerns. By monitoring AQI, you can make informed decisions about outdoor activities and take necessary precautions to minimize exposure to harmful pollutants.

How Can Clime Help?

Clime offers real-time air quality monitoring, providing up-to-date AQI information for your location. With Clime, you can receive timely alerts about changes in air quality, helping you plan your activities and protect your health effectively.

Understanding AQI categories empowers you to take control of your health by staying informed about air quality conditions in your area. Utilizing tools like Clime ensures you have access to accurate and timely information, enabling you to make the best decisions for your well-being.

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Frequently Asked Questions