Understanding Air Quality Index (AQI) Categories During Severe Weather

The Air Quality Index (AQI) is a standardized system used to communicate daily air quality levels and associated health risks. It measures concentrations of five major pollutants regulated by the Clean Air Act: ground-level ozone, particulate matter (PM₂.₅ and PM₁₀), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Understanding AQI categories is crucial, especially during severe weather events that can exacerbate air pollution levels.

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 some health concern for a small number of unusually sensitive individuals.
• Unhealthy for Sensitive Groups (101–150): Sensitive individuals may experience health effects; the general public is less likely to be affected.
• 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 (301–500): Health warnings of emergency conditions; the entire population is more likely to be affected.

These categories help individuals understand the potential health impacts of current air quality levels. (epa.gov)

How Does Severe Weather Affect AQI?

Severe weather events, such as wildfires, hurricanes, and heavy storms, can significantly impact air quality:

• Wildfires: Emit large amounts of smoke and particulate matter, leading to elevated AQI levels.
• Hurricanes and Storms: Can stir up dust and pollutants, temporarily degrading air quality.
• Temperature Inversions: Common during severe weather, inversions trap pollutants near the ground, increasing AQI values.

Monitoring AQI during such events is essential to protect health. (epa.gov)

Protecting Your Health During High AQI Levels

When AQI levels are elevated, especially during severe weather, consider the following precautions:

• Stay Informed: Regularly check local air quality reports.
• Limit Outdoor Activities: Reduce prolonged or heavy exertion outdoors.
• Create a Clean Indoor Environment: Keep windows closed and use air purifiers if available.
• Use N95 Masks: These masks can filter out harmful particles from the air.

By understanding AQI categories and their implications during severe weather, you can take proactive steps to safeguard your health.

Highlights:

• Air Quality Index Report | US EPA, Published on Monday, March 09
• Air Quality Index Daily Values Report | US EPA, Published on Tuesday, March 24