What is PM2.5 and Why Does it Matter?

PM2.5 refers to atmospheric particulate matter (PM) that has a diameter of less than 2.5 micrometers, which is about 3% the diameter of a human hair. These fine particles are particularly dangerous because they are small enough to penetrate deep into the lungs and even enter the bloodstream. Sources of PM2.5 include vehicle exhausts, power plants, wood burning, and industrial processes. High levels of PM2.5 are associated with respiratory issues, heart disease, and decreased lung function.

How to Use the PM2.5 Calculator

Using our PM2.5 to AQI (Air Quality Index) calculator is simple. Simply input the concentration of fine particulate matter measured in micrograms per cubic meter (μg/m³). The tool uses the standard EPA conversion formula to provide you with an AQI score. This score helps you understand whether the air quality is safe or if you should limit your time outdoors.

Understanding AQI Categories

The Air Quality Index is divided into six color-coded categories:

• Good (0-50): Air quality is satisfactory, and air pollution poses little or no risk.
• Moderate (51-100): Air quality is acceptable; however, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
• Unhealthy for Sensitive Groups (101-150): Members of sensitive groups may experience health effects. The general public is less likely to be affected.
• Unhealthy (151-200): Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.
• Very Unhealthy (201-300): Health alert: The risk of health effects is increased for everyone.
• Hazardous (301+): Health warnings of emergency conditions: The entire population is more likely to be affected.

Frequently Asked Questions

What is a safe level of PM2.5?

According to the World Health Organization (WHO), the annual average concentration of PM2.5 should not exceed 5 μg/m³, and 24-hour average exposure should not exceed 15 μg/m³. Any level above these guidelines increases long-term health risks.

How is AQI calculated from PM2.5?

AQI is calculated using a linear interpolation formula that maps specific concentration ranges to specific AQI ranges. For example, a concentration of 12.0 μg/m³ corresponds exactly to an AQI of 50. As the concentration increases, the AQI value rises, indicating poorer air quality.