Air Quality Health Index

1. Air Quality Health Index

The **Air Quality Health Index** (AQHI) is a tool used to communicate the health risks associated with air pollution to the public. It provides a numerical scale that helps individuals understand the level of air pollution in their area and the potential health effects. The AQHI is designed to help people make informed decisions about outdoor activities to minimize exposure to air pollution.

Overview

The AQHI is calculated based on the concentrations of several key air pollutants, including:

• Ozone (O₃) at ground level
• Particulate Matter (PM₂.₅ and PM₁₀)
• Nitrogen Dioxide (NO₂)

These pollutants are known to have significant health impacts, particularly on the respiratory and cardiovascular systems. The AQHI provides a simple, easy-to-understand scale that ranges from 1 to 10+, with higher values indicating a greater health risk.

Health Risk Categories

The AQHI is divided into four health risk categories:

• **Low Risk (1-3):** Air quality is considered satisfactory, and air pollution poses little or no risk.
• **Moderate Risk (4-6):** Air quality is acceptable; however, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
• **High Risk (7-10):** Health effects may be experienced by sensitive groups, and the general public may not be affected.
• **Very High Risk (10+):** Health warnings of emergency conditions. The entire population is more likely to be affected.

Health Advice

The AQHI provides specific health advice for different risk categories, particularly for vulnerable groups such as children, the elderly, and individuals with pre-existing health conditions like asthma or heart disease. For example, on days with a high AQHI, it is recommended to reduce or reschedule strenuous outdoor activities, especially for sensitive individuals.

Calculation

The AQHI is calculated using a formula that combines the concentrations of the key pollutants. The formula is designed to reflect the relative health risks associated with each pollutant. The index is updated regularly, often hourly, to provide current information to the public.

Implementation

The AQHI is used in several countries, including Canada, where it was first developed. It is part of a broader effort to improve public awareness of air quality issues and to promote actions that can reduce exposure to harmful air pollutants.

Also see

• Air Pollution
• Environmental Health
• Public Health
• Ozone Layer
• Climate Change