Why Your Air Quality Index Might Be Misleading You—And What Health Experts Want to Change

The air quality index you check on your phone might not be telling you the whole story about the pollution you're breathing. A new report from the World Health Organization (WHO) Regional Office for Europe reveals that conventional air quality indexes (AQIs)—the tools most countries use to communicate pollution levels to the public—often fail to capture the combined health risks of multiple pollutants at once. The WHO's updated guidance, released in January 2026, offers a roadmap for countries to improve how they measure and communicate air quality information to protect public health.

What's Wrong With How We Currently Measure Air Quality?

Most air quality indexes rely on regulatory thresholds for single pollutants, meaning they measure one type of pollution at a time. This approach misses a critical reality: we don't breathe pollutants one at a time. In real life, you're exposed to a mixture of harmful substances simultaneously—particulate matter, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide all at once. The current system doesn't reflect how these pollutants interact or their combined effect on your health.

Air pollution remains a major public health concern globally, contributing to an estimated 6.7 million deaths each year. Despite this staggering toll, the tools we use to warn people about dangerous air quality haven't kept pace with what science tells us about how pollution actually harms health.

How Can Health-Based Indexes Better Protect You?

The WHO report supports a shift toward health-based multipollutant indexes—a more sophisticated approach that draws on epidemiological evidence (real-world health data from populations) to provide a more accurate picture of actual health risks. Rather than simply checking whether pollution levels exceed regulatory limits, these new indexes would tell you what the pollution is actually doing to your body based on scientific evidence about how different pollutant combinations affect health.

The report was coordinated by the WHO European Centre for Environment and Health in Bonn, Germany, and prepared with input from international experts across multiple disciplines. It supports the 2023 Budapest Declaration and the updated 2025 road map on air pollution, both of which call for stronger public communication and integration of air quality information into health systems.

Steps to Improve Air Quality Communication and Protection

• Develop Locally Adapted Indexes: Create health-based air quality indexes tailored to each region's specific pollution patterns and population health needs, rather than using one-size-fits-all regulatory thresholds.
• Increase Transparency in Data: Publish both the overall air quality index values and the individual concentrations of specific pollutants so the public understands what's in the air they're breathing.
• Strengthen Public Communication: Use clear, culturally tailored messages and digital tools to help people understand air quality information and take protective action when needed.
• Ensure Equity and Accessibility: Make air quality information accessible to vulnerable and susceptible populations, including elderly people, children, and those with respiratory or heart conditions who are most at risk from pollution.

Why Should You Care About How Air Quality Is Measured?

The way air quality information is communicated directly affects whether you take protective action. If your air quality index says conditions are "moderate" but doesn't account for the combined effects of multiple pollutants, you might not realize you should keep your children indoors or wear a protective mask. For countries, regions, and cities applying the WHO report's guidance, the result is strengthened risk communication and improved protection for the people most vulnerable to air pollution's health effects.

The report includes 21 key considerations on the development, validation, communication, and refinement of air quality indexes, with a focus on ensuring that information reaches and protects those who need it most. Co-funded by the European Union and Germany, this guidance represents a significant step toward aligning how we measure air quality with what we actually know about how pollution damages human health.