In January 2026, the World Health Organization (WHO) published a new report, Air quality indexes: key considerations and roadmaps for best practices, calling for a shift in how air pollution risks are assessed and communicated. The report highlights the limitations of traditional air quality indexes (AQIs) and advocates for health-based, multipollutant, and equity-sensitive approaches, a direction that closely aligns with the work of ENACT.
No safe threshold for air pollution
A central conclusion of the WHO report is clear: there is no safe level of air pollution exposure. Based on extensive epidemiological evidence, the WHO states that:
“Epidemiological studies have shown that, at population level, no thresholds of effect can be identified for the common air pollutants; thus, an impact can be expected for some individuals even at low levels of exposure.”
This evidence underpinned the tightening of WHO Air Quality Guidelines in 2021 and reinforces the need to move beyond regulatory compliance towards a health-centred understanding of exposure—a core principle of ENACT’s exposomic approach.
From single pollutants to combined health risks
The report also underlines the shortcomings of conventional AQIs, which are typically driven by the single pollutant that exceeds its regulatory limit the most. According to WHO, this approach does not reflect real-world exposures:
“Limitations of single-pollutant-oriented (conventional) AQIs include … an inability to capture the cumulative health risks of multiple air pollutants.”
To address this, WHO promotes health-based Air Quality Health Indexes (AQHIs), which link air quality directly to health outcomes and account for pollutant mixtures:
“AQIs provide a scale related to the concentration of the pollutant whose level most exceeds its national standard, whereas AQHIs provide a scale related to the short-term health risks of exposure to a mixture of pollutants.”
This focus on combined exposures mirrors ENACT’s methodology, which analyses how multiple environmental stressors—such as air pollution, noise, temperature and socio-economic factors—interact to influence disease risk.
Communicating health risk and addressing inequalities
WHO also stresses that air quality information should be designed to support meaningful health risk communication. Concentration-based labels such as “good” or “moderate” may unintentionally suggest the absence of risk, even though health effects occur at low exposure levels.
Health-based approaches, by contrast, make risk explicit and can be adapted to local contexts and vulnerable groups:
“By capturing health risks due to the combined actions of multiple air pollutants, AQHI values convey more information than AQIs to the public.”
The report further recommends that governments move towards locally adapted, multipollutant tools, explicitly considering vulnerable and socio-economically disadvantaged populations.
A shared direction for WHO and ENACT
The WHO report confirms that improving air quality communication is a public health priority. Its call for health-based, multipollutant and equity-sensitive tools strongly aligns with ENACT’s objectives: to integrate exposomic data, digital technologies and AI models to better understand environmental health risks and support prevention and policy action across Europe.
As global guidance and EU-funded research converge, ENACT contributes practical evidence and tools to help translate WHO recommendations into real-world health protection.