AUTHOR=Amini Heresh , Yousefian Fatemeh , Faridi Sasan , Andersen Zorana J. , Calas Ellénore , Castro Alberto , Cervantes-Martínez Karla , Cole-Hunter Thomas , Corso Magali , Dragic Natasa , Evangelopoulos Dimitris , Gapp Christian , Hassanvand Mohammad Sadegh , Kim Ingu , Le Tertre Alain , Medina Sylvia , Miller Brian , Montero Stephanie , Requia Weeberb J. , Riojas-Rodriguez Horacio , Rojas-Rueda David , Samoli Evangelia , Texcalac-Sangrador Jose Luis , Yitshak-Sade Maayan , Schwartz Joel , Kuenzli Nino , Spadaro Joseph V. , Krzyzanowski Michal , Mudu Pierpaolo TITLE=Two Decades of Air Pollution Health Risk Assessment: Insights From the Use of WHO’s AirQ and AirQ+ Tools JOURNAL=Public Health Reviews VOLUME=Volume 45 - 2024 YEAR=2024 URL=https://www.ssph-journal.org/journals/public-health-reviews/articles/10.3389/phrs.2024.1606969 DOI=10.3389/phrs.2024.1606969 ISSN=2107-6952 ABSTRACT=Objectives: We evaluated studies that used the World Health Organization’s (WHO) AirQ and AirQ+ tools for air pollution (AP) health risk assessment (HRA) and provided best practice suggestions for future assessments. Methods: We performed a comprehensive review of studies using WHO’s AirQ and AirQ+ tools, searching several databases for relevant articles, reports, and theses from inception to Dec 31, 2022. Results: We identified 286 studies that met our criteria. The studies were conducted in 69 countries, with most (57%) in Iran, followed by Italy and India (~8% each). We found that many studies inadequately report air pollution exposure data, its quality, and validity. The decisions concerning the analysed population size, health outcomes of interest, baseline incidence, concentration-response functions, relative risk values, and counterfactual values are often not justified, sufficiently. Many studies lack an uncertainty assessment. Conclusions: Our review found a number of common shortcomings in the published assessments. We suggest better practices and urge future studies to focus on the quality of input data, its reporting, and associated uncertainties.