The French Agency for Environmental and Occupational Health Safety (Afsset) has established a system for collective expert review to address the requests submitted to it. These requests concern issues related to environmental health and/or occupational health, on which the agency is expected to provide an opinion to inform public decision-making. Committed to a voluntary quality approach, Afsset conducts its expert assessments in accordance with standard NF X 50-110 (quality in expert assessment), with the goal of applying five fundamental principles: competence, independence, traceability, transparency, and compliance of the response with legislative and regulatory provisions, as well as with the question posed. It was within this framework that the collective assessment regarding covered parking garages took place, aimed at providing the ministries responsible for the Environment and Health with a pre-regulatory assessment of the air quality criteria applicable to these facilities, in order to prevent health risks for users and workers. Identifying four pollutants (carbon monoxide, nitrogen dioxide, particulate matter, and benzene) as particularly problematic in terms of health risks among those that may be found in the air within these spaces, this study led to various recommendations, including a proposal for air quality criteria to be met in covered parking garages. Three possible options are presented, thereby allowing public authorities to decide on the criteria to be enforced based on a level of risk they would consider acceptable. (R.A.)