Indoor car parks

As part of an amendment to the regulations governing indoor car parks, the Ministry of the Interior prepared a draft decree to define the administrative and regulatory provisions for these establishments and in particular provisions relating to fire safety and the risk of panic, as well as provisions intended to avoid any health risk for these public buildings.
In this context, the Ministry of Health and the Ministry of Ecology formally requested the Agency to appraise the air quality criteria applicable to indoor car parks. The compounds primarily concerned were carbon monoxide (CO) and nitrogen oxides.

A dual-phase expert appraisal

The Agency began by initiating work on a general commentary on the limit values proposed in a draft order. It based its work on the available literature, as well as on existing standards and reference values. A first Opinion was therefore issued that concluded on the inadequacy of the limits in this draft text. The Agency also suggested a more stringent review of the proposed limit values, taking into account other air pollutants than CO and NO2 and focusing on the management of ventilation.
Following on from this Opinion, the Agency set up a working group seeking firstly to collect and analyse recent data on pollutant concentrations encountered in indoor car parks, and secondly to propose concentration levels of pollutants that should be complied with to better protect the health of people required to spend time in this type of enclosed space (users and workers). This work was also supported by a review of the French and international literature on pollutant concentrations in indoor car parks.
Finally, to substantiate the analysis of the working group, the Agency also funded measurement campaigns in several indoor car parks.

Results and recommendations

This work led to a Report and Opinion being published in May 2007. Based on this expert appraisal, the Agency considers that the health risks associated with indoor car parks are difficult to assess, but cannot be regarded as negligible, especially for prolonged or repeated exposure, given the concentrations of pollutants measured and the understanding of their toxic effects. The Agency also believes that, with regard to monitoring air quality in indoor car parks, nitrogen monoxide (NO) is the most relevant “reference indicator” pollutant for routine monitoring.

The Agency also recommends:

• considering the issue of air quality when designing new indoor car parks: scaling ventilation systems, implementing regular measurements, studying the placing of pedestrian footpaths in areas with better air quality, etc.;
• guaranteeing a certain air quality within indoor car parks by complying with an NO concentration measured over 30 minutes. Three options are proposed (400 µg/m3, 600 µg/m3 or 800 µg/m3) corresponding to different implications in health terms;
• locating sedentary occupations in specifically ventilated areas and informing the exposed people of the identified risks;
• periodically assessing air quality in representative indoor car parks in order to monitor possible changes in emissions and adjust the recommendations accordingly;
• continuing research aiming to improve characterisation of air quality in car parks and the health effects associated with the pollutants found in these areas.