Particulate pollution in the outdoor air - Summary and recommendations for protecting health

Air pollution includes particulate matter (PM) with a size less than or equal to 10 µm (PM₁₀) and 2.5 µm (PM_2.5). Their short and long term impacts on health are well-known. French regulations define the daily information and recommendation (50 µg/m³) and alert (80 µg/m³) standards for PM₁₀. A European Directive also prescribes values that are not to be exceeded over a day or the year for this air pollutant.

The HCSP recommends the following values:

• for air quality objectives (annual average): 15 µg/m³ for PM_2.5; 25 µg/m³ for PM₁₀;
• for information and recommendation standards (daily average): 30 µg/m³ for PM_2.5; 50 µg/m³ for PM₁₀;
• for alert standards (daily average): 50 µg/m³ for PM_2.5; 80 µg/m³ for PM₁₀;

These recommendations are based on the state of knowledge on the effects of PM on health using the most recent publications and on an evaluation of the health impact of various scenarios for decreasing particulate pollution in France. The HCSP underlines that a policy focusing on managing "peaks" has little impact on long-term exposure of the population to both PM_2.5 and PM₁₀, and that priority has to be given to reducing chronic exposures to these air pollutants.

The HCSP suggests various improvements in current procedures, tools and circuits for information and formulates health messages intended for both vulnerable people and the entire population, according to the PM concentrations in the air.

The HCSP recommends a representation of PM levels measured over the last 365 days by using a "journal on daily standards exceeded", providing good public readability of air quality in a city and allowing for comparisons over time and between cities. It reiterates that communication on air quality and on the efforts aimed at guaranteeing it must be regular, and the occurrence of daily "peaks" should be considered as an opportunity to reactivate the vigilance in order to achieve this objective. Procedures should be implemented in order to inform the populations that reside in zones that are most exposed to local sources of pollution, as soon as the modeling tools will allow it.