Air quality — Level of fine particles with a diameter of less than 2.5 µm (PM2.5) in Pays de la Loire

Hourly, daily, monthly and annual averages of fine particulate matter concentrations of less than 2.5 µm (PM2.5) in ambient air from the permanent network of measurements in the Pays de la Loire region. Ambient air quality measurement is carried out in accordance with the recommendations of the Central Air Quality Monitoring Laboratory (LCSQA) business benchmark, in compliance with the regulatory requirements in force. These requirements cover the entire measurement chain, both from the point of view of the criteria for the location of the measurement sites, the choice of analytical methods used, the monitoring of the metrological conformity of the measurement process, the validation and aggregation of the measurement data. In order to produce this data in particular, Air Pays de la Loire implements automated systems for measuring the concentration of particulate matter in accordance with the standard NF EN 16450, using two measurement methods (oscillating microbalance or attenuation of beta radiation). The latter are located in on-site measuring stations, combined with measurement data acquisition systems, which they aggregate in quarter-hour averages. These raw data are then teletransmitted to the central computer server and then evaluated at different levels of aggregation (technical and environmental validations). Validated quarter-hour data are thus aggregated into hourly averages, aggregated in daily, monthly or annual averages. The information layer produced is available for exploitation on a scale ranging from 1/250 000th to 1/10 000th and can be categorised by type of station: Traffic station: 1/10 000 Bottom station: 1/30 000 (urban) to 1/250 000 (rural) Industrial station: 1/100 000