Expansion of UFP measuring capabilities of the Dutch National Air Quality Monitoring Network

The health effects of ultrafine particles (UFP) have come under increased scrutiny. In 2021, the Health Council of the Netherlands published the advisory report “Risks of ultrafine particles in the outside air”, which highlighted that our knowledge of UFP exposure and health effects is limited by a lack of structural measurements of UFP concentrations in the Netherlands. The report therefore recommendedmeasuring UFP concentrations structurally in the Dutch National Air Quality Monitoring Network andperforming structural and validated model calculations to obtain a national overview of UFP exposure.At the subsequent request of the Ministry of Infrastructure and Water Management, RIVM made an inventory of available data, knowledge and measurement equipment, and developed integrated strategies for incorporating structural UFP measurements into the national network and improving UFP models.The National Air Quality Monitoring Network currently performs indicative UFP measurements with three TSI EPC 3783 instruments. Diurnal and weekly cycles can already be observed in these indicative data, and they have been used to scale an updated empirical map of average UFP concentrations in the Netherlands as well. On a project base, short-term measurements of UFP are performed using more compact equipment.Newer counting equipment (TSI CPC 3750-CEN10) has been purchased recently to perform stationary UFP concentration measurements according to the latest technical standard (EN 16976:2024). The locations where the new measurement equipment will be placed are selected with the specific aim to improve the yearly average concentration map and obtain better estimates for the exposure of the Dutch population to UFP. The data will be made available to the public.This presentation will discuss the progress so far, first experiences with the new equipment and next steps, including steps required for compliance with the new EU Air Quality Directive.