Assessing reduction in annual and daily fine particulate matter impact in Paris

The study analyzes PM2.5 concentrations in Paris and the Île-de-France region from 2009 to 2018, finding that reductions in annual averages and high-concentration days were primarily driven by local emission decreases. However, regional transport remains a significant factor, contributing up to 70% of annual PM2.5 at urban background sites, suggesting that regional emission reductions are necessary to meet WHO guidelines.

• Between 2009 and 2018, there were significant reductions in both annual average PM2.5 concentrations and the number of days where 24-hour concentrations exceeded 25 μgm−3. Annual concentrations decreased by an average of 0.79 μgm−3 per year (a 33% reduction), while the number of days exceeding the 24-hour threshold decreased by 6 days per year (a 62% reduction).
• The observed reductions in PM2.5 were driven by local emission decreases in Paris and the Île-de-France region. This is evidenced by greater reductions at urban traffic sites and a change in hourly patterns, where the highest concentrations occurred less often during rush hour and the lowest concentrations occurred more frequently during the day.
• Regional transport contributes significantly to PM2.5 levels in Paris. Regional contributions to the annual average PM2.5 are approximately 50% at urban traffic sites and 70% at urban background sites, with the highest hourly concentrations showing the largest regional contributions.
• Air mass back trajectories indicate that moderate and high hourly PM2.5 concentrations are linked to air masses spending more time over European geographic regions than over the ocean, highlighting the role of regional transport.

APA

Stockholm Environment Institute (2019). Assessing reduction in annual and daily fine particulate matter impact in Paris. https://www.sei.org/publications/assessing-reduction-in-annual-and-daily-fine-particulate-matter-impact-in-paris/

Chicago

Stockholm Environment Institute. Assessing reduction in annual and daily fine particulate matter impact in Paris. 2019. https://www.sei.org/publications/assessing-reduction-in-annual-and-daily-fine-particulate-matter-impact-in-paris/.

Wikipedia

{{cite report |author=Stockholm Environment Institute |title=Assessing reduction in annual and daily fine particulate matter impact in Paris |date=6 May 2019 |url=https://www.sei.org/publications/assessing-reduction-in-annual-and-daily-fine-particulate-matter-impact-in-paris/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stockholmenvironmentinstitute2019assessing, author = {{Stockholm Environment Institute}}, title = {{Assessing reduction in annual and daily fine particulate matter impact in Paris}}, institution = {Stockholm Environment Institute}, year = {2019}, month = may, url = {https://www.sei.org/publications/assessing-reduction-in-annual-and-daily-fine-particulate-matter-impact-in-paris/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }