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

A research paper analyzing PM2.5 concentrations in Paris and the Île-de-France region from 2009 to 2018. It finds that while local emission reductions have decreased annual and daily PM2.5 levels, regional transport remains a major contributor, particularly for the highest hourly concentrations, suggesting that regional emission reductions are necessary to meet WHO air quality guidelines.

• Between 2009 and 2018, there were reductions in both annual PM2.5 concentrations and the number of days where 24 h PM2.5 concentrations exceeded 25 μgm−3. Annual concentrations decreased by an average of −0.79 μgm−3 y−1 across three urban background sites, representing a 33% average reduction. The number of days exceeding the 24 h threshold decreased by 6 days y−1, a 62% average reduction.
• The observed reductions in PM2.5 metrics 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: highest concentrations occurred less often during rush hours, while lowest concentrations occurred more frequently during the day.
• Regional transport contributes significantly to PM2.5 levels in Paris. Regional contributions to annual PM2.5 concentrations are approximately 50% at urban traffic sites and 70% at urban background sites. The highest hourly PM2.5 concentrations show the largest regional contributions compared to moderate concentrations.
• Air mass back trajectories indicate that when moderate and high hourly PM2.5 concentrations are measured, air masses spent more time over European geographic regions than over the ocean during the preceding four days, suggesting an increased relative contribution from 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} }