Multi-city comparative PM_2.5 source apportionment for fifteen sites in Europe: The ICARUS project

Area of Science:

• Atmospheric Chemistry and Physics
• Environmental Science
• Air Quality Monitoring

Background:

• Particulate Matter (PM2.5) is a critical air pollutant with European Union reduction targets.
• Identifying and characterizing PM2.5 sources is essential for developing effective control strategies.
• The ICARUS EU2020 project aimed to address this challenge by creating a comprehensive PM2.5 database.

Purpose of the Study:

• To identify and quantify PM2.5 sources across diverse urban and rural environments in Europe.
• To compare the chemical fingerprints and contributions of PM2.5 sources between traffic, urban background, and rural sites.
• To investigate the homogeneity and meteorological influences on PM2.5 source profiles.

Main Methods:

• Creation of a comprehensive database of PM2.5 concentration and chemical composition (ions, metals, carbon, PAHs).
• Data collected from three types of sites (traffic, urban background, rural) in five European cities over two seasons.
• Application of a harmonized Positive Matrix Factorization (PMF) model to analyze source contributions and chemical profiles.

Main Results:

• Traffic exhausts contributed significantly (8.8-23.3%), with higher levels at traffic sites.
• Biomass burning was a major source (22-30%), especially in urban background and rural areas.
• Fuel oil combustion, traffic non-exhausts, and soil dust showed dissimilar profiles across sites, while biomass burning, sea salt, and traffic exhaust were relatively homogenous.

Conclusions:

• PM2.5 source contributions vary significantly depending on the site type (traffic, urban, rural).
• Biomass burning and traffic exhausts are key PM2.5 sources across European cities.
• Source profile homogeneity differs, with traffic exhaust, biomass burning, and sea salt being more consistent across locations.