Source attribution of air pollution using a generalized additive model and particle trajectory clusters

Area of Science:

• Atmospheric Chemistry
• Environmental Science
• Data Science

Background:

• Air pollution in urban, industrial, and port environments poses significant health risks.
• Understanding pollutant sources and transport mechanisms is crucial for effective air quality management.

Purpose of the Study:

• To speciate hourly fine aerosol measurements over two years in Busan, Korea.
• To develop and apply a Generalized Additive Model (GAM) to deconvolve factors influencing pollutant concentrations.
• To quantify the impact of long-range transport using an expanded GAM with FLEXPART back trajectory clusters and the Trajectory Cluster Contribution Function (TCCF).

Main Methods:

• Speciated hourly measurements of fine aerosols at three distinct sites in Busan.
• Application of a Generalized Additive Model (GAM) to analyze time-series data.
• Integration of FLEXPART back trajectory clusters and fuzzy c-means clustering within the GAM framework.
• Development and use of the Trajectory Cluster Contribution Function (TCCF) for quantifying long-range transport impacts.

Main Results:

• Local transport significantly influences primary pollutants (e.g., NO2, elemental carbon), explaining up to 72% of variance.
• Large-scale/seasonal factors are dominant for secondary pollutants (PM2.5, inorganic species), accounting for up to 56% and 80% of variance, respectively.
• The study identified distinct impacts of the COVID-19 pandemic on different pollutants and sites, including local, industrial, and long-term changes.

Conclusions:

• The GAM, enhanced with trajectory clustering, effectively distinguishes local and long-range pollutant transport contributions.
• Pollution dynamics in Busan are a complex interplay of local emissions, meteorological factors, and transboundary transport.
• The COVID-19 pandemic introduced unique, site-specific alterations to air pollution patterns, highlighting the model's sensitivity to external events.