Source Apportionment of PM2.5 in Delhi, India Using PMF Model

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Air Pollution Research

Background:

• Particulate matter (PM2.5) poses significant health risks, especially in urban areas like Delhi, India.
• Understanding PM2.5 sources is crucial for developing effective air quality management strategies.
• Previous studies highlight the complexity of PM2.5 composition and seasonal variations in Delhi.

Purpose of the Study:

• To conduct a comprehensive chemical characterization of PM2.5.
• To perform source apportionment of PM2.5 using a receptor model.
• To identify and quantify the major sources contributing to PM2.5 pollution in urban Delhi.

Main Methods:

• Collected PM2.5 samples over two years (January 2013-December 2014) at an urban site in Delhi.
• Performed detailed chemical analysis, including organic carbon, elemental carbon, water-soluble inorganic ions, and major/trace elements.
• Applied the positive matrix factorization (PMF) receptor model for source apportionment.

Main Results:

• The annual average PM2.5 concentration was 122 ± 94.1 µg m⁻³.
• PM2.5 levels exhibited strong seasonal variations, peaking in winter and minimizing during the monsoon season.
• The PMF model identified secondary aerosols (21.3%), soil dust (20.5%), vehicle emissions (19.7%), biomass burning (14.3%), and fossil fuel combustion (13.7%) as major sources.

Conclusions:

• Source apportionment revealed a diverse mix of PM2.5 contributors in Delhi.
• Vehicle emissions and biomass burning are significant sources, necessitating targeted control measures.
• Seasonal patterns underscore the impact of meteorological conditions and emission activities on PM2.5 pollution.