Insight Study of Trace Elements in PM_2.5 During Nine Years in Delhi, India: Seasonal Variation, Source Apportionment,...

Area of Science:

• Environmental Science
• Public Health
• Atmospheric Chemistry

Background:

• Particulate Matter (PM2.5) poses significant health risks in urban environments.
• Heavy elements in PM2.5 contribute to adverse health outcomes.
• Delhi faces severe air pollution challenges, necessitating detailed investigation.

Purpose of the Study:

• To determine concentrations, seasonal trends, and sources of heavy elements in Delhi's PM2.5.
• To assess human health risks associated with exposure to these heavy elements.
• To provide data for effective air quality management and public health strategies.

Main Methods:

• Long-term monitoring of PM2.5 and associated heavy elements (As, Al, Pb, Cr, Mn, Cu, Zn, Ni) from 2013-2021.
• Seasonal analysis of pollutant concentrations.
• Positive Matrix Factorization (PMF) for source apportionment.
• Health risk assessment using Hazard Quotient (HQ), Hazard Index (HI), and Carcinogenic Risk (CR).

Main Results:

• Average PM2.5 concentration (127 µg m⁻³) significantly exceeded national standards.
• Post-monsoon and winter seasons showed the highest PM2.5 and heavy element levels.
• Major sources identified: dust, vehicular emissions, biomass burning, combustion, and industrial emissions.
• Elevated HQ for Cr and Mn, and high CR for Cr indicated significant health risks.
• Combined HI > 1 suggested considerable non-carcinogenic risks.

Conclusions:

• Heavy element pollution in Delhi's PM2.5 is a critical concern, particularly during post-monsoon and winter.
• Multiple sources contribute to the pollution, requiring integrated control strategies.
• Significant health risks, including carcinogenic effects, are associated with PM2.5-bound heavy elements.
• Findings underscore the urgent need for targeted interventions to improve air quality and protect public health in Delhi.