Integrated Composition-Toxicity Assessment Reveals Seasonal Drivers of PM_2.5 Health Risks in Hefei, China.

Area of Science:

• Environmental Science
• Toxicology
• Public Health

Background:

• Rapid urbanization in China has intensified air quality concerns, particularly regarding fine particulate matter (PM2.5).
• PM2.5 poses significant health risks due to its complex chemical makeup and varied emission sources.
• Understanding seasonal variations in PM2.5 composition and toxicity is crucial for effective environmental management.

Purpose of the Study:

• To conduct a seasonally resolved analysis of PM2.5 chemical composition and multifaceted toxicity in Hefei, China.
• To identify the key components driving PM2.5-induced health risks across different seasons.
• To inform risk-based air quality management strategies tailored to specific pollutant characteristics.

Main Methods:

• Collection and chemical characterization of PM2.5 samples across four seasons.
• Analysis included water-soluble ions, carbonaceous components, metals, and polycyclic aromatic hydrocarbons (PAHs).
• Toxicological assessments involved oxidative potential (OP), cytotoxicity, and reactive oxygen species (ROS) generation in BEAS-2B cells.

Main Results:

• Significant seasonal variations in PM2.5 concentration and composition were observed, with winter showing the highest levels.
• Winter PM2.5 exhibited the highest oxidative potential, cytotoxicity, and ROS induction, linked to secondary inorganic aerosols (SIAs) and toxic metals.
• Specific components like SIAs (NO3-, NH4+), redox-active metals (Cu, Zn), and PAHs were identified as key drivers of toxicity.

Conclusions:

• The elevated health risks associated with winter PM2.5 in Hefei are driven by a combination of secondary aerosols and combustion-derived toxicants.
• A component-specific, risk-based approach to air quality management is essential for mitigating health impacts.
• Findings highlight the need for targeted pollution control strategies addressing seasonal variations in PM2.5 composition and toxicity.