PAHs in Chinese atmosphere: Gas/particle partitioning

Area of Science:

• Environmental Chemistry
• Atmospheric Science
• Pollutant Fate and Transport

Background:

• Polycyclic Aromatic Hydrocarbons (PAHs) are significant atmospheric pollutants.
• Understanding the gas/particle (G/P) partitioning of PAHs is crucial for assessing their environmental fate.

Purpose of the Study:

• To investigate the G/P partitioning behavior of 16 priority PAHs across 11 urban sites in China.
• To analyze the influence of molar weight, physical-chemical properties, and geographical location (northern vs. southern China) on PAH partitioning.

Main Methods:

• Conducted a one-year monitoring program collecting gaseous and particulate PAH concentrations.
• Analyzed 7647 pairs of concentration data for 16 priority PAHs.
• Calculated and compared the G/P partitioning coefficient (K_P) across different sites and PAH congeners.

Main Results:

• PAH concentrations varied significantly across the 11 urban sites.
• Particulate PAH concentrations were significantly higher in northern Chinese cities compared to southern cities.
• The proportion of PAHs in the particle phase increased with molar weight.
• Log K_P values showed significant differences between northern and southern cities for most PAHs, attributed to physical-chemical properties.

Conclusions:

• Geographical location and intrinsic physical-chemical properties significantly influence PAH G/P partitioning in China.
• The study provides a substantial database of K_P values essential for future atmospheric research on PAHs.