Atmospheric polycyclic aromatic hydrocarbons in north China: a winter-time study

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Pollution Studies

Background:

• Investigated atmospheric polycyclic aromatic hydrocarbons (PAHs) in the Chinese Northern Plain, a region with high emission density.
• PAH concentrations in the study area were found to be higher than in developed countries and southern Chinese cities.

Purpose of the Study:

• To investigate the contamination and outflow of atmospheric PAHs in the Chinese Northern Plain.
• To compare PAH concentrations across urban, rural, and remote control sites.
• To understand the factors influencing PAH partitioning and identify outflow patterns.

Main Methods:

• Collected Polyurethane foam (PUF) and PM10 samples from 46 sites across urban, rural, and remote areas.
• Analyzed atmospheric PAH concentrations and their partitioning to PM10.
• Utilized forward trajectory and cluster analysis to identify outflow patterns.

Main Results:

• No significant difference in air PAH concentrations between urban (514 ± 563 ng/m³) and rural (610 ± 645 ng/m³) areas.
• PAH concentrations at control sites (57.1 ± 12.6 ng/m³) were one order of magnitude lower.
• Widespread biomass and domestic coal combustion were identified as the primary sources for similar urban and rural PAH levels.
• PAH partitioning to PM10 was dominated by adsorption, indicated by steep regression slopes (log K(PM10) vs. log pL0).
• Three distinct outflow patterns from the study area were identified.

Conclusions:

• Widespread domestic fuel combustion significantly contributes to high atmospheric PAH levels in both urban and rural areas of the Chinese Northern Plain.
• PAH behavior in the atmosphere is strongly influenced by adsorption onto particulate matter.
• Understanding outflow patterns is crucial for regional air quality management.