An improved method to determine PM-bound nitro-PAHs in ambient air.

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Air Pollution Monitoring

Background:

• No standard method exists for determining particulate-bound nitro-PAHs (NPAHs).
• Current methods involve complex procedures and lack the sensitivity for daily PM10 analysis, limiting temporal resolution.
• This impacts understanding of NPAH exposure and sources.

Purpose of the Study:

• To develop and validate a sensitive analytical method for quantifying NPAHs in daily PM10 filter samples.
• To improve the temporal resolution of NPAH concentration monitoring.
• To assess NPAH levels and identify sources in an industrial and urban area.

Main Methods:

• Microwave-assisted extraction for NPAH recovery from 47 mm filter samples.
• Analysis using gas chromatography-triple quadrupole mass spectrometry in MRM mode.
• Validation of the method for 14 target NPAHs, including recovery, repeatability, and limits of detection.

Main Results:

• Extraction recovery exceeded 95% for all target NPAHs.
• Repeatability (RSD%) was generally below 10%, with slightly higher values for specific dinitro-PAHs.
• Low limits of detection were achieved, ranging from 12-84 pg/mL for most NPAHs.

Conclusions:

• The developed method is suitable for analyzing NPAHs in daily PM10 samples.
• Application to real samples in Taranto identified combustion processes, particularly near a major steel plant, as a primary source of NPAHs under specific weather conditions.