Evaluating the PAS-SIM model using a passive air sampler calibration study for pesticides

Area of Science:

• Environmental Chemistry
• Atmospheric Science
• Analytical Chemistry

Background:

• Passive air samplers (PAS) are crucial for monitoring atmospheric pollutants.
• Understanding pesticide uptake kinetics in PAS is essential for accurate environmental assessment.
• Previous models lacked comprehensive field validation for pesticide accumulation.

Purpose of the Study:

• To evaluate the performance of the PAS-SIM model in simulating pesticide uptake on XAD-resin based PAS.
• To compare model-derived passive sampling rates (PSRs) with empirical data and literature values.
• To assess the model's ability to account for meteorological influences on PAS performance.

Main Methods:

• Deployment of XAD-resin PAS at a rural agricultural site in Ontario, Canada (2006-2007).
• Collection of concurrent active air samples and meteorological data.
• Application of the PAS-SIM model to simulate pesticide accumulation and determine PSRs.

Main Results:

• PAS-SIM model demonstrated good agreement (within a factor of two) with experimental pesticide accumulation data.
• Most pesticides showed continuous accumulation, with exceptions like trifluralin and pendimethalin suggesting degradation.
• Model-derived PSRs were consistent with empirical measurements and existing literature values, considering temperature and wind variations.

Conclusions:

• The PAS-SIM model provides a reliable tool for simulating pesticide uptake on PAS.
• The model's accuracy supports its use in understanding field-level sampler kinetics.
• Further application of PAS-SIM is recommended for spatial and temporal variability studies at monitoring sites with meteorological data.