A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers

We have developed and evaluated a mathematical model to determine
the effective sampling volumes (Veff)
of PCBs and similar compounds captured using polyurethane foam passive
air samplers (PUF–PAS). We account for the variability in wind
speed, air temperature, and equilibrium partitioning over the course
of the deployment of the samplers. The model, provided as an annotated
Matlab script, predicts the Veff as a
function of physical-chemical properties of each compound and meteorology
from the closest Integrated Surface Database (ISD) data set obtained
through NOAA’s National Centers for Environmental Information
(NCEI). The model was developed to be user-friendly, only requiring
basic Matlab knowledge. To illustrate the effectiveness of the model,
we evaluated three independent data sets of airborne PCBs simultaneously
collected using passive and active samplers: at sites in Chicago,
Lancaster, UK, and Toronto, Canada. The model provides Veff values comparable to those using depuration compounds
and calibration against active samplers, yielding an average congener
specific concentration method ratio (active/passive) of 1.1 ±
1.2. We applied the model to PUF–PAS samples collected in Chicago
and show that previous methods can underestimate concentrations of
PCBs by up to 40%, especially for long deployments, deployments conducted
under warming conditions, and compounds with log Koa values less than
8.