Application of a dual fine particle sequential sampler, a tapered element oscillating microbalance, and other air monitoring methods to assess transboundary influences of PM2.5

Transboundary influences of particulate matter less than or equal to 2.5 mm in aerodynamic diameter (PM2.5) have been investigated in a U.S.-Mexican border region with the use of a dual fine particle sequential sam- pler (DFPSS) and a tapered element oscillating micro- balance (TEOMT). Daily measurements of PM2.5 were con- ducted with the DFPSS. Short-term variations in the concentration of PM2.5 were measured and analyzed on site with the use of a tapered element oscillating micro- balance (TEOMT) to assess episodic emissions that may have crossed the border. Fine particle carbon measure- ments, taken with a dichotomous sampler, and meteo- rological measurements were also performed. Ambient monitoring with these sampling methods was conducted for 1 year at three fixed sites very close to the border of the Lower Rio Grande Valley. Elemental tracer analyses and wind sector analyses were performed to assess transboundary influences. Ad hoc sampler comparisons were also presented. Presentation of advantages and limitations of sampling methods in this study can help establish a baseline for assessing future air quality con- ditions of a transboundary nature in the Valley. Q 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 201-217, 1999