Comparison Between Tapered Element Microbalance (TEOM) and Federal Reference Method (FRM) for PM_2.5 Measurement in East Tennessee

Particulate matter (PM) of 2.5 microns or less is linked to serious negative health and visibility effects, and consequently is gaining increased regulatory attention. Therefore, accurate and timely measurement of ambient PM_{2.5 is an essential task for both researchers pursuing productive investigations, and local air quality administrators in evaluating, modeling, planning for compliance, and generally making the highest productive use of their control resources. However, accurate and timely may be conflicting needs.}

Many studies have concluded that a significant difference in measurements exists between the Tapered Element Oscillating Microbalance Monitors (TEOM) and the Federal Reference Method (FRM). The difference is generally related to lower ambient temperatures (i.e., at lower temperatures, the TEOM has been cited to under report PM2.5 concentrations).

To determine if this same relationship exists in East Tennessee, PM2.5 concentration and ambient temperature data were obtained from TEOM, FRM and IMPROVE sites in both an urban and a rural East Tennessee area. The urban site is a heavily developed location near downtown Knoxville, Tennessee, and the rural site is at Look Rock, located on the edge of the Great Smoky Mountains National Park overlooking the Tennessee Valley.

Using TEOM and FRM data from the Knox County site and TEOM and IMPROVE data from Look Rock, comparisons were made between the 24-hr TEOM and the 24-hr FRM/IMPROVE data for PM2.5 concentration, and investigations were conducted to determine the effect of the 24-hr average ambient temperature on the ratio of TEOM/FRM and TEOM/IMPROVE.