EVALUATION OF THE TEOM(R) METHOD FOR MEASUREMENT OF AMBIENT PARTICULATE MASS IN URBAN AREAS

Increased interest in the health effects of ambient particulate mass ( PM) has focused attention on the evaluation of existing mass measureme nt methodologies and the definition of PM in ambient air. The Rupprech t and Patashnick Tapered Element Oscillating MicroBalance (TEOM(R)) me thod for PM is compared with time-integrated gravimetric (manual) PM m ethods in large urban areas during different seasons. Comparisons are conducted for both PM10 and PM2.5 concentrations. In urban areas, a su bstantial fraction of ambient PM can be semi-volatile material. A larg er fraction of this component of PM10 may be lost from the TEOM-heated filter than the Federal Reference Method (FRM). The observed relation ship between TEOM and FRM methods varied widely among sites and season s. In East Coast urban areas during the summer, the methods were highl y correlated with good agreement. In the winter, correlation was somew hat lower, with TEOM PM concentrations generally lower than the FRM. R ubidoux, CA, and two Mexican sites (Tlalnepantla and Merced) had the h ighest levels of PM10 and the largest difference between TEOM and manu al methods. PM2.5 data from collocation of 24-hour manual samples with the TEOM are also presented. As most of the semi-volatile PM is in th e fine fraction, differences between these methods are larger for PM2. 5 than for PM10.