Field evaluation of particulate matter measurements using tapered element oscillating microbalance in a layer house

Abstract

The tapered element oscillating microbalance (TEOM) is one type of continuous ambient particulate matter (PM) monitor. Adsorption and desorption of moisture and semivolatile species may cause positive or negative artifacts in TEOM PM mass measurement. The objective of this field study was to investigate possible uncertainties associated with TEOM measurements in the poultry operation environment. For comparisons of TEOM with filter-based gravimetric method, four instruments (TEOM-PM 10 , low-volume PM 10 sampler, TEOM-PM 2.5 , and PM 2.5 speciation sampler) were collocated and tested inside a poultry house for PM 2.5 and PM 10 (PM with aerodynamic equivalent diameter 2.5 and 10 m, respectively) measurements. Fifteen sets of 24-hr PM 10 concentrations and 13 sets of 24-hr PM 2.5 measurements were obtained. Results indicate that compared with filter-based gravimetric method, TEOM gave significantly lower values of both PM 10 and PM 2.5 mass concentrations. For PM 10 , the average ratio of TEOM to the gravimetric method was 0.936. For PM 2.5 , the average ratio of TEOM to the gravimetric method was 0.738. Particulate matter in the poultry houses possibly contains semivolatile compounds and moisture due to high levels of relative humidity (RH) and gas pollutants. The internal heating mechanism of the TEOM may cause losses in mass through volatilization. To investigate the effects of TEOM settings on concentration measurements, the heaters of two identical TEOMs were set at 50 C, 30 C, or no heating at all. They were collocated and tested for total suspended particle (TSP), PM 10 , and PM 2.5 measurements in layer house for 6 weeks. For all TSP, PM 10 , and PM 2.5 measurements, the internal TEOM temperature setting had a significant effect (P < 0.05). Significantly higher PM mass concentrations were measured at lower temperature settings. The effects of environmental (i.e., temperature, RH, NH 3 and CO 2 concentrations) and instrumental (i.e., filter loading and noise) parameters on PM measurements were also assessed using regression analysis.Implications: Because of its potential health and environmental effects, particulate matter (PM) emissions from animal feeding operations (AFOs) have been a great concern to the public and to the regulatory agencies. The tapered element oscillating microbalance (TEOM) PM monitor has been was adapted for continuous PM measurements in some AFO air quality studies. This study investigated possible uncertainties associated with TEOM measurements in an egg production environment. It was discovered that there was a significant bias in TEOM measurements of PM 10 as compared with federal reference method. Internal temperature settings of a TEOM have significant impact on its PM measurement.

Urban impacts on regional carbonaceous aerosols: Case study in central Texas

“…The Waco (Mazanec), Houston Clinton, and Dallas Hinton monitoring sites determine PM 2.5 mass using a tapered-element oscillating microbalance (TEOM). The TEOM has been shown to underestimate PM 2.5 mass when compared to gravimetrical measurements (Li et al, 2012), and this may explain the positive bias in the comparison between Riesel and Waco (Supplemental Materials, Figure S3). Despite the possible underestimation by the TEOM, PM 2.5 concentrations in Dallas and Houston are, on average, greater than Riesel and Waco PM 2.5 concentrations.…”

Characteristics and Source Analysis of Trace Elements in PM2.5 in the Urban Atmosphere of Wuhan in Spring

“…Negative artifacts (i.e., loss of mass) are because of the internal heating mechanism of the TEOM monitor (PM 10 ), which is reported in literature when particulate matter in the poultry houses possibly contains semi-volatile compounds and moisture due to high levels of relative humidity (RH) and gas pollutants. TEOM may cause losses in mass through volatilization (Li et al, 2012).…”

Combining Cluster Analysis of Air Pollution and Meteorological Data with Receptor Model Results for Ambient PM2.5 and PM10

“…The reason for this discrepancy is ascribed to the different PM 2.5 measurement techniques: filter samples were taken in low-volume dichotomous samplers (Andersen Instrument, Inc, Smyrna, GA, USA, 15 L/min) while continuous measurements were made with a Tapered Element Oscillating Microbalance equipment (TEOM, Rupprecht & Patashnick, MA, USA). The latter instrument is known to present negative artifacts (i.e., underestimation of PM 2.5 concentrations) due to partial volatilization of sampled PM 2.5 in the TEOM's heating inlet used to dry the samples [92]. We think this instrument artifact explains why filter-based RM results are higher than the CA results reported here.…”