title: Temperature effect of tapered element oscillating microbalance (TEOM) system measuring semi-volatile organic particulate matter.
abstract: The tapered element oscillating microbalance (TEOM) system is widely used to measure continuous particle mass concentrations in air quality networks. However, the semi-volatile aerosol material is lost under normal operation conditions (50 °C). This study has evaluated the error in the organic fraction of the TEOM-measured secondary organic aerosols formed from the degradation of biogenic pollutants. Experiments were carried out under controlled, water-free conditions in a fully equipped, high volume atmospheric simulator--the European PhotoReactor (EUPHORE). The ozonolysis of α-pinene, β-pinene and limonene provided a reproducible source of organic aerosol. Particulate matter concentration profiles were registered for different TEOM operating temperatures. When these values were compared with values from a filter-based gravimetric method and a scanning mobility particle sizer (SMPS), they showed that the differences between monitoring systems increased with increasing TEOM temperature. According to our results, when the TEOM is operated at 50 °C, it fails to measure 32-46% of the organic particulate material, depending on the aerosol precursor. This study has also identified and quantified the multi-oxygenated organic compounds lost in the TEOM monitoring by using a method based on the gas chromatography-mass spectrometry technique. Important losses have been calculated for relevant ambient aerosol compounds such as pinonic acid, pinonaldehyde, norpinone and limonalic acid. In conclusion, the present study has demonstrated that a high operating temperature of the TEOM monitor reduces the humidity interference but underestimates the semi-volatile organic fraction.
authors.affiliation: Dpto. Química-IDM, Universidad Politécnica de Valencia, Camino de Vera, s/n, 46022 Valencia, Spain. luitorge@qim.upv.es
authors.forename: Luis-Antonio
authors.initials: LA
authors.lastname: Tortajada-Genaro
authors.forename: Esther
authors.initials: E
authors.lastname: Borrás
mesh_terms: D000336:Aerosols; D004784:Environmental Monitoring / Q000379:methods; D015203:Reproducibility of Results; D013696:Temperature; D013818:Thermogravimetry; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000336:Aerosols; D055549:Volatile Organic Compounds