A Comparison of High Volume and Diffusion Denuder Samplers for Measuring Semivolatile Organic Compounds in the Atmosphere

Abstract

A detailed comparison of two inherently different ambient air samplers has been conducted to fully characterize and compare their performance in sampling and measuring the partitioning of a suite of 29 semivolatile organic compounds (SVOCs). A high volume air sampler (hi-vol) utilizing polyurethane foam (PUF) adsorbent for vapor-phase trapping and an annular diffusion denuder sampler were operated concurrently. Sampling artifacts were observed and can be related to the physicochemical properties of the analytes and the designs of the samplers. The results suggest that high volume air samplers equipped with PUF are unsuitable for measuring those organochlorine compounds and 2-and 3-ring PAHs which have subcooled liquid vapor pressures (p°L) greater than ca. 0.2 Pa (log-[p°L] ) -0.7), owing to their breakthrough on PUF sampling media at relatively low sample volumes (170 m 3 ) and ambient temperatures typical of temperate regions (mean ) 11 °C, max ) 18 °C). Theoretical calculations of breakthrough volumes for SVOCs on PUF are presented and in most cases these successfully predict observed behavior. The denuder sampler is more efficient at measuring the relatively volatile SVOCs. For total SVOC measurements the hi-vol and denuder were in good agreement for those compounds which were efficiently sampled, and the denuder yielded total SVOC concentrations which differed by a mean factor of 1.2 relative to those obtained with the hi-vol sampler. The hi-vol sampler provides good agreement with the Junge-Pankow model for partitioning of the relatively less volatile PAHs (log[p°L] < -3), though the fraction of the PCBs in the particle-phase is underestimated. The results from the diffusion denuder indicate that for the more volatile SVOCs (log[p°L] > -3), particulate loadings are overestimated with respect to the Junge-Pankow model, and for less volatile SVOCs, particulate loadings tend to be underestimated. An important observation is that the results from the denuder indicate that PCBs may be adsorbed on atmospheric particulate matter to a similar degree as PAHs.

U.S. National PM2.5Chemical Speciation Monitoring Networks—CSN and IMPROVE: Description of networks

“…Examples of these include use of a single QFF backup filter behind the primary QFF, such as IMPROVE uses, or use of a QFF behind a Teflon filter; use of a denuder (e.g., activated-carbon-impregnated strips or XAD-coated glass annular denuder) in front of a reactive backup filter (e.g., carbonor XAD-impregnated glass-fiber filter) behind the primary QFF, and application of a linear regression method where OC (y-axis) is plotted versus PM 2.5 mass as obtained on a Teflon filter (Peters et al, 2000;Turpin et al, 2000;Solomon et al, 2000;Lewtas et al, 2001;Tolocka et al, 2001;Subramanian et al, 2004;Kim et al, 2005;Watson et al, 2009;Chow et al, 2010;Maimone et al, 2011). Other statistical methods also have been investigated for CSN (Kim et al, 2001).…”

Measurements of semivolatile and particulate polycyclic aromatic hydrocarbons in a bus station and an urban tunnel in Salvador, Brazil

“…20 The GC/MS analysis was performed using a system consisting of an HP1701 column (30 m 6 0.25 mm diameter) (Agilent, CA), an HP6890 Plus gas chromatograph, an HP6890 GC autosampler and an HP5973 quadrupole mass selective detector (Agilent, CA). The following conditions were employed: (i) oven: 60 uC Table 2 represent individually collected samples from two different days.…”

Microscale spectrophotometric methods for quantification of functional groups in oxidized organic aerosol

“…The same constraints hold true for ambient samples. For example, in a polluted urban environment with an organic aerosol mass concentration of 10 mg m ¡3 (Zhang et al 2007) it would take »24 h to collect 1 mg of organic mass for functional group analysis using a high volume sampler with a flow of 60 L min ¡1 (Peters et al 2000). Because the spectrophotometric methods used thus far have employed a conventional UV-VIS spectrophotometer with a standard 1 cm path length quartz cuvette to measure sample absorbance, the final volume of solution required for analysis of each functional group is at least 3 mL.…”