The Magnitude of Bias in the Measurement of PM_(2.5) Arising from Volatilization of Particulate Nitrate from Teflon Filters
- Creators
- Hering, Susanne
- Cass, Glen
Abstract
Because the Federal Reference Method for PM_(2.5) specifies the collection of ambient particles on Teflon filters, we have examined the loss of a known volatile species, particulate nitrate, during sampling. Data are presented from two studies in southern California for which parallel samples were collected by different methods. Differences in collected nitrate are modeled using an evaporation model based on the work of Zhang and McMurry. The average nitrate obtained from sampling with Teflon filters was 28% lower on average than that measured by denuded nylon filters. In contrast, cascade impactor samples were within 5% of the denuded nylon filter on average. A simple model is presented that accounts for the particulate nitrate loss from Teflon filters either by scavenging nitric acid and ammonia in the sampler inlet or by heating the filter substrate during sampling. The observed magnitude of loss is explained by any of the following situations: (1) 100% nitric acid and ammonia vapor loss in the inlet, (2) 5 °C heating of the filter substrate above ambient temperature during sampling, or (3) a combination of these factors, such as 50% vapor loss in the inlet and 3 °C heating of the filter.
Additional Information
© 1999 Air & Waste Management Association. We thank the California Air Resources Board for their support of this work. We thank Dr. Paul Solomon and Michael Chan for their diligent efforts in producing the data sets analyzed here, and the South Coast Air Quality Management District for providing the temperature data at their sites. We also thank Dr. Mark Stolzenburg and Dr. Walter John for their helpful comments.Additional details
- Eprint ID
- 61243
- Resolver ID
- CaltechAUTHORS:20151019-091415651
- California Air Resources Board
- Created
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2015-10-19Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field