 |
| Titel |
The influence of temperature calibration on the OC–EC results from a dual-optics thermal carbon analyzer |
| VerfasserIn |
J. Pavlovic, J. S. Kinsey, M. D. Hays |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 9 ; Nr. 7, no. 9 (2014-09-05), S.2829-2838 |
| Datensatznummer |
250115890
|
| Publikation (Nr.) |
 copernicus.org/amt-7-2829-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Thermal–optical analysis (TOA) is a widely used technique that fractionates
carbonaceous aerosol particles into organic and elemental carbon (OC and EC),
or carbonate. Thermal sub-fractions of evolved OC and EC are also used for
source identification and apportionment; thus, oven temperature accuracy
during TOA analysis is essential. Evidence now indicates that the "actual"
sample (filter) temperature and the temperature measured by the built-in oven
thermocouple (or set-point temperature) can differ by as much as
50 °C. This difference can affect the OC–EC split point selection and
consequently the OC and EC fraction and sub-fraction concentrations being
reported, depending on the sample composition and in-use TOA method and
instrument. The present study systematically investigates the influence of an
oven temperature calibration procedure for TOA. A dual-optical carbon
analyzer that simultaneously measures transmission and reflectance (TOT and
TOR) is used, functioning under the conditions of both the National Institute of Occupational Safety and
Health Method 5040 (NIOSH) and
Interagency Monitoring of Protected Visual Environment (IMPROVE) protocols. The application of the oven calibration procedure to our dual-optics instrument significantly changed NIOSH 5040 carbon fractions (OC and
EC) and the IMPROVE OC fraction. In addition, the well-known OC–EC split
difference between NIOSH and IMPROVE methods is even further perturbed
following the instrument calibration. Further study is needed to determine if
the widespread application of this oven temperature calibration procedure
will indeed improve accuracy and our ability to compare among carbonaceous
aerosol studies that use TOA. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|