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Document Type |
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Article In Journal |
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Document Title |
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Sensitivity of a Chemical Mass Balance model to different molecular marker traffic source profiles حساسية نموذج التوازن الكمى الكيميائى لكشافات جزيئية مختلفة لمصادر المرور |
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Subject |
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Enviromental sciences |
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Document Language |
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English |
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Abstract |
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Use of the Chemical Mass Balance (CMB) model for aerosol source apportionment requires the input
of source profiles of chemical constituents. Such profiles derived from studies in North America are
relatively abundant, but are very scarce from European studies. In particular, there is a lack of data
from European road vehicles. This study reports results from a comparison of road traffic source
profiles derived from (1) US dynamometer studies of individual vehicles with (2) a traffic profile
derived from measurements in a road tunnel in France and (3) new data derived from a twin-site
study in London in which concentrations at an urban background site are subtracted from those
measured at a busy roadside to derive a traffic increment profile. The dynamometer data are input as
a diesel exhaust, gasoline exhaust and smoking engine profile, or alternatively as just a diesel exhaust
and gasoline exhaust profile. Running the CMB model with the various traffic profiles together with
profiles for other sources of organic carbon gives variable estimates of the contribution of traffic to
organic carbon and to PM2.5 concentrations. These are tested in two ways. Firstly, unassigned organic
carbon in the output from the CMB model, assumed to be secondary organic carbon, is compared to
secondary organic carbon estimated independently using the elemental carbon tracer method.
Secondly, the estimated traffic contribution to organic carbon and PM2.5 is compared with an estimate
derived simply from the measured elemental carbon concentrations, and the effect on aerosol
mass closure is investigated. In both cases the CMB model results correlate well with the independent
measures, but there are marked differences according to the traffic source profile employed. As
a general observation, it appears that the use of dynamometer data with inclusion of a smoking
engine profile has a tendency to over-estimate traffic emissions at some sites whereas the tunnel
profile shows a tendency to under-estimate. Overall, study gives probably the best overall estimate, but the quality of fit with independent estimates of
secondary organic carbon and traffic particle mass depends upon the site and dataset for which the
test is conducted.the traffic profile derived from the twin-site |
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ISSN |
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1352-2310 |
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Journal Name |
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Atmospheric Environment |
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Volume |
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82 |
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Issue Number |
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1 |
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Publishing Year |
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1435 AH
2014 AD |
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Article Type |
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Article |
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Added Date |
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Sunday, February 16, 2014 |
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Researchers
| Pallavi Pant | Pant, Pallavi | Researcher | | |
| Jianxin Yin | Yin, Jianxin | Researcher | | |
| Roy M. Harrison | Harrison, Roy M. | Researcher | | r.m.harrison@bham.ac.uk |
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Files
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36519.pdf
| pdf | Sensitivity of a Chemical Mass Balance model to different molecular
marker traffic source profiles |
|