 |
| Titel |
Contributions of vehicular carbonaceous aerosols to PM2.5 in a roadside environment in Hong Kong |
| VerfasserIn |
X. H. H. Huang, Q. J. Bian, P. K. K. Louie, J. Z. Yu |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 17 ; Nr. 14, no. 17 (2014-09-09), S.9279-9293 |
| Datensatznummer |
250119014
|
| Publikation (Nr.) |
 copernicus.org/acp-14-9279-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Hourly measurements of elemental carbon (EC) and organic carbon (OC) were
made at Mong Kok, a roadside air quality monitoring station in Hong Kong, for
a year, from May 2011 to April 2012. The monthly average EC concentrations
were 3.8–4.9 μg C m−3, accounting for 9.2–17.7% of the
PM2.5 mass (21.5–49.7 μg m−3). The EC concentrations showed
little seasonal variation and peaked twice daily, coinciding with the traffic
rush hours of a day. Strong correlations were found between EC and NOx
concentrations, especially during the rush hours in the morning, confirming
vehicular emissions as the dominant source of EC at this site. The analysis
by means of the minimum OC / EC ratio approach to determine the OC / EC ratio representative
of primary vehicular emissions yields a value of 0.5 for
(OC / EC)vehicle. By applying the derived (OC / EC)vehicle ratio to
the data set, the monthly average vehicle-related OC was estimated to account
for 17–64% of the measured OC throughout the year. Vehicle-related OC
was also estimated using receptor modeling of a combined data set of hourly
NOx, OC, EC and volatile organic compounds characteristic of different
types of vehicular emissions. The OCvehicle estimations by the two
different approaches were in good agreement. When both EC and
vehicle-derived organic matter (OM) (assuming an OM-to-OC ratio of 1.4) are
considered, vehicular carbonaceous aerosols contributed ~ 7.3 μg m−3 to PM2.5, accounting for ~ 20% of
PM2.5 mass (38.3 μg m−3) during winter, when Hong Kong received
significant influence of air pollutants transported from outside, and
~ 30% of PM2.5 mass (28.2 μg m−3) during
summertime, when local emission sources were dominant. A reduction of 3.8 μg m−3 in vehicular carbonaceous aerosols was estimated during
07:00–11:00 (i.e., rush hours on weekdays) on Sundays and public holidays.
This could mainly be attributed to less on-road public transportation (e.g.,
diesel-powered buses) in comparison with non-holidays. These multiple lines
of evidence confirm local vehicular emissions as an important source of
PM2.5 in an urban roadside environment and suggest the importance of
vehicular emission control in reducing exposure to PM2.5 in busy
roadside environments. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|