 |
| Titel |
Trends of non-methane hydrocarbons (NMHC) emissions in Beijing during 2002–2013 |
| VerfasserIn |
M. Wang, M. Shao, W. Chen, S. Lu, Y. Liu, B. Yuan, Q. Zhang, Q. Zhang, C.-C. Chang, B. Wang, L. Zeng, M. Hu, Y. Yang, Y. Li |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 3 ; Nr. 15, no. 3 (2015-02-11), S.1489-1502 |
| Datensatznummer |
250119404
|
| Publikation (Nr.) |
 copernicus.org/acp-15-1489-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Non-methane hydrocarbons (NMHCs) play a critical role in the photochemical
production of ozone (O3) and organic aerosols. Obtaining an accurate
understanding on temporal trends of NMHC emissions is essential for
predicting air quality changes and evaluating the effectiveness of current
control measures. In this study, we evaluated temporal trends of
anthropogenic NMHC emissions during August in Beijing based on ambient
measurements during selected summer periods at an urban site in Beijing from
2002 to 2013. In the contrast to the results from the most recent inventory
(Multi-resolution Emission Inventory for China, MEIC), which reported that
anthropogenic NMHC emissions during August increased by 28% from 2004 to
2012, whereas mixing ratios of NMHCs measured at this urban site decreased by
37% during the same time period. A positive matrix factorization (PMF)
model was applied to these NMHC measurements for source apportionment. The
results showed that the relative contributions of vehicular exhaust and
gasoline evaporation to measured NMHC concentrations decreased by 66%
during August from 2004 to 2012, comparable to the relative decline of
67% for transportation-related NMHC emissions reported by the MEIC
inventory. This finding indicates that the implementation of stricter
emissions standards for new vehicles and specific control measures for in-use
vehicles has been effective for reducing transportation-related NMHC
emissions. In addition, the PMF results suggested that there were no
significant temporal changes in NMHC concentrations from solvent use and
industry during August from 2004 to 2012, in contrast with the rapid rate of
increase (8.8% yr−1) reported by the MEIC inventory. To
re-evaluate the NMHC emissions trends for solvent use and industry, annual
variations in NMHC / NOx ratios were compared between ambient
measurements at the PKU site and the MEIC inventory. In contrast to the
significant rise in NMHC / NOx ratios from the MEIC inventory,
the measured NMHC / NOx ratios declined by 14% during
August from 2005 to 2012. The inferred NMHC / NOx ratios based
on PMF results exhibited a comparable decline of 11% to measured ratios.
These results indicate that the increase rate for NMHC emissions from solvent
use and industry in Beijing might be overestimated in the current inventory;
therefore, additional research is necessary to verify the NMHC emission
trends for this source. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|