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| Titel |
Advantages of a city-scale emission inventory for urban air quality research and policy: the case of Nanjing, a typical industrial city in the Yangtze River Delta, China |
| VerfasserIn |
Y. Zhao, L. P. Qiu, R. Y. Xu, F. J. Xie, Q. Zhang, Y. Y. Yu, C. P. Nielsen, H. X. Qin, H. K. Wang, X. C. Wu, W. Q. Li, J. Zhang |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 21 ; Nr. 15, no. 21 (2015-11-12), S.12623-12644 |
| Datensatznummer |
250120160
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| Publikation (Nr.) |
 copernicus.org/acp-15-12623-2015.pdf |
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| Zusammenfassung |
| With most eastern Chinese cities facing major air quality challenges, there
is a strong need for city-scale emission inventories for use in both chemical
transport modeling and the development of pollution control policies. In this
paper, a high-resolution emission inventory (with a horizontal resolution of
3 × 3 km) of air pollutants and CO2 for Nanjing, a typical
large city in the Yangtze River Delta, is developed, incorporating the best
available information on local sources. Emission factors and activity data at
the unit or facility level are collected and compiled using a thorough on-site
survey of major sources. Over 900 individual plants, which account for
97 % of the city's total coal consumption, are identified as point
sources, and all of the emission-related parameters including combustion
technology, fuel quality, and removal efficiency of air pollution control
devices (APCD) are analyzed. New data-collection approaches including
continuous emission monitoring systems and real-time monitoring of traffic
flows are employed to improve spatiotemporal distribution of emissions.
Despite fast growth of energy consumption between 2010 and 2012, relatively
small interannual changes in emissions are found for most air pollutants
during this period, attributed mainly to benefits of growing APCD deployment
and the comparatively strong and improving regulatory oversight of the large
point sources that dominate the levels and spatial distributions of Nanjing
emissions overall. The improvement of this city-level emission inventory is
indicated by comparisons with observations and other inventories at larger
spatial scale. Relatively good spatial correlations are found for SO2,
NOx, and CO between the city-scale emission estimates and concentrations
at nine state-operated monitoring sites (R = 0.58, 0.46, and 0.61,
respectively). The emission ratios of specific pollutants including BC to CO,
OC to EC, and CO2 to CO compare well to top-down constraints from ground
observations. The interannual variability and spatial distribution of
NOx emissions are consistent with NO2 vertical column density
measured by the Ozone Monitoring Instrument (OMI). In particular, the Nanjing
city-scale emission inventory correlates better with satellite observations
than the downscaled Multi-resolution Emission Inventory for China (MEIC) does
when emissions from power plants are excluded. This indicates improvement in
emission estimation for sectors other than power generation, notably industry
and transportation. A high-resolution emission inventory may also provide a
basis to consider the quality of instrumental observations. To further
improve emission estimation and evaluation, more measurements of both
emission factors and ambient levels of given pollutants are suggested; the
uncertainties of emission inventories at city scale should also be fully
quantified and compared with those at national scale. |
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