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@ARTICLE{Liu:276243,
      author       = {Liu, Ying and Yuan, B. and Li, Xin and Shao, M. and Lu, S.
                      and Li, Y. and Chang, C.-C. and Wang, Z. and Hu, W. and
                      Huang, X. and He, L. and Zeng, L. and Hu, M. and Zhu, T.},
      title        = {{I}mpact of pollution controls in {B}eijing on atmospheric
                      oxygenated volatile organic compounds ({OVOC}s) during the
                      2008 {O}lympic {G}ames: observation and modeling
                      implications},
      journal      = {Atmospheric chemistry and physics},
      volume       = {15},
      number       = {6},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2015-06706},
      pages        = {3045 - 3062},
      year         = {2015},
      abstract     = {Oxygenated volatile organic compounds (OVOCs) are important
                      products of the photo-oxidation of hydrocarbons. They
                      influence the oxidizing capacity and the ozone-forming
                      potential of the atmosphere. In the summer of 2008, 2 months
                      of emission restrictions were enforced in Beijing to improve
                      air quality during the Olympic Games. Observational evidence
                      reported in related studies that these control measures were
                      efficient in reducing the concentrations of primary
                      anthropogenic pollutants (CO, NOx and non-methane
                      hydrocarbons, i.e., NMHCs) by $30–40\%.$ In this study,
                      the influence of the emission restrictions on ambient levels
                      of OVOCs was explored using a neural network analysis with
                      consideration of meteorological conditions. Statistically
                      significant reductions in formaldehyde (HCHO), acetaldehyde
                      (CH3CHO), methyl ethyl ketone (MEK) and methanol were found
                      to be 12.9, 15.8, 17.1 and $19.6\%,$ respectively, when the
                      restrictions were in place. The effect of emission controls
                      on acetone was not detected in neural network simulations,
                      probably due to pollution transport from surrounding areas
                      outside Beijing. Although the ambient levels of most NMHCs
                      were reduced by $~35\%$ during the full control period, the
                      emission ratios of reactive alkenes and aromatics closely
                      related to automobile sources did not present much
                      difference (< $30\%).$ A zero-dimensional box model based on
                      the Master Chemical Mechanism version 3.2 (MCM3.2) was
                      applied to evaluate how OVOC production responds to the
                      reduced precursors during the emissions control period. On
                      average, secondary HCHO was produced from the oxidation of
                      anthropogenic alkenes $(54\%),$ isoprene $(30\%)$ and
                      aromatics $(15\%).$ The importance of biogenic sources for
                      the total HCHO formation was almost on par with that of
                      anthropogenic alkenes during the daytime. Anthropogenic
                      alkenes and alkanes dominated the photochemical production
                      of other OVOCs such as acetaldehyde, acetone and MEK. The
                      relative changes of modeled HCHO, CH3CHO, methyl vinyl
                      ketone and methacrolein (MVK + MACR) before and during the
                      pollution controlled period were comparable to the estimated
                      reductions in the neural network, reflecting that current
                      mechanisms can largely explain secondary production of those
                      species under urban conditions. However, it is worth noting
                      that the box model overestimated the measured concentrations
                      of aldehydes by a factor of 1.4–1.7 without consideration
                      of loss of aldehydes on aerosols, and simulated MEK was in
                      good agreement with the measurements when primary sources
                      were taken into consideration. These results suggest that
                      the understanding of the OVOCs budget in the box model
                      remains incomplete, and that there is still considerable
                      uncertainty in particular missing sinks (unknown chemical
                      and physical processes) for aldehydes and absence of direct
                      emissions for ketones.},
      cin          = {IEK-8},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-8-20101013},
      pnm          = {243 - Tropospheric trace substances and their
                      transformation processes (POF3-243)},
      pid          = {G:(DE-HGF)POF3-243},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000352157600004},
      doi          = {10.5194/acp-15-3045-2015},
      url          = {https://juser.fz-juelich.de/record/276243},
}