Abstract

Precursor emissions and the sensitivities of ozone to these emissions are the two fundamental problems for understanding ozone pollution problems. Modeling analysis of in situ observations from the CAREBEIJING-2007 experiments indicates the deficiencies in current 3-D model representation of chemical processes. Observed high concentrations of aromatics and daytime HONO are quite different from standard 3-D simulation results. Observation constrained 1-D modeling suggests that near-surface ozone production is neither NOx nor VOC limited, but in a transition regime, where reduction of either NOx or VOCs could result in reduction of ozone production. The transition regime implies more flexibility in the ozone control strategies than a binary system of either NOx or VOC limited regime. 

We make use of satellite observations and 3-D model simulations to estimate the emissions of aromatics and NOx. Top-down aromatics emissions are estimated by using the measurements of SCanning Imaging Absorption SpectroMeter for Atmospheric CartograpHY (SCIAMACHY). The estimate is a factor of ~5 higher than the a priori bottom-up inventory, which implies much greater increases in regional ozone production and global secondary organic aerosol (SOA) formation. The emission trends of NOx are estimated through inverse modeling of Ozone Monitoring Instrument (OMI) observations. We found lower average NOx emission growth rates in more recent years than during 1996-2005. The geographical and seasonal differences are very large. The reasons and implications will be discussed.

Speaker: Yuhang Wang (Georgia Institute of Technology, USA)

Time：13rd, June, 10:00 am

Location：Room 301, Old Geology Building