AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Contribution of Uncertainties in Anthropogenic Emission Inventories to SOA Simulations for the Los Angeles Basin
RAVAN AHMADOV, Stuart McKeen, Roya Bahreini, Ann Middlebrook, Joost de Gouw, Carsten Warneke, Jose-Luis Jimenez, Patrick Hayes, Allen Robinson, Michael Trainer, NOAA ESRL
Abstract Number: 572 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract In recent years significant research has been focused on understanding of secondary organic aerosol (SOA) formation and evolution processes in the atmosphere. The appropriate representation of chemical and physical processes pertinent to SOA in the atmospheric models is an essential task. However, uncertainties of the anthropogenic emission inventories can have a large impact on the prediction of SOA concentrations from urban areas. Inaccuracies in the emission inventories arise due to several factors: mainly changing economic activity, impact of regulations on the vehicle emissions, contrast between week-end and week-day emissions.
An intensive field campaign CalNex took place during May-June 2010, focusing on Los Angeles basin. The available measurements for meteorological fields, gas-phase and particle species from the NOAA P3 aircraft and the Caltech supersite in Pasadena during CalNex provide us with valuable datasets to evaluate models and emission inventories.
The state-of-the-art SOA parameterization based on volatility basis set and updated SOA yields are implemented in the WRF-CHEM model. We perform full meteorology and chemistry simulations including SOA species for the Los Angeles area by using different emission inventories. The reference simulations are done using U.S. EPA National Emission Inventory version 2005 processed according to EPA recommendations. Initial comparison of the model results with the observations of gas and particle species reveal a significant overestimation of the emissions by the inventory, consequently affecting simulated SOA concentrations over the region. The emission inventory used for WRF-CHEM is corrected for CalNex period using various datasets, such as observations, the fuel sale, the trend information and updated inventory from EPA. We present the sensitivity of SOA simulations to the change in anthropogenic emissions. We also discuss the contribution of different emission categories (point, mobile-onroad, mobile-nonroad, and area) to primary and secondary organic aerosol budget over the Los Angeles region.