Open AccessModeling regional haze during the BRAVO study using CMAQ‐MADRID: 2. Source region attribution of particulate sulfate compounds
Author(s) -
Knipping Eladio M.,
Kumar Naresh,
Pun Betty K.,
Seigneur Christian,
Wu ShiangYuh,
Schichtel Bret A.
Publication year - 2006
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004jd005609
Subject(s) - cmaq , air quality index , haze , environmental science , particulates , meteorology , attribution , sulfate , climatology , source model , aerosol , atmospheric sciences , geography , geology , chemistry , computer science , psychology , social psychology , organic chemistry , theoretical computer science
Regional source attribution is conducted for fine particulate sulfate at Big Bend National Park, Texas, using a comprehensive regional air quality model, Community Multiscale Air Quality model augmented with the Model of Aerosol Dynamics, Reaction, Ionization and Dissolution (CMAQ‐MADRID), as part of the Big Bend Regional Aerosol Visibility and Observational (BRAVO) Study. The overall PM 2.5 sulfate load at Big Bend National Park over the 9 July to 28 October 1999 period is attributed as follows: 31% to Mexico, 19% to Texas, 39% to the eastern United States, 6% to the western United States, and 5% to areas outside the modeling domain (boundary conditions). The arithmetic mean of the daily PM 2.5 sulfate loads at BBNP over the 9 July to 28 October 1999 period is attributed as follows: 42% to Mexico, 14% to Texas, 27% to the eastern United States, 9% to the western United States, and 7% to areas outside the modeling domain. These results illustrate the potential for significant contributions from distant sources to regional haze in remote areas. An examination of source contributions and model performance by month and for specific episodes shows that model performance can affect the results of a source attribution. Therefore caution is advised when interpreting the results of source attribution obtained using Eulerian air quality models. In lieu of estimating the uncertainty of the apportionment procedures, source region attribution results obtained for sulfate using CMAQ‐MADRID are refined using an inverse modeling technique. Comparison of original attribution results with refined attribution estimates obtained using inverse modeling techniques shows that these methods can reduce in part the biases introduced in the model by uncertainties and errors in the emissions, meteorology, and chemical transport modeling. The refined attribution estimates of overall PM 2.5 sulfate load at Big Bend National Park over the 9 July to 28 October 1999 period using inverse modeling are 37% to Mexico, 17% to Texas, 31% to the eastern United States, 9% to the western United States, and 6% to areas outside the modeling domain.