TY - JOUR
T1 - Modeling the ozone weekend effect in very complex terrains
T2 - A case study in the Northeastern Iberian Peninsula
AU - Jiménez, Pedro
AU - Parra, René
AU - Gassó, Santiago
AU - Baldasano, José M.
N1 - Funding Information:
This work was developed under the research contract REN2003-09753-C02 of the Spanish Ministry of Science and Technology. The Spanish Ministry of Education and Science is also thanked for the FPU doctoral fellowship hold by P. Jiménez. The authors gratefully acknowledge O. Jorba for providing meteorological inputs and E. López for the implementation of EMICAT2000 into a GIS system. Air quality stations data and information for implementing industrial emissions were provided by the Environmental Department of the Catalonia Government (Spain).
PY - 2005/1
Y1 - 2005/1
N2 - Ambient ozone (O 3) concentrations tend to be higher on weekends than on weekdays in urban areas, a phenomenon known as the weekend effect. Nevertheless, its downwind influence could be diverse. The MM5-CMAQ model has been used to assess the causes of weekday/weekend O 3 differences in the north-eastern Iberian Peninsula during an episode of photochemical pollution covering the whole Western Mediterranean Basin (13-16 August 2000). Emissions were estimated with EMICAT2000 model. The key differences between weekday and weekend on-road vehicle emissions are in magnitude and timing. On-road traffic accounts for ∼57% of the anthropogenic NO x and VOC emissions in the modeling domain, and are principally located along the coast and mainly in the Barcelona Geographical Area. The drop of heavy-duty tracks traffic on weekends involves a 22% reduction of NO x emissions and just a slight change in VOC emissions. Changes in the timing of emissions are directly related to differences in weekday/weekend traffic profiles, being emissions shifted 1-2 h later on weekends. The response of both ambient and simulated O 3 concentrations to day-of-week differences in emissions varies by location. The combination of VOC-sensitive regimes and NO x-titration in urban areas as Barcelona, in addition to the different magnitude and timing of emissions (decreasing NO x/VOC ratios on weekend mornings) causes the raise of O 3 on weekends (+54%). In non-urban regimes, principally associated to NO x-sensitive chemistry, a lower concentration of O 3 is observed in non-labor days (decreases of -10% in downwind areas). Rural locations, dominated by medium-long range transport, depict similar O 3 concentrations. Both discrete and categorical model evaluations are shown in order to test the accuracy of the model for representing weekdays/weekends differences within the air basin. This work helps identifying the major causes of the weekend effect in the considered domain, as the changing in mass and time of precursors emissions, and may be a useful tool to reduce ambient O 3 levels.
AB - Ambient ozone (O 3) concentrations tend to be higher on weekends than on weekdays in urban areas, a phenomenon known as the weekend effect. Nevertheless, its downwind influence could be diverse. The MM5-CMAQ model has been used to assess the causes of weekday/weekend O 3 differences in the north-eastern Iberian Peninsula during an episode of photochemical pollution covering the whole Western Mediterranean Basin (13-16 August 2000). Emissions were estimated with EMICAT2000 model. The key differences between weekday and weekend on-road vehicle emissions are in magnitude and timing. On-road traffic accounts for ∼57% of the anthropogenic NO x and VOC emissions in the modeling domain, and are principally located along the coast and mainly in the Barcelona Geographical Area. The drop of heavy-duty tracks traffic on weekends involves a 22% reduction of NO x emissions and just a slight change in VOC emissions. Changes in the timing of emissions are directly related to differences in weekday/weekend traffic profiles, being emissions shifted 1-2 h later on weekends. The response of both ambient and simulated O 3 concentrations to day-of-week differences in emissions varies by location. The combination of VOC-sensitive regimes and NO x-titration in urban areas as Barcelona, in addition to the different magnitude and timing of emissions (decreasing NO x/VOC ratios on weekend mornings) causes the raise of O 3 on weekends (+54%). In non-urban regimes, principally associated to NO x-sensitive chemistry, a lower concentration of O 3 is observed in non-labor days (decreases of -10% in downwind areas). Rural locations, dominated by medium-long range transport, depict similar O 3 concentrations. Both discrete and categorical model evaluations are shown in order to test the accuracy of the model for representing weekdays/weekends differences within the air basin. This work helps identifying the major causes of the weekend effect in the considered domain, as the changing in mass and time of precursors emissions, and may be a useful tool to reduce ambient O 3 levels.
KW - Air quality modeling
KW - Ozone
KW - Photochemistry
KW - Very complex areas
KW - Weekend effect
UR - http://www.scopus.com/inward/record.url?scp=11044232282&partnerID=8YFLogxK
U2 - 10.1016/j.atmosenv.2004.09.065
DO - 10.1016/j.atmosenv.2004.09.065
M3 - Artículo
AN - SCOPUS:11044232282
SN - 1352-2310
VL - 39
SP - 429
EP - 444
JO - Atmospheric Environment
JF - Atmospheric Environment
IS - 3
ER -
