Historical Cases

EMEP model results for 2010

The EMEP/MSC-W model has been run on 0.5×0.5 degree resolution for 2010 and the global domain, using HTAPv2 emission data. The figures below show examples zoomed in on an Asian sub domain for PM2.5 in different seasons. Click on images to enlarge.

EMEP_PM25_S0_MAMEMEP_PM25_S0_JJA

EMEP_PM25_S0_SONEMEP_PM25_S0_DJF

 


WRF-Chem model results for 2010

The WRF-Chem model (version V3.6 / MOZART chemical scheme) has been run for an Asian domain on 60km x 60km resolution with MACCity emissions for January and July, and a smaller domain (sub-regional) on 20km x 20km resolution with HTAPv2 emissions (also January and July). The plots below show examples of modeled PM2.5 for January and surface ozone for July 2010. Click images to enlarge.

WRF_PM2_5_DRY_surface_60km_maccity_JanWRF_PM2_5_DRY_surface_20km_htap_Jan

WRF_o3_surface_60km_maccity_JulWRF_o3_surface_20km_htap_Jul

 


EMEP Source-Receptor calculations

The EMEP MSC-W model is run for an Asian domain extending from 5°N to 55°N in the latitude direction and from 62°E to 134°E in the longitude direction, i.e. including China, India, Japan and other major emitting countries in Asia. Lateral boundary conditions are taken from ECMWF C-IFS. In the Base run, all emissions are included in full, while in the perturbation runs anthropogenic emissions are reduced by 15% either within the city or outside the city in consideration. By differencing the perturbation runs with the Base run, the bar charts in the Figures below are created. The charts visualize the effect of emission changes  on concentrations of various chemical species. Comparison between Figures 1 and 2 gives hints on the efficiency of local measures and on whether measures outside the region are necessary to meet air quality standards.

SR_fig1

SR_fig2

A 15% reduction in anthropogenic emissions within different cities on air pollutant concentrations within these cites (upper figure) give large reductions in NO, while ozone increases (an effect known as titration). In some cases NO can decrease by even more than 15%, due to shifts in the NO/NO2 ratio related to changes in the chemical regime. A 15% reduction in anthropogenic emissions outside the cities leads, in January, to large impacts on particulate matter in Delhi, as well as to an increase in ozone in Beijing and Shanghai. In July Beijing is largely impacted by external emissions. Increases in NO are related to shifts in the NO/NO2 ratio.

Source-receptor calculations scientifically underpin international emission reduction agreements and help policy makers in assessing the efficiency of local versus national/international emission reduction measures. As the effects of emission reductions in different regions depend on factors that vary in space and time, calculations have to be made repeatedly for different regions and with current meteorology, in order to make accurate assessments for any given situation.