NOx emission estimates during 2014 Youth Olympic Games in Nanjing

J. Ding1,2, R. J. van der A1, B. Mijling1, P. F. Levelt1,2, and N. Hao3[1] Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands[2] Delft University of Technology, Delft, the Netherlands[3] German Aerospace Center (DLR), Oberpfaffenhofen, GermanyCorrespondence to: J. Ding (jieying.ding@knmi.nl)

NOx emission estimates during 2014 Youth Olympic Games in Nanjing*

* Ding,J., vanderA,R.J., Mijling,B., Levelt,P.F., and Hao,N.: NOxemission estimates during the 2014 Youth Olympic Games in Nanjing, Atmos. Chem. Phys., 15, 9399-9412, doi:10.5194/acp-15-9399-2015, 2015OutlineIntroduction MethodsImprovement of emission estimatesEmission analysisConclusions Introduction2008 Olympic Games in Beijing2010 Asian Games in Guangzhou2013 Asian Youth Games in Nanjing2014 Youth Olympic Games in Nanjing (Youth Olympic Games blue sky)2014 Asia-Pacific Economic Cooperation in Beijing (APEC blue sky)Events with emission reductions

NanjingCapital of Jiangsu provincePopulation: 8.2 million

Youth Olympic GamesDate: 16 to 24 August, 2014Regulations taken by local government

PeriodRegulations1st May - 30th June The local government started to shut down the coal-burning factories. 1st July - 15th JulyAll coal-burning factories have been shut down.16th July - 31st July The work on one third of construction sites was stopped. The parking fees in downtown increased sevenfold.1st August 15th AugustThe work on 2000 construction sites was stopped. Heavy-industry factories reduced manufacturing by 20 percent. Vehicles with high emissions were banned from the city. Open space barbecue restaurants were closed. 900 electric buses and 500 taxis have been put into operation.16th August-31st AugustThe work at all construction sites was put on hold.

MethodsDECSO (Daily Emission estimates Constrained by Satellite Observation)

More details in Mijling and van der A (2012, JGR)NO2 satellite observationsOMIOverpass time: 13:30 local timeSpatial resolution: 24 x 13 km2 in nadir till 150 x 28km2 at the end of swathFilter: Cloud radiance fraction larger than 70%Surface albedo larger than 20%Clouds below 800 hPa4 pixels at either side of the swath (after filtering the largest pixel size is 75x21 km2)Chemical transport modelCHIMERE Domain: East Asia (18 50o N, 102 1320 E )Horizontal resolution: 0.250 x 0.25 0Vertical resolution: 8 layers up to 500 hPaMeteorological data: ECMWFInitial emission inventory: MEIC (2010) for China, INTEX-B (2006) for outside China

Improvement of Emission estimatesNew version of CHIMERE modelOld one: CHIMERE V2006Landuse: The Global Land Cover Facility (1994)New one: CHIMERE V2013Biogenic emissions, new transport schemes, secondary organic aerosol chemistry, updated chemical reaction ratesNew landuse data: GlobCover Land cover (2009)

Model improvement

19952009Ground measurementsWebsite: aqicn.org based on China National Urban air quality real-time publish platform

Location: Nanjing Peoples government (center of Nanjing)

The only ground measurements we can find have a lot of limitations

Model comparison

Absolute Observation minus Forecast (OmF)

Quality control of satellite data

April to October, 201370% OmF in [-5, 10]

November, 2013 to March, 201450% OmF in [-5, 10]Unrealistic

Whole domain 201397% OmF in [-5, 10]Adding the histogram of whole domain15OmF criterion OmF in the interval of [-5, 10] 1e15 molecules/cm2For example:CHIMERE runs with DECSO emissions and MEIC emissions In 2013 summer in Nanjing

NOx emissions9.2 1e15 molecules/cm2/h

NOx column concentration: 4.8 1e15 molecules/cm2 OmF of 5 1e15 molecules/cm2 NOx emission change of 9.6 1e15 molecules/cm2/hRemove all emissions in Nanjing or add 2 large-sized coal-fired power plants in a single day 16Emission analysis

No significant improvement in surface NO2 concentration during the game periodA decrease of 32% in August. But this could be caused by the rainy weather.Emission reduction

A reduction of about 25% A reduction of about 10%

ConclusionsNew CHIMERE is better performing than old CHIMERE.OmF filtering is necessary to avoid wrong emission estimates.The OMI observations show a 32% decrease in NO2 column during the YOG.DECSO results show NOx emissions have a reduction of at least 25% during the YOG period and afterwards.The observed NO2 columns and the derived emissions show different patterns that provide complimentary information.DECSO has the capacity to capture the change of NOx emissions on a monthly scale.Any questions?Thank you.