1. Goals of the work: (1)A review publication on the major developments in historical global and regional anthropogenic emissions during the past decades, and evaluation of these inventories (to be submitted in early 2016 in Atmospheric Environment). (2)Evaluate historical emissions in the Los Angeles Basin using ratios of the concentrations of several compounds measured since the 1960s. Anthropogenic Emissions from 1970 to 2010 1

2. Methodology:  gather inventories developed during the past decades, at the global and regional scales, and make a systematic evaluation  use surface observations from different networks in California, and compare ratios between different species Data and People Involved Involve many groups, many from the GEIA community: -C. Granier, K. Sindelarova, T. Doumbia, L. Granier, LATMOS, Paris, France -C. Liousse, S. Darras, Lab. Aerologie, OMP, Toulouse, France -H. Denier van der Gon, TNO, Utrecht, The Netherlands -B. Hassler, G. Frost, T. Ryerson, M. Trainer, K. Rosenlof, NOAA, Boulder, USA -B. Barletta, Univ Calif. Irvine, USA -I. Bouarar, MPI-Meteorology, Hamburg, Germany -G. Maenhout-Janssens, JRC, Ispra, Italy -E. von Schneidemesser, IASS, Potsdam, Germany -J. Kaiser, MPI-Chemistry, Mainz, Germany Want to participate : see last slide 2

3.  Use the most recent developments in global and regional inventories of anthropogenic emissions + older inventories Only public emissions inventories considered in this work Most recent datasets: -EDGAR v4.2 (1970-2008) and EDGAR v4.3 (1970 and 2010) (from JRC, Italy) -HTAPv2 (2008 and 2010) (from JRC, Italy) -ECLIPSE v4 (2005-2010) and v5 (1990-2010) (from IIASA, Austria) -REAS-v2 for Asia (1980-2020) (from NIES, Japan) -MEIC v1.0 and 1.2 for China (2008-2012) (from Tsinghua Univ., Beijing) -TNO-MACC (2003-2007), TNO-MACCII (2003-2009) and TNO-MACCIII (2003-2011) for Europe (from TNO, Utrecht) + data published in different papers, focusing mostly on the global scale, India and China Evaluation of Global/Regional Emissions 3

4. Many datasets have been developed in the past decade, which provide anthropogenic emissions for different periods: more data now available for Europe, North America and China, but regional accurate data are lacking for the other regions. Large differences remain between the inventories, which are difficult to analyze. Systematic differences are highlighted in several regions for some species, which should help define better future studies on a specific species or region. The contribution of several regions to global anthropogenic emissions has changed significantly since the 1970s. The emissions in several regions are now important when looking at global budgets. More information from local groups on the emissions in these regions would be very beneficial, for example in the Middle East, Africa, South-East Asia and South America. Growth rates of the NOx/CO ratios obtained from observations in California much faster than for the NOx/CO MACCity emissions ratios, especially in the 1970s-1980s. Conclusions 4

5. The 23 regions considered in the study Why MACCity as a reference? -It is the only inventory providing emissions from 1960 to 2015 -It is used by several international projects, for example CCMI (IGAC), MACC and CAMS (forecasting of atmospheric chemistry), EU PEGASOS And CityZen projects, etc. Results : Comparison of the Different Inventories, using the MACCity Dataset as a Reference 5

6. 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 NOx in Western Europe SO 2 in the USA 1.3 1.2 1.1 1.0 0.9 0.8 0.7 What is shown: for each year, ratio of the emissions in a region to the MACCity emissions in the same region Ratio to MACCity between 0.7 and 1.3, and no inventory systematically much higher/lower than the others. Years: 70, 80, 90, 95 and each year from 2000 to 2013 Name of the inventories Ratios of different inventories to MACCity 6

7. 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 Three Examples of Low Agreement between Datasets NMVOCs in China Name of the inventories Years: 70, 80, 90, 95 and each year from 2000 to 2013 Difference between larger and smaller total emissions for a region can reach a factor > 2-3 2.2 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 7 OC in Western Africa NH 3 in India Name of the inventories

8. -In 1970, contribution of US, Europe and China different -In 2008, large differences in the contribution of the Middle East and N. America Emissions in many regions have significantly increased, and should be studied further, i.e. Africa, Middle East, SE Asia Contribution of the different world regions in 1970 and 2008 to the global NMVOCs emissions. 1970 2008 MACCity EDGAR 4.2ECLIPSE v5 8

9. Measurements Concentrations enhancement ratios, a quantity comparable to emissions ratios Use of hourly data: between 5am-9am, weekdays, May- September. Compare with MACCity emissions Calculate NOx/CO ratios from MACCity emission fluxes for 6 grid points close to measurement stations Annual means from MACCity are calculated from monthly means from May-September (only enhancement ratios with r 2 >0.7 are used for the comparison) Evaluation of Historical Trends in Emissions using Observations in the Los Angeles area: NOx/CO 9

10. Grey symbols/grey dashed line = data from Pollack et al. (JGR, 2013) Blue symbols = ratios using observations from the California Air Resources Board (CARB) Thick blue line = trend calculated from all CARB data and Pollack et al. Red line = MACCity average NOx/CO ratio from the six selected grid cells Thin purple lines = NOx/CO ratio for each of the six grid cells individually.  NOx/CO ratio from observations increases much faster than in MACCity 1 0.1 0.01 0.001 Results of the Comparison of NOx/CO Ratios 10

11. Reference: Granier, C. and 26 co-authors, Evolution of anthropogenic and biomass burning emissions of air pollutants at global and regional scales during the 1980–2010 period, Atmos. Env., 2011 If you are interested in participating in the new evaluation paper, contact T. Doumbia during the conference or Claire Granier by email: claire.granier@latmos.ipsl.fr Study on trends in emissions in the LA basin: Hassler et al., in preparation for Geophys. Res. Lett. References and Additional Information 11