You are right, this is the actual question. The mechanism for localizing the emissions is a chemical transport/interaction model, and data from remote sensing

You are right, this is the actual question. The mechanism for localizing the emissions is a chemical transport/interaction model, and data from remote sensing and in situ sampling to constrain the model. The model allows you to interpolate temporally/spatially between the observations you have. The linked study (abstract is at http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014GL060754/ http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014GL06...) apparently uses this approach. You can't tell from the press release what they have done, and the full-text is not online (which is a shame). (I'm not at work or I could look it up.) But you can find other work that uses the same approach (e.g.: http://www.atmos-chem-phys.net/10/10421/2010/acp-10-10421-2010.pdf http://www.atmos-chem-phys.net/10/10421/2010/acp-10-10421-20...). They divided the Earth land surface into gross regions and computed mean source and sink values (the ocean is a sink). Their conclusion: "[...] Although industry data imply that the global industrial emissions were substantially declining with large interannual variations, the optimized results show only small interannual variations and a small decreasing trend. The global surface CCl4 mole fractions were declining in this period because the CCl4 oceanic and stratospheric sinks exceeded the industrial emissions. Compared to the a priori values, the inversion results indicate substantial increases in industrial emissions originating from the South Asian/Indian and Southeast Asian regions, and significant decreases in emissions from the European and North American regions." In short: industry claims that emissions are dropping are contradicted by data showing the gross decrease is explained by higher-than-expected absorption; also, we identify substantial increased emissions from South/Southeast Asia. As atmospheric chemistry models improve, and remote sensing constraints increase, we'll know a lot more about the origins of pollution. E.g., for CO2, the just launched OCO2 (http://oco.jpl.nasa.gov http://oco.jpl.nasa.gov) which is finishing checkout -- it returned its first data last Wednesday.