CO over megacities based on MOPITT observations from space, Moscow case

In most towns and cities around the world, the levels of carbon monoxide in air are below levels that are hazardous for human health, but on larger urban areas, like some of capital cities or high industrial zone, there is potential to have harmful levels of carbon monoxide.

MOPITT can even detect smaller, isolated emitting areas like individual cities [Pommier 2013], [Dekker 2017].
     Using our 2018 version V7 (TIR, day observations), an average over full MOPITT mission of the total CO column can clear detect without any sophisticated technique, a stable local CO maximum over the Moscow cluster.

So, the bigest poluted city in the world seems to be indeed, a vergy large one: Moscow. Loking to the CO polution trend over the perod of our mission (see below, the total CO colum trend as well as thetrend of CO concentration at the 700 hPa level) we can observe a tendency similar to the global trend obseved by MOPITT as well as by other instruments (see here : Trends) 

References:

Pommier, M., C. A. McLinden, and M. Deeter, 2013: Relative changes in CO emissions over megacities based on observations from space. Geophysical Research Letters, 40, 3766-3771, doi:10.1002/grl.50704.

Iris N. Dekker, Sander Houweling, Ilse Aben, Thomas Röckmann, Maarten Krol1, Sara Martínez-Alonso, Merritt N. Deeter4, and Helen M. Worden. Quantification of CO emissions from the city of Madrid using MOPITT satellite retrievals and WRF simulations. Atmos. Chem. Phys., 17, 14675–14694, 2017
https://doi.org/10.5194/acp-17-14675-2017,