Air pollution in the middle of an ocean? Really?
How can there by high concentrations of PM2.5 air pollutants in the middle of an ocean? And usually around a city the air over the ocean seems to have much worse air pollution that right over the city. What am I missing here? It doesn't seem to make any sense.
Sea salt is part of the particulate matter over ocean in addition to plumes of anthropogenic pollutants. PM2.5 is measured by Copernicus (CAMS) whose data is used by Windy for PM 2.5 map.
What is more difficult to understand for me is the large differences between the 40km resolution global map and the 10km resolution European map. It seems the global data is overestimated or shows a bias. Same as for NO2:
I’ve never got an answer about it.
A hypothesis to explain these differences could be:
the global data would be the total particulate matter in a vertical column of the atmosphere while the data over Europe would be the amount near surface.
In the information about the data (shown by the small circled i in bottom right corner of screen) it is said that both are near surface values. This needs to be checked.