Can we get a scale bar? or legend? and what is being plotted here? and where does the data come from? what's the difference between the contours and the dots?
Clicking the big dots just takes me to a completely different page that doesn't have that much more information. I'd expect a popup on the map that tells me what the color/size of the dot means.
Also the lack of differentiation between PM10 and PM2.5 numbers is very unhelpful. What's actually being measured? Just saying PM isn't useful. Plus, the scale only goes to 150 -- LOL, I'm in China, a scale that only goes 150 is useless. Finally, for the activities, what's the difference between "take care" and "take it easy"?
The unit/metric descibed by each graph seems to be:
The Plume Air Quality Index™
I'm not sure how the index value is determined, but it seems to factor in measured values for Nitrogen Dioxide, Ozone, Carbon Monoxide, and particulate matter (exhaust soot and toxic dust being worse than dust comprised of ambient organic material such as pollen).
The dots appear to be city-specific reports. Darker/brown appears to mean more pollution whereas lighter/blue appears to mean less. The size of the dot may mean population size.
Too bad the color of the dot doesn't always relate to the pollution level it represents. Take for example the one for Mexico City, if you click on it, you will get a different pollution level than what's indicated on the initial map.
Clicking the big dots just takes me to a completely different page that doesn't have that much more information. I'd expect a popup on the map that tells me what the color/size of the dot means.