SO2 units

wag51

Hi,
In map, SO2 is expressed in mg/m², but don't you think it's in microgram/m²? In Europe we should have more than 100 "mg/m²" this weekend according to Windy. But alert rate is only at 0.300 mg/m²!
Are you sure the units are correct?!
SO2

RobertBuk

Hi Windy team,
please have a look of todays SO2 concentration over europe. The limit value (treshold) is 350 microgramm / m³.
1 Milligramm (mg) = 1 tausendstel Gramm = 10^(−3) g. 1 Mikrogramm (μg) = 1 millionstel Gramm = 10^(−6) g.
Please check the unit of SO2 and correct the legend accordingly.
Thanks

idefix37

@robertbuk
You are talking about SO2 amount per cubic meter. This is how this gas content is expressed at ground level.
What Windy shows is totally different. It is the amount of SO2 in a column from ground to the top of atmosphere expressed per square meter.
Click the small circled i in bottom right of your screen to get information about this layer.
https://community.windy.com/topic/13315/probably-wrong-units-of-so2-concentration?_=1618411932003

This SO2 layer shows the plume of the volcano in altitude, not the SO2 content at ground level which is given by the Air quality stations in Windy. For example:

At this Air quality station with a 89 quality index, the SO2 content is 11μg/m3 at station level while in the total height of the atmosphere the value is 209.35mg/m2.