@benclarkee Thanks for the clarification! I appreciate the quick response. I must’ve just noticed the difference more prominently today it looked a lot darker than usual, so I wondered if something had changed recently. I’ll check out the 2021 post you mentioned for reference. Thanks again for pointing me in the right direction!

@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: [image: 1634649481485-714545e3-b683-45e7-8d9a-ad32c6d0303d.jpeg] 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.

@korina Probably a typo km/m2 >>kg/m2

We can see the anomaly in SO2 actual from the NASA data itself: https://so2.gsfc.nasa.gov/pix/special/time_sres/time_series.html This clearly shows some crazy spikes right then and there for Eastern Asia. Look at the scale, ffs, its off the charts: [image: china_so2pca_pbl_ts_plot.png] And there's also a weird data hole around Feb 2 (0 everywhere). Doesn't mean we know what it was from, but it cannot be denied that there are/were crazy spikes in SO2 over that region recently.

@Naiyana4 Yes there no unhealthy level of SO2 in Hawaï right now: https://www.hawaiiso2network.com/ Which means that the SO2 concentration is below 0.10 ppm (part per million) [image: 1565336909241-284edb1c-fcbe-4b39-8214-8c3a3ae5d92b.jpeg] 0.1 ppm is close to 300μg/m3 [image: 1565337296705-e14253b8-1bb1-4f03-9e0b-97c3fdf8902e.jpeg] At 9:00 UTC Windy showed less than 100μg/m3, so this level was unhealthy. [image: 1565337461539-e86bc3b8-fe74-431f-80aa-18e47d76e6ec.jpeg] But at 12:00UTC, the figure raised to 400μg/m3 (With modified colors) [image: 1565373902499-4cfc0a87-3cb1-47e3-9ff8-3d31df6541d8.jpeg] Quite strange