Eastbourne has enjoyed some pleasantly PM2.5-free air over the last week. Levels have been low, only rising above 15ug/m³ once before Saturday. Since Saturday levels have climbed again. For the last 5 or so hours levels have been above 35ug/m³ and spending most of the time in the 40-45ug/m³ range.
It's difficult to know what the cause is. It's not exactly been warm for the last week, but over the last 24 hours temperatures have dropped again spending some time below zero (down to a minimum of -1°C, observed at the time of writing). Pressure is rising slowly (1012-1025hPa in the last 24 hours), wind speed has dropped but not much (average wind speed today 1mph compared to yesterday's 3mph).
So not much really to explain the steep rise ... unless of course it is that things are ramping up for the blood-red supermoon* due early this morning (Monday)! For myself, I fully expect to observe the special occasion by sleeping through it.
* You may have detected that the header image on this post is a fake!