Storm Gareth has been making its presence felt this week with very high winds and some rain in Eastbourne. As you can see from the weather summary graph below, for the last seven days wind direction has been consistent and reported gust speed has been hitting 35mph. I commented previously that I think the anemometer on my weather station is underreporting wind speed. Certainly the forecast wind speeds were much higher. So I would use the wind speed data only as a relative indicator (ie. we can safely say it was windier on Friday than it was on Tuesday, but not by how much, or what the accurate absolute values were). Weather data for Eastbourne for seven days to 16 March 2019

PM2.5 for the last week shows ups and downs. The maximums are far lower than the recent end-of-February highs, and they only reach the middle of the DAQI "Low" band, which is good news. Intriguingly the levels vary on what looks like a 24h cycle during the middle of the week. I haven't got time right now to do a graph mashup to work out how PM2.5 has varied with weather variables. I would assume the wind is the strongest influence on PM2.5 this week, but I wonder how that correlates with a 24h cycle.

PM2.5 in Sovereign Harbour Eastbourne for seven days to 16 March 2019

The wind has been so strong that I would expect its turbulence to disperse and dilute pollutants from usual sources like Paris. Perhaps it has done so, but not completely, so the wind, coming from the south as it has, has in fact brought pollution from Paris, hence the 24h cycle, but the strength of the wind has diluted the pollution to the levels observed? But then I would have expected the variation in wind speed to have disguised the 24h cycle (because the amount of time taken to bring the pollution from Paris depends on wind speed).

Need to check out MetClim again...