It could also be due to some illegal activity, such as a facility with emitting harmful substances outside standards. This is the time with the less likelihood for them to be noticed as most people sleep. Does the air smell funny as well?
the time series is a bit short, but combining the data from PM sensors with those of temperature and humidity, there could be a correlation between high humidity, temperature going below zero and PM sensors working outside operating conditions.
The data is similar on sensors around some km away, so it must be a more spreaded source.
The metro is near, as is the airport. But both are not operating much in the night, at least not more than during daytime.
Could the reason be a storm/heavy wind?
And is there data available in grafana older than 24h ?
Yes, true. It seems too early to draw conclusions. I have no idea what’s to be considered normal, healthy, or critical. At least our stove is not contributing in a significiant way - there’s next to no correlation between when we heated it and measured PM values. That makes me happy.
What is running there? port/api/service?
That is all I’ve been looking for! 24h/td/4w/1y - perfect. Thank you for pointing that out.