New Year's Eve 2022 particulate matter sensing

Measuring particulate matter(PM) has now become an annual tradition of mine.

This year I started earlier, but only slightly: on December the 30th(sigh...). I wanted to add CO2, humidity and temperature to the readings. These are all present on a SCD30. I connected up the sensor and did the programming, but I found out that you can't read both around the same time, idk, something with the i2c. Not sure how it works. So the next day I programmed that you roughly read ~25 seconds the first one, and then the other one, without booting them down. Cursed, but I was running out of time.

The sensors were located in a rural village in the south east of the Netherlands, same as the other years. It was exceptionally warm that day, never before a temperature this high on December 31th was measured.weerplaza - see this image for further context It was exceedingly comfortable weather — even at night you could almost take off your coat — but also concerning at the same time. Where prior 1950 having a winter week with an average temperature of 10°C was virtually zero, now it's roughly 50%.knmi There was also a fresh wind(~3-4 bft) coming from the sea, with little PM(screenshot of for context). When I connected the sensor, I couldn't believe the readings, so nice was the air. Checking and confirmed the readings.

With the fresh wind with little PM, and few bangs in the morning, and a ban on fireworks,rijksoverheid I started to doubt if I'd get high readings in at eve. This was proven wrong though. I was with friends somewhere else, but I asked someone in my household to make a recording, and it seem that there were more fireworks set off than last year, when there was also a ban on fireworks. The place where I was, if I didn't know you could've seriously convinced me there was no fireworks ban, let alone a lockdown: I saw people gathering outside. I was with 3 friends outside as well which was not allowed, though you were allowed on the 31st and 1st to have 4 people over. There were a lot of fireworks, though I wasn't there in 2019, so it's probably less than pre-covid but still very much if you think it is forbidden. My observations are consistent with data on firework related injuries, were there were this nye more injuries than in 2020, but less than in 2019.veiligheid Despite the comfortable breeze, I noticed I breathed in a lot of fumes.

The CO2 readings proved to be of little use; I highly doubt the readings, they seem to be physically impossible. I think it works though for indicative measurements, as indoors you can clearly observe the difference. Perhaps the sensor got confused after gathering dust so long. Comparing with the thermostat(for the heating of the house), the temperature readings seemed roughly 2°C too high, so I subtracted 2°C from every reading. Also take that with a grain of salt. Also keep in mind that the PM sensor isn't perfect as well, and values should be considered indicative. You can see all of the data here.

As you can see from the PM data, there was once again a big peak shortly after 00:00, but it seemed to recover much more quickly than previous year, where the opposite seemed to happen. Also the air was a lot worse last year, even during its most low, though should be noted that I don't have data from the afternoon. This difference is likely because previous year there was barely any wind, and this year there was a fresh wind blowing everything away and supplying "fresh" air.

Another change this year was the WHO guideline max values. These have been reduced, PM2.5 in particular; its annual max exposure was halved. Why? to quote the WHO: "Since WHO’s last 2005 global update, there has been a marked increase of evidence that shows how air pollution affects different aspects of health. For that reason, and after a systematic review of the accumulated evidence, WHO has adjusted almost all the AQGs levels downwards, warning that exceeding the new air quality guideline levels is associated with significant risks to health. At the same time, however, adhering to them could save millions of lives."WHO

WHO guideline max values
Annual mean15 μg/m35 μg/m3
24-hour mean45 μg/m315 μg/m3


it seems this was a year change with less air pollution. It is possible that the PM2.5 24 hour mean is below the 15 μg/m3 as recommended by the WHO, and likely the PM1 was below 15 μg/m3, which is much better than last year, where the mean was ~42.5 μg/m3 and even the minimum exceeded 22 μg/m3(though these values are from different times). Although what must be said is that around new year's eve the air quality was still poor.

link to previous year(2021) - the rest of the 2022 data - reference values/control group whatever