I have an air purifier with built in particulate sensor. It doesn't provide numbers, but has a multi-color LED indicator to report PM2.5 level as good/mediocre/bad/terrible. Running a vacuum cleaner that supposedly has a good filter consistently increases the reported PM2.5 level from the first band to the second. The air purifier (or faster/cheaper depending on the weather, just open some windows) can bring it back down again.