Workshops and garages are concerned with fine dust from cutting or milling metal and wood.
2020 paper reviewed 50 PM sensors and discussed calibration, https://www.mdpi.com/1424-8220/20/23/6819/htm
> We present an extensive review of the LCPMS currently available on the market, their electronic characteristics, and their applications in published literature and from specific tests. Most of the reviewed LCPMS can accurately monitor PM changes in the environment and exhibit good performances with accuracy that, in some conditions, can reach R2 values up to 0.99. However, such results strongly depend on whether the device is calibrated or not (using a reference method) in the operative environment; if not, R2 values lower than 0.5 are observed.
2021 Lawrence Berkeley paper, https://escholarship.org/content/qt2fm3s5zv/qt2fm3s5zv.pdf
> End-users should be made aware that the PM data from the current low-cost sensors needs to be understood as an indication of a state change or a rough estimation rather than actual concentration in indoor environments.