Performed quarterly maintenance on all accessible deployed dust monitors. 

CS HAM6 and the Biergarten dust monitors passed the Zero Count and Flow tests. No problems noted. 

Optics Lab - Both dust monitors passed the Zero Count and Flow tests. No problems noted. 

Diode Room - The dust monitor passed the Zero Count test. The flow is a bit on the low side but still within spec. Will continue to watch for change. 

PSL - These check were made before the holidays. All was normal. 

Did not check the End Station dust monitors due to tumbleweeds blocking the access roads.