In field testing, these samplers have been demonstrated to vary (CV) only 11.6% from [Federal Reference Methods](/wiki/pm-monitoring-regulations), when measuring course particulates (PM10-2.5), making this the most precise published passive particle monitor design (Ott, Cyrs, & Peters, 2008).  Public Lab is evaluating the deployment of this technology. 

####SEM Stub Monitor Documentation: 

* [Assembly](/wiki/passive-pm-assembly)
* [Deployment](/wiki/passive-pm-deployment)
* [Imaging](/wiki/passive-pm-imaging)
* [Analysis](/wiki/passive-pm-analysis)

###Background

Developed originally for indoor dust monitoring at the University of North Carolina by Jeff Wagner and David Leith, this tiny monitor (in the middle of the housing, below) consists of a fine mesh cap over top of a Scanning Electron Microscopy (SEM) pin stub, a small aluminum object that looks like a pin.  Thomas Peters and Darrin Ott at the University of Iowa added a wind-and-rain housing so the monitors can be used outside.  They also added a glass microscope slide cover on top of the stub, allowing lower-cost analysis with a standard visible-light microscope. 

[![Amber Wise removing a stub cover](//i.publiclab.org/system/images/photos/000/012/171/original/IMG_20151020_175427.jpg)](//i.publiclab.org/system/images/photos/000/012/171/original/IMG_20151020_175427.jpg)

[![IMG_20151015_120027-trim.png](//i.publiclab.org/system/images/photos/000/013/521/medium/IMG_20151015_120027-trim.png)](//i.publiclab.org/system/images/photos/000/013/521/original/IMG_20151015_120027-trim.png)

Citation: 
Darrin K. Ott, William Cyrs, Thomas M. Peters, Passive measurement of coarse particulate matter, PM10-2.5, Aerosol Science 39:156 – 167, 2008

###Capabilities