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Passive Particle Monitoring

###Introduction A passive particle monitor measures particles without the use of mechanical or electrical systems, depending instead on natural wind-blown deposition of particles on a collection surface. Passive particle monitoring is frequently used for qualitative "nuisance dust" measurements, and more recently to extrapolate [airborne PM concentrations]( and the direction dust comes from. Passive monitoring promises to be less expensive and more robust than active monitors' mechanical and electrical components, but comes with a different set of challenges. Public Lab is investigating one [promising passive monitor](/wiki/sem-stub-pm) as a tool for measuring airborne PM concentrations. [Read more in Public Lab PM tool development.](/wiki/pm-dev) ###Advantages and Disadvantages **Advantages** | **Disadvantages** --------------------|--------------------- low cost (less than $100 devices) | deployed for 3-7 days, low temporal resolution deployed without electricity | not real-time (results must be analyzed after collection) simple setup and calibration | analysis can be labor intensive or expensive actual particles are collected | particle speciation is limited by method and cost can generate airborne particle concentrations | no way to extrapolate to airborne concentrations of speciated particles may correlate well with [Federal Reference Methods]( | not an officially recognized method electret methods are particle-specific | electret methods are particle-specific ###Devices ####[SEM Stub Monitors](/wiki/SEM-stub-pm) In field testing, these samplers have been demonstrated to vary (CV) only 11.6% from [Federal Reference Methods](, 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. [Read More](/wiki/SEM-stub-pm) 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](//](// [![IMG_20151015_120027-trim.png](//](// Analysis is performed in [ImageJ]( roughly: [![Analysis Steps](//](// [Read More](/wiki/SEM-stub-pm) Citation: Darrin K. Ott, William Cyrs, Thomas M. Peters, Passive measurement of coarse particulate matter, PM10-2.5, Aerosol Science 39:156 – 167, 2008 ###Sticky Pad Monitors Developed to track 'nuisance dust,'(i.e. any visible dust blowing onto properties adjacent from a dust producing industrial operation), sticky pads are pieces of tape that collect wind-blown dust. No system for speciating particles or correlating particle accumulations with airborne concentrations has been developed, however, sticky pads are the only dust monitoring system that records the direction dust came from. The most advanced system, developed at the University of Leeds and spun off into the [DustScan]( company, uses two sticky pads-- a cylindrical pad used to track the direction dust comes from, and an upward-facing sticky pad to track total dust. The devices are made from standard sizes of ABS drainage pipe and commercially available tape. [![DustScan Sticky Pads](//](// For analysis, sticky pads are scanned at low resolution, and the relative darkness or lightness (albedo) is measured by software to quantify dust accumulation. [Read More](/notes/mathew/06-05-2014/the-development-of-stickypad-monitoring) ###Other Passive Monitors ####Vinzents Passive monitor A small dual-sticky pad system designed for indoor use only, with one pad facing up and the other one horizontal. This system uses a similar deposition model as SEM stub monitors, and analysis can be performed using optical microscopy. See: Vinzents, PS. A Passive Personal Dust Monitor. Annals of Occupational Hygiene, 40: 261-80, 1996. Schneider et al. Passive Sampler Used for Simultaneous Measurement of Breathing Zone Size Distribution, Inhalable Dust Concentration and other Size Fractions Involving Large Particles, Annals of Occupational Hygiene, 46:187-195, 2002. ####Exposed Filter Systems ####Ferm Passive Monitor Martin Ferm has developed two different monitors: 1) a series of vertical strings less than 1mm in diameter collect particles from all directions for analysis with mass spectrometry, not investigated because of the expense of analysis. 2) a polypropylene container with an exposed filter, for mass spectrometry. See: Fern, Martin, Development and Test of a Passive Sampler for Fine Particles, Swedish Environmental Research Institute, 2010. ####Einstein–Lioy Deposition Sampler A similar arrangement to the Ferm monitor, with four exposed 37mm filters for mass spectrometry analysis. See: Einstein et al, Design and Validation of a Passive Deposition Sampler, Journal of Environ Monitoring 2012 September ; 14(9): 2411–2420 ####Brown Electret Sampler A system with an 'electret,' or semi-permanent charged material, filter. Requires expensive analytical chemistry methods. See: Brown, R. C., Hemingway, M. A., Wake, D., and Thompson, J. . Field Trials of an Electret-Based Passive Dust Sampler in Metal Processing Industries, Ann. Occup. Hyg. 39:603– 622. 1995 ####Personal Aeroallergen Sampler (PAAS) Unknown operation, couldn't get the article. Support open science. Yamamoto et al. A passive sampler for airborne coarse particles Journal of Aerosol Science Volume 37, Issue 11, November 2006, Pages 1442–1454...

Author Comment Last activity Moderation
marlokeno "One possibility in order to get a clearer image is to try using the "threshold" filter in photoshop, or photoshop elements, GIMP, etc. It's helped ..." | Read more » almost 7 years ago
marlokeno "It is possible the wikipedia article on Reynolds numbers might help- At any rate, the article does g..." | Read more » almost 7 years ago
wsg "Hi Gretchen, Really interesting project which you should be able to generate some very interesting metals data with the WheeStat. I have been work..." | Read more » almost 7 years ago
marlokeno "There is an article in "Aeolian Research", Dec. 2014, entitled "The size distribution of desert dust aerosols and its impact on the Earth system." ..." | Read more » almost 7 years ago
jeffalk "You probably know about the EPA site with monitoring data around the Chicago coke facilities. The EPA data could be used to compare to whatever dat..." | Read more » almost 7 years ago
liz "This is incredible work!!!! You guys are awesome! " | Read more » almost 7 years ago
mathew "further followup on analysis of samples. " | Read more » almost 7 years ago
mathew "read my follow-up on imaging the samples " | Read more » almost 7 years ago
bareczek "interesting " | Read more » almost 7 years ago
mathew "That candle protector is a great way to picture how this sensor works! I think the tiny grate on top of the sensor itself does something similar. ..." | Read more » almost 8 years ago
marlokeno "Markdown In order to measure particles in sand mine areas of W. Wisconsin/ SE Minn., I noticed from a google/NASA map today that average wind spee..." | Read more » almost 8 years ago
el_tonio "Hi Mat, have you thought of using a microscope? you can get ones that connect to smartphones, which depending on your phone should give you good re..." | Read more » almost 8 years ago
amysoyka "Hey Matt, We just had an asbestos scare in my neighbourhood - so I wanted to make some cheap and simple collectors that can be hung up by resident..." | Read more » almost 8 years ago
mathew " Usually gravimetric tests are done on particles after they have been captured in the field. Given environmental vibrations, it sounds tough to pi..." | Read more » almost 8 years ago
amysoyka "This is a gravimetric sensor: In theory, don't PM particles have different weight, depending on atomic content. If you were to use a mesh to re..." | Read more » almost 8 years ago
warren "I was wondering if, since the silica kind of redirects the light (a little like fiber optic), if you could illuminate it with a directional light d..." | Read more » about 8 years ago
mathew "From the literature on stickypads, concentrations of particles smaller than the resolution of the scanned image can be roughly estimated by albedo ..." | Read more » about 8 years ago
jefffalk "I may not be understanding this method fully but keep in mind that PM2.5 indicates particulate of aerodynamic diameter less than or equal to 2.5µm...." | Read more » about 8 years ago
eustatic "Mat, thanks for working on this crucial issue. lung cancer sucks, and you should apply for an NIH grant for your work to cure it. <3 " | Read more » about 8 years ago
stevie "Hm.. disappointing! I have faith though, keep on geekin on :) " | Read more » about 8 years ago
mathew "right-- and with an SLR the image capture would be much faster than waiting for a scanner. " | Read more » about 8 years ago
cfastie "I had a similar experience when I was figuring out how to copy old film negatives. The best (very expensive) scanner at Middlebury College made a b..." | Read more » about 8 years ago
amysoyka "Thanks for sharing the know-how. Directional scanning, eh? I shall have to make a query to a few people I know about that one. " | Read more » about 8 years ago
cindy_excites "Thanks for this Mat! Let us know how your scanners testing goes. It might be something interesting for people here in London - air pollution is a b..." | Read more » about 8 years ago