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Public Lab Wiki documentation


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Types of monitoring equipment

Most monitors give a mass-based particle concentration for all particles in a size category, meaning they do not differentiate between the relative mass contribution of different sizes of particles within that category. Only systems that capture and save particulate matter can identify, or ‘speciate’ particles by size or elemental composition.

The sections below briefly describe different approaches to PM monitoring and show what the Public Lab community is asking and saying about each approach.

Filter-based systems

Used for: regulatory monitoring, supplementary monitoring

Filter-based systems can collect particles for laboratory methods of speciation, and are the basis of Federal Reference Methods. Data can only be analyzed after collection, not in real-time. Usually samples are collected over a 24-hour period and the weighted average concentration (by mass) for that 24-hours is produced. Filter-based gravimetric systems are usually the most precise measurements of PM.

Optical systems

Used for: personal exposure monitoring, supplementary monitoring, hotspot identification, hotspot characterization, education

Optical electronic systems offer the possibility of real-time particle counts which are valuable for hotspot identification, recording short-term high emissions events, and identifying when air may pose a health threat. Their data is significantly affected by humidity though. More precise monitors usually include a filter-based system to correct data after collection, such as what Public Lab plans to do by collocating optical systems with passive monitors.

Passive systems

Used for: personal exposure monitoring, supplementary monitoring, education, hotspot characterization, education

Passive systems have no moving parts and are easy to deploy for long-term monitoring without electricity. They can approach the precision of regulatory monitoring and are within the accuracy and precision ranges necessary for supplementary monitoring. Passive monitors generally require longer sample collection periods (3-10 days) than active filter-based monitoring, and are better used to characterize hotspots than to identify them.

Passive monitors collect particles onto filters or slides, so there is the opportunity to do some limited speciation analyses of particles.

Title Author Created | Updated Likes Views Type
Choosing a method for Particulate Matter Monitoring @stevie 3 months ago 22
SEM stub monitor for particulate matter @mathew about 3 years ago 17
What is the scenario under which you would use an optical vs. a passive monitor to measure dust? @kgradow1 over 3 years ago 1
Can a passive dust monitoring housing be made from a cheaper/easier material? @warren over 4 years ago 1
Sizing particles in microscope images at Portland Science Hackday @mathew over 4 years ago 1
Calibrating a Microscope @mathew over 4 years ago 1
OpenFlexure Microscope: high-resolution assembly @mathew over 4 years ago 1
Sample prep for Passive Particle Monitors @mathew over 4 years ago 1
Automating ImageJ for particle image analysis @SimonPyle almost 5 years ago 1
Making an OpenFlexure Microscope @mathew almost 5 years ago 1
Mapping dust hotspots with low-cost monitors @mathew almost 5 years ago 1
Automating Passive Particle Monitor Analysis @mathew almost 5 years ago 1
Passive Particle Monitor Deployments: feedback @mathew about 5 years ago 1
ImageJ exporting data into Excel: Used for Analysing Images of particulate matter @pagyebo over 5 years ago 1
Systematic Imaging of Passive particle monitors on an SEM @mathew over 5 years ago 1
Deploying Passive Particle Monitors @mathew over 5 years ago 1
Using imageJ to adjust threshold using mode Entropy @damarquis over 5 years ago 1
Coal Ash and Citizen Monitoring @gretchengehrke over 5 years ago 1
When $100,000 is not enough: how citizen data (could) relate to government regulation @liz over 5 years ago 1
Deploying UNC passive sampler on South Side of Chicago @AmberWise over 5 years ago 1
Using ImageJ to process passive particle monitor samples @mathew over 5 years ago 1
analyzing passive monitors @mathew over 5 years ago 1
Optical Imaging of Passive Particle Monitors @mathew over 5 years ago 1
Replicating a Passive Dust Monitor & Method @mathew over 5 years ago 1
Low-cost passive aerosol monitors @mathew over 6 years ago 1
a first look at dust with consumer scanners @mathew over 6 years ago 1
The development of stickypad monitoring @mathew almost 7 years ago 1
Imagining & testing Polarized Light Microscopy for Silica dust speciation @mathew almost 7 years ago 1

Further reading and resources