sandbox-pm-monitoring
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.
| Title | Author | Created | Updated | Likes | Views | Type |
|---|---|---|---|---|---|
| Overview: MiniVol PM monitor | @mathew | over 7 years ago | 3 | 1 | note |
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.
| Title | Author | Created | Updated | Likes | Views | Type |
|---|---|---|---|---|---|
| Optical Monitoring of Particulate Matter | @mathew | about 4 years ago | 4 | 24 | page |
| Is it important to account for humidity using optical particulate matter monitors? | @stevie | almost 7 years ago | 0 | 1 | note |
| Can the New Auburn, WI Recreation Area be used to identify downwind dust from Great Northern Sand? | @mathew | about 7 years ago | 2 | 1 | note |
| How do we measure particulate stuff in the air? | @donblair | almost 10 years ago | 5 | 1 | note |
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.
Further reading and resources
- See more on monitoring silica