Levels of airborne particulate pollution is measured as a means of monitoring air quality. Airborne particulates (PM) can be solid particles or liquid droplets. They come in different sizes, compositions and origins (i.e. natural or synthetic) and this means they can all have differing effects on human health. PM2.5 and PM10 are two standard particle sizes that are monitored:
- Coarse particles (PM10) – inhalation factors. This sort of particle size is typical of dust originating for example from building sites and fires. Particles of this size can be inhaled into the lungs and high levels of exposure can be associated with certain lung diseases and breathing problems.
- Fine particles (PM2.5) are particles typically found in haze from exhaust fumes and due to their smaller size, will be suspended in the air for much longer. These particulates can cause health issues even at very low concentrations and are small enough that when breathed in, can penetrate the lungs and enter into the blood stream. High exposure has been linked with premature death.
Smoke and exhaust fumes can contribute to particulate pollution of air.
What filters are used?
Analysis of PM2.5 and PM10 particulates is typically performed as a gravimetric analysis. Following this, testing and specific chemical analysis may be carried out to provide more detailed information on the composition of the particulates, such as heavy metal and organics prescence. This later testing will influence the selection of filter paper being used.
A number of different filter papers/membranes are used when monitoring the levels of particulate pollution following a number of standardised test methods – these are usually glass microfiber papers, quartz microfiber papers and PTFE membrane filters, the most commonly used filters are:
GF/A – Binder-free glass microfiber paper with fine particle retention. Used for gravimetric analysis and organic determination of PM2.5 & PM10.
EPM 2000 – binder-free glass microfiber paper for use in high volume PM10 air sampling equipment and is approved in US EPA method. Suitable for gravimetric analysis and organic determination.
TE Type PTFE Membranes – are general purpose PTFE membrane, they are chemically resistant with a low background for low chemical interference.
PM2.5 PTFE Membrane – used in PM2.5 ambient air monitoring. Supplied with a chemically resistant PP support ring, this filter adheres to US EPA PM 2.5 reference method under the requirements of 40 CFR Part 50 Appendix L. Suitable for gravimetric analysis, heavy metal and organic determinations.
Cytiva (manufacturers of Whatman papers) have produced this handy overview table for the suitable papers for a number of applications:
All of these filters are available to purchase through Camlab. You can shop our entire filter range here. Please contact us at firstname.lastname@example.org if you have any queries.
Source: https://www.who.int/en/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health & https://www.cytivalifesciences.com/en/gb/solutions/lab-filtration/industry/environmental/air-monitoring