What is particulate matter?
Particulate matter (PM) consists of airborne particles in solid or liquid form. It includes aerosols, smoke, fumes, dust, ash and pollen. Particulate matter is characterized according to size - mainly because of the different health effects associated with particles of different diameters. Some particles are emitted directly into the atmosphere. Other particles result from gases that are transformed into particles through physical and chemical processes in the atmosphere.
Total Suspended Particulate (TSP) -airborne particulate matter with an upper size limit of approximately 100 micro metre (µm) in aerodynamic equivalent diameter. Particulate Matter <10 microns (PM10) - also referred to inhalable particulates, are airborne particulate matter with a mass median diameter less than 10 µm. A variety of emission sources and meteorological conditions contribute to ambient PM10. Particulate Matter < 2.5 microns (PM2.5) – also referred to as respirable particulates are airborne particulate matter with a mass median diameter less than 2.5 µm.
How do we measure particulate matter (PM10)?
TEOM-MASS CONCENTRATION: A TEOM (tapered element oscillating microbalance), is a micro weighing technology that provides true mass real-time measurements of particulate matter. The sampling head is outfitted with a PM10 size selective inlet. A sampling filter is mounted on the microbalance, sample gas deposit particulates on the filter reducing the microbalance frequency. This reduced frequency is directly proportional to the amount of mass on the filter. A mass flow controller maintains the sampling flow to calculate the mass concentration in µg/m3.
BETA RADIATION: At the start of the sampling period, beta ray transmission is measured across a clean section of filter tape. This section of filter tape is then mechanically advanced to the sampling inlet. Particulate matter is then drawn into the sample inlet and deposited on the filter paper. At the completion of the sampling period, the filter tape is returned to its original location and the beta ray transmission is re-measured. The difference between the two measurements is used to determine, with exceptional accuracy, the particulate concentration. The sampling head is outfitted with a PM10 size selective inlet.
THE 5030 SHARP CONTINUOUS AMBIENT PARTICULATE MONITOR consists of a C14 source, detector and a light scattering Nephelometer in a rack-mountable enclosure. It distinguishes itself from other beta gauge measurement methods by utilizing a continuous (non-step wise) hybrid mass measurement with two proven industry technologies, which provides for long term unattended operation. It automatically advances the filter tape based upon a user defined frequency or particulate loading.
Air quality standards
MECP: 24- hour PM10 AAQC (Ambient Air Quality Criteria) 50µg/m3 (micrograms per cubic metre)
Ontario's Ambient Air Quality Criteria
Links- more information on particulate matter
Environment Canada - Air - Particulate Matter