How Monitoring Instruments Work
As outlined under Network Description, British Columbia's air quality monitoring network includes both automated and manual monitoring stations, which are also known as continuous and non-continuous stations respectively. This page gives an overview of the instruments used in these stations and how they work.
Automated (Continuous) Monitoring
Continuous monitoring stations are equipped with data analyzers that draw air in through various tubes for continuous analysis. These analyzers are attached to data acquisition systems, called data loggers. A central computer in Victoria then draws information from (polls) the data loggers and incorporates these measurements into its databases. From here the data is posted to B.C.'s Air Quality Readings, and is validated by Ministry of Environment staff.
The Ministry of Environment uses a wide range of automated instruments to collect and measure air quality data, including the following (with instrument acronyms and parameters measured in parenthesis):
- Tempered Element Oscillating Microbalance (TEOM) (PM2.5 and PM10)
- Beta Attenuated Monitoring (BAM) (PM2.5)
- UV Photometry (ozone)
- Chemiluminscence (nitrogen dioxide)
- UV Fluorescence (sulphur dioxide)
- Nondispersive Infrared Photometry (carbon monoxide)
- Pulsed Fluorescence (total reduced sulphur or H2S)
Manual (Noncontinuous) Monitoring
Manual sampling is preferred in some cases because it is easier and less expensive than continuous, automatic sampling, while producing equally valuable results.
Manual sampling is performed by Ministry of Environment staff and by industry and institutions that are required to conduct air quality sampling as a condition of their operation (permittees). The sampling must follow strict and comprehensive guidelines set out by the Ministry of Environment.
In manual sampling, filters or canisters are placed in the field by technicians for a discrete period of time (such as 24 hours), and then sent to registered laboratories where they are weighed and analyzed
to determine their content. The laboratory then uploads the data to a central Ministry of Environment database.
The Ministry of Environment uses a range of manual instruments to collect and measure air quality data, including the following:
- Single Channel 16.7l/m (PM2.5 and PM10) monitors
- Dichotomous (Coarse and Fine PM) monitors
- Speciation monitors
- Volatile Organic Compound monitors (VOCs)
- PAH monitors
- Passive samplers
For further details on the operation and use of these instruments, see How Instruments are Calibrated and Maintained.