Many of the adverse health effects from air pollution can be attributed to fine particulates, so the accuracy and reliability of the UK’s ambient particulate monitoring network is extremely important. Since the early 1990s, this network has relied on TEOM and more recently the TEOM-FDMS direct mass measurement technology, but Air Monitors MD Jim Mills is concerned that the reputation of this technology’s reliability “is being unfairly tarnished as a direct result of poor maintenance by some other service companies.”
Air Monitors is responsible for servicing a sizable proportion of the AURN monitoring network and Jim says “the performance of the instruments that we service has been consistently high, so if the national average performance is low, it is obvious that other service providers must be dragging down the overall figures on data capture.
“Unfortunately, when the performance figures are low, there is a temptation to blame the equipment – but you know what they say about a poor workman!”
In recent years a new version of the TEOM has become widely adopted; the FDMS (Filter Dynamic Measurement System) ensures the correct measurement of semi-volatile particulate matter without a requirement for correction factors. The TEOM - FDMS is the preferred monitor of the UK AURN network and more recently the new 1405 series has been introduced with many design improvements making it easier to operate and even more reliable.
The data capture performance figures for the TEOM-FDMS are determined by an independent third party and are publically available. To support his case Jim refers to the data shown herewith, which demonstrates that the TEOM-FDMS stations that are serviced by Air Monitors consistently perform above the required 90% data capture rate, whereas the average performance of all monitors in the AURN is around 20% lower than this. As Jim says, “You don’t need a mathematician to tell you that these averages are obviously being dragged down by stations that are not being serviced properly.”