New Beginnings for TBD Presentations

The New Year has brought new opportunities for us here at TBD Presentations.  We are delighted to be acting as exclusive agents in the UK and Ireland for Pegasor, a Finnish Company that has developed the world’s first continuously operating, real-time fine particle monitoring system. 

Fine particles (and ultrafine particles which can also be monitored using this system) are considered to be a significant contributory factor in the development of the high levels of respiratory disease associated with urban air and automotive emissions. 

For many years airborne particulate has been controlled using mass based parameters such as PM10 and PM2.5 (effectively the mass concentration of airborne material with aerodynamic sizes less than 10 or 2.5 microns). Over the last thirty years the majority of industrialised economies have taken huge steps to reduce the emission of particles to the ambient atmosphere. Given what we then knew about the inhalation of particles into, and their deposition within, the respiratory tract, the emphasis has historically been on particles between say 0.5 and 25 to 50 microns. Epidemiology, occupational hygiene and toxicology studies have traditionally been based on mass based concentrations, and this size range encompassed the majority of particles that could be inhaled and deposited within the respiratory tract. So, abatement technologies were designed to remove these particles from emissions from factories and power plants etc into our breathing air.  Real improvements have been made, as can be seen from this graph taken from the National Atmospherics Emissions Inventory web site.  

Most of the reductions can be attributed to the reduction in fossil fuel burning and it can readily be seen that there have been no real reductions in that fraction caused by transport.  The problem is that the frequency and severity of respiratory disease and various other systemic diseases that can be attributed to particle inhalation have not been as significantly reduced and can no longer be said to trend with the  mass based particulate concentrations for the same period. Epidemiologists still have to rely on air quality data that corresponds to those criteria that were most relevant in the past: PM10 and PM2.5, both mass based criteria that no longer trend against observed health effects as well as they used to.  The general consensus is that residual health effects are not primarily related to mass deposition within the respiratory tract but to either the frequency of deposition or the surface are of the material deposited. Emissions have got a lot cleaner, flue gas cleaning on power plant, the decline in fossil fuel as a power source, lean burn fuel technology and exhaust gas treatment on vehicles have all contributed to a reduction in the mass concentration of particulate present in the air we breathe, but some of these processes may have only served to reduce the mass concentration at the expense of the ultrafine and fine particle fraction of suspended particulate material. There is even concern that some ultrafine materials can have significantly different toxic effects than the same material presented in much larger form. New parameters were needed; if you cannot monitor a process then you cannot adequately control it, and controls on the quality of our urban air are urgently needed. Two candidates  have been considered and both look as though they describe the relationship between the particulate fraction of our urban air and the observed health effects. Number concentration is a fairly easy concept to grasp; you simply count all the particles in a given volume of air and come up with a concentration. It does get more complicated but we can come back to that at a later date. The second parameter is surface area concentration which is less easily grasped and is certainly more difficult to measure let alone monitor, than number concentration. At it's most basic, this parameter reflects the sum of the surface area of all the particles present within a given volume of air. 

The patented Pegasor sensor is, like all great designs, deceptively simple in concept and realisation. Air is pulled from the atmosphere to be measured through a charging volume where charged air ions become attached to the particles. As they pass out through the detector these charges induce a virtual charge on the surface of an electrode array which is connected to a sensitive amplifier. The signal from the amplifier is transmitted to a recording device and is proportional to the flow of particles through the sensing volume. Experimentation and validation has allowed this signal to be  to either number concentration or surface area concentration within the defined size range of the sensor. In addition to these two parameters we have determined that excellent extrapolations can be made to mass concentration as well across a range of applications and aerosol types.

The signal can be sampled internally at up to 100 Hz and can be output via a range of standard formats to different data collection and collation packages.

The Pegasor range of particle sensors are available in different configurations to best meet your fine particle monitoring needs. Please contact TBD Presentations to learn more, to set up a visit and to see just what these astonishing monitors can do for you.