Do we care about our air? Do we need to? Yes. That is why we have air quality testers. What do they test for? Pollution, weather conditions and trends in these things.
Monitors and testers help us identify problems, verify findings reported by other means and establish a basis for policy decisions. Air quality modelling can confirm what the testers find. It can also direct planners while putting together a monitoring strategy.
Testing adds an empirical element to the theoretical predictions put forth by modelling. Air quality monitoring also confirms the impact of changes to an industrial design that have been forecast by modelling. Air quality tester results are described in terms of concentration of contaminants in the atmosphere.
Ambient air concentrations
Concentration is really the density of one substance when mixed within another. It is similar to specific gravity in the fact that they are both measured in mass per unit volume. We use units like micrograms per cubic meter to express air quality concentrations. Or parts per million, each of which is one millionth of the density that would occur if the volume were filled with pure sulfur dioxide or whichever chemical we were dealing with.
The concept can also be applied to small solid particles. Air quality modelers express particulate concentrations in the same units they would if they were working with gaseous emissions.
Plants have complex laws to obey, many of which lead to mounds of paperwork. And if changes in design are required for air quality purposes, it can become an administrative nightmare. Especially if nobody on staff knows what to do. Management may find it needs an environmental consulting company for its expertise and help.
For a more elaborate explanation of concentration and density, see the web page at http://www.stuffintheair.com/grams per liter.html
Who conducts air pollution dispersion modeling?
Air quality dispersion meteorologists, engineers and atmospheric modellers. If they are really good, they also train regulatory personnel within the relevant governing bodies. It is important to keep abreast of changes and the latest developments in the business, because regulations and software technology in this field improve regularly.
Sometimes these professionals perform air quality & emissions reporting on behalf of their clients. If the plant wants to implement equipment or operational changes, regulatory bodies will usually require that updates to registrations, licenses and/or approvals be made first. Most new industrial facilities need permitting as well.
These applications require air quality dispersion modeling and careful guidance through the approval process. Good consultants know the people involved in the process in addition to the technical requirements.
Another thing some consultants will do is prepare quality assurance plans. A continuous emissions monitoring system, better known as a CEMS, is a commonly used industrial technology. One of these probes will automate stack emissions monitoring and save a great deal of labour, but it needs to be quality controlled and regularly calibrated. The same can be said for ambient air monitoring devices.
This itself is a labour intensive process that requires an elite set of skills. But it only needs to be done occasionally and does not justify staffing any full time positions in the manufacturing company. This is where outsourcing to a consulting company makes sense, and using one with extensive experience in the field makes even more sense. Someone familiar with the requirements and the process easily understands a good quality assurance plan.
Some meteorological consultants prepare climate summaries. Where are climate summaries used? Environmental Impact Assessments and engineering design companies use this data quite frequently. Highly varied experience and a large data bank serve as major assets in this field.
Finally, some people working in this field determine optimum locations for air quality & meteorological monitoring. This is another tricky thing to do, and it might seem like a black art to the uninitiated. But it requires the application of some good solid science. Monitoring also includes leak detection and repair, LDAR programs that are very labour intensive and technical. It is really a part of emissions management more so than modelling.
The air quality tester and modeler occupations have been exciting ones and that shall continue.
Barry Lough has more than 12 years experience dispersion meteorology, modelling, environmental permitting and consulting. http://www.stuffintheair.com/airqualitytesters.html provides an extensive list of air quality services. http://www.stuffintheair.com/WeatherMan.html - more about Barry.
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