We have long advocated that government and industry refrain from using the metric-looking units—typified by the infamous milligrams per cubic meter—when discussing gas concentrations. The obvious reason is that the volume of a gas is affected by temperature and pressure. Thus, a concentration reading in mg/cubic meter is only valid for a particular set of…
In our Gas Detection Applications Primer, we describe the notion of recommended and regulatory limits, as applied to toxic gases in the workplace. Discussed therein are the OSHA parameters of Permissible Exposure Limit, Action Level, and Ceiling Value. If this “Action Level” is detected during initial monitoring of the occupancy in question, that is the…
One of our older sales reps faced this issue many years ago, on a source monitoring job. His instruments were set up in a trailer, ready to demo to a prospective customer. The customer had provided a nice new cylinder labeled “sulfur dioxide in air, 500 ppm.” However, when this gas was applied to an…
Have you ever heard that “The solution to pollution is dilution”? This little aphorism is usually stated as a sort of inside joke, although it is public policy for radon in residences. We saw this principle in action when home builders affected by the Chinese drywall disaster would sometimes open all windows while the homes…
A complete list of nitrogen oxides would include… Nitric oxide, aka nitrogen monoxide (NO), nitrogen(II) oxide Nitrogen dioxide (NO2), nitrogen(IV) oxide Nitrous oxide (N2O), nitrogen(−I,III) oxide Nitrosylazide (N4O), nitrogen(−I,0,I,II) oxide Oxatetrazole (N4O) Dinitrogen trioxide (N2O3), nitrogen(II,IV) oxide Dinitrogen tetroxide (N2O4), nitrogen(IV) oxide Dinitrogen pentoxide (N2O5), nitrogen(V) oxide Trinitramide (N(NO2)3 or N4O6), nitrogen(0,IV) oxides Of primary…
In most cases, the goal is to establish some sort of ventilation control, such that a balance can be achieved between energy conservation and guarding against toxic exposure. Carbon monoxide is usually chosen as the target analyte, unless the vehicular traffic will be largely diesel. While diesel engines do emit CO, it is less than…
In most cases, gas monitoring applications focus on a single gas. There may well be interest in detecting this compound at several points, but the end-user has determined that it has one particular target analyte. Sometimes, though, there will be two gases of interest. Common examples are hydrazine and nitrogen tetroxide; and carbon monoxide and…
The classical first year chemistry definition of “pH” refers back to Danish biochemist Søren Sørenson, who originated the term, alluding to the “potential of hydrogen ion.” Specifically, pH is the negative logarithm of the molar concentration of the hydrogen ion (H+) in the particular solution. This is usually expressed as a formula… pH = -log[H+]…