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…
Go directly to conversion calculators Early on, in our first chemistry classes, we learn about solutions, and different ways of expressing their concentrations. Since a solution is any homogeneous mixture of two or more substances, gas mixtures are indeed solutions. In the world of gas detection, we tend to be concerned with combustible or toxic…
“Dew Point” is defined as the temperature to which a given volume of air must be cooled at constant pressure and constant water vapor content in order for saturation to occur. If the air is cooled further, some of the moisture will condense. The notion of “Saturated Vapor Pressure” can be understood by considering the…
Sometimes, it is necessary to calibrate gas detection instruments at a barometric pressure (atmospheric pressure) different from that of the measurement location. In such cases, a correction factor must be applied. When a gas concentration is measured or reported, we may talk in terms of ppm, but in reality we are measuring the partial pressure…