This change in resistance is used to calculate the gas concentration.

There are only two ways to stabilize concentration of greenhouse gases.

Samples of air from the spacecraft are examined both before and after flight for gas concentrations.

He formulated a simple mathematical relationship between the gas concentration and the necessary exposure time.

This means that atmospheric concentrations of greenhouse gases would continue to grow.

Since about 1750 human activity has increased the concentration of carbon dioxide and other greenhouse gases.

Any sharp increase in key gas concentration is indicative of a potential problem within the transformer.

In many applications, however, the gas concentration is known and other parameters are in focus.

There also appears to be general agreement that atmospheric concentrations of greenhouse gases are rising.

Just picking up a telephone receiver can cause electrical activity that, if the gas concentration is high enough, could lead to disaster.