What happens to the dry gas standard over time?

The correct response indicates that the dry gas standard remains stable over time. Dry gas standards are specifically designed to maintain their properties and accuracy, which is critical for calibration and testing purposes in breath alcohol testing devices like the Intoxilyzer 8000.

This stability is essential because the reliability of breathalyzer results depends significantly on the precision of the calibration gases used. If these gases were to change, either in composition or concentration, it would lead to inaccurate results when testing a subject's breath. Therefore, the dry gas standard does not experience changes that would lead to degradation or alteration in its performance, allowing it to effectively serve as a dependable reference point over long periods in calibrating devices.

In contrast, the options reflecting increased pressure, decreased accuracy, or evaporation suggest changes or deterioration that are not characteristics of dry gas standards. These possible changes would indeed compromise the effectiveness of the standards if they were to occur, further highlighting why stability is a vital feature of dry gas standards.