When sampling is performed by canisters or bags, the reactivity among the different compounds could compromise air sample stability and cause artifacts. For this reason, it is necessary that samples should be analyzed as soon as possible after sampling in order to minimize sample losses, degradation or alteration. Cheremisinoff [60] asserts that samples are still useful as long as 48 h after collection. In most cases, efforts are made to assess samples within 24 h of collection. The European Standard EN 13725/2003 states that odour samples must be analyzed within 30 h from sampling [37].