Which of the following is NOT considered a common respiratory hazard?

High humidity is not typically classified as a respiratory hazard in the same way that the other options are. Respiratory hazards generally involve conditions that can directly impair an individual's ability to breathe or compromise their respiratory health.

Oxygen deficiency is a critical danger since it can lead to asphyxiation and other severe health issues. Gases and vapours, such as carbon monoxide or chemical inhalants, pose significant risks as they can be toxic and lead to respiratory distress. Particulate contaminants, including smoke and dust, can irritate the lungs and airways, leading to various health complications.

In contrast, while high humidity can be uncomfortable and may exacerbate certain respiratory conditions, it does not inherently interfere with the function of the respiratory system in the same immediate and serious way that the other options do. Thus, high humidity does not meet the definition of a common respiratory hazard like the others mentioned do.