A preliminary survey, sometimes called an observational survey, involves a walking tour of the workplace (hence the more descriptive name, “walk-through”).

Some of the benefits of a preliminary survey include:

• obtaining an overview of the whole operation;
• identifying the key hazards in each area; and
• assessing the effectiveness of any control methods in place.

During a walk-through, the occupational hygienist will be asking:

• Are measurements needed in this area?
• If so, what hazards should be measured?
• Where should they be taken?
• Which workers should have their exposure assessed?
• When should the measurements be made?
• What conclusions might be drawn from the results?

The Occupational Hygienist might then recommend an Occupational hygiene or monitoring survey to obtain quantitative exposure levels or even a formal occupational health and safety risk assessment.

Occupational hygiene survey or monitoring survey is the quantitative measurement of workplace stressors including the following:

• Noise (occupational and environmental)
• Hazardous chemical substances (including lead and asbestos)
• Thermal stress
• Indoor air quality
• Illumination
• Vibration