Introduction

There are many thousands of hazardous substances to which people can be exposed in the workplace. Not only is air sampling used to assess risk to these substances, but it can be used for a number of additional purposes.

The outcome of choosing the wrong sampling strategy may lead to the selection of an inappropriate control strategy. On the other hand, seemingly simple mistakes as to whom, where and when to sample could result in errors in estimating worker exposure, leading to potential illness and death.

How can workers be exposed to hazardous substances in their job?

1. By inhalation
2. By skin contact and absorption
3. By ingestion

Where inhalation is a potential route of exposure we may want to consider carrying out air sampling to measure the concentration of the contaminant in the air. This can then give us a good indication of the amount of material workers are breathing in and help us to make an assessment of the degree of risk.

Ingestion can be a route of entry but typically, this would be accidental, e.g. active pharmaceutical ingredients (APIs) ingested from contaminated hands and clothing.

Whatever the reason for carrying out sampling, it is important that we first think about what we are trying to achieve - then decide on:

• What type of sample we need to collect
• The sampling methods we are going to use
• Whom or where we sample
• When to sample
• How long to sample
• How many samples we need to collect.

In answering these questions, we will have developed what is commonly referred to as a "sampling strategy" for our survey.