This was measured by Dimesimeters being put close to the eye to measure individual light exposure.

The researchers estimated radiation doses by looking at hospital records; they didn't measure exposure directly.

Only now is the Environmental Protection Agency conducting research in the oilfields to measure radiation levels and exposure.

The exposure-based approach, which measures exposure via pollutant levels, is used to calculate the environmental burden of disease.

"They measured exposure before the disease occurred, while in most studies you have to rely on people's recollections."

Biological Monitoring - is another approach to measuring exposure.

For asbestos, in contrast, there are no tests available to measure past exposure, and no early symptoms, like rashes.

The cholinesterase serum test is usually done to measure exposure to organophosphate insecticides.

The directive also places huge new costs and administrative burdens on industry in terms of measuring vibration levels and recording exposure.