Industrial Hygiene Field and Laboratory Tests

Total Dust

Sampling for total dust in the workplace entails the use of a sampling train which consists of a calibrated air sampling pump, a tygon tube, and a filter casette assembly that houses the pre-weighed filter paper. After collection, the samples are transported to the DEOH laboratory for gravimetric analysis.



Environmental Lead

Aside from determining lead levels in blood, DEOH conducts sampling and analysis of lead in the environment. Sample collection makes use of a sampling train similar to the one used in total dust sampling although lead is collected in a different type of filter. Analysis of samples by Atomic Absorption Spectrophotometry is performed at the DEOH laboratory.

Respirable Dust

Respirable dust is collected by using the standard sampling train for dust with a cyclone attached. This cyclone separates the respirable fraction of dust from larger dust particles by rapid air circulation. Collected samples are transported to the laboratory for filter weight analysis.


The DEOH offers evaluation of sound levels using a sound level meter (SLM). Noise or sound causes variations in air pressure which are detected by the SLM. Prior to measurement, the instrument is calibrated using a calibrator which is set at a specific sound frequency.


In an occupational setting, evaluation of lighting is necessary to ensure that optimum comfort and safety is provided to the worker. The DEOH performs measurement of illumination levels by means of an illumination or light meter which consists of a detector/meter and a sensor. Measurement is performed in general work areas within the facility and in specific worksurfaces.

Solvent Gases. (Detector Tubes)

Determination of the concentration of specific solvents and gases in the workplace entails the use of colorimetric detector tubes. Detector tubes provide both qualitative and quantitative measurements of specific chemical contaminants. The detector tube reagents react with the chemical contaminant to produce a color change and the length-of-stain provides an estimate of the concentration of the contaminant. These detector tubes are attached to pumps which draw a constant volume of air into the tube.


The DEOH conducts qualitative and quantitative tests for both general and local exhaust ventilation systems. Ventilation smoke tubes which reveal air direction and movement provide qualitative assessment of the ventilation system whereas the quantitative test for ventilation involves a measurement of air velocity using a thermo anemometer.

Heat Stress

Measurement of heat stress involves a determination of the wet-bulb globe temperature (WBGT) index. The portable heat stress monitor used by the DEOH is similar to the classical set up for heat stress monitoring. It consists of a dry-bulb thermometer, a wet-bulb thermometer, and a globe thermometer which measures ambient air temperature, humidity, and radiant heat, respectively.