Q.Define TLV.

TLV is the safe upper-limit concentration of a pollutant/toxic substance in workplace air, used as an industrial hygiene standard.

TLV stands for Threshold Limit Value. It is defined as the concentration of a substance in air (usually expressed in ppm or mg/m³) to which it is believed that a normal, healthy worker can be exposed repeatedly, day after day, for a normal 8-hour working day / 40-hour week, without suffering any adverse or harmful effects on health.

• It is set by occupational-health bodies for individual chemicals (e.g., ammonia, chlorine, SO2 vapours) found in industrial workplace air. …