Absorption Indices Of Airborne Pollutants And Their Practical Use

The amount of airborne compounds polluting the workplace and absorbed via the lungs of exposed populations [uptake (U)] can be expressed as the difference between the inhaled (I) and exhaled (E) quantities:U=I-E=(V) over dot (CAMB- C(E) over dot)where (V) over dot, CAME and C (E) over bar are the pulmonary ventilation, the mean environmental and the mean expired concentrations, respectively.Two supplementary indices of absorpion are the retention index (R):R=(CAMB-C (E) over bar)/(CAMB)and the alveolar clearance (ClA):ClA = (V) over dot x RTaken all in all, the uptake is also the product of 4 parameters:U = (V) over dot x CAMB x R x T(where T is the time of exposure).These indices are of practical use in the field of the kinetics of inhaled and absorbed foreign compounds. In particular they can be used in the following frameworks:a) In epidemiological surveys for the classification of populations according to "occupational risk indicators"b) Calculation of biotransformation ratesc) Effect of workload during the wokshifts on the biological levels of pollutants taken up via the lungs; environmental concentrations being equal.Some explanatory examples and some experimental data on these subjects are reported.