Passive sampling costs

To develop a feeling for the sensitivity of the allocation scheme to values of ol and ag, we have prepared examples that reflect passive sampling, followed by TEM analysis. Me use values of Cl = 20 and C2 = 500 and evaluate the solution for total budgets of 5,000 and 15,000. These figures are based on typical costs for TEM analysis. Costs will vary among laboratories and depend on the analytical method (TEM, SEM, or PCM) chosen. Mote that Ol and Og... 

Thermal desorption is a high-cost method it consumes the entire sample in one analysis. Nevertheless it is preferred over solvent extraction in active and passive sampling methods for the analysis of volatiles mainly due to the enhanced. 

Passive samplers are widely used in monitoring volatile organic chemicals (VOCs) in groundwater. Such samplers have the potential to reduce costs of monitoring from the high levels associated with the use of pumps to sample the test wells. Moreover, the risk of loss of volatile analytes during sample transport and storage is substantially reduced once the compounds are accumulated in the sampler sorption phase. 

Analysis of 02 as well as C02 in exhaust gas is becoming generally accepted and is likely to be applied as a standard measuring technique in bioprocessing. It is possible to multiplex the exhaust gas lines from several reactors in order to reduce costs. However, it should be taken into account that the time delay of measurements with classical instruments is in the order of several minutes, depending on the efforts for gas transport (active, passive) and sample pretreatment (drying, filtering of the gas aliquot). 

However, these costs cannot be directly compared. Passive samplers are, for example, deployed for two weeks or one month and deliver a time-integrated information for this period. It is obvious, that one spot sample in the same period... 

Table 6.1.3 Cost of passive samplers and spot sampling in the Czech and German case studies...

Cost of passive samplers for 4 times 1 month Cost of one spot sample with classical methods Number of spot samples possible... 

A diffusive/passive sampler is a device which is capable of taking samples of gas or vapour pollutants from the atmosphere at a rate controlled by a physical process such as diffusion through a static air layer or permeation through a membrane, but which does not involve the active movement of air through the sampler (Brown, 1993 Moore, 1987). Compared with methods requiring pumps for active air movement, diffusive samplers are more convenient and have lower associated costs. 

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