 |
Screening studies are often undertaken to perform a preliminary assessment of the air quality in a given area. Several methods may be applied for performing these screening studies.
Screening techniques may be based on the use of simple inexpensive integrated sampling techniques, the use of mobile laboratories, arrays of passive samplers or other manual methods. Because of their relatively low cost and their simple and fast operation they will only serve as limited time period indicative tools, in comparison with fixed monitoring stations. Three different approaches have been proposed:
- Diffusive sampling technique
(passive samplers);
- Use of
a mobile laboratory in areas of maximum concentrations;
- Use
manual methods of a mobile laboratory for grid measurements.
or a combination of one or more of the proposed approaches.
Also the use of "grab samples" may be used, where a simple sampler is brought to a potential area of maximum concentration, and a short-term (5 min to 1 hour) sample is collected and brought to the laboratory for analyses. These types of data have to be carefully connected to other observation such as wind directions, weather conditions, time and position and possible accidental or irregular releases.
|
