Traditionally, air quality monitoring has been carried out using point, or lately, remote sensing measurements, often with a high time resolution (hours, days). Due to economical aspects this can only be made at rather few sites in a region.

In order to achieve a high spatial resolution of the concentration distribution of different air pollutants, the use of diffusive samplers has become an interesting tool. The diffusive samplers give average air concentrations with continuous time coverage from a few days up to a month. The technique offers a cost-effective method for air quality monitoring and the samplers are easy to handle.

The use of diffusive samplers, in combination with a careful selection of measurement sites, has been shown to be a fruitful strategy in mapping geographical variations in levels of air pollutants in a region with a complex emission pattern.