About 360 fine nylon strings are arranged to form a 50-cm high cylindrical `fog catcher'. Fog water droplets collect on the fine nylon strings and the droplets run down into sample bottles enclosed inside the base of the collector. During a fog event, the collector can accumulate up to 0.5 litres in 8 hrs. For mercury and heavy metals, 100 ml of fog water is needed for each sample.  But for organochlorines, because they are present in very low concentrations, 4 litres of fog water (collected in acid-washed glass bottles) are needed per sample.

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