Final report from NMR project 'Test of a filter pack combined with a PM10 inlet'. Project number 04FOX5

The EMEP filter pack for measuring gaseous and particulate reduced and oxidised nitrogen compounds in air has been modified with a PM10 inlet to meet the EU air quality directive for particle measurements. The filter pack also collects sulphur compounds as well as base cations and sodium chloride. The EMEP filter pack has been used for 20 years now and it is important that the PM10 inlet doesn't affect the results. The cut-off for the filter pack recommended by EMEP is unknown and may be affected by wind. Here it was found that the cut-off for the EMEP filter pack is larger than it is for PM10. This implies that higher calcium concentrations will be obtained with the original EMEP filter pack without a PM10 inlet. All comparisons of the two filter packs show excellent agreement for sulphur dioxide and man made sulphate particles. Some losses of total nitrate have been found with the PM10 inlet especially of particulate nitrate. Some losses of particulate ammonium also take place but do not affect the total concentration.

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