ECN publication
Characteristics of the ultra fine particle fraction on various distances along motorways
Published by: Publication date:
ECN Biomass, Coal and Environmental Research 24-11-2008
ECN report number: Document type:
ECN-E--08-084 ECN publication
Number of pages: Full text:
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Number concentration data of ultrafine particles (diameter less than 100 nm) were collected along two Dutch motorways. Measurements were performed with a scanning mobility particle sizer (SMPS; size range 13-284 nm) and a condensation particle counter (CPC) sequentially positioned at increasing distances downwind from the roadside and at one upwind location measuring the background air. It is found that the magnitude of the local wind speed substantially affects particle number levels due to dilution: a higher wind speed results in fewer particles in the air. After correction for this effect the decrease in particle number downwind of the motorway can be described rather well by exponentially decaying functions.

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