WIT Press

Ozone And NOy In The Milan Plume: The Episode Of June 19-21,1998

Price

Free (open access)

Paper DOI

10.2495/AIR990611

Volume

37

Pages

10

Published

1999

Size

988 kb

Author(s)

A. Thielmaim, A.S.H. Prevot and J. Staehelin

Abstract

Nitrogen oxides (NOx=NO+NC>2), total reactive nitrogen NOy, ozone (Og), JNO% and volatile organic compounds (VOC) were measured for 10 weeks during spring and summer 1998 in the highly polluted Milan agglomeration. The concentrations during the episode of June 19 to 21 are analyzed. During this period ozone peaks at 160 ppb, NOy at 36 ppb. The high NOz/NOy-ratio in the afternoon indicates aged air masses reaching the station. We refer to NOz as the difference between NOy and NOx. It stands for NOx consumed during the photochemical aging of the air mass. Depending on the origin of the air mass the limitation of the ozone production shifts between VOC- and N

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