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HONO-Measurements During the OS Field Campaign at AMS13

Informal Lunchtime Atmospheric Chemistry Discussion Series
Presented by:
Kevin Nikelski, Graduate Student
April 7th, 2015 at Noon - 1PM
317 Petrie Science and Eng. Bldg.

Description: Nitrous acid (HONO) is of particular relevance to atmospheric chemistry in regards to its significant contribution to photochemical production of the OH radical, which serves as the main daytime oxidant in the troposphere. Many studies have reported observing significant HONO mixing ratios during daylight hours, which could be due to an as yet unexplained continuous daytime source and/or indicating a method of HONO uptake and storage during the night with subsequent release the next day. In this talk, I will discuss HONO measurements from Aug 17th- Sept 11th during the OS field campaign in the region near Fort McMurray Alberta at the AMS13 ground site. The measurements in question were obtained through use of a DOAS 2000 telescope and 30 corner cube retro-reflector, along a 2.304 km path length. The methodology for spectral fitting of HONO using (DOASIS) will be discussed in some detail, as will both night-time and daytime preliminary mixing ratios. Preliminary results indicate that HONO mixing ratios at night during the OS field campaign were typically less than 300ppt, much lower than those observed in the urban area of Toronto (York University), which has a median nighttime maxing ratio of 1.0ppb. The lower levels of HONO at AMS13 is consistent with the lower night-time mixing ratios of the main precursor, NO2, which had a night-time median of 1.1 ppb during dark periods at AMS13, compared to a nighttime median of 16ppb in Toronto.
Bring your own Coffee/Tea mug. Snacks will be served.

Updated on March 26th, 2015.