Mark your calendars for the first Rocky Mountain States Section’s luncheon meeting of 2017, which will be held Thursday, January 12th at Tri-State Generation & Transmission, 1100 W 116th Ave, Westminster, CO 80234. We plan to start with lunch and networking at 11:30, followed by our guest speaker, Detlev Helmig of the Institute of Arctic and Alpine Research at the University of Boulder, at noon.

Topic: 2000 – 2015 Changes in the Summertime Ozone Chemistry in Colorado. Detlev will present an assessment of long-term (2000-2015) ambient ozone mixing ratios, diurnal amplitudes, and trends using hourly ozone data from a total of 47 sites in the State of Colorado, focusing on summer ozone values (June, July, August), which is the time when most exceedances of the ozone National Air Quality Standard have been recorded. For sites with at least 10 years of complete datasets, (19 sites total) trends were determined for the yearly 5th, 50th and 95th percentile values of the ozone mixing ratios, and for the daily ozone amplitudes. For ozone mixing ratios, most sites show an increase of the 5th and 50th percentile values, whereas the majority of sites experienced a decrease of the 95th percentile values. In contrast, most of the sites show a decrease of the yearly 50th and 95th percentile values of the daily amplitudes. The dichotomy of ozone diurnal amplitudes and trends, and their spatial distribution is discussed in terms of the influence of ozone precursors, i.e. volatile organic compounds (VOC) and nitrogen oxides (NOx) emission and reported ambient concentration in the State of Colorado.

Speaker Bio: Detlev Helmig is an Associate Research Professor, Institute of Alpine and Arctic Research (INSTAAR) and Program in Atmospheric and Oceanic Sciences (PAOS), University of Colorado, Boulder. He received his PhD in Chemistry at the University of Duisburg/Germany, has published numerous atmospheric chemistry articles, and been an invited speaker for the American Geophysical Union, the National Oceanic and Atmospheric Administration, and other scientific organizations in France, Germany, Great Britain, Switzerland and the United States. A more detailed bio can be found at

If you plan to attend this meeting, please RSVP by Wednesday, January 11 to Bethany Moffat at [email protected].