Reactivit'Air

An important part of my Academy Research Fellow project (2017-2022) funded by Academy of Finland was the development of an instrument to measure total ozone (O3) reactivity. The paper describing the method we use, based on an idea by Dr. Detlev Helmig, and developed together with his group, has just been published in Atmospheric Measurement Techniques . At the time of my proposal submission in 2016, there had been only one publication on the topic of total O3 reactivity measurement by Prof. Jun Matsumoto (Waseda University, Tokyo, Japan). I was also aware of measurements that had been done by Dr. Helmig's group that had been presented at conferences. This is why I visited Prof. Matsumoto in Tokyo in December 2017 and then went to Boulder CO, U.S.A. , with Anssi Liikanen , in January 2018. Anssi stayed almost two months to work in Dr. Helmig's laboratory, performing many tests on the total O3 reactivity monitor (TORM).   Figure 1. Left: TORM at the Toolik Field Station, Alaska...

In our latest publication, we investigated with total hydroxyl radical (OH) reactivity measurements our understanding of emissions from three tree species found in the boreal forest. The unexplained fraction of the reactivity remain high in some circumstances. We recently published in Biogeosciences the results of our study from 2017, where we analysed the emissions from three different trees with gas chromatographic methods and total OH reactivity instrumentation. We analysed emissions at the branch level with enclosure for birch, spruce, and pine. Our findings are that emissions do vary in amount and composition throughout the growing season and we could show, based on reactivity measurements, that the emissions are not fully characterized chemically. In particular when trees were subject to stress (that was clearly visible with, for instance, browning leaves or needles) the reactivity of the emissions increased a lot and we observed simultaneously an increase of emissions of Green L...