BVOC emission potentials for street and park trees of five common species is Montreal (Canada) and Helsinki (Finland)

The dataset contains BVOC emission rates (unit ng g-1 (DW) h-1) and emission potentials (emission rates normalised to T 30ᵒC and PAR 1000 µmol m-2 s-1 based on Guenther, 1997, https://doi.org/https://doi.org/10.1890/1051-0761(1997)007[0034:SASVIN]2.0.CO;2 , unit µg g-1 (DW) h-1) calculated from direct measurements from leaves of mature urban trees Montreal, Canada and Helsinki, Finland. For BVOC measurements, we used lightweight enclosures and adsorbent tubes that were analysed using thermal desorption - gas chromatograph - mass spectrometer (TD-GC-MS). In both cities, we targeted five common broadleaved species: Quercus macrocarpa, Populus x cansecens, Acer platanoides, Tilia cordata and Gleditsia triacanthos in Montreal; and Quercus robur, Betula pendula, Acer platanoides, Tilia x europaea and Ulmus glabra in Helsinki. We sampled BVOCs from three trees in parks and three trees on streets (sidewalk pit or planting strip) per species, twice in Montreal (in June and in August 2022) and once in Helsinki (July 2022). Supporting measurements include ambient and enclosure temperature and relative humidity, photosynthetically active radiation beside the enclosure, ambient ozone (O3) concentration, leaf water potential, and leaf area and dry mass of the enclosed shoot. Dataset is structured by measured tree and date on the rows, and each additional information, measured variable, BVOC and sum of monoterpenoids, sesquiterpenoids and green leaf volatiles (GLV) on the columns. Compounds not included in GC-MS calibration standards and calibrated based on the closest compound by retention time and identifier ion are marked with _x. Monoterpenoids, sesquiterpenenoids and GLVs that were detected and tentatively but not reliably identified are marked as monoterpenoids_no_x, sesquiterpenoid_no_x and GLV_no_x. Due to their tentative identification, their quantification carries more uncertainty than the compounds that were in the calibration standards.