This study presents the first gaseous formic acid (HC(O)OH) concentration measurements collected over the Fenno-Scandinavian wetlands (67.9–68.0° N, 22.1–27.8° E) as part of the MAMM (Methane and other greenhouse gases in the Arctic-Measurements, process studies and Modelling) aircraft campaigns conducted in August and September 2013. A boundary layer box model approach has been used to calculate a regionally representative (~240 km2) surface flux for HC(O)OH of 0.0098 (±0.0057) mg[HCOOH]·m−2·h−1. A surface-type classification map was used to estimate proportional source contributions to the observed HC(O)OH flux over the measurement region. The removal of expected source contributions (using available literature parameterisations) from the calculated surface flux identified that 75% remained unaccounted for. This may suggest that HC(O)OH emission from wetland within the Fenno-Scandinavian region could contribute up to 29 times higher per unit area than previous theoretical HC(O)OH globally-averaged wetland estimates, highlighting a need for further constrained wetland studies of HC(O)OH emission to better understand its potentially significant impact on the Arctic HC(O)OH budget and consequent impacts on oxidative capacity.
