Supplement of Atmos. Chem. Phys. Discuss., 14, 24863–24914, 2014 http://www.atmos-chem-phys-discuss.net/14/24863/2014/ doi:10.5194/acpd-14-24863-2014-supplement © Author(s) 2014. CC Attribution 3.0 License. Supplement of Investigation of secondary formation of formic acid: urban environment vs. oil and gas producing region B. Yuan et al. Correspondence to: B. Yuan (
[email protected]) 31 Table S1. Comparisons of measured and modeled formic acid in previous studies. Studies Location and time Model Notes Atlantic Ocean 1 MOGUNTIA Model results are 8 times lower than observations. (1996.10-11) Amazonia, Congo, Model underestimates HCOOH both in free 2 MOGUNTIA Virginia troposphere and boundary layer. Marine air, and MATCH- Measurements are underestimated by a factor of 2 or 3 those in Poisson et MPIC more, except in Amazon. al. MATCH- Measured concentrations are substantially higher than 4 Kitt Peak, US MPIC the model-calculated values. Model underestimates HCOOH compared to 5 Various sites IMPACT observations at most sites. Various sites Sources of formic acid may be up to 50% greater than 6 (MILAGRO, GEOS-Chem the estimates and the study reports evidence of a long- INTEX-B) lived missing secondary source of formic acid. Model underestimates HCOOH concentrations by up Trajectory to a factor of 2. The missing sources are considered to model with 7 North Sea (2010.3) be both primary emissions of HCOOH of MCM V3.2 & anthropogenic origin and a lack of precursor CRI emissions, e.g. isoprene. The globally source of formic acid (100-120 Tg) is 2-3 Satellite times more than that estimated from known sources.