Our paper on isocyanic acid (HNCO) is in press at the Journal of Geophysical Research-Atmospheres. HNCO is emitted from fires, and some other sources, and is potentially harmful at high concentrations (> 1 ppb). The study is the first to investigate the global distribution of HNCO, following on from Jim Roberts et al.'s work in measuring the chemical in the atmosphere and understanding some of its physical and chemical properties - see their paper in PNAS.
We modeled high concentrations in several regions with large fire sources. The first figure below shows a map of the number of days where the model predicts surface concentrations of HNCO greater than 1 ppb, on a grid cell (2°x2°) basis. The second figure weights the data in a different way, showing the size of the population potentially impacted. The populations are for areas where HNCO is greater than 1 ppb for 7 days or more. Click on the images for larger versions.
Overall, we hope this study encourages atmospheric and health scientists to make more measurements and better understand any potential risks from exposure.
Some more information can be found from the NOAA Research article, CIRES press release or AGU blog post.
Young, P. J., L. K. Emmons, J. M. Roberts, J.-F. Lamarque, C. Wiedinmyer, P. R. Veres and T. C. VandenBoer (2012). Isocyanic acid in a global chemistry transport model: Tropospheric distribution and budget, and identification of regions with potential health impacts. Journal of Geophysical Research. doi:10.1029/2011JD017393.