The increase of pollutants (nitrogen oxides and ozone) in the summertime Midwest
We use the Geophysical Fluid Dynamics Laboratory (GFDL) Global Chemical Transport Model, with the six known sources for tropospheric NOx and off-line calculations of daytime gas-phase nitrogen photochemistry and night-time heterogeneous chemistry, to simulate the summer time concentrations of reactive nitrogen compounds for pre-industrial, current and future emission scenarios. We predict that NOx levels will increase another 30% by 2020. Using a simple relationship that relates NOy and NOx concentrations to the net chemical production of ozone at rural sites (Trainer et al. 1993) we estimate, conservatively, that the ozone, which was at relatively harmless levels in the pre-industrial period, is now at the crop-damage threshold of 50-70 ppbv in parts of Illinois, Indiana and Ohio. -from Authors
