Isoprene emission in the U.S. in summer is estimated to be 5×1011 molecules cm-2 s-1. The glyoxal molar yield from isoprene oxidation is 10%. Assume a mixing depth of 1 km and an aerosol lifetime of 3 days, and further assume that glyoxal is in steady state. Calculate the resulting mean concentration of organic aerosol (in units of µg carbon m-3) from the glyoxal formation pathway. Compare to typical U.S. observations of 2 µg C m-3 for the concentration of organic aerosol. (Problem 4)