The low ozone probability plot also includes offshore areas all along the north, central and south Atlantic and Gulf Coasts, which are also obviously areas of low emissions density, but which are not obviously areas of high wind speeds. It is likely that air masses moving to inland receptors from these marine areas will often be associated with clouds, fog or precipitation. We certainly don't believe that low wind speed provides a justification for high emissions, or a distortion of the perceived influence of emissions contributing to high ozone concentrations. Meanwhile, we suggest some overview of the above-referenced climatological studies would be a useful section to include in the AQA summary. Don't Indicate Origin of Emissions Causing High Ozone Summary.
Short trajectories mean lower wind speeds near the receptor.
This increases the potential for ozone accumulation near the receptor. Low wind speeds are also correlated with other parameters which are associated with high ozone concentrations. The short trajectories are markers of stagnation relatively near the point of ozone impact, not of stagnation farther upwind. Since ozone has a finite lifetime in the atmosphere, the farther upwind in time that ozone is formed, the less proportional impact that that ozone will have on the downwind receptor. Most of the ozone formed near the beginning of a 3-day trajectory has already been deposited or reacted with VOC s.