Here is a snapshot of how precipitation affects pollution estimates in i-Tree Eco from our Environmental Modeler.
- For carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), air pollutant removal becomes greater without precipitation. This is because dry deposition only happens when no precipitation occurs. When it is raining, dry deposition doesn't happen.
- For particulate matter less than 2.5 microns (PM2.5), air pollutant removal becomes much smaller without precipitation. PM2.5 is considered removed from the atmosphere when those particles accumulated on leaves are washed off by precipitation. In other words, without precipitation PM2.5 only goes back and forth between atmosphere and leaves (re-suspension) and thus no PM2.5 is removed. For the annual result, the final value accumulated on the leaves is considered removed in Eco.
i-Tree Eco Dry Deposition Model Descriptions - Provides an overview of the i-Tree Eco dry deposition model and descriptions of its calculations, updated Feb 27, 2015.
https://www.itreetools.org/eco/resource ... ptions.pdf