Determination of variable PAN in wrf chem output wrfout

[peng]

I noticed an output variable PAN in the wrfout file in wrf chem4.1. I believe this variable is Peroxyacetyl nitrate (CH3C (O) OONO2), but I did not provide a clear explanation in the manual or other places. If you could provide some more detailed information on the PAN variable, I would greatly appreciate it