I also learned that to study the aerosol indirect effect, the options "wetscav_onoff" and "cldchem_onoff" should be set to 1. And it is mentioned in the "Best Practices for Applying WRF-Chem 3.9.1.1" tutorial presentation that in the "chem" section of the namelist, "conv_tr_aqchem" and "conv_tr_wetscav" should be set to 1 to include aqueous chemistry and convective wet scavenging. So, what should I set for the options "chem_conv_tr", "conv_tr_wetscav", and "conv_tr_aqchem" for d02 (4 km)? "0" or "1"'? Could someone please help me sort this out? It will be very helpful for me. Thank you for your time and consideration. With regards, Ankan