Dear Windy. You have created an app that I know is creating significant environmental awareness. Almost every day I tell people about your literally stunning product. I wish to press you on the merge layers request as my desire is to "combine" layers such as aerosol, CO2, SO2, dust, NO2 to show areas of major polution. If we could make this historical then we have a major tool to reveil polution and spread awareness. This is you challeng my friends :-) together I hope we can make a difference. Maybe this can be done offline as an export of a set time.