thank you for your message. In the Depositon Manual several methods to estimate dry deposition are currently mentioned, i.e. 1) based onmeasurements of throughfall and wet-only deposition in the open field, 2) using different canopy budget models and 3) inferential method using air concentrations and deposition velocities. Regarding your proposal, I assume you mean different methods, e.g. to measure dry deposition directly? A substantial update of the Manual as you suggest can be done only once every 5 years (latest update 2016). So the next Expert Panel meeting in Brussels (25-29 March 2019) would be an ideal moment to make a start. Would you like to present your ideas to the other deposition experts there? You could indeed create a working group thereafter and try to come up with a proposal for an addition to the Deposition Manual before the Task Force in 2021. What do you think?