How do you prevent contamination from nearby conventional farms?

We are sometimes adjacent to conventional farms. Part of the organic certification inspection is the scientific establishment of an appropriate buffer between an organic farm and any nearby risk. We have to take into account topography, weather, prevailing winds, activities, and all other risks, then propose a buffer of sufficient size to mitigate the risks. This is why the size of buffers is not established in the organic standards – each buffer is established based on local specifics.