and so what what you know what we do to make contributions so that basically we go and do things like put in uh high-tech scrubber systems uh that uh scrub out the NOX and uh VOCs and and the ammonia compounds uh like all the acids uh to a certain level we are very um uh aware of the opacity which is the thickness of a stack emissions so if you don't see anything coming out of a stack the opacity is zero or twenty or there abouts