John Smith turns on his industrial fan to vent his noxious fumes to the atmosphere and shortly can smell "Mary Jane."
I worked for years at moving air and am still good at it. John's problem is his make-up air (intake) is in the wrong location, it would be the same with fried chicken or burgers. Methinks he would not pro-test so much. He did not spend enough thought (money) on his ventilation system, now it's every-body else's fault .
Alan J. Wilden Chilliwack