what's required for booth exhaust depends on where you are - for starters most up to the minute systems now are downdraft, but vent straight up, and particulate filters have also gotten very high tech, but some areas do require very spendy scrubbers, water washing, or even carbon filters - I'd think CA would have the toughest standards
work out a way to 'biofilter' the exhaust and you've got it covered - pump the exhaust air into a mound of soil
Bill
