Section 675.006 - Air Sampling Requirements(A) Operators of indoor skating rinks which utilize combustion resurfacing equipment shall take regular air samples of both carbon monoxide and nitrogen dioxide within their skating rinks as follows: (1) an air sample for both carbon monoxide and nitrogen dioxide must be taken at least three times a week, including at least twice during the week and at least once during weekend operations;(2) all air samples must be taken 20 minutes after resurfacing is completed;(3) all air samples required by 105 CMR 675.000 must be taken no sooner than four hours before, and no later than one hour before the end of the last scheduled use of the ice in any given day.(4) all air samples must be taken either at center ice or the perimeter of the ice surface at the center ice line at a height of three to six feet above the ice surface;(B) If an operator of an indoor skating rink utilizes combustion resurfacing equipment less than four times in any week, the operator shall take an air sample in accordance with the requirements of 105 CMR 675.006(A)(2) and (4) each time it utilizes the combustion resurfacing equipment.(C) Any individual conducting air sampling must be familiar with the requirements of 105 CMR 675.000 and must be properly trained in the appropriate use of the air monitoring equipment.(D) The operator shall be responsible for the recording of all air sampling conducted in accordance with the requirements of 105 CMR 675.000 in the record keeping log, in a manner specified in 105 CMR 675.007. Any air sample of nitrogendioxide which results ina reading below 0.5 ppm shall be recorded in the record keeping log as "below detection".