Section 445B.420 - Limitations on duration; annual review1. The following limitations of duration apply to all variances: (a) If the variance is granted because no practical means is known or available for prevention, abatement or control of the air pollution involved, the variance shall continue only until such means become known and available.(b) If the variance is granted because compliance with applicable regulations will require measures which, because of extent or cost, must be spread over a period of time, the variance shall be granted only for the requisite period as determined by the Commission, and shall specify the time when the successive steps are to be taken.(c) If the variance is granted for any other reason, it shall be granted for 1 year or less.2. A variance whose duration is limited by paragraph (a) or (b) of subsection 1 shall be reviewed at least once each year to determine whether practical measures have become available or required steps have been taken.Added to NRS by 1971, 1198(Added to NRS by 1971, 1198)-(Substituted in revision for NRS 445.516 )