The 1971 regulation on Air Quality, which was promulgated under the Israeli 1961 Abatement of Nuisances Law, defined ambient air quality standards for pollutants (SO2, H2S, O3, Pb, CO, NOx, and total suspended particulate matter) and the corresponding averaging time periods. New revised and expanded standards became effective in May 1992, which cover 21 air pollutants, including gases and particulate not covered previously. The air quality standards are absolute standards (SO2 excepted)( ) and cannot be exceeded.