The Mojave Desert Air Quality Management District (MDAQMD) is scheduled to consider adoption of amendments to Rule 1160 - Internal Combustion Engines on January 22, 2018. This proposed rule change is to satisfy federal Clean Air Act requirements for ozone non-attainment areas to implement Reasonably Available Control Technology (RACT) for major sources of VOC and NOx. The rule amendments also satisfy state PM control measure requirements. Rule 1160 regulates NOx, VOC, and CO emissions from Internal Combustion Engines that are greater than 500 bhp. The rule update will lower the NOx limit for Spark-Ignited, Lean Burn Engines from 140 ppmv to 125 ppmv and will substantially reduce the NOx limit of Compression-Ignited Engines from 700 ppmv to 80 ppmv.

This proposed rule change will affect many existing internal combustion engines covered by 23 existing permits, most of which are held at two existing PG&E and Southern California Gas facilities; these include five existing engines currently in compliance with the proposed rule updates. Note that these changes do not apply to portable, emergency, or agricultural operation engines. MDAQMD is requiring that engines installed with Emission Control Equipment to meet the new NOx limit also provide continuous measurement and recording of emission control system operating parameters. The requirement for compliance testing every 12 months remains unchanged. Facilities must keep records on site for a minimum of 5 years. There are 28 engines registered under MDAQMD that will be affected by the rule changes (see the Technical Report and Feasibility Analysis provided in Appendix F of the District's Staff Report).

For more information and support related to the details and impact of these changes, please contact our office at (949) 567-9880 or see the District's Staff Report on the rule amendments.