{"data":{"id":"us/40-cfr-1039.105","jurisdiction":"us","citation":"40 CFR 1039.105","heading":"What smoke opacity standards must my engines meet?","body":"(a) The smoke opacity standards in this section apply to all engines subject to emission standards under this part, except for the following engines:\n(1) Single-cylinder engines.\n(2) Constant-speed engines.\n(3) Engines certified to a PM emission standard or FEL of 0.07 g/kW-hr or lower.\n(b) Measure smoke opacity as specified in § 1039.501(c). Smoke opacity from your engines may not exceed the following standards:\n(1) 20 percent during the acceleration mode.\n(2) 15 percent during the lugging mode.\n(3) 50 percent during the peaks in either the acceleration or lugging modes.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER U—AIR POLLUTION CONTROLS","PART 1039—CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES","Subpart B—Emission Standards and Related Requirements"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"2f3c5f96aa3f11a81e74648362444f35b4efabad5cdb89ea839e51a7838ad315","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-1039.104","next":"us/40-cfr-1039.107"},"notice":"GroundRules: Original legal text. Not legal advice."}