### United States Code

USC most recently checked for updates: May 28, 2023

In the case of sulfur oxide and particulate matter, each applicable implementation plan shall contain measures assuring that maximum allowable increases over baseline concentrations of, and maximum allowable concentrations of, such pollutant shall not be exceeded. In the case of any maximum allowable increase (except an allowable increase specified under section 7475(d)(2)(C)(iv) of this title) for a pollutant based on concentrations permitted under national ambient air quality standards for any period other than an annual period, such regulations shall permit such maximum allowable increase to be exceeded during one such period per year.

Pollutant
| Maximum allowable increase (in micrograms per cubic meter) |
---|---|

Particulate matter: | |

Annual geometric mean | 5 |

Twenty-four-hour maximum | 10 |

Sulfur dioxide: | |

Annual arithmetic mean | 2 |

Twenty-four-hour maximum | 5 |

Three-hour maximum | 25 |

Pollutant
| Maximum allowable increase (in micrograms per cubic meter) |
---|---|

Particulate matter: | |

Annual geometric mean | 19 |

Twenty-four-hour maximum | 37 |

Sulfur dioxide: | |

Annual arithmetic mean | 20 |

Twenty-four-hour maximum | 91 |

Three-hour maximum | 512 |

Pollutant
| Maximum allowable increase (in micrograms per cubic meter) |
---|---|

Particulate matter: | |

Annual geometric mean | 37 |

Twenty-four-hour maximum | 75 |

Sulfur dioxide: | |

Annual arithmetic mean | 40 |

Twenty-four-hour maximum | 182 |

Three-hour maximum | 700 |