Most noise ordinances set maximum levels for two time periods: Day (7am to 10pm) and Night (10pm to 7am). San Diego (Article 9.25)sets three periods: Day (7am to 7pm), Evening (7pm to 10pm), and Night (10pm to 7am) and exempts industrial zones from time based restrictions. Seattle, WA (Chapter 25.08) sets two time periods but changes 7am to 9am on weekends and holidays. Several states have maximum permissible land use sound levels in dB(A). Most have Day and Night periods and three use categories: residential, Commercial and Industrial. Washington (Chapter 70.107) sets maximum levels in dB(A) but allows 5 dB(A) more if the sound is only 15 minutes in an hour, or 10 dB(A) for 5 minutes in an hour. Numerous cities have fixed levels, permitting excess levels for short times (e.g., Dallas, TX, Chapter 30) while others use Leq (Lincoln, NE, Chapter 8.24). Los Angeles, CA (Chapter XI) uses a relative level with a stated but "presumed" ambient. New York City, NY (Chapter 19) requires Leq measurements to be made over one hour. Atlanta, GA () limits impulsive sound to 100 dB(C) at property lines, while most reduce the maximum level by 5 dB for pure tones and impulsive sounds.