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result of their concerns for security/safety, noise, dust, and odor concerns (Price, 2007). In the CNHS field study, 32% of the homes did not use their windows during the 24-hour Test Day, and 15% of the homes did not use their windows during the entire preceding week. Most of the homes with no window usage were homes in the winter field session. Thus, a substantial percentage of homeowners never open their windows, especially in the winter season. The median 24-hour measurement was 0.26 air changes per hour (ach), with a range of 0.09 ach to 5.3 ach. A total of 67% of the homes had outdoor air exchange rates below the minimum California Building Code (2001) requirement of 0.35 ach. Thus, the relatively tight envelope construction, combined with the fact that many people never open their windows for ventilation, results in homes with low outdoor air exchange rates and higher indoor air contaminant concentrations. According to the Draft Subsequent Environmental Impact Report Metro East Mixed -Use Overlay District Expansion and Elan Development Project (ICF, 2018), the Project is close to roads with moderate to high traffic (e.g., I-5, East 4th Street, North Cabrillo Park Avenue, etc.). This report state in Table T3.7.1, the existing 2018 ambient noise levels range from 63.7 to 73.0 dBA CNEL. Thus this Project is located in a sound impacted area. In order to design the buildings for this Project such that interior noise levels are acceptable, an acoustic study with actual on -site measurements of the existing ambient noise levels and modeled future ambient noise levels needs to be conducted. The acoustic study of the existing ambient noise levels should be conducted over a one -week period. and report the dBA CNEL or Ldn. This study will allow for the selection of a building envelope and windows with a sufficient STC such that the indoor noise levels are acceptable. A mechanical supply of outdoor air ventilation to allow for a habitable interior environment with closed windows and doors will also be requires. Such a ventilation system would allow windows and doors to be kept closed at the occupant's discretion to control exterior noise within building interiors. 11 of 19