The existence of CO in a vehicle park signifies that other harmful fumes (e.g. benzene) may also be present. Due to this, the German authorities have reduced the limits for CO in vehicle parking facilities from one hundred ppm to fifty-sixty ppm, with regards to the federal condition in concern. https://basement-ventilation90012.win-blog.com/17371283/getting-my-car-park-ventilation-to-work