The presence of CO in a vehicle park implies that other dangerous fumes (e.g. benzene) will also be present. As a result of this, the German authorities have decreased the limits for CO in car parking services from 100 ppm to 50-60 ppm, dependant upon the federal point out in https://car-park-ventilation80124.spintheblog.com/36872525/basement-ventilation-things-to-know-before-you-buy