Ground-level ozone is a growing problem in many cities, especially on the US west coast. As noted by the EPA, it causes respiratory problems like throat irritation, tightness in the chest, and increased occurrence of asthma attacks. That’s why, on October 1st2015, the National Ambient Air Quality Standard was lowered from 75 to 70 ppbn. This has implications for the fuel burnt in automobile and truck engines, and supports increased use of compressed natural gas (CNG.) CNG for vehicles is delivered through specially-designed filling stations, which are good applications for ChemTec flow monitors and excess flow valves.