… cleaning or doing hobbies. PCE evaporates into the air. People are commonly exposed to PCE by breathing air containing its vapors. PCE can contaminate home air when people use cleaning … billion by volume (ppbv). The action level is considered to be protective of public health. Breathing PCE for a lifetime at 6 ppbv is very unlikely to be harmful to people. If PCE … The following symptoms may occur immediately or shortly after exposure to high levels: Breathing air containing more than 100 ppm (or 100,000 ppbv) of PCE may cause dizziness, …