What does dose mean?
The amount of a chemical that is absorbed or inhaled is called the dose. The dose depends on two factors: (1) The amount of the chemical, and (2) the length of time you?re exposed. This is to say that the ceiling of the safe range of exposures could be exceeded by the amount of a chemical (too much chemical) or the length of exposure time (too much time), or both. When we try to determine the safe amount of a chemical, we usually assume the worst-case; that is, if you breathed the chemical 24 hours a day, 7 days a week, over the 52 weeks of a year. That way, we can be sure we don’t underestimate the dose. Safe amounts of some chemicals are also determined for one-time exposures at shorter periods. The other aspect of determining the dose is the concentration. In regard to air quality monitoring around the ConocoPhillips-Rodeo refinery, these concentrations are determined by instruments at the facility’s fenceline. The instruments record both peak levels and the averages over various pe
