21.   The results found a small deviation from the Standard Model in how the particles move on the order of one part per million, according to Roberts.

22.   The steels are alloys, with titanium, columbium and vanadium each used in ratios of a few parts per thousand.

23.   Even in its tiniest proportions, five parts per billion, MTBE has an easily detectable smell.

24.   In controlled testing conditions, the machine can detect odors at two parts per billion, which equals the performance of trained dogs.

25.   Pollutants are measured in parts per billion.

26.   Space station program manager Tommy Holloway notes that every shuttle flight has risks, given the million-plus parts per ship.

27.   The maximum contaminant level allowed for PCE in drinking water is five parts per billion.

28.   The salinity is usually diluted to about two to four parts per thousand, the level considered suitable for inland shrimp farms.