PPB

Definitions

1. Initialism of parts per billion.
   abbreviation, alt-of, initialism, plural, plural-only
2. Initialism of production-possibility boundary.
   abbreviation, alt-of, initialism

Equivalents

Examples

“The International Organization for Standardization (ISO)² does not accept⟳ the common use⟳ of parts per billion (ppb) for two reasons: the meaning of billion is ambiguous, and parts is also ambiguous because it could refer⟳ to volume, mass, number⟳, or some other measure⟳.”

“. Therefore, Great River Energy expects ozone and NO concentrations associated with the Project to be negligible, and well below all federal standards (nitrogen dioxide (NO2) – 100 parts per billion (ppb) as one-hour average, 53 ppb as annual average; ozone 70 ppb as 8-hour average).”

CEFR level