Respirator Recommendations. NIOSH/OSHA. Up to 100 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode*. (APF = 50) Any chemical cartridge respirator with a full facepiece and cartridge(s) providing protection against the compound of concernÂ¿. (APF = 25) Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern*Â¿.
A molecule is a particle containing two or more atoms. If it contains only one type of atom it is called an element. An exception to this is diatomic gases (for example: Oxygen, O 2, where the molecule contains two atoms of the same element, bonded covalently.
1. the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound. 2. a quantity of a substance, the weight of which is numerically equal to the molecular weight; gram molecule. 3. any very small particle.