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In fractions like "2 nanometers per meter" (2 n m / m = 2 nano = 2×10 −9 = 2 ppb = 2 × 0.000 000 001), so the quotients are pure-number coefficients with positive values less than or equal to 1. When parts-per notations, including the percent symbol (%), are used in regular prose (as opposed to mathematical expressions), they are still pure ...
Atmospheric pollutant concentrations expressed as mass per unit volume of atmospheric air (e.g., mg/m 3, μg/m 3, etc.) at sea level will decrease with increasing altitude because the atmospheric pressure decreases with increasing altitude.
Within each table, the units are listed alphabetically, and the SI units (base or derived) are highlighted. ... ≈ 1.660 539 068 92 (52) × 10 −27 kg ...
Notes: 1 atm = absolute pressure of 101.325 kPa or 1.01325 bar; mol = gram mole and kmol = 1000 gram moles Pollution regulations in the United States typically reference their pollutant limits to an ambient temperature of 20 to 25 °C as noted above.
Toggle the table of contents. Orders of magnitude (mass) 16 languages. ... kg: kilogram: 10 −6 g μg: microgram (mcg) 10 6 g Mg megagram 10 −9 g ng: nanogram:
In the metric system, a microgram or microgramme is a unit of mass equal to one millionth (1 × 10 −6) of a gram. The unit symbol is μg according to the International System of Units (SI); the recommended symbol in the United States and United Kingdom when communicating medical information is mcg .
The examples don't seem to be too accurate. A drop is usually defined as 0.05 ml, which then gives;. 1 drop in 50 ml = 1‰, 50ml is a very small cup 1 drop in 50 l = 1ppm 50 l is about 11 gallons, not 40 1 drop in 50 cubic metres = 1 ppb 1 drop = 1ppt, a 50 m swimming pool is 50*25*2 = 2,500 m^3 1 drop in 50,000,000 cubic metres = 1ppq, 50,000,000 m^3 is equivalent to a lake covering a square ...
The provisional tolerable daily intake (PTDI) for patulin was set at 0.43 μg/kg body weight by the FDA [3] based on a NOAEL of 0.3 mg/kg body weight per week. [3] Monte Carlo analysis was done on apple juice to compare exposure and the PTDI. Without controls or an action limit, the 90th percentile of consumers would not be above the PTDI.