Search results
Results From The WOW.Com Content Network
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.
Some express the concentrations as ppmv (parts per million by volume) and some express the concentrations as mg/m 3 (milligrams per cubic meter), while others require adjusting or correcting the concentrations to reference conditions of moisture content, oxygen content or carbon dioxide content.
Its units are in parts per million (ppm) for gases and in milligrams per cubic meter (mg/m 3) for particulates such as dust, smoke and mist. The basic formula for converting between ppm and mg/m 3 for gases is ppm = (mg/m^3) * 24.45 / molecular weight. This formula is not applicable to airborne particles.
Criteria can be set in different units (e.g. μg/m 3, parts per billion by volume (ppbv), parts per billion by mass (ppb (mass)), parts per million (ppm)) and it is possible to convert between all of these units if the molecular mass of the pollutant and the temperature are known. Different standard temperatures are used throughout the world ...
For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air (Molar mass of CFC-11 / Mean molar mass of air = 137.368 / 28.97 = 4.74). For volume fraction, the suffix "V" or "v" is sometimes appended to the parts-per notation (e.g. ppmV, ppbv, pptv).
where TDS is expressed in mg/L and EC is the electrical conductivity in microsiemens per centimeter at 25 °C. The conversion factor k e varies between 0.55 and 0.8. [5] Some TDS meters use an electrical conductivity measurement to the ppm using the above formula. Regarding units, 1 ppm indicates 1 mg of dissolved solids per 1,000 g of water. [6]
conversion combination output units Metric: kilogram per cubic metre: kg/m3 kg/m 3: 1.0 kg/m 3 (1.7 lb/cu yd) kg/m3 lb/ft3 (kg/m3 lb/cuft) kg/m3 lb/yd3 (kg/m3 lb/cuyd) gram per cubic metre: g/m3 g/m 3: 1.0 g/m 3 (0.0017 lb/cu yd) g/m3 kg/m3; g/m3 lb/ft3 (g/cm3 lb/cuft) g/m3 lb/yd3 (g/cm3 lb/cuyd) Imperial & US customary: pound per cubic foot ...
2 Conversions. 3 See also. 4 References. Toggle the table of contents. Grain per gallon. ... 1 mg/L (ppm) = 0.058417831 grains per US gallon; See also. dGH; References