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A normal cubic meter (Nm 3) is the metric expression of gas volume at standard conditions and it is usually (but not always) defined as being measured at 0 °C and 1 atmosphere of pressure. A standard cubic foot (scf) is the USA expression of gas volume at standard conditions and it is often ( but not always ) defined as being measured at 60 ...
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.
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 ...
The amount of pollutant present in air is usually expressed as a concentration, measured in either parts-per notation (usually parts per billion, ppb, or parts per million, ppm, also known as the volume mixing ratio), or micrograms per cubic meter (μg/m³).
Toggle the table of contents. ... 9 ppm Nitrogen dioxide 1 hour 0.12 ppm ... (PM 2.5) concentration of 26.4 micrograms per cubic meter. The equation above results in ...
Celsius heat unit (International Table) CHU IT: ≡ 1 BTU IT × 1 K/°R = 1.899 100 534 716 × 10 3 J: cubic centimetre of atmosphere; standard cubic centimetre: cc atm; scc ≡ 1 atm × 1 cm 3 = 0.101 325 J: cubic foot of atmosphere; standard cubic foot: cu ft atm; scf ≡ 1 atm × 1 ft 3 = 2.869 204 480 9344 × 10 3 J: cubic foot of natural ...
The table below lists units supported by {{convert}}. More complete lists are linked for each dimension. For a complete list of all dimensions, see full list of units. {{Convert}} uses unit-codes, which are similar to, but not necessarily exactly the same as, the usual written abbreviation for a given unit. These unit-codes are displayed in ...
The World Health Organization guidelines were most recently updated in 2021. [1] The guidelines offer guidance about these air pollutants: particulate matter (PM), ozone (O 3), nitrogen dioxide (NO 2), sulfur dioxide (SO 2) and carbon monoxide (CO). [2]