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  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    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 ...

  3. Total dissolved solids - Wikipedia

    en.wikipedia.org/wiki/Total_dissolved_solids

    Fresh water: TDS is less than 1,000 ppm. Brackish water: TDS = 1,000 to 10,000 ppm. Saline water: TDS = 10,000 to 35,000 ppm. Hypersaline: TDS greater than 35,000 ppm. Drinking water generally has a TDS below 500 ppm. Higher TDS Fresh Water is drinkable but taste may be objectionable.

  4. Immediately dangerous to life or health - Wikipedia

    en.wikipedia.org/wiki/Immediately_dangerous_to...

    1000 ppm: 79243: 10102-44-0: 0930: Nitrogen dioxide: 37.6 mg/m 3: 20 ppm: 10102440: 7783-54-2: 1234: Nitrogen trifluoride: 2900 mg/m 3: 2000 ppm: 7783542: 55-63-0: 0186: Nitroglycerine: 75 mg/m 3-55630: 75-52-5: 0522: Nitromethane: 1875 mg/m 3: 750 ppm: 75525: 108-03-2: 1050: 1-Nitropropane: 3640 mg/m 3: 1000 ppm: 108032: 79-46-9: 0187: 2 ...

  5. Per mille - Wikipedia

    en.wikipedia.org/wiki/Per_mille

    Major dictionaries do not agree on the spelling, [1] [2] [3] giving other options of per mil, [2] per mill, [1] [3] permil, [1] [4] permill, [1] permille. [ 5 ] [ 6 ] The word promille is the cognate in Dutch, German, Finnish and Swedish, and is sometimes seen as a loanword in English with the same meaning as per mille .

  6. Useful conversions and formulas for air dispersion modeling

    en.wikipedia.org/wiki/Useful_conversions_and...

    For example, such a regulation might limit the concentration of NOx to 55 ppmv in a dry combustion exhaust gas corrected to 3 volume percent O 2. As another example, a regulation might limit the concentration of particulate matter to 0.1 grain per standard cubic foot (i.e., scf) of dry exhaust gas corrected to 12 volume percent CO 2.

  7. Per cent mille - Wikipedia

    en.wikipedia.org/wiki/Per_cent_mille

    Visualisation of 1%, 1‰, 1‱, 1 pcm and 1 ppm as fractions of the large block . A per cent mille or pcm is one one-thousandth of a percent. [1] It can be thought of as a "milli-percent". It is commonly used in epidemiology, and in nuclear reactor engineering as a unit of reactivity.

  8. Carbon dioxide - Wikipedia

    en.wikipedia.org/wiki/Carbon_dioxide

    A study of humans exposed in 2.5 hour sessions demonstrated significant negative effects on cognitive abilities at concentrations as low as 0.1% (1000 ppm) CO 2 likely due to CO 2 induced increases in cerebral blood flow. [52] Another study observed a decline in basic activity level and information usage at 1000 ppm, when compared to 500 ppm. [53]

  9. 1,1-Dichloroethylene - Wikipedia

    en.wikipedia.org/wiki/1,1-Dichloroethylene

    1,1-Dichloroethylene, commonly called vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula CCl 2 CH 2.It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water but soluble in organic solvents. 1,1-DCE was the precursor to the original clingwrap, Saran, for food, but this application has been phased