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  2. Useful conversions and formulas for air dispersion modeling

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

    As an example, given a concentration of 260 mg/m 3 at sea level, calculate the equivalent concentration at an altitude of 1,800 meters: C a = 260 × 0.9877 18 = 208 mg/m 3 at 1,800 meters altitude Standard conditions for gas volumes

  3. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    At 1 ppm the solution is a very pale yellow. As the concentration increases the colour becomes a more vibrant yellow, then orange, with the final 10,000 ppm a deep red colour. In science and engineering , the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities , e.g. mole fraction or ...

  4. Abundance of elements in Earth's crust - Wikipedia

    en.wikipedia.org/wiki/Abundance_of_elements_in...

    The abundance of elements in Earth's crust is shown in tabulated form with the estimated crustal abundance for each chemical element shown as mg/kg, or parts per million (ppm) by mass (10,000 ppm = 1%).

  5. Activated alumina - Wikipedia

    en.wikipedia.org/wiki/Activated_alumina

    Activated alumina filters can easily reduce fluoride levels from 10 ppm to less than 1 ppm. The amount of fluoride leached from the water being filtered depends on how long the water is actually touching the alumina filter media. Basically, the more alumina in the filter, the less fluoride will be in the final, filtered water.

  6. Alkalinity - Wikipedia

    en.wikipedia.org/wiki/Alkalinity

    Alkalinity is frequently given as molar equivalents per liter of solution or per kilogram of solvent. In commercial (e.g. the swimming pool industry) and regulatory contexts, alkalinity might also be given in parts per million of equivalent calcium carbonate (ppm CaCO 3) [citation needed].

  7. 1-Nitropropane - Wikipedia

    en.wikipedia.org/wiki/1-Nitropropane

    1-nitropropane is toxic to humans and can cause damage to the kidneys and liver. The vapours are irritating for the lungs and eyes and the maximum exposure rate is 25 ppm. [1] It is not known to be a carcinogen.

  8. Lethal dose - Wikipedia

    en.wikipedia.org/wiki/Lethal_dose

    In toxicology, the lethal dose (LD) is an indication of the lethal toxicity of a given substance or type of radiation.Because resistance varies from one individual to another, the "lethal dose" represents a dose (usually recorded as dose per kilogram of subject body weight) at which a given percentage of subjects will die.

  9. Bromoform - Wikipedia

    en.wikipedia.org/wiki/Bromoform

    It is somewhat soluble in water and readily evaporates into the air. Bromoform is the main trihalomethane produced in beachfront salt water swimming pools with concentrations as high as 1.2 ppm (parts per million). Concentrations in freshwater pools are 1000 times lower. [9] Occupational skin exposure limits are set at 0.5 ppm. [10]