Concentration

{
  "id": "MLC-T-ENV-006043",
  "term": "Concentration",
  "field": "Environment",
  "definition": "1. The relative amount of a substance in an environmental medium, expressed by relative mass (e.g., mg/kg), volume (ml/L), or number of units (e.g., parts per million).\n\n2. Amount of a substance or material in a given unit volume of solution; usually measured in milligrams per liter (mg/L) or parts per million (ppm).\n\n3. The relative amount of a substance mixed with another substance. An example is five parts per million of carbon monoxide in air or 1 milligram/liter of iron in water.\n\n4. The amount of one material dispersed or distributed in a larger amount of another material.\n\n5. See \"beneficiation.\" The amount of one material dispersed or distributed in a larger amount of another material.\n\n6. The relative amount of a substance mixed with another substance. An example is five ppm of carbon monoxide in air or 1 mg/l of iron in water.\n\n7. The amount of a particular substance that exists within a certain volume or weight of air, water, soil, or other medium. For example, scientists measure the concentration of a particular gas (such as carbon dioxide) in the atmosphere in units of parts per million.\n\n8. Amount of a material or agent dissolved or contained in unit quantity in a given medium or system.\n\n9. Amount of a chemical in a particular volume or weight of air, water, soil, or other medium. See parts per billion, parts per million.\n\n10. The quantity of one constituent dispersed in a defined amount of another.\n\n11. The amount of a substance present in a certain amount of soil, water, air, food, blood, hair, urine, breath, or any other media.\n\n12. A way to describe how much of a pollutant is in the air. Concentration is usually shown as an amount, or mass, of pollutant per certain volume of air. In AirToxScreen, most concentrations are in micrograms (µg) of air pollutant per cubic meter (m³) of air (a \"box\" of air one meter on each side).",
  "subject": "Health and safety",
  "references": [
    "Waste and Cleanup Risk Assessment Glossary",
    "Sediment Total Maximum Daily Loads (TMDLs) Glossary",
    "Pesticides Glossary",
    "Superfund for Students and Teachers Glossary",
    "Abandoned Mine Lands (AML) Glossary",
    "Terms of Environment; EPA 2005b, EPA 2005e",
    "Student's Guide to Global Climate Change",
    "Exposure Factors Handbook: Glossary",
    "Glossary of Climate Change Terms; Greenhouse Gas Emissions",
    "I-BEAM Glossary of Terms",
    "ATSDR 2004",
    "AirToxScreen Glossary of Terms"
  ],
  "url": "https://mlchart.com/terminology/environment/concentration/"
}