Unit Risk Estimate

{
  "id": "MLC-T-ENV-029129",
  "term": "Unit Risk Estimate",
  "field": "Environment",
  "definition": "1. The upper-bound excess lifetime cancer risk estimated to result for continuous exposure to an agent at a concentration of 1 Fg/L in water, or 1 Fg/m3 in air. The interpretation of unit risk would be as follows: if unit risk = 1.5 x 10-6 Fg/L, 1.5 excess tumors are expected to develop per 1,000,000 people if exposed daily for a lifetime to 1 Fg of the chemical in 1 liter of drinking water.\n\n2. The upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1μ g/L in water, or 1 μg/m3 in air. The interpretation of unit risk would be as follows: if the water unit risk = 2 x 10-6 μg/L, 2 excess tumors may develop per 1,000,000 people if exposed daily for a lifetime to 1 μg of the chemical in 1 liter of drinking water.\n\n3. The upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an air toxic at a concentration of 1 microgram per cubic meter (µg/m3) in air. You can interpret the URE as follows: If the URE = 1.5 x 10-6 per µg/m3, as many as three more people might be expected to develop cancer per one million people exposed daily for a lifetime to 1 microgram (µg) of the chemical in 1 cubic meter (m3) of air. UREs are considered upper-bound estimates designed to keep us from underestimating risks. The true risk may be lower and is considered unlikely to be higher. In AirToxScreen, we multiply the model-output concentrations for an air toxic by that pollutant's URE to calculate exposure risks from that air toxic.\n\n4. The upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an air toxic at a concentration of 1 microgram per cubic meter (µg/m3) in air. You can interpret the URE as follows: If the URE = 1.5 x 10-6 per µg/m3, as many as three more people might be expected to develop cancer per one million people exposed daily for a lifetime to 1 microgram (µg) of the chemical in 1 cubic meter (m3) of air. UREs are considered upper-bound estimates designed to keep us from underestimating risks. The true risk may be lower and is considered unlikely to be higher. In NATA, we multiply the model-output concentrations for an air toxic by that pollutant's URE to calculate exposure risks from that air toxic.\n\n5. The upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1μ g/L in water, or 1 μg/m3 in air. The interpretation of unit risk would be as follows: if the water unit risk = 2 x 10-6 μg/L, 2 excess tumors may develop per 1,000,000 people if exposed daily for a lifetime to 1 μg of the chemical in 1 liter of drinking water. [EPA 2004]",
  "abbreviation": "URE",
  "subject": "Air",
  "references": [
    "Community-Based Air Pollution Projects Glossary",
    "EPA 2004",
    "AirToxScreen Glossary of Terms",
    "National Air Toxics Assessment (NATA) Glossary",
    "Thesaurus of Terms Used in Microbial Risk Assessment"
  ],
  "url": "https://mlchart.com/terminology/environment/unit-risk-estimate/"
}