How is the hazard quotient used in toxic release evaluation?

• A. It compares treatment cost to risk
• B. It is the ratio of exposure to reference dose
• C. It indicates odor intensity
• D. It measures ventilation efficiency

Answer: (C)

In toxic release evaluation, the hazard quotient is used to compare the estimated exposure to a chemical with a reference safety level to gauge non-cancer health risk. It’s a dimensionless ratio, calculated as exposure divided by a reference dose (for intake) or exposure concentration divided by a reference concentration (for inhalation). If the ratio is around or below one, the exposure is considered within safe limits; if it exceeds one, there’s potential for adverse effects and a more detailed assessment is warranted. This concept specifically targets exposure and safety thresholds, not odor, ventilation efficiency, or treatment cost. Odor intensity, for example, isn’t tied to the hazard quotient, which is about whether the exposure level may pose health risks.