Mixture Formula - QHSE Link

Additive Mixture Hazard Index Calculator

Calculate the combined exposure from multiple airborne contaminants that have similar toxicological effects using the additive mixture formula.

Formula: Hazard Index = C₁/TLV₁ + C₂/TLV₂ + … + Cₙ/TLVₙ

Concentration unit All measured concentrations and exposure limits must use the same unit.

Contaminants

Enter the measured concentration and corresponding exposure limit for each contaminant.

Contaminant	Measured concentration (C)	Exposure limit (TLV/OEL)	Hazard ratio (C ÷ TLV)	Remove

Mixture exposure assessment —

Enter the contaminant data and select Calculate.

Important: Use this additive approach only when the contaminants have similar toxicological effects or act on the same target organ or system. Confirm applicability with the relevant regulation, exposure-limit documentation, or a competent occupational hygiene professional.