Nishat Tasnim

Hazard Quotient (HQ), Hazard Index (HI), and cancer risk are key parameters in assessing the impact of metals present in the air on human health. Hazard Quotient (HQ) is calculated as the ratio between the actual concentration of a contaminant in the air and the reference dose considered safe for human health. If HQ is greater than 1, it indicates a potentially high health risk. Hazard Index (HI) is used when assessing the effects of multiple contaminants that may act synergistically, and is calculated as the sum of individual HQ values for all present metals. If HI exceeds 1, it means the health risk is elevated. Cancer risk is calculated using the cancer slope factor for a specific metal and its concentration in the air, providing an estimate of the likelihood of developing cancer due to exposure. In some cases, HI can have three-digit values, particularly in situations where metal concentrations in the air are very high, indicating a serious health risk. High HI values suggest the need for urgent protective measures and exposure reduction to prevent potential health issues.