Abstract

In everyday life, humans are constantly exposed to complex mixtures of chemicals—from air pollution and pesticides to substances in personal care products. Understanding how these combinations affect human health has become a central challenge in environmental health research. Traditionally, scientists have measured the overall impact of a mixture, treating it as if all chemicals act in the same direction. Yet, the reality is more complicated: within these mixtures, some chemicals may be harmful while others may be protective, creating what researchers call “partial effects.” In a recent study, Kamenetsky et al. (2025) took a critical step forward by evaluating how well current methods can disentangle these opposing effects within environmental mixtures.