Quaternary ammonium compounds (QACs) are common active ingredients in chemical disinfectants, household cleaners, cosmetics, pesticides, etc. Recently QACs have been detected in human blood and breast milk during the COVID-19 pandemic. Humans can be exposed to QACs through dermal adsorption during application, hand-to-mouth ingestion of disinfectant residues, and inhalation of indoor air upon treatment with disinfectant spray. Exposure to these chemicals can cause respiratory illness such as asthma and chronic obstructive pulmonary disease, increase inflammatory cytokines, decrease mitochondrial function, and disrupt cholesterol biosynthesis. However, the complete biological fate of QACs is currently unknown. Therefore, a real-time continuous monitoring system in complex biological environments is crucial to learn the long-term effects of QACs on human health.