Environmental effects of key contaminants from methanol fuel exhaust

• Develop an evaluation system from the micro level to the macro level, and the exposure risks of typical pollutants of methanol fuel are comprehensively evaluated. • Compare the impacts on human health and the environment between the use of methanol fuel and that of traditional gasoline and diesel. • Demonstrate the possible environmental and ecological effects that may be caused by the large-scale use of methanol fuel in the future. With the rapid development of global industrialization in recent years, the energy demand and consumption around the world are increasing. Methanol has garnered significant attention as a highly promising carbon–neutral liquid fuel. But the environmental-biological effects of emissions from methanol fuels have not yet been explored. In this study, we evaluated the effects of characteristic contaminants in the exhaust of methanol mix fuel: phenanthrene (PHE), methanol, and formaldehyde on the growth and physiological properties of model plants, enzyme activity in soil, respiratory and immune system cell activity. Our results showed that phenanthrene, methanol, and formaldehyde had significant adverse effects on the growth of model plants and mammalian cells, and on the activity of key enzymes in soil, especially under the co-stress of contaminants. The conclusions innovatively reveal the comprehensive biological toxicity of combined pollutants from methanol fuel exhaust, clarify the environmental risks of large-scale methanol application as an emerging carbon–neutral fuel, provide empirical support for relevant authorities to address its potential negative impacts, and lay a theoretical foundation for the formulation of methanol fuel emission standards.