Sysco Environmental Ltd recently undertook a diesel exhaust fumes monitoring project in Folkestone to evaluate the risks posed to maintenance crews. Our team conducted a comprehensive air quality assessment during the maintenance works, focusing on specific exposure risks such as diesel fumes and metal fumes. As part of the project, we also performed a microscopic identification of dust particulates carried in the airstream within the tunnel. This detailed analysis enabled us to accurately assess the environmental conditions and potential health risks to the crews, ensuring that effective measures could be implemented to protect their safety and well-being.