Aqua Blue Diesel Exhaust Fluid (DEF) is a high-quality product that can provide several advantages through the BlueME brand, including Reducing harmful emissions: Aqua Blue DEF is a urea-based solution that is injected into the exhaust stream of diesel vehicles to convert harmful nitrogen oxide (NOx) emissions into harmless nitrogen gas and water vapor. This reduces the environmental impact of diesel vehicles, making them more eco-friendly.