The microAeth AE51 is a real-time aerosol monitor that measures black carbon (BC) concentrations in air. It works by measuring the rate of change in light absorption on a filter from collected aerosol particles at a wavelength of 880 nm. It has a measurement range of 0-1 mg BC/m3, resolution of 0.001 μg BC/m3, and precision of ±0.1 μg BC/m3 over 1 minute. Data is stored internally and uploaded to analysis software via USB connection.