The Photoacoustic Extinctiometer (PAX), shown in Figure 1, is a sensitive, high-resolution, fast-response instrument for measuring aerosol optical properties relevant for climate change and carbon particle sensing. The instrument directly measures in-situ light absorption and scattering of aerosol particles, from which it derives extinction, single scattering albedo and black carbon (soot) mass concentration.

Intuitive menus may be navigated with the integrated graphical touch-screen on the PAX front panel, affording access to real-time data and instrument status information.