The Light Absorption Heating Method for Measurement of Light Absorption by Particles Collected on Filters

A new instrument for the quantification of light absorption by particles collected on filters has been developed to address long standing environmental questions about light-absorbing in air, water, and snow ice. The Light Absorption Heating Method (LAHM) uses temperature changes when are exposed quantify absorption. Through use calibration standards, observed response unknown materials can be related cross section substance filter. Here, we present a detailed description calibration. results tests using common surrogate black carbon, Fullerene soot, show that provides stable even adverse laboratory conditions, there is little drift over longer periods time. Calibration studies soot suspended airborne propane as well atmospheric particulates consistent accepted values mass compared from 3-wavelength photoacoustic instrument. While filter sampling cannot provide time resolution other instrumentation, LAHM fills niche where averaging reasonable high-cost instrumentation not available. optimal range sections 0.1 5.0 cm2 (~1.0–50.0 µg soot) 25 mm 0.4 20 (4.0–200.0 47 filters, with reduced sensitivity higher values.