Multi-wavelength optical measurement to enhance thermal/optical analysis for carbonaceous aerosol
نویسندگان
چکیده
A thermal/optical carbon analyzer equipped with seven-wavelength light source/detector (405–980 nm) for monitoring spectral reflectance (R) and transmittance (T) of filter samples allowed “thermal spectral analysis (TSA)” and wavelength (λ)-dependent organic-carbon (OC)–elementalcarbon (EC) measurements. Optical sensing was calibrated with transfer standards traceable to absolute R and T measurements, adjusted for loading effects to report spectral light absorption (as absorption optical depth (τa,λ)), and verified using diesel exhaust samples. Tests on ambient and source samples show OC and EC concentrations equivalent to those from conventional carbon analysis when based on the same wavelength (∼ 635 nm) for pyrolysis adjustment. TSA provides additional information that evaluates blackcarbon (BC) and brown-carbon (BrC) contributions and their optical properties in the near infrared to the near ultraviolet parts of the solar spectrum. The enhanced carbon analyzer can add value to current aerosol monitoring programs and provide insight into more accurate OC and EC measurements for climate, visibility, or health studies.
منابع مشابه
Interactive comment on “Multi-wavelength optical measurement to enhance thermal/optical analysis for carbonaceous aerosol” by L.-W. A. Chen et al
We thanks for the reviewer’s comments. In the abstract, we have mentioned that optical measurements were adjusted for loading effects to infer aerosol light absorption. All other suggested technical corrections will also be made in the revised manuscript. Regarding the wavelength-dependent OC-EC split, it would facilitate the discussion by treating two cases, i.e., samples without and with BrC,...
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