Metrological traceability of black carbon measurement based on optical methods and its challenges in China: A review

Black carbon aerosol has received much more attention as the most light-absorbing aerosol in recent years. The accuracy, traceability and comparability of its optical measurements, which could be realized by unified and comprehensive calibration and correction system, are essential for the estimation of emission factor, radiative forcing, and the resulting international regulations such as the United Nations Framework Convention on Climate Change. This manuscript summarizes the current optical-based methods applied in China including in-situ and filter-based methods. We detail the metrological traceability of BC optical measurement by comparing the calibration and correction methods in China, as well as BC metrology in other countries. We provide some insight into existed challenges of BC optical measurements in China and potential future direction. The significance of traceability of BC optical measurements in radiative forcing and emission estimation is emphasized. This review will improve our understanding of the traceability of BC measurement based on optical methods.

Automated summary

Black carbon aerosol has gained significant attention for its light-absorbing properties. Accurate and traceable optical measurements are essential for estimating emission factors, radiative forcing, and international regulations. This review summarizes optical-based methods in China and discusses challenges and future directions in black carbon measurement. Emphasis is placed on the significance of traceability in estimating radiative forcing and emissions.