Abstract
Abstract. Source-specific optical properties of light-absorbing carbonaceous (LAC) aerosols in the atmosphere are poorly understood because they are generated by various sources. In this study, a receptor model combining multi-wavelength absorption and chemical species was used to explore the source-specific optical properties of LAC aerosols in a tropical marine monsoon climate zone. The results showed that biomass burning and ship emissions were the dominant contributors to average aerosol light absorption. The source-specific absorption Ångström exponent (AAE) indicated that black carbon (BC) was the dominant LAC aerosol in ship and motor vehicle emissions. Moreover, brown carbon (BrC) was present in biomass-burning emissions. The source-specific mass absorption cross section (MAC) showed that BC from ship emissions had a stronger light-absorbing capacity compared to emissions from biomass burning and motor vehicles. The BrC MAC derived from biomass burning was also smaller than the BC MAC and was highly dependent on wavelength. Furthermore, radiative effect assessment indicated a comparable atmospheric forcing and heating capacity of LAC aerosols between biomass burning and ship emissions. This study provides insights into the optical properties of LAC aerosols from various sources. It also sheds more light on the radiative effects of LAC aerosols generated by ship emissions.
Highlights
Carbonaceous aerosols are abundant in PM2.5 (e.g., 20 %– 50 % of PM2.5 mass; Putaud et al, 2010; Tao et al, 2017) and have extensively been explored due to their implications on global climate forcing (IPCC, 2013)
Through a combination of chemical species and multi-wavelength absorption in a positive matrix factorization model, it was shown that biomass burning had the highest contribution to Abspri(λ) (32 %–44 %) followed by ship (30 %–39 %) and motor vehicle emissions (17 %–24 %)
The low spectral dependence of light absorption indicated that light-absorbing carbonaceous (LAC) aerosols were dominated by black carbon (BC) in ship and motor vehicle emissions
Summary
Carbonaceous aerosols are abundant in PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 μm) (e.g., 20 %– 50 % of PM2.5 mass; Putaud et al, 2010; Tao et al, 2017) and have extensively been explored due to their implications on global climate forcing (IPCC, 2013). Among the complex carbonaceous compounds are the light-absorbing carbonaceous (LAC) aerosols which are mainly associated with absorption of light. BC is a short-lived climate forcer with a strong ability to absorb sunlight. It is regarded as the second largest contributor of positive anthropogenic climate forcing after carbon dioxide (Bond et al, 2013). BrC refers to a class of light-absorbing organic compounds with enhanced light absorption at short wavelengths (e.g., near-ultraviolet region). It is a potential contributor to atmospheric heating at both global and regional scales (Laskin et al, 2015)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
