AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Changes of Black Carbon Sources in Beijing with Three-Year Continuous Measurements
YUE LIU, Yazhen Wu, Caiqing Yan, Tony Hansen, Mei Zheng, Peking University
Abstract Number: 486 Working Group: Carbonaceous Aerosol
Abstract Black carbon (BC) plays an important role in climate change, air quality and human health, especially in Beijing, China, where air pollution is still a severe problem with large population and high population density. In the past three years, BC levels in Beijing exhibit a clear decreasing trend. In this study, our objective is to examine the trend of BC in the past few years and the major sources that contribute to the reduction of BC pollution in Beijing based on 3-year continuous black carbon measurement with high-time resolution (1 min) at an urban ambient monitoring site. Information of BC measured by the 7-wavelength Aethalometer (AE-33), along with other chemical components including elemental carbon and organic carbon by a Sunset instrument, multiple metals by the Xact 625, and ions by the IGAC (in-situ Gas and Aerosol Compositions monitor) are combined to identify sources of BC. Our results show that (1) the average BC concentration was the highest in winter and the lowest in summer with a bi-modal diurnal variation in each season, (2) when comparing the dominant sources of BC between haze and non-haze periods, it was found that traffic source was the predominant source for black carbon aerosol in non-haze periods while the contribution of coal combustion and biomass burning sources increased during haze periods, (3) the three-year continuous measurements showed that the concentration of BC in Beijing significantly decreased from 2015 to 2018, (4) by comparing source apportionment results in winter from 2015 to 2018, it could be seen that Beijing has an effective control of coal combustion source especially during nighttime and it was mainly from the residential sector. However, at the same time, there is an increased importance of traffic source to BC in Beijing.