Reduction of black carbon aerosols in Tokyo: Comparison of real-time observations with emission estimates
Reduction of black carbon aerosols in Tokyo: Comparison of real-time observations with emission estimates
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DOI：
10.1016/j.atmosenv.2012.02.003
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发表时间：
2012-07
影响因子：
5
通讯作者：
Y. Kondo;K. Ram;N. Takegawa;L. Sahu;Y. Morino;X. Liu;T. Ohara
中科院分区：
文献类型：
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作者：
Y. Kondo;K. Ram;N. Takegawa;L. Sahu;Y. Morino;X. Liu;T. Ohara
黑碳（BC）气溶胶直接（通过吸收太阳可见辐射）和间接（通过充当云凝结核）改变辐射收支，并造成不利的健康影响。BC的吸收效率和直接辐射效应在很大程度上取决于其质量浓度（MBC）和发射源类型。在本研究中，我们报告了位于东京城市边界中心的先进科学技术研究中心（RCAST） 2003 - 2005年使用EC-OC分析仪和2007-2010年基于过滤器的连续烟尘监测系统（COSMOS）对MBCat的测量结果。结果表明，2003年至2010年间，MBChave从2.6 μg m−3显著下降到0.5 μg m−3（减少约80%）。在东京，车辆排放是BC的主要来源，而mbci的减少主要归因于日本政府对车辆颗粒物排放的严格规定。此外，这一观测结果也得到了使用东京mbcc日-周变化的排放估计的支持，并解释了观测到的减少幅度在20%左右。这是东京BC排放量显著减少的第一个明确证据，表明为减少交通源BC排放而采取的措施对大城市的空气质量有很强的影响，也减少了交通排放对气候的影响。我们强调长期和可靠的测量在检测BC趋势以及验证和监管特大城市排放控制措施方面的重要性。
Black carbon (BC) aerosols alter the radiation budget both directly (by absorbing solar visible radiation) and indirectly (by acting as cloud condensation nuclei) and cause adverse health effects. The absorbing efficiency and direct radiative effect of BC strongly depend on its mass concentration (MBC) and type of emission source. In the present study, we report measurements of MBCat the Research Center for Advanced Science and Technology (RCAST), located at the center of the urban boundary of Tokyo, using an EC-OC analyzer from 2003 to 2005 and a filter-based Continuous Soot Monitoring System (COSMOS) during 2007–2010. The results indicate that MBChave decreased significantly from 2.6 μg m−3to 0.5 μg m−3(∼80% reduction) between 2003 and 2010. Vehicular emissions are the dominant source of BC in Tokyo, and the observed reduction in MBCis mainly attributed to the stringent regulations of particulate matter exhaust from vehicles imposed by the Japanese government. In addition, this observation is also supported from emission estimates using diurnal-weekly variations of MBCin Tokyo and explains the observed reduction to within about 20%. This is the first clear evidence of a significant reduction in BC emissions in Tokyo and shows that measures taken to reduce BC emissions from traffic sources have a strong effect on air quality in a mega-city and also reduce the climate impact of traffic emissions. We highlight the importance of long-term and reliable measurements in detecting BC trends and for the validation and regulation of emission control measures in mega-cities.