National Atmospheric Research Laboratory (NARL), Gadanki, India.
National Atmospheric Research Laboratory (NARL), Gadanki, India.
Environ Pollut. 2019 Nov;254(Pt A):112932. doi: 10.1016/j.envpol.2019.07.100. Epub 2019 Jul 20.
Black carbon (BC) aerosol emitted in incomplete combustion processes is known for causing warming in the climate system also poses serious health issues. Identification of the sources of BC is essential for the development of mitigation strategies to regulate their effects in changing climate. Among different observational and analytical techniques currently available, source apportionment methods based on optical measurements are relatively simple. For example, 'Aethalometer model' was developed based on Aethalometer observations. However, there are a few limitations with this model arising from assumption of wavelength and angstrom exponent pairs. We have developed an empirical method which also relies on Aethalometer observations named as 'Two alpha method' which assumes angstrom exponent from fossil fuel as 1 and estimates bio-mass fraction and angstrom exponent for bio-mass burning. This method has been applied to Aethalometer observations from five different locations (rural, semi-urban and urban) over Indian sub-continent to quantify sources of BC. Fossil fuel is found to be the major source of BC (∼70%) irrespective of the location. Collocated measurements of Carbon Monoxide (CO) over rural site correlated well with derived bio-mass fraction. Results from this study demonstrated the capabilities of empirical method and shall provide spatio-temporal variability in sources of BC if applied to more locations.
黑碳（BC）气溶胶是不完全燃烧过程中排放的物质，已知其会导致气候系统变暖，同时也对健康造成严重影响。识别 BC 的来源对于制定缓解策略以调节其在气候变化中的影响至关重要。在目前可用的不同观测和分析技术中，基于光学测量的源分配方法相对简单。例如，基于 Aethalometer 观测开发了“Aethalometer 模型”。然而，该模型存在一些局限性，源于对波长和 Angstrom 指数对的假设。我们开发了一种基于 Aethalometer 观测的经验方法，称为“双 α 方法”，该方法假设化石燃料的 Angstrom 指数为 1，并估计生物质燃烧的生物质分数和 Angstrom 指数。该方法已应用于印度次大陆五个不同地点（农村、半城市和城市）的 Aethalometer 观测，以量化 BC 的来源。无论地点如何，化石燃料都是 BC 的主要来源（约 70%）。农村站点的一氧化碳（CO）的共测结果与推导的生物质分数相关性良好。这项研究的结果展示了经验方法的能力，如果将其应用于更多地点，将提供 BC 来源的时空变化。
