College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
Environ Int. 2018 Jul;116:92-100. doi: 10.1016/j.envint.2018.04.009. Epub 2018 Apr 13.
Both climate change and intensive human activities are thought to have contributed to the impairment of atmospheric visibility in Beijing. But the detailed processes involved and relative roles of human activities and climate change have not been quantified. Optical extinction of aerosols, the inverse of meteorological visibility is especially sensitive to fine particles <1.0 μm. These submicron particles are considered more hazardous than larger ones in terms of cardiovascular and respiratory diseases. Here we used the aerosol optical extinction (inverse of visibility) as the indicator of submicron particles pollution to estimate its inter-annual variability from 1980 to 2015. Our results indicated that optical extinction experienced two different periods: a weakly increasing stage (1980-2005) and a rapidly increasing stage (2005-2015). We attributed the variations of optical extinction to the joint effects of human activities and climate change. Over the past 36 years, human activities played a leading role in the increase of optical extinction, with a positive contribution of 0.077 km/10 y. While under the effects of climate change, optical extinction firstly decreased by 0.035 km/10 y until 2005 and then increased by 0.087 km/10 y. Detailed analysis revealed that the abrupt change (around 2005) of optical extinction resulted from the trend reversals of climate change. We found since 2005 the decreasing trend by 0.58 m·s/10 y in wind speed, the growing trend at 8.69%/10 y in relative humidity and the declining trend by 2.72 hPa/10 y in atmospheric pressure have caused the rapid increase of optical extinction. In brief, the higher load of fine particles <1.0 μm in Beijing in recent decades could be associated with both human activities and climate change. Particularly after 2005, the adverse climate change aggravated the situation of submicron particles pollution.
气候变化和人类活动的加剧被认为是导致北京大气能见度下降的原因。但是，人类活动和气候变化的详细过程及其相对作用尚未量化。气溶胶的光衰减（能见度的倒数）对小于 1.0μm 的细颗粒特别敏感。这些亚微米颗粒在心血管和呼吸道疾病方面被认为比更大的颗粒更危险。在这里，我们使用气溶胶光学衰减（能见度的倒数）作为亚微米颗粒污染的指标，从 1980 年到 2015 年估算其年际变化。我们的结果表明，光学衰减经历了两个不同的阶段：一个是缓慢增加的阶段（1980-2005 年），另一个是快速增加的阶段（2005-2015 年）。我们将光学衰减的变化归因于人类活动和气候变化的共同作用。在过去的 36 年里，人类活动在光学衰减的增加中起主导作用，其正贡献为 0.077km/10y。而在气候变化的影响下，光学衰减首先减少了 0.035km/10y，直到 2005 年，然后又增加了 0.087km/10y。详细分析表明，光学衰减的突然变化（大约在 2005 年）是气候变化趋势逆转的结果。我们发现，自 2005 年以来，风速的下降趋势为 0.58m·s/10y，相对湿度的增长趋势为 8.69%/10y，大气压力的下降趋势为 2.72hPa/10y，这导致了光学衰减的快速增加。总之，北京近几十年来细颗粒物<1.0μm 的负荷较高，可能与人类活动和气候变化有关。特别是 2005 年以后，不利的气候变化加剧了亚微米颗粒污染的状况。
