Short-lived climate pollutants (SLCPs) including black carbon (BC), methane (CH 4 ), and tropospheric ozone (O 3 ) are major climate forcers after carbon dioxide (CO 2 ). These SLCPs also have detrimental impacts on human health and agriculture. Studies show that the Hindu Kush Himalayan (HKH) region, which includes Nepal, has been experiencing the impacts of these pollutants in addition to greenhouse gases. In this study, we derive a national-level emission inventory for SLCPs, CO 2 , and air pollutants for Nepal and project their impacts under reference (REF) and mitigation policy (POL) scenarios. The impacts on human health, agriculture, and climate were then estimated by applying the following: (1) adjoint coefficients from the Goddard Earth Observing System (GEOS)-chemical transport model that quantify the sensitivity of fine particulate matter (PM 2.5 ) and surface O 3 concentrations in Nepal, and radiative forcing in four latitudinal bands, to emissions in 2 × 2.5° grids, and (2) concentration–response functions to estimate health and crop loss impacts in Nepal. With the mitigating measures undertaken, emission reductions of about 78% each of BC and CH 4 and 87% of PM 2.5 could be achieved in 2050 compared with the REF scenario. This would lead to an estimated avoidance of 29,000 lives lost and 1.7 million tonnes of crop loss while bringing an economic benefit in present value of 2.7 times more than the total cost incurred in its implementation during the whole period 2010–2050. The results provide useful policy insights and pathways for evidence-based decision-making in the design and effective implementation of SLCP mitigation measures in Nepal.

中文翻译：

---

减轻尼泊尔空气污染物的影响和气候协同效益：基于情景的方法

包括黑碳 (BC)、甲烷 (CH 4 ) 和对流层臭氧 (O 3 ) 在内的短寿命气候污染物 (SLCP) 是继二氧化碳 (CO 2 ) 之后的主要气候驱动因素。这些 SLCP 还对人类健康和农业产生不利影响。研究表明，包括尼泊尔在内的兴都库什喜马拉雅 (HKH) 地区，除了温室气体外，还受到这些污染物的影响。在本研究中，我们导出了尼泊尔 SLCP、CO 2 和空气污染物的国家级排放清单，并在参考 (REF) 和减缓政策 (POL) 情景下预测了它们的影响。然后通过应用以下方法估计对人类健康、农业和气候的影响：(1) 来自戈达德地球观测系统 (GEOS)-化学传输模型的伴随系数，用于量化尼泊尔细颗粒物 (PM 2.5 ) 和地表 O 3 浓度以及四个纬度带的辐射强迫对 2 中排放的敏感性× 2.5° 网格，以及 (2) 浓度-响应函数，用于估计尼泊尔的健康和作物损失影响。通过采取缓解措施，与 REF 情景相比，到 2050 年，BC 和 CH 4 的排放量可分别减少约 78% 和 PM 2.5 的 87%。这将导致估计避免 29,000 人丧生和 170 万吨作物损失，同时带来的经济利益现值是 2010-2050 年整个期间实施所产生总成本的 2.7 倍。