Mitigating the impacts of air pollutants in Nepal and climate co-benefits: a scenario-based approach

Abstract

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.

Environmental, energy security, and energy equity (3E) benefits of net-zero emission strategy in a developing country: A case study of Nepal

“…This study considers the seven major air pollutants emission which are responsible for the negative effects on the public health, crops yield, forest and other socio-economic and environmental effects (Karlsson et al, 2020;Nakarmi et al, 2020;Sonwani et al, 2022). The air pollutants considered in this study are carbon monoxide, nitrogen oxides, non-methane volatile organic compound, sulphur dioxide, particulate matter, black carbon, and organic carbon.…”

“…Reduction in AP emissions are mostly due to the fuel switching from emission intensive fossil fuels to electricity from renewable energy like hydropower in the energy sector and reduction in the uncontrolled burning of agri-residue and waste in non-energy sector. This reduction in AP emissions would result in clear health benefits in terms of avoided sickness and deaths, as well as reduced crop yield loss due to the effects of air pollutants (Kuylenstierna et al, 2020;Nakarmi et al, 2020;UNEP, 2019a). It is worth it mentioning two key species here, namely CH 4 and BC, which are short-lived climate-forcing pollutants (SLCPs).…”

“…Pradhan et al (2019) studied the strategies to achieve net-zero GHG emissions for Nepal, but did not analyze co-benefits. Nakarmi et al (2020) reported health and crop yield benefits with the implementation of measures to reduce short-lived climate-forcing pollutants (SLCP) consisting of black carbon, methane, and PM 2.5 , but they did not analyze co-benefits related to energy security, energy equity and broader air pollutants. The detailed historical emissions of GHGs and air pollutants from technology use in Nepal for 2001 to 2016 were analyzed by Sadavarte et al (2019), while Shrestha (2018) reported emissions of GHGs and air pollutants from all sectors for one year (2008/09), though again neither explicitly considered the range of co-benefits.…”

Integrated climate change and air pollution mitigation assessment for Togo

“…Approximately 5 million premature deaths per year are associated with exposure to ambient and household air pollution (Murray et al, 2020), as well as millions of cases of non-fatal health outcomes such as asthma exacerbations and adverse pregnancy outcomes (Anenberg et al, 2018;Malley et al, 2017). A large number of global, regional and national assessments have identified the substantial opportunity to simultaneously take actions that reduce GHGs and short-lived climate pollutants (SLCPs), while also reducing air pollutant emissions Nakarmi et al, 2020;UNEP/WMO, 2011;UNEP, 2019).…”

Multi-scale Analysis and Synergistic Scenario Simulation of Pollution and Carbon Reduction Efficiency in Guangdong-Hong Kong-Macao Greater Bay Area

“…Predict pollutant emissions in China based on carbon neutrality roadmap and clean air policy evolution. They used air quality models to simulate national and regional PM2.5 and O3 concentrations in 2030 (the carbon peak target year), 2035 (the "Beautiful China 2035" target year launched by the Chinese government to improve air quality fundamentally), and 2060 (the carbon neutrality target year) Nakarmi et al (2020). developed a national-level SLCP, CO2, and air pollutant emission inventory for Nepal.…”