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1. Long-term trends of impacts of global gasoline and diesel emissions on ambient PM _2.5 and O ₃ pollution and the related health burden for 2000–2015

   https://doi.org/10.1088/1748-9326/ac9422  

   Xiong, Ying; Partha, Debatosh; Prime, Noah; Smith, Steven J.; Mariscal, Noribeth; Salah, Halima; Huang, Yaoxian (October 2022, Environmental Research Letters)

   Abstract Global economic development and urbanization during the past two decades have driven the increases in demand of personal and commercial vehicle fleets, especially in developing countries, which has likely resulted in changes in year-to-year vehicle tailpipe emissions associated with aerosols and trace gases. However, long-term trends of impacts of global gasoline and diesel emissions on air quality and human health are not clear. In this study, we employ the Community Earth System Model in conjunction with the newly developed Community Emissions Data System as anthropogenic emission inventory to quantify the long-term trends of impacts of global gasoline and diesel emissions on ambient air quality and human health for the period of 2000–2015. Global gasoline and diesel emissions contributed to regional increases in annual mean surface PM_2.5(particulate matter with aerodynamic diameters ⩽2.5μm) concentrations by up to 17.5 and 13.7µg m⁻³, and surface ozone (O₃) concentrations by up to 7.1 and 7.2 ppbv, respectively, for 2000–2015. However, we also found substantial declines of surface PM_2.5and O₃concentrations over Europe, the US, Canada, and China for the same period, which suggested the co-benefits of air quality and human health from improving gasoline and diesel fuel quality and tightening vehicle emissions standards. Globally, we estimate the mean annual total PM_2.5- and O₃-induced premature deaths are 139 700–170 700 for gasoline and 205 200–309 300 for diesel, with the corresponding years of life lost of 2.74–3.47 and 4.56–6.52 million years, respectively. Diesel and gasoline emissions create health-effect disparities between the developed and developing countries, which are likely to aggravate afterwards. 

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2. The impacts of improving heavy-duty internal combustion engine technology on reducing NOx emissions inventories going into the future

   https://doi.org/10.1016/j.scitotenv.2025.179781  

   Hurren, Troy; Durbin, Thomas D; Johnson, Kent C; Karavalakis, Georgios (July 2025, Science of The Total Environment)

   In an effort to reduce nitrogen oxide (NOx) emissions and other pollutants from heavy-duty vehicles (HDVs), regulators have been implementing more stringent regulations that have included a combination of significantly more stringent emissions standards with the introduction of battery electric vehicles (BEVs). This study analyzed in-use NOx emissions data from 63 HDVs across various vocations, model years, and engine technologies/fuels to assess which current technologies offer a realistic path toward reducing NOx emissions without significantly burdening fleet operators or electrical infrastructure. All 63 HDVs were equipped with portable emissions measurement systems when they were tested for in-use NOx emissions during their routine operation on California roadways. The data was analyzed using the moving average window method proposed by the Environmental Protection Agency (EPA) in which the in-use emissions are broken up into two bins dependent on the engine load: ≤6 % (idle) and >6 % of maximum rated power. It was found that diesel engines manufactured after 2020 and natural gas engines certified to the 0.02 g/bhp-h NOx standard met the 2027 and 2035 EPA in-use NOx standards for both bins even though the future standards do not apply to these older engines. In addition, over an 80 % reduction in average NOx emissions is seen in both bins and fuels as modern NOx and greenhouse gas standards were implemented in 2017. With the implementation of ultralow NOx diesel technology engines, capable of meeting 0.035 g/bhp-h NOx limits, it was found that reductions in the NOx emissions inventories from 90.0 to 91.9 % could be achieved by 2050, depending on the deployment of BEVs. In conclusion, current and upcoming engine technologies can serve as benchmark powertrain solutions for emissions inventory reductions in the near and intermediate terms solutions even to the extent that the transition to battery electric HDVs becomes more gradual. 

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3. Neighborhood-scale air quality, public health, and equity implications of multi-modal vehicle electrification

   https://doi.org/10.1088/2634-4505/acf60d  

   Visa, Maxime A.; Camilleri, Sara F.; Montgomery, Anastasia; Schnell, Jordan L.; Janssen, Mark; Adelman, Zachariah E.; Anenberg, Susan C.; Grubert, Emily A.; Horton, Daniel E. (September 2023, Environmental Research: Infrastructure and Sustainability)

   Abstract Electric vehicles (EVs) constitute just a fraction of the current U.S. transportation fleet; however, EV market share is surging. EV adoption reduces on-road transportation greenhouse gas emissions by decoupling transportation services from petroleum, but impacts on air quality and public health depend on the nature and location of vehicle usage and electricity generation. Here, we use a regulatory-grade chemical transport model and a vehicle-to-electricity generation unit electricity assignment algorithm to characterize neighborhood-scale (∼1 km) air quality and public health benefits and tradeoffs associated with a multi-modal EV transition. We focus on a Chicago-centric regional domain wherein 30% of the on-road transportation fleet is instantaneously electrified and changes in on-road, refueling, and power plant emissions are considered. We find decreases in annual population-weighted domain mean NO₂(−11.83%) and PM_2.5(−2.46%) with concentration reductions of up to −5.1 ppb and −0.98µg m⁻³in urban cores. Conversely, annual population-weighted domain mean maximum daily 8 h average ozone (MDA8O₃) concentrations increase +0.64%, with notable intra-urban changes of up to +2.3 ppb. Despite mixed pollutant concentration outcomes, we find overall positive public health outcomes, largely driven by NO₂concentration reductions that result in outsized mortality rate reductions for people of color, particularly for the Black populations within our domain. 

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4. Public Health and Climate Benefits and Trade‐Offs of U.S. Vehicle Electrification

   https://doi.org/10.1029/2020GH000275  

   Peters, D. R.; Schnell, J. L.; Kinney, P. L.; Naik, V.; Horton, D. E. (October 2020, GeoHealth)

   Abstract Vehicle electrification is a common climate change mitigation strategy, with policymakers invoking co‐beneficial reductions in carbon dioxide (CO₂) and air pollutant emissions. However, while previous studies of U.S. electric vehicle (EV) adoption consistently predict CO₂mitigation benefits, air quality outcomes are equivocal and depend on policies assessed and experimental parameters. We analyze climate and health co‐benefits and trade‐offs of six U.S. EV adoption scenarios: 25% or 75% replacement of conventional internal combustion engine vehicles, each under three different EV‐charging energy generation scenarios. We transfer emissions from tailpipe to power generation plant, simulate interactions of atmospheric chemistry and meteorology using the GFDL‐AM4 chemistry climate model, and assess health consequences and uncertainties using the U.S. Environmental Protection Agency Benefits Mapping Analysis Program Community Edition (BenMAP‐CE). We find that 25% U.S. EV adoption, with added energy demand sourced from the present‐day electric grid, annually results in a ~242 M ton reduction in CO₂emissions, 437 deaths avoided due to PM_2.5reductions (95% CI: 295, 578), and 98 deaths avoided due to lesser ozone formation (95% CI: 33, 162). Despite some regions experiencing adverse health outcomes, ~$16.8B in damages avoided are predicted. Peak CO₂reductions and health benefits occur with 75% EV adoption and increased emission‐free energy sources (~$70B in damages avoided). When charging‐electricity from aggressive EV adoption is combustion‐only, adverse health outcomes increase substantially, highlighting the importance of low‐to‐zero emission power generation for greater realization of health co‐benefits. Our results provide a more nuanced understanding of the transportation sector's climate change mitigation‐health impact relationship. 

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5. Spatially and Temporally Detailed Water and Carbon Footprints of U.S. Electricity Generation and Use

   https://doi.org/10.1029/2024WR038350  

   Siddik, Md_Abu_Bakar; Shehabi, Arman; Rao, Prakash; Marston, Landon_T (December 2024, Water Resources Research)

   Abstract Electricity generation in the United States entails significant water usage and greenhouse gas emissions. However, accurately estimating these impacts is complex due to the intricate nature of the electric grid and the dynamic electricity mix. Existing methods to estimate the environmental consequences of electricity use often generalize across large regions, neglecting spatial and temporal variations in water usage and emissions. Consequently, electric grid dynamics, such as temporal fluctuations in renewable energy resources, are often overlooked in efforts to mitigate environmental impacts. The U.S. Department of Energy (DOE) has initiated the development of resilient energyshed management systems, requiring detailed information on the local electricity mix and its environmental impacts. This study supports DOE's goal by incorporating geographic and temporal variations in the electricity mix of the local electric grid to better understand the environmental impacts of electricity end users. We offer hourly estimates of the U.S. electricity mix, detailing fuel types, water withdrawal intensity, and water consumption intensity for each grid balancing authority through our publicly accessible tool, the Water Integrated Mapping of Power and Carbon Tracker (Water IMPACT). While our primary focus is on evaluating water intensity factors, our dataset and programming scripts for historical and real‐time analysis also include evaluations of carbon dioxide (equivalence) intensity within the same modeling framework. This integrated approach offers a comprehensive understanding of the environmental footprint associated with electricity generation and use, enabling informed decision‐making to effectively reduce Scope 2 water usage and emissions. 

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