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The changes in the concentration and composition of biomass-burning organic aerosol (OA) downwind of a major wildfire are simulated using the one-dimensional Lagrangian chemical transport model PMCAMx-Trj. A base case scenario is developed based on realistic fire-plume conditions and a series of sensitivity tests are performed to quantify the effects of different conditions and processes. Temperature, oxidant concentration and dilution rate all affect the evolution of biomass burning OA after its emission. The most important process though is the multi-stage oxidation of both the originally emitted organic vapors (volatile and intermediate volatility organic compounds) and those resulting from the evaporation of the OA as it is getting diluted. The emission rates of the intermediate volatility organic compounds (IVOCs) and their chemical fate have a large impact on the formed secondary OA within the plume. The assumption that these IVOCs undergo only functionalization leads to an overestimation of the produced SOA suggesting that fragmentation is also occurring. Assuming a fragmentation probability of 0.2 resulted in predictions that are more consistent with available observations. Dilution leads to OA evaporation and therefore reduction of the OA levels downwind of the fire. However, the evaporated material can return to the particulate phase later on after it gets oxidized and recondenses. The sensitivity of the OA levels and total mass balance on the dilution rate depends on the modeling assumptions. The high variability of OA mass enhancement observed in past field studies downwind of fires may be partially due to the variability of the dilution rates of the plumes.

The decarbonisation of the transport sector is an imperative step in our efforts to drastically reduce greenhouse gas emissions. In this context, electric vehicles (EVs) powered by lithium-ion batteries have emerged as one of the most promising options. However, in order to make the transition from internal combustion engine vehicles towards EVs economically and environmentally beneficial, it is crucial to reduce battery life cycle costs and carbon footprint. To do so, a key strategy is to increase the battery lifetime as an increased use phase can reduce the pressure on raw materials and counterbalance the cost and environmental impacts incurred during battery manufacturing. Battery lifetime is impacted by several factors such as depth of discharge and cycling rates [1]. Furthermore, temperature-induced stress can lead to accelerated capacity fade. Elevated temperatures can lead to capacity fade caused by chemical side reactions such as solid-electrolyte interface growth or electrolyte decomposition; too low temperatures can result in lithium plating. Therefore, efficient thermal management systems (TMS) are crucial as they ensure an optimal cell operating temperature during usage and thus slow down adverse temperature effects and battery degradation. In this study, the impact of the TMS on battery lifetime and in turn on life cycle cost and carbon footprint is evaluated [2]. To this end, the battery lifetime for various TMS including air cooling, surface cooling, tab cooling and immersion cooling is simulated. The cycle lifetime is then further implemented in carbon footprint and life cycle cost models to calculate economic and environmental impacts during the manufacturing and use phase. Indeed, it is demonstrated that by switching the battery TMS from air cooling to liquid cooling, the battery life cycle cost and carbon footprint can be reduced by 27 % and 25 %, respectively. Moreover, an optimised cell design is proposed, which increases the achievable heat extraction rate through the tabs enabling a more efficient tab cooling system. Tab cooling has the advantage towards surface cooling that cell temperature gradients, which accelerate battery degradation, are reduced thus leading to a prolonged battery cycle life [3]. Implementing tab cooling, the carbon footprint and life cycle cost can be reduced by 35 % and 40 %, respectively, compared with conventional cell designs combined with air cooling systems. This study reveals that engineering solutions such as battery management systems are a swift and impactful tool to significantly increase the economic and environmental benefits of EVs.[1] Birkl, C.R., Roberts, M.R., NcTurk, E., Bruce, P.G., Howey, D.A. J. Power Sources 341 (2017), pp. 373-386. [2] Lander, L., Kallitsis, E., Hales, A., Edge, J.S., Korre, A., G. Offer, G. Appl. Energy 289 (2021), p. 116737. [3] Hunt, I.A., Zhao, Y., Patel, Y., Offer, G. J. Electrochem. Soc. 163 (2016); pp. A1846–52. Figure 1