The life cycle human health (HH) impacts related to aviation biofuels have been understood in a limited way. Life cycle impact assessment (LCIA) methods for assessing HH are often associated with a high level of uncertainty and a low level of consensus. As a result, it remains challenging to perform a robust assessment of HH impacts with a suitable LCIA method. This study aims to systematically compare six commonly used LCIA methods for quantifying HH impacts, in order to empirically understand the potential impacts of aviation biofuel production on HH and how the results are affected by the choice of methods. Three aviation biofuel production pathways based on different feedstocks (sugarcane, eucalyptus, and macauba) were analyzed and compared to fossil aviation biofuels, on the basis of a functional unit of 1 MJ aviation fuel. The majority of the LCIA methods suggest that, in respect to midpoint impacts, macauba-based biofuel is associated with the lowest impacts and eucalyptus-based biofuel the highest; whereas at endpoint level, the results are more scattered. The LCIA methods agree that biomass conversion into aviation biofuel, H2 production, and feedstock cultivation are major contributors to life cycle HH impacts. Additionally, we provide a guideline for determining an appropriate method for assessing HH impacts.

Derived from renewable feedstocks, aviation biofuel is generally perceived as inherently sustainable. However, its production involves a wide range of sectors and interacts with different actors in society. It is therefore important to understand and evaluate not only the environmental impacts of that process, but also its socioeconomic effects. At present, empirical studies assessing socioeconomic aspects of aviation biofuel are rare in scientific literature. The aim of this study, therefore, is to assess key effects of aviation biofuel production on employment, GDP, and trade balance. A scenarios-based Input-Output (IO) analysis was used to evaluate these socioeconomic effects, taking Brazilian aviation biofuel production to 2050 as an example. To address the uncertainty of IO analysis, we have proposed a stochastic simulation approach for the technical coefficients in the IO model. Four distinct scenarios were developed. In each, three potential combinations of technologies and feedstocks for producing aviation biofuel were evaluated: sugarcane via alcohol to jet (ATJ), macauba via hydro-processed esters and fatty acids (HEFA), and eucalyptus via Fischer-Tropsch (FT). Among other things, we found that the production of aviation biofuel would create around 12,000–65,000 jobs, while contributing US$200-1100 million to Brazil's GDP under different scenarios with different supply chains. The socioeconomic effects calculated deterministically were generally higher than the stochastic outcomes, which can be explained by factors such as technological learning and economic growth. Aviation biofuel production showed large positive net socioeconomic effects on employment and GDP, although some of the fossil sectors would be negatively affected. Overall, the macauba-HEFA chain (with the highest effects on employment and GDP, and the lowest effects on imports) seemed to be the most favorable of the scenarios studied, despite the relatively high level of uncertainty associated with it.

Aviation fuels derived from biomass are generally perceived as sustainable alternatives compared with their fossil counterparts. However, the production of jet biofuels will have impacts on environment, economy and society simultaneously. Despite that a large number of studies have evaluated environmental impacts or techno-economic feasibility of aviation biofuels, very few studies took social aspects into consideration. Thus, this study seeks to provide a social sustainability evaluation for aviation biofuels with a supply chain perspective. Three potential jet biofuel supply chains, based on different feedstocks, i.e. sugarcane, eucalyptus and macauba, were analyzed in the context of Brazil. The assessment is performed mainly with a process-based approach combined with input-output analysis. A set of social sustainability issues, including employment, working condition, labor right, gender equity and social development, were evaluated in a quantitative manner. The results show the three supply chains lead to differentiated levels of social effects. The macauba-based supply chain generates the highest number of jobs and highest GDP value, whereas the eucalyptus-based supply chain offers more employment opportunities for women. In comparison, the sugarcane-based supply chain has relatively moderate social effects. For future work, the assessment of social sustainability needs to cover a wider range of social issues, in order to extend the comprehension of social sustainability regarding biofuels. Additional research is suggested to bridge the methodological gaps in social sustainability assessment.