Biodiesel at the Crossroads of Clean Energy and Cancer Prevention: A Double-Edged Sword in Sustainable Transport

Air pollution is a major environmental risk factor for cancer, driven in part by emissions from the transportation sector. Biodiesel, a renewable alternative to petrodiesel, has emerged as a promising strategy to reduce toxic emissions from diesel engines. This review critically examines the relationship between biodiesel use and cancer risk, evaluating its impact across key pollutants including particulate matter (PM), unburned hydrocarbons (UHCs), carbon monoxide (CO), and nitrogen oxides (NOₓ). Biodiesel combustion generally results in lower emissions of PM, UHCs, and CO, pollutants known to induce DNA damage, oxidative stress, and chronic inflammation, all of which contribute to carcinogenesis. These benefits are largely attributed to biodiesel’s intrinsic oxygen content, absence of aromatic compounds, and higher cetane number, which collectively promote more complete combustion. However, biodiesel is consistently associated with increased NOₓ emissions, which can lead to secondary carcinogenic pollutants like ozone and PAHs. Additionally, potential cancer risks may arise during biodiesel production and processing. The paper concludes that while biodiesel significantly improves air quality and reduces several cancer-related exposures, optimizing its formulation and combustion conditions is essential to minimize unintended health trade-offs. Biodiesel thus represents both an opportunity and a challenge in the broader effort to achieve cleaner energy and cancer prevention.