Cardiovascular effects of exposure to biodiesel exhaust
Abstract: Context: Urban air pollution is considered a significant factor contributing to increased respiratory and cardiovascular mortality in cities. Many studies focused on the relationship between exposure to diesel exhaust and human health effects, demonstrating the toxicity of such gases. Biodiesel is described as a more carbon-neutral alternative to petroleum derivatives, but few studies have been conducted yet to assess its effects on human health. Objective: The present work investigates the influence of exposure to biodiesel exhaust gases on cardiovascular function in human. Methods: PPG and ECG recordings of 19 study participants are recorded during exposure to various gases, including biodiesel exhaust. PPG pulses are decomposed into five waves by implementing a pulse decomposition analysis (PDA). Morphological features, including the percentage of amplitude loss between waves, are calculated among others. Measures of changes in PPG waveforms, complemented by computation of pulse transit time (PTT) are performed for assessment of vascular compliance properties. In addition, calculation of heart rate variability (HRV) indicators is used for evaluation of the state of the autonomic nervous system (ANS). Results: Statistically significant individual differences between exposure to pure air and biodiesel exhaust were found regarding percentage of amplitude loss in the second and third reflected waves. Increase in those parameters after three hours was reasonably consistent among study participants. There was no effect of exposure to biodiesel exhaust on PTT intervals and HRV indicators. Conclusion: An increase in amplitude loss in reflected waves is associated with reduced vascular compliance. Exposure to biodiesel may thus induce a slight increase in arterial stiffness. Further studies are necessary to assess the effects of biofuel exhaust on cardiovascular function and should be based on larger groups of study participants to compensate for the large range of responses obtained by PDA and HRV analysis.
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