Subclinical responses in healthy cyclists briefly exposed to traffic-related air pollution: an intervention study

Abstract

BackgroundNumerous epidemiological studies have demonstrated adverse health effects of a sedentary life style, on the one hand, and of acute and chronic exposure to traffic-related air pollution, on the other. Because physical exercise augments the amount of inhaled pollutants, it is not clear whether cycling to work in a polluted urban environment should be encouraged or not. To address this conundrum we investigated if a bicycle journey along a busy commuting road would induce changes in biomarkers of pulmonary and systematic inflammation in a group of healthy subjects.Methods38 volunteers (mean age: 43 ± 8.6 years, 26% women) cycled for about 20 minutes in real traffic near a major bypass road (road test; mean UFP exposure: 28,867 particles per cm3) in Antwerp and in a laboratory with filtered air (clean room; mean UFP exposure: 496 particles per cm3). The exercise intensity (heart rate) and duration of cycling were similar for each volunteer in both experiments. Exhaled nitric oxide (NO), plasma interleukin-6 (IL-6), platelet function, Clara cell protein in serum and blood cell counts were measured before and 30 minutes after exercise.ResultsPercentage of blood neutrophils increased significantly more (p = 0.004) after exercise in the road test (3.9%; 95% CI: 1.5 to 6.2%; p = 0.003) than after exercise in the clean room (0.2%; 95% CI: -1.8 to 2.2%, p = 0.83). The pre/post-cycling changes in exhaled NO, plasma IL-6, platelet function, serum levels of Clara cell protein and number of total blood leukocytes did not differ significantly between the two scenarios.ConclusionsTraffic-related exposure to particles during exercise caused a small increase in the distribution of inflammatory blood cells in healthy subjects. The health significance of this isolated change is unclear.

A rapid assessment of the impact of hazard reduction burning around Sydney, May 2016

“…Studies of acute (20 minutes to 2 hours) effects of real-life traffic exposure on healthy volunteers have been unremarkable and are limited to a small increase in the percentage of blood neutrophils (Jacobs et al, 2010), modest effects on peak flow, exhaled nitric oxide and airway resistance (Zuurbier et al, 2011a, b). A study by Strak et al (2012) was specifically designed to evaluate the contribution of different pollutants.…”

Prediction of ultrafine particle number concentrations in urban environments by means of Gaussian process regression based on measurements of oxides of nitrogen

“…Kumar et al (2011a) have shown significant contributions to excess mortality due to the exposure to traffic-derived UFP in urban areas. Jacobs et al (2010) and Bos et al (2011) have shown that even brief exposure of healthy people to traffic UFP seems to induce some health effects. Moreover, those particles may also cause cardio-vascular damage (de Hartog et al, 2003) and could cause brain stroke when penetrating into the bloodstream and being transported to other organs (Hong et al, 2002).…”

Physiological Responses to Acute Airborne Particle Exposure during Maximal Aerobic Power

“…Nitric oxide is conveyed by different cell types in the respiratory tract including epithelial cells, macrophages, neutrophils, mast cells and vascular endothelial cells (Ricciardolo, 2003;Jacobs et al, 2010). A number of demographic, anthropometric and biological factors (such as age, gender, height, smoking, infection and allergy), reviewed by Abba (2009), can affect the eNO concentration levels.…”