Abstract
BackgroundExposure to diesel exhaust causes inflammatory responses. Previous controlled exposure studies at a concentration of 300 μg/m3 of diesel exhaust particles mainly lasted for 1 h. We prolonged the exposure period and investigated how quickly diesel exhaust can induce respiratory and systemic effects.MethodsEighteen healthy volunteers were exposed twice to diluted diesel exhaust (PM1 ~300 μg/m3) and twice to filtered air (PM1 ~2 μg/m3) for 3 h, seated, in a chamber with a double-blind set-up. Immediately before and after exposure, we performed a medical examination, spirometry, rhinometry, nasal lavage and blood sampling. Nasal lavage and blood samples were collected again 20 h post-exposure. Symptom scores and peak expiratory flow (PEF) were assessed before exposure, and at 15, 75, and 135 min of exposure.ResultsSelf-rated throat irritation was higher during diesel exhaust than filtered air exposure. Clinical signs of irritation in the upper airways were also significantly more common after diesel exhaust exposure (odds ratio=3.2, p<0.01). PEF increased during filtered air, but decreased during diesel exhaust exposure, with a statistically significant difference at 75 min (+4 L/min vs. -10 L/min, p=0.005). Monocyte and total leukocyte counts in peripheral blood were higher after exposure to diesel exhaust than filtered air 20 h post-exposure, and a trend (p=0.07) towards increased serum IL-6 concentrations was also observed 20 h post-exposure.ConclusionsDiesel exhaust induced acute adverse effects such as symptoms and signs of irritation, decreased PEF, inflammatory markers in healthy volunteers. The effects were first seen at 75 min of exposure.
Highlights
Exposure to diesel exhaust causes inflammatory responses
The results demonstrated that Diesel exhaust (DE) exposure caused inflammatory responses at 6 h and 18 h
No significant differences between exposures were detected in self-rated nose or chest symptoms
Summary
Exposure to diesel exhaust causes inflammatory responses. Previous controlled exposure studies at a concentration of 300 μg/m3 of diesel exhaust particles mainly lasted for 1 h. Epidemiological studies have shown associations between DE and respiratory diseases, but the underlying mechanisms are still not fully understood and the exposure needs to be better characterized to improve the basis for risk assessment in occupational and environmental settings Part of this knowledge gap was filled by a series of controlled human diesel exhaust exposure studies carried out in Umeå, Sweden. The results demonstrated that DE exposure caused inflammatory responses at 6 h and 18 h This was indicated by increased cell counts (neutrophils, B lymphocytes and eosinophils) and concentrations of fibronectin and methyl histamine in airway lining fluid, as well as increase neutrophils and mast cells, up-regulation of endothelial adhesion molecules and interleukins in bronchial biopsies [17,18,19,22]. This airway inflammation was followed by an increase of neutrophils and platelets in peripheral blood [19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
