Biological effects of inhaled nitrogen dioxide in healthy human subjects
- 1.8k Downloads
Several epidemiological studies indicate that inhaled nitrogen dioxide (NO2) at low concentrations have been statistically associated with adverse health effects. However, these results are not reflected by exposure studies in humans. The aim of the study was to assess the acute functional and cellular responses to different NO2 concentrations in healthy human subjects with various techniques.
Twenty-five subjects were exposed for 3 h to NO2 concentrations 0, 0.1, 0.5, and 1.5 ppm in a randomized crossover study design during 4 consecutive weeks. In each subject, lung function, diffusion capacity and exhaled nitric oxide were measured and inflammation markers were assessed in blood, nasal secretions, induced sputum and exhaled breath condensate.
From all lung function indices under consideration, only intrathoracic gas volume was borderline significantly increased after 0.5 ppm (p = 0.048) compared to 0.1 ppm NO2. Regarding the cellular effect parameters, the macrophage concentration in induced sputum decreased with increasing NO2 concentration, although these changes were only borderline significant (p = 0.05).
These results do not suggest a considerable acute adverse response in human subjects after 3 h of exposure to NO2 in the NO2 concentration range investigated in this study.
KeywordsNitrogen dioxide Exposure Human subjects Topic effects Systemic effects
This study has been financially supported by the European Research Group on Environment and Health in the Transport Sector (EUGT).
Compliance with ethical standards
Conflict of interest
None of the authors have a conflict of interest to declare in relation to this work.
- Brand P et al (2010) Internal exposure, effect monitoring and lung function in welders after acute short term exposure to welding fumes from different welding processes. JOEM 52:887–892Google Scholar
- Davidson CA, Kaminski PM, Wu M, Wolin MS (1996) Nitrogen dioxide causes pulmonary arterial relaxation via thiol nitrosation and NO formation. Am J Physiol 270(3 Pt 2):H1038–H1043Google Scholar
- Folinsbee LJ (1992) Does nitrogen dioxide exposure increase airways responsiveness? Toxicol Ind Health 8(5):273–283Google Scholar
- Frampton MW et al (2002) Nitrogen dioxide exposure: effects on airway and blood cells. Am J Physiol Lung Cell Mol Physiol 282(1):L155–L165Google Scholar
- Hazucha MJ et al (1983) Effects of 0.1 ppm nitrogen dioxide on airways of normal and asthmatic subjects. J Appl Physiol 54(3):730–739Google Scholar
- Jorres R, Magnussen H (1990) Airways response of asthmatics after a 30 min exposure, at resting ventilation, to 0.25 ppm NO2 or 0.5 ppm SO2. Eur Respir J 3(2):132–137Google Scholar
- MAK-Commission (2012) Stickstoffdioxid [MAK Value Documentation in German language], vol 1–9. WhileyGoogle Scholar
- Sandström T et al (1991) Inflammatory cell response in bronchoalveolar lavage fluid after nitrogen dioxide exposure of healthy subjects: a dose-response study. Eur Respir J 4(3):332–339Google Scholar
- Sandström T, Helleday R, Bjermer L, Stjernberg N (1992a) Effects of repeated exposure to 4 ppm nitrogen dioxide on bronchoalveolar lymphocyte subsets and macrophages in healthy men. Eur Respir J 5(9):1092–1096Google Scholar
- Sandström T, Ledin MC, Thomasson L, Helleday R, Stjernberg N (1992b) Reductions in lymphocyte subpopulations after repeated exposure to 1.5 ppm nitrogen dioxide. Br J Ind Med 49(12):850–854Google Scholar
- Tsoukias NM, George SC (1998) A two-compartment model of pulmonary nitric oxide exchange dynamics. J Appl Physiol 85(2):653–666Google Scholar
- US Environmental Protection Agency (2008) Integrated science assessment for oxides of nitrogen—health criteria. National Center for Environmental Assessment-RTP Division. U.S. Environmental Protection Agency, Research Triangle ParkGoogle Scholar
- von Nieding G, Wagner HM (1979) Effects of NO2 on chronic bronchitics. Environ Health Perspect 29:137–142Google Scholar