Impact of air pollution exposure on lung function and exhaled breath biomarkers in children and adolescents

Impact of environmental exposures on exhaled breath and lung function: NELA Birth Cohort

Introduction

Exposure to environmental factors (i.e. air pollution and second-hand tobacco smoke) have been associated with impaired lung function. However, the impact of environmental factors on lung health is usually evaluated separately and not with an exposomic framework. In this regard, breath analysis could be a noninvasive tool for biomonitoring of global human environmental exposure.

Methods

Data come from 337 mother-child pairs from the Nutrition in Early Childhood Asthma (NELA) birth cohort. Levels of BTEX (benzene, toluene, ethylbenzene and xylenes) in exhaled breath from mothers and children at 3 months after birth were estimated using gas chromatography-mass spectrometry. Short-term residential exposures (breath sampling day and 15 days before breath sampling) to nitrogen dioxide, particulate matter (PM2.5) and ozone were determined by chemical dispersion/transport modelling. Forced vital capacity, forced expiratory volume in 0.5 s (FEV0.5) and forced expiratory flow at 75% of FVC and at 25%-75% of FVC were measured in infants according to the raised-volume rapid thoracoabdominal compression technique.

Results

The results showed significant associations between short-term exposure to external agents and levels of benzene and toluene in exhaled breath. It was observed that exhaled levels of benzene and toluene were influenced by smoking status and outdoor air pollution in mothers, and by air pollution in infants (3 months of age). No significant relationship was observed between exposure to maternal tobacco smoking and/or short-term air pollution and lung function in healthy infants. However, there was a significant relationship between FEV0.5 and exhaled toluene in children.

Discussion

These findings indicated a significant relationship between environmental exposures and exhaled levels of benzene and toluene, suggesting that breath analysis could be a helpful exposure biomonitoring tool.

The mediating role of exhaled breath condensate metabolites in the effect of particulate matter on pulmonary function in schoolchildren: A crossover intervention study

The role played by metabolites in exhaled breath condensate (EBC) in the effect of PM on schoolchildren's pulmonary function has received little attention. Accordingly, we examined whether metabolites in EBC mediated the effect of PM10, PM2.5, and PM1 on the pulmonary function of schoolchildren at a residential primary school who had received an air-cleaner cross-over intervention. Samples of EBC were collected from a total of 60 schoolchildren and subjected to metabolomics analysis. We found that the effect of PM on six pulmonary function indicators was mediated by the following nine lipid peroxidation-related and energy metabolism-related metabolites present in EBC: 4-hydroxynonenal, arachidoyl ethanolamide, dl-pyroglutamic acid, 5-deoxy-d-glucose, myristic acid, lauric acid, linoleic acid, l-proline, and palmitic acid. However, while all nine of these metabolites mediated the effects of PM on boys' pulmonary function, only 4-hydroxynonenal, arachidoyl ethanolamide, and dl-pyroglutamic acid mediated the effects of PM on girls' pulmonary function. Overall, our results show that (1) short-term exposure to PM affected the schoolchildren's pulmonary function by causing an imbalance between lipid peroxidation and glutathione-based antioxidant activity and by perturbing energy metabolism in respiratory system and (2) there was a sex-dependent antioxidant response to PM exposure, with boys being less resistant than girls.