Investigating short-term lung inflammation using exhaled breath VOCs from exposure to candles: a randomized controlled crossover study among young mild asthmatics.

Lung inflammation is associated with a response to pollution or irritants and is reported to release volatile organic compounds (VOCs) in breath, that can be monitored non-invasively. An approach to studying acute lung inflammation is exposure to environmental emissions. This study used short-term exposure to two burning candle types as fine particle (PM2.5) emissions. This was used to discern potential differences in acute airway inflammation among mildly asthmatic individuals. The aim was to explore VOCs linked to lung inflammation by exposure to candle emissions. Seventeen non-smoking asthmatics participated in a randomized controlled double-blind crossover study including two exposure sessions: i) air with candle A emissions (mean PM2.5 54.1 µg/m3), and ii) air with candle B emissions (mean PM2.5 98.4 µg/m3). Emissions were generated and fed into an exposure chamber, where participants were exposed at rest for five hours. Exhaled breath VOCs were assessed before exposure start (0h), immediately after exposure (5h) and the next morning (24h). Ten statistically significant exhaled VOCs showed differences between pre-exposure and immediate post-exposure. Samples collected after 24h resembled baseline samples. For exposure to candle B, there was a distinct differentiation between 0h, 5h and 24h samples, which was not found for candle A. An emission-specific, exhaled breath, multi-VOC profile can detect individuals exposed to inflammation triggers, i.e., candles, suggesting that VOCs could detect acute airway inflammation. This is indicated by a systematic difference in VOCs after 5h in candle B. Keywords: Candle emissions, Particles, VOCs, Acute respiratory effects, Breath biomarkers.