Table 1.

Conditions from ozone exposure/reactive oxygen species*

Authors, year (reference)	Pollutant exposure	Type of study	Respiratory condition of focus	Co-existing conditions	Number of subjects	Types of analysed markers and results
Alexis et al., 2008 [36]	Ozone	Double-blind, placebo-controlled, randomised, three-period crossover study	O3-induced lung function decline	N/A	8 female (9 male)	CC16 levels: statistically significantly increased pre-vs post-O3 exposure.
						SP-D levels: not statistically significantly altered pre-vs post-O3 exposure.
Bennet et al., 2016 [37]	Ozone	Randomised controlled exposure study	O3-induced lung function decline	Obese	19 females	IL-6 levels: increased in healthy subjects’ pre-vs post-O3 exposure as well as in obese subjects but to a greater degree.
						FP significantly reduced the percent of neutrophils in sputum by 18% and 35% for 0.5 mg and 2 mg FP, respectively.
						FP also significantly reduced the total number of neutrophils per milliliter of sputum by 14% and 43% for 0.5 mg and 2 mg FP, respectively.
Arjomandi et al., 2018 [38]	Ozone	Randomised crossover-controlled exposure study, MOSES study	O3-induced lung function decline	Geriatric population; exercise intervention	52 females (35 males)	CC16 levels: four hours post-exposure, significantly increased pre-vs post-O3 exposure dependent on the concentration.
Balmes et al., 2019 [8]	Ozone	Randomised double-blind crossover study, MOSES study†	O3-induced lung function decline	Geriatric population; exercise intervention	52 females (35 males)	CRP, IL-6, 8-isoprostane, or P-selectin: no change.
						Nitrotyrosine: decreased after 120 ppb ozone.
Rich et al., 2020 [39]	Ozone	Randomised double-blind crossover study, MOSES study†	O3-induced lung function decline	Geriatric population; exercise intervention	52 females (35 males)	After extending the time for pre-collection and standardising for ambient air pollution, results changed.
						Increasing ambient NO2, CO, and PES altered pulmonary function responses in a concentration-dependent manner which means previous MOSES studies are accurately measuring markers’ relationships.
Chamitava et al., 2020 [40]	ROS	Observational study	COPD, chronic bronchitis, and asthma	Some smokers	Current asthma: 212 females. Past asthma: 84 females. Chronic bronchitis: 50 females. Controls: 2270 females	Chronic bronchitis subjects showed a higher rate of expression of oxidative stress biomarkers compared to asthmatic subjects.
s						Asthmatics: blood leukocytes, basophils, and eosinophils heightened with ozone exposure.
						Chronic bronchitis: glutathione and lymphocytes more heightened than normal.

C16 – club cell secretory protein 16, CO – carbon monoxide, COPD – chronic obstructive pulmonary disorder, CRP: C-reactive protein, FP – fluticasone propionate, IL-6 – interleukin 6, MOSES – Multicenter Ozone Study in oldEr Subjects, NO₂ – nitrogen dioxide, O₃ – ozone

PES – potential environmental susceptibility, ppb – parts per billion, ROS – reactive oxygen species, SP-D – surfactant protein D

*Potential ozone-related inflammation candidates: CC16, nitrotyrosine, and IL-16 dysregulated.

†Same trial as above, different marker analysis.