Baseline characteristics of non-smoking participants (n=80)
| Parameter | Value |
| Mean age, years | 34.3±12.5 |
| No. (%) of women, n (%) | 31 (38.7) |
| Education, years | 11.0±2.3 |
| History of asthma*, n (%) | 5 (6.2%) |
| Hours worked in current job/week | 50.7±13.4 |
| At least one evening shift/week, n (%) | 38 (47.5%) |
| Time working in current job, years | 4 (1–6) |
Values are mean ±SD or median (IQR).
↵* Self-reported and those on asthma medication.26