Global mixed model main effect analysis of the cross-over design
BAL cells 
Filtered air (FA)mean (allergen-saline)
Treatment effect (UFP-FA)
Main effect analysis analyzing total BAL cells and eosinophils using a mixed model with fixed factors exposure, period, sequence, and subjects within sequence as random factor. Estimated mean differences (between allergen challenge and saline) of total cells and absolute eosinophils in BAL are shown 42 h after ultrafine particle (UFP) and filtered air (FA) exposure. Additionally, absolute treatment differences between UFP and filtered air, with 95% confidence levels and p-values are shown.