Fig. 3From: Role of nitrous acid in the association between nitrogen dioxide and asthma symptoms: effect of nitrous acid exposure on specific airway resistance in guinea pigsChange in sRaw and grade of respiratory waveform for each animal over time. Data for 0 weeks of exposure are averages of sRaw of the 3-week preliminary housing period. Grade of respiratory waveform is indicated as follows: circle, normal; triangle, affected; square, strongly affected.Back to article page