Fig. 2
From: The association of exhaled nitric oxide with air pollutants in young infants of asthmatic mothers
eNO50 measured in each infant (transformed to square root) and plotted by month of test through the duration of the study, with sinterm regression line overlayed. eNO50SqR: square root eNO50 (exhaled nitric oxide interpolated to expiratory flow rate 50ml per second); sinterm: parameterized sine model with assumed value of zero at June, peak in March, and trough in September with increasing amplitude for each year