NOS2 and asthma: Additional file 1: Figures S3 and S4 show that the severe distortion in the upper tails of FeNO distribution are more dramatic among children with asthma and among the Hispanic white group for a 10 μg/m3 increases in short-term PM2.5 exposure and 10 percentage decreases in iNOS promoter methylation, and comparing 0 to 2 copies of NOS2 haplotype.