Figure 1From: Impact of a countywide smoke-free workplace law on emergency department visits for respiratory diseases: a retrospective cohort studyED visit rates for COPD before and after smoke-free law. Visit rates are presented monthly from 1/1/2005 through 12/31/2009. The vertical dashed lines indicate the time period between when the law was passed and when the law took effect. Solid lines represent the predicted rates from segmented Poisson regression.Back to article page