Fig. 3
Percent change (95% confidence interval) in respiratory mortality associated with a 10 μg/m3 increase in 7-day average of 8-h maximum O3 concentrations by previous hospitalizations for chronic obstructive pulmonary disease (COPD), pneumonia, other respiratory diseases, other diseases, or by absence of any hospitalization between 0 to 3 years, or since 1987. All categories are mutually exclusive. Black markers indicate results from time series analyses and grey markers from case-crossover analyses