Spatiotemporal Patterns of Ozone and Cardiovascular and Respiratory Disease Mortalities Due to Ozone in Shenzhen

In order to explore the temporal-spatial patterns and possible health effects of ozone in Shenzhen, daily concentrations of ozone and the daily mortality caused by cardiovascular and respiratory diseases were collected. Using Geographic Information System (GIS) and SPSS, the spatial and temporal patterns of ozone in Shenzhen were illustrated. Using a generalized additive model (GAM), the associations between ozone and cardiovascular and respiratory diseases causing mortality were analyzed, adjusted for meteorological factors and other major air pollutants including fine particulate matter (PM2.5), nitrogen dioxide (NO2) and carbon monoxide (CO), and stratified by lag, age, and gender. The results showed that, during 2013, ozone was the second main air pollutant in Shenzhen apart from PM2.5, with average daily concentrations of 95.9 µg/m3 and 76.8 µg/m3 for the ozone 1-h mean and the daily ozone 8-h maximum concentration, respectively. The daily level of ozone had a higher concentration from September to October, and relatively low concentration from May to June. Obviously, a higher concentration was found in central parts of Shenzhen with the largest population, indicating higher risks. The excess risk (ER) percentage of the cardio-respiratory mortality rate showed a clearly accumulative effect at L03, with the highest ER percentage of 1.08 (0.88–1.27) per 10 µg/m3 increase in the ozone 8-h maximum concentration for all the population. Males were found to be more sensitive to ozone compared with females, and the elderly were more susceptible to ozone exposure than younger people.