Ozone and ozone injury on plants in and around Beijing, China.

Ozone (O3) levels were assessed for the first time with passive samplers at 10 sites in and around Beijing in summer 2012. Average O3 concentrations were higher at locations around Beijing than in the city center. Levels varied with site locations and ranged from 22.5 to 48.1 ppb and were highest at three locations. Hourly O3 concentrations exceeded 40 ppb for 128 h and 80 ppb for 17 h from 2 to 9 in August at one site, where it had a real-time O3 analyzer. Extensive foliar O3 injury was found on 19 species of native and cultivated trees, shrubs, and herbs at 6 of the 10 study sites and the other 2 sites without passive sampler. This is the first report of O3 foliar injury in and around Beijing. Our results warrant an extensive program of O3 monitoring and foliar O3 injury assessment in and around Beijing.