Our study demonstrated that concentrations of air pollutants
were significantly associated with delays in spring phenology.
However, inconsistencies between long- and short-term exposure
effects of pollution suggest some caution when interpreting results.
Since ongoing global change will be associated with an increase in
air pollution (Pozzer et al., 2012), especially in the city, further
monitoring of direct and indirect effects on vegetation, also withincontrolled experiments, seems inevitable.