However, NO2, NOx and PM2.5 abs were significantly and positively
correlated with onset dates of full flowering (delayed phenology
with increasing pollution), especially when solely urban sites were
regarded. In this case the coefficients were higher and even significant
correlations with PM2.5 and PM10 were revealed. These
correlations were especially high for PM10 (r = 0.634, p < 0.01).