Table 2.

Statistics for the correlation analysis between meteorological variables [averages of vapour pressure deficit (VPD), relative humidity (RH), temperature (T) and wind speed (u)] and response variables (averages of Betula and OTC and time fractions (f) of; Bet > 100, Bet > 100 and NO_{2 max} > 60, Bet > 100 and PM_{10 max} > 50, Bet > 100 and O_{3 max} > 80

Response variables	VPD		RH		T		u
	r	Sign	r	Sign	r	Sign	r	Sign
Gothenburg
Betula	0.90	***	0.82	**	0.94	***	0.45	NS
f Bet > 100	0.92	***	0.97	***	0.90	***	0.61	NS
f Bet > 100 and NO2 max > 60	0.93	***	0.92	***	0.82	**	0.59	NS
f Bet > 100 and PM10 max > 50	0.94	***	0.92	***	0.88	***	0.42	NS
f Bet > 100 and O3 max > 80	0.80	**	0.71	*	0.82	**	0.44	NS
OTC	0.82	**	0.83	**	0.75	*	0.43	NS
Malmö
Betula	0.62	NS	0.51	NS	0.65	*	0.05	NS
f Bet > 100	0.54	NS	0.47	NS	0.57	NS	0.16	NS
f Bet > 100 and NO2 max > 60	0.67	*	0.58	NS	0.27	NS	0.60	NS
f Bet > 100 and PM10 max > 50	0.59	NS	0.50	NS	0.48	NS	0.15	NS
f Bet > 100 and O3 max > 80	0.53	NS	0.36	NS	0.53	NS	0.12	NS
OTC	0.82	**	0.77	**	0.46	NS	0.23	NS

All relationships are based on averages or time fractions for each LWT and thus consist of 10 points. The strength of the relationship was determined using Pearson product correlation coefficient (r) and significance level, using the F-test with p values referring to: * p < 0.05, ** p < 0.01, ***p  < 0.001, NS not significant

The bold correlation coefficients indicate a strong relationship with a value equal to or above 0.80