Longitudinal Trends of the Annual Exposure to PM_2.5 Particles in European Countries

Table 2

The number of countries and mean annual change for each pattern.

Pattern	Number of countries	Mean exposure at 2010		Mean annual change
		Estimate	SE	Estimate	SE
First	2	31.47	6.52	0.09	0.43
Second	39	16.95	1.02	−0.50	0.04