Table 1.

Summary of particulate matter (PM, annual mean) concentration in μg/m³ in the study period. SD = standard deviation.

	Mean	SD	Min	Max	Frequency of Municipalities Exceeding the Limit Value Defined for PM2.5 N (%)
2010	21.28	5.37	6.70	31.54	51 (27.12%)
2011	22.48	6.11	7.50	34.45	75 (39.88%)
2012	23.58	6.49	8.13	37.07	103 (57.78%),
2013	19.40	5.77	5.88	31.39	31 (16.48%)
2014	17.52	5.08	5.44	28.02	4 (2.12%)
2015	21.38	6.33	6.92	35.31	55 (29.25%)