Table 2 Descriptive statistics for personal and outdoor PM_2.5 (µg/m³) and outdoor ultrafine particles (1/cm³)

	n	Av.time(h)	25th per-cent-tile	Median	75th per-cent-ile	Max
Personal	175	1	7.0	11.5	17.2	746.3
PM_2.5,	175	4	5.9	10.1	15.7	189.6
all values	175	8	5.0	8.1	13.3	117.8
included	175	12	5.2	7.8	12.4	79.4
	175	22	6.6	9.3	13.2	52.9
Personal PM_2.5,	169	1	6.9	11.2	15.8	41.5
extreme	169	4	5.9	10.0	14.6	41.3
values	172	8	5.0	7.9	13.0	34.9
excluded	172	12	5.2	7.8	12.1	28.8
	171	22	6.6	9.3	13.0	30.2
Outdoor PM_2.5	221	1	8.9	12.9	17.8	42.9
	221	4	8.8	12.5	17.6	40.8
	222	8	8.3	12.1	17.2	39.2
	221	12	8.3	11.9	17.0	37.0
	221	24	9.0	12.5	17.7	30.5
Outdoor	223	1	14 500	21 700	33 100	123 500
ultrafine	223	4	15 200	22 500	32 100	88 800
particles	223	8	12 500	18 000	26 600	69 800
	223	12	10 400	15 000	21 100	52 400
	223	24	11 300	14 400	21 800	50 300

Av., averaging.