. Author manuscript; available in PMC: 2015 May 11.

Published in final edited form as: Environ Mol Mutagen. 2014 Jan 17;55(4):322–335. doi: 10.1002/em.21838

Table II.

Level of Personal Exposure to PM_2.5 and Elemental Carbon (EC) During Work Hours and Level of Ambient PM₁₀, Outdoor Temperature, and Humidity on the Examination Days

Time window	Office Workers (60 participants, 2 measures per participant)^a								Truck Drivers (60 participants, 2 measures per participant)^a

	^# Obs	Mean	SD	10^th pct	25^th pct	Median	75^th pct	90^th pct	^# Obs	Mean	SD	10^th pct	25^th pct	Median	75^th pct	90^th pct	P value
Personal PM_2.5^b (µg/m³) on the examination days, from personal monitors
8 hours^a	120	94.6	64.9	22.4	48.5	86.2	126.6	183.4	119	126.8	68.8	46.3	73.9	116.8	160.5	213.9	<0.001
Personal EC^b (µg/m³) on the examination days, from personal monitors
8 hours^a	118	13.0	4.0	7.3	10.1	13.2	15.7	18.4	120	17.2	6.6	9.2	12.9	16.7	20.8	25.5	<0.001
Ambient PM (µg/m³) from ambient monitors on the day of the study
24 hours^c	120	116.7	50.2	60.0	82.0	114.0	141.0	181.0	120	123.5	50.1	72.0	88.0	116.0	150.0	188.0	0.29
Outdoor relative humidity (%) on the day of the study
24 hours^c	120	20.6	2.1	17.5	20.0	21.0	21.5	23.0	120	20.6	2.1	17.0	20.0	21.0	22.0	23.0	0.93
Outdoor temperature (°C) on the day of the study
24 hours^c	120	25.4	2.5	22.0	23.0	26.0	28.0	29.0	120	25.3	2.5	22.0	23.0	26.0	28.0	28.0	0.96

Each of the truck drivers (n = 60) and office workers (n = 60) was studied on two different examination days for a total of 120 observations in each of the two groups. Mixed-effect regression was used in the statistical analyses to account for the lack of independence of the repeated measures and to compute P values.

Measured during the work hours of examination days using lightweight personal monitors.

24-hour average of ambient PM₁₀, relative humidity, or temperature on the examination days.

Obs, number of observations; SD, standard deviation; pct, percentile