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Table 2 Average measured pollutant concentrations over different time periods in the Mexico City Metropolitan Area, February 2002

From: Traffic-related air pollution exposures and changes in heart rate variability in Mexico City: A panel study

  5-minute 30-minute 60-minute 90-minute
  Mean Median Mean Median Mean Median Mean Median
( n, SD) (IQR) ( n, SD) (IQR) ( n, SD) (IQR) ( n, SD) (IQR)
PM2.5, mean (μ g/m3) 14 11 14 12 14 12 14 12
(3314, 12) (10) (3140, 9) (11) (2939, 8) (9) (2733, 8) (8)
Ozone, max (ppb) 84 69 85 73 87 77 89 83
(4406, 66) (65) (4118, 52) (66) (3832, 46) (73) (3550, 43) (65)
CO, max (ppm) 6 2 6 2 6 3 6 3
(4353, 8) (8) (4086, 7) (10) (3806, 6) (10) (3524, 6) (9)
CO2, max (ppm) 461 426 462 431 462 433 462 432
(4371, 97) (96) (4088, 79) (106) (3802, 73) (104) (3520, 69) (105)
Formaldehyde, max (ppb) 35 23 34 25 35 26 35 27
(1784, 39) (26) (1663, 26) (30) (1519, 24) (31) (1379, 23) (34)
NO2, max (ppb) 130 68 131 69 130 71 128 74
(4406, 135) (114) (4118, 121) (137) (3832, 114) (155) (3550, 108) (156)
NOx, max (ppb) 131 23 131 23 130 25 128 25
(4406, 187) (186) (4118, 176) (240) (3832, 169) (237) (3550, 161) (226)
  1. Sample sizes are the total number of repeated observations across all 16 subjects.