Skip to main content

Table 1 Air pollutants, climatic variables and traffic density during the study period

From: Traffic-related air pollution and respiratory symptoms among asthmatic children, resident in Mexico City: the EVA cohort study

  Mean (SD) Interquartile Range
1 hr maximum, O3 (ppb) 86.5(34.4) 48.0
1 hr maximum, NO2(ppb) 68.6(25.8) 34.0
24-hr average, PM2.5 (μg/m3) 27.8(14.9) 17.5
PM2.5 absorbance (10 -5m-1)& 10.3(4.9) 8.5
Temperature minimum, (°C) 11.3(3.1) 4.2
Humidity minimum 34.8(11.6) 18.1
Traffic density, hourly average   
   A 423.0(303.1, 1840.2) 1537.1
   B 30.1(13.1, 512.5) 499.5
   C 20.1(14.2, 144.5) 130.3
Distance from the main avenue to the child's residence(m) 147.0(67.9, 279.9) 212.0
  1. Median (Q25, Q75). Definition: Standard Deviation (SD). A: Private cars (Gasoline); B: Small buses for public transportation (Gasoline or natural gas); C: School buses, other buses, pick up trucks and heavy trucks (Diesel); Ozone(O3), Nitrogen dioxide(NO2) and particles less than 2.5 μg/m3 in diameter(PM2.5),
  2. &Light absorption in inverse meters.
  3. 95% of the children lived less than 500 m from the main avenue