Table 1.
Characteristics of children attending school in a low and a high pollution urban area
| Characteristics | Low Pollution School (n=73) | High Pollution School (n=93) | P-value |
|---|---|---|---|
| Male sex - no. (%) |
46 (63%) |
46 (49.4%) |
|
| Age - yr |
10.0 (8.0-11.0) |
10.0 (9.0-11.0) |
0.2 |
| Height - cm |
134 (125–143) |
134 (130–138) 0.9 |
0.9 |
| Weight - kg |
27.0 (22.0-34.0) |
27.0 (25.0-31.0) |
0.9 |
| BMI - kg/m2 |
15.3 (14.1-16.4) |
15.3 (14.4-17.1) |
0.9 |
| Passive smoking |
22 (30%) |
34 (36%) |
0.3 |
| Socio-economic class§ |
|
|
0.001 |
| Low |
7 (10%) |
31 (34%) |
|
| Middle |
24 (33%) |
22 (24%) |
|
| High |
41 (57%) |
39 (42%) |
|
| Outdoor PM1 - μg/m3 |
7.3 (5.3) |
58.2 (9.6) |
<0.0001 |
| Outdoor PM2.5 - μg/m3 |
28.5 (10.3) |
183.0 (30.2) |
<0.0001 |
| Outdoor PM10 - μg/m3 |
223.0 (93.5) |
728.6 (53.5) |
<0.0001 |
| Indoor PM1 - μg/m3 |
8.4 (5.5) |
52.7 (12.1) |
<0.0001 |
| Indoor PM2.5 - μg/m3 |
29.1 (15.1) |
163.0 (61.6) |
<0.0001 |
| Indoor PM10 - μg/m3 |
222.9 (119.4) |
590.7 (219.4) |
<0.0001 |
| Outdoor temperature - °C |
15.5 (3.3) |
14.9 (4.5) |
0.4 |
| Relative humidity - % | 58.4 (16.4) | 67.1 (18.5) | 0.001 |
The data is mentioned as median (25th - 75th percentile), number (%), or mean (standard deviation) § according to paternal educational level (no information for one participant in each group). Particulate Matter (PM) was measured continuously with Aerocet 531 device during the previous 24 hours (outdoor) or between 10 and 11 am on the day of examination (indoor); corresponding averages were calculated for the different fractions, i.e. particles with diameter below 1 μm (PM1), 2.5 μm (PM2.5) and 10 μm (PM10). Values of PM were excluded when humidity was > 80% (4 days, high pollution school).