Table 1.
School and geographical averages for the pollutants measured in the study
| Schools in the south | Average schools | Schools in the north | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Nizam | Enthu | Assegai | Dirkie Uys | South | North | Briardale | Ferndale | Ngazana | |
| PM10 (µg/m3) | |||||||||
| Mean (±SD) | 50.1 (±25.2) | 51.6 (±26.3) | 57.9 (±34.6) | 45.6 (±24.2) | 51.3 (±28.0) | 48.5 (±35.4) | 40.9 (±23.8) | 45.3 (±30.0) | 59.0 (±45.9) |
| Range | 14.0 – 179.4 | 9.6 – 173.8 | 1.2 – 208.0 | 1.4 – 170.6 | 1.2 – 208.0 | 0.7 – 266.6 | 1.9 – 133.8 | 4.5 – 178.7 | 0.7 – 266.6 |
| PM2.5 (µg/m3) | |||||||||
| Mean (±SD) | - | - | - | - | 20.7 (±15) | 20.0 (±23.6) | - | - | - |
| Range | - | - | - | - | 3.6 – 78.6 | 4.4 – 131.4 | - | - | - |
| SO2 (ppb)* | |||||||||
| Mean (±SD) | 8.3 (±8.4) | 6.7 (±8.0) | 11.9 (±10.1) | 7.0 (±5.5) | 8.7 (±8.2) | 1.9 (±2.0) | 1.6 (±2.6) | 2.5 (±2.2) | 1.2 (±1.2) |
| Range | 0.01 – 61.9 | 0.05 – 46.8 | 0.43 – 73.4 | 0.17 – 32.2 | 0 – 73.4 | 0 – 16.8 | 0 – 24.1 | 0 – 16.3 | 0 – 6.0 |
| NO2 (ppb)† | |||||||||
| Mean (±SD) | - | - | - | - | 17.2 (±8.8) | 10.9 (±6.2) | - | - | - |
| Range | - | - | - | - | 3.7 (±63.8) | 0 – 47.5 | - | - | - |
| NO (ppb)*,† | |||||||||
| Mean (±SD) | - | - | - | - | 40.9 (±30.5) | 22.1 (±22.2) | - | - | - |
| Range | - | - | - | - | 3.2 – 192.2 | 0 – 115.7 | - | - | - |
PM10 and PM2.5 = particulate matter ≤10 µm and ≤2.5 µm in aerodynamic diameter, respectively; SD = standard deviation; SO2 = sulphur dioxide; ppb = parts per billion; NO2 = nitrogen dioxide; NO = nitric oxide.
*
p<0.05 (t-test comparing north v. south).
†
These pollutants were monitored only at single sites in the north and south respectively, and the table reflects data from the municipal monitoring sites.