Table 2.
Associations of the lower respiratory tract symptom score and PEF to exposure to various environmental parameters.
| Meteorological Exposure | ||||
|---|---|---|---|---|
| Sand Dust Particles | Aerosolized Air Pollutants | SPM | PM2.5 | |
| IQR | 0.02 km−1 | 0.06 km−1 | 12.8 μg/m3 | 13.6 μg/m3 |
| Change in the symptoms score | 0.04 | 0.02 | 0.06 | 0.07 |
| 95% CI | 0.03, 0.05 | −0.01, 0.04 | 0.04, 0.08 | 0.04, 0.08 |
| P value | <0.001 | 0.085 | <0.001 | <0.001 |
| Change in the PEF (L/min) | 0.01 | −0.17 | −0.13 | −0.20 |
| 95% CI | −0.62, 0.11 | −0.67, 0.33 | −0.60, 0.35 | −0.80, 0.41 |
| P value | 0.946 | 0.507 | 0.588 | 0.526 |
Associations to sand dust particles, aerosolized air pollutants, SPM, and PM2.5 were evaluated in a linear mixed-effects model after adjusting for individual characteristics, gaseous air pollutants, and meteorological variables. Daily median levels were analyzed to investigate the association of sand dust particles and aerosolized air pollutants with PEF. The daily (24-h) average levels of air pollutants (SPM, PM2.5, SO2, NO2, and Ox) and meteorological variables (daily temperature, humidity, and atmospheric pressure) were used in the analysis. IQR, interquartile range; CI, confidence interval; NO2, nitrogen dioxide; Ox, photochemical oxidants; PEF, peak expiratory flow; PM2.5, particulate matter < 2.5 μm in diameter; SO2, sulfur dioxide; SPM, suspended particulate matter.