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Table 4 Associations between inter-quartile range increases in entire pregnancy average air pollution exposures and preterm birth based on multi-pollutant models.a

From: Traffic-related air toxics and preterm birth: a population-based case-control study in Los Angeles county, California

Pollutant Model 1 Model 2 Model 3 Model 4 Model 5 Model 6 Model 7
NO LUR_S 1.01 (0.96-1.06) 1.03 (0.98-1.08) 1.03 (0.99-1.08) 1.03 (0.98-1.07) 1.02 (0.97-1.07) 1.02 (0.96-1.09) 1.03 (0.98-1.08)
Ammonium nitrate PM2.5 1.47 (1.34-1.62) 1.41 (1.29-1.53) 1.38 (1.29-1.48) 1.26 (1.15-1.38) 1.40 (1.31-1.50) 1.51 (1.39-1.64) 1.38 (1.29-1.47)
Ammonium sulfate PM2.5 0.87 (0.80-0.94) 0.90 (0.84-0.96) 0.91 (0.86-0.96) 0.91 (0.86-0.96) 0.93 (0.87-0.98) 0.83 (0.77-0.90) 0.90 (0.84-0.96)
Geological PM2.5 0.80 (0.75-0.85) 0.82 (0.77-0.87) 0.80 (0.76-0.85) 0.83 (0.78-0.88) 0.82 (0.77-0.87) 0.80 (0.74-0.87) 0.81 (0.77-0.86)
PM2.5 vanadium 1.02 (0.97-1.07)       
Residual oil PM2.5   1.02 (0.97-1.07)      
CO    1.04 (1.00-1.10)     
PM2.5     1.11 (1.02-1.20)    
O3 (10 am-6 pm)      0.96 (0.90-1.02)   
Gasoline PM2.5       0.95 (0.89-1.01)  
Sea salt PM2.5        1.02 (0.96-1.09)
  1. a All models adjusted for maternal age, race/ethnicity and education, and parity. Pollutants were selected to represent each of the five factors identified by the factor analysis. The same models, but replacing ammonium nitrate PM2.5 with diesel PM2.5 to represent Factor 1, indicated odds increases of 8-26% per IQR increase in entire pregnancy diesel PM2.5.