Table 4.

Associations of respiratory emergency department visits and ambient pollutants in St. Louis, 1 June 2001–30 April 2003.^a

Pollutant	IQR	Respiratory diseasebRR (95% CI)	Pneumonia RR (95% CI)	Chronic obstructive pulmonary disease RR (95% CI)	Asthma/wheeze RR (95% CI)
Fine particles and components
24-hr avg PM2.5	11.1 μg/m3	0.994 (0.979, 1.010)	0.977 (0.951, 1.004)	0.990 (0.946, 1.037)	1.040 (1.009, 1.071)**
Major ions
24-hr avg SO42–	3.2 μg/m3	0.998 (0.986, 1.011)	0.990 (0.967, 1.014)	0.983 (0.946, 1.021)	1.029 (1.004, 1.055)**
24-hr avg NO3–	2.3 μg/m3	0.999 (0.982, 1.016)	0.991 (0.962, 1.021)	0.984 (0.933, 1.038)	1.011 (0.977, 1.046)
Carbon
24-hr avg OC	2.4 μg/m3	0.995 (0.980, 1.009)	0.982 (0.956, 1.009)	1.016 (0.971, 1.063)	1.029 (1.000, 1.060)*
24-hr avg EC	0.42 μg/m3	0.998 (0.987, 1.009)	0.982 (0.961, 1.004)	1.017 (0.982, 1.054)	1.020 (0.998, 1.044)*
n-Alkanes
24-hr avg Oct	0.77 ng/m3	0.999 (0.994, 1.005)	1.003 (0.994, 1.013)	1.017 (1.001, 1.033)**	1.003 (0.993, 1.013)
24-hr avg Non	1.98 ng/m3	1.000 (0.993, 1.008)	0.998 (0.984, 1.012)	1.015 (0.992, 1.039)	1.003 (0.989, 1.018)
Hopanes
24-hr avg Nor	0.43 ng/m3	0.993 (0.981, 1.005)	0.987 (0.966, 1.009)	1.037 (1.000, 1.077)*	1.011 (0.988, 1.036)
24-hr avg Hop	0.24 ng/m3	1.001 (0.991, 1.012)	0.994 (0.975, 1.013)	1.021 (0.989, 1.054)	1.027 (1.006, 1.047)**
PAHs
24-hr avg Chry	0.39 ng/m3	0.993 (0.982, 1.004)	0.983 (0.963, 1.004)	1.033 (0.996, 1.070)*	1.018 (0.995, 1.042)
24-hr avg BbkF	0.61 ng/m3	0.997 (0.986, 1.008)	0.984 (0.964, 1.004)	1.029 (0.995, 1.064)*	1.017 (0.996, 1.039)
24-hr avg BaP	0.19 ng/m3	1.001 (0.995, 1.006)	0.996 (0.986, 1.007)	1.013 (0.996, 1.029)	1.006 (0.996, 1.017)
24-hr avg IcdP	0.27 ng/m3	1.005 (0.996, 1.015)	0.998 (0.981, 1.016)	1.014 (0.986, 1.042)	1.013 (0.996, 1.031)
Metals and metalloids
24-hr avg Si	70.2 ng/m3	1.001 (0.997, 1.005)	1.005 (0.998, 1.012)	0.995 (0.982, 1.008)	1.002 (0.994, 1.010)
24-hr avg K	35.5 ng/m3	0.998 (0.989, 1.006)	1.000 (0.985, 1.015)	0.988 (0.964, 1.013)	1.012 (0.994, 1.029)
24-hr avg Ca	86.0 ng/m3	1.004 (0.993, 1.016)	1.001 (0.980, 1.023)	1.003 (0.966, 1.040)	1.024 (1.001, 1.048)**
24-hr avg Fe	85.9 ng/m3	1.001 (0.991, 1.011)	1.006 (0.989, 1.024)	0.985 (0.955, 1.016)	1.014 (0.994, 1.034)
24-hr avg Cu	21.9 ng/m3	0.997 (0.992, 1.003)	1.003 (0.992, 1.013)	1.001 (0.984, 1.018)	1.000 (0.989, 1.011)
24-hr avg Zn	37.9 ng/m3	0.991 (0.985, 0.997)**	0.996 (0.986, 1.007)	0.991 (0.972, 1.010)	0.993 (0.981, 1.006)
24-hr avg Pb	14.1 ng/m3	0.998 (0.993, 1.004)	1.001 (0.991, 1.011)	0.989 (0.973, 1.006)	1.002 (0.992, 1.013)
Criteria gases
8-hr max O3	28.3 ppb	1.052 (1.018, 1.087)**	1.041 (0.979, 1.106)	0.978 (0.886, 1.080)	1.067 (1.001, 1.137)**
1-hr max CO	0.7 ppm	0.998 (0.988, 1.009)	1.002 (0.983, 1.022)	1.015 (0.982, 1.049)	1.015 (0.993, 1.036)
1-hr max NO2	12.0 ppb	1.006 (0.990, 1.023)	1.005 (0.975, 1.036)	1.023 (0.973, 1.075)	1.050 (1.018, 1.084)**
1-hr max SO2	24.0 ppb	0.995 (0.988, 1.002)	0.992 (0.978, 1.005)	0.978 (0.956, 1.001)*	0.996 (0.981, 1.011)
Abbreviations: avg, average; max, maximum. aAll results from primary 3-day (lags 0–2) distributed lag models, with indicator variables to control for season, day-of-week, holidays, and to account for one hospital not providing data after 26 April 2002; cubic splines for day of visit with monthly knots; cubic spline for lag 0 maximum temperature with knots placed at the 25th and 75th percentiles; and cubic terms for 1- to 2-day moving-average minimum temperature and 0- to 2-day moving-average dew point temperature. bRD outcome included visits for pneumonia (ICD-9 codes 480–486), chronic obstructive pulmonary disease (ICD-9 codes 491, 492, 496), asthma/wheeze (ICD-9 codes 493, 786.07), and other RD (ICD-9 codes 460–466, 477; i.e., upper respiratory infection and bronchiolitis). *0.05 ≤ p < 0.10. **p < 0.05.