Endo 0.00 –0.03 0.01 10.93** 1.69 2.18 –0.04 –2.21 0.06 0.00 –0.18 –0.01 –0.04 –0.08 0.92 –0.05 2.75 –0.07 –1.93 –1.94 –0.02 –0.01 –0.02 –0.04 4.89 2.95 Endo 0.02 0.09 0.02 –1.31** –0.08 –0.07 0.05 0.58* –0.04 0.00 0.06 0.00 0.01 0.04 –0.78** –0.02 –0.53 0.00 –0.06 –0.11 0.01 0.01 0.01 0.34 –2.06** –1.01* NO3–a 0.10 0.25 0.09 11.55** 2.16 2.63 0.11 –1.04 0.52 0.01 0.37 0.01 0.00 –0.01 1.09 0.11 4.09 –0.07 –2.11 –1.32 0.01 0.02 0.02 –1.37 7.03 4.33 NO3–a 0.02 0.08 0.01 –1.41** –0.11 –0.11 0.04 0.50 –0.04 0.00 0.04 0.00 0.01 0.04 –0.78** –0.02 –0.54 0.00 –0.06 –0.16 0.01 0.01 0.01 0.34 –1.81** –0.91* SO42–a 0.06 0.12 0.06 11.02** 2.09 2.54 0.07 –1.10 0.00 0.01 0.32 0.00 0.00 –0.06 0.64 0.03 3.14 –0.07 –1.07 –2.05 –0.01 0.01 0.00 –1.25 7.33 4.40 SO42–a 0.02 0.08 0.01 –1.32** –0.13 –0.14 0.04 0.50 –0.05 0.00 0.04 0.00 0.01 0.04 –0.82** –0.02 –0.52 0.00 0.06 –0.12 0.01 0.00 0.01 0.34 –1.80** –0.90* OPAA 0.56 0.98 0.52 14.66** 10.10** 11.16** 0.71 –2.88 1.28 0.07 0.66 0.06 –0.01 0.34 1.29 0.11 2.47 –0.07 –4.08* –2.86 0.01 0.08 0.20 –2.88 6.56 5.82 OPAA –0.08 –0.01 –0.10 –1.40** –1.13** –1.08** –0.02 0.56 –0.55** –0.02 –0.13 –0.02 0.00 –0.08 –0.93** –0.16 –1.34** 0.00 –0.19 –0.07 0.01 –0.03 –0.07 1.78** –2.33** –1.51** OPGSH 0.54 0.42 0.68 14.58** 10.51** 10.39** 0.46 –4.11 1.37 0.05 0.36 0.00 –0.04 0.15 1.21 –0.08 2.35 –0.06 –4.13* –2.83 –0.09 0.01 –0.18 –2.15 6.43 5.47 OPGSH 0.00 0.20 –0.06 –1.36** –0.82 –0.66 0.17 0.79* –0.69** 0.00 0.00 0.00 0.00 0.01 –1.02** –0.15 –1.40** 0.00 –0.18 –0.08 0.04 0.00 0.09 1.61** –2.27** –1.34** OPTOTAL 0.69 0.83 0.70 14.63** 11.53** 11.85** 0.79 –3.63 1.37 0.08 0.49 0.04 –0.02 0.27 1.26 0.03 2.42 –0.07 –4.10* –2.84 –0.19 0.15 0.01 –2.71 6.51 5.68 OPTOTAL –0.07 0.11 –0.11 –1.39** –1.13** –0.98* 0.07 0.68 –0.64** –0.01 –0.06 –0.02 0.00 –0.05 –0.98** –0.17 –1.37** 0.00 –0.19 –0.07 0.08 –0.06 0.01 1.86** –2.32** –1.45** Table 4. continued Adjustment pollutant Environmental Health Perspectives • volume 120 | number 8 | August 2012 PM characteristics and acute changes in respiratory function fine-fraction (F) EC [EC(F)], OC(F), OP, Fe, Cu, vanadium (V), and water-soluble nickel (Ni) [see Supplemental Material, p. 3 (http:// dx.doi.org/10.1289/ehp.1104389); see also Strak et al. 2012, Table R1.] [Tables in the web-based additional supplement (Strak et al. 2012) are denoted with an “R” to distinguish them from tables in the Supplemental Material Table 3. continued Adjustment pollutant PM10 PM2.5 PM2.5–10 PNC Absa EC(F) EC(C) OC(F) OC(C) Fe(tot) Fe(sol) Cu(tot) Cu(sol) Ni(tot) Ni(sol) V(tot) V(sol) Endo NO3–a SO42–a OPAA OPGSH OPTOTAL O3 NO2 NOx PM10 PM2.5 PM2.5–10 PNC Absa EC(F) EC(C) OC(F) OC(C) Fe(tot) Fe(sol) Cu(tot) Cu(sol) Ni(tot) Ni(sol) V(tot) V(sol) Endo NO3–a SO42–a OPAA OPGSH OPTOTAL O3 NO2 NOx V(tot) 0.28 0.34 0.30 11.17** 6.60** 7.91** 0.17 –1.68 –0.20 0.03 0.33 0.00 –0.02 –0.10 1.54 0.13 2.84 –0.07 –2.09 –2.13 0.00 0.02 0.01 –2.65 6.71 4.82 V(tot) 0.13* 0.39** 0.08 –1.19** –0.11 –0.08 0.16* 0.71** –0.01 0.02 0.07 0.02 0.01 0.16* –1.29** –0.02 –0.58 0.00 –0.05 –0.11 0.03* 0.02 0.03 0.91 –2.02** –0.99* V(sol) 0.08 0.15 0.08 10.94** 2.27 2.76 0.10 –0.66 –0.30 0.01 0.41 0.01 –0.01 0.02 0.06 0.00 2.84 –0.07 –2.66 –2.26 0.01 0.01 0.01 –0.88 5.93 3.98 V(sol) 0.03 0.10 0.02 –1.18** –0.09 –0.07 0.04 0.46 0.01 0.00 0.03 0.00 0.01 0.04 –0.73 0.02 –0.53 0.00 0.03 –0.05 0.01 0.01 0.01 0.25 –1.67** –0.77 O3 –0.11 –0.42 –0.04 12.04** 9.58** 9.96** –0.15 –2.77 –0.40 –0.02 0.14 –0.04 –0.04 –0.23 0.95 –0.35 2.54 –0.07 –2.17 –2.06 –0.07 –0.03 –0.07 –1.23 8.02 6.13 O3 0.26** 0.64** 0.21** –1.15** 0.62 0.64 0.33** 0.85** 0.09 0.03** 0.16 0.04** 0.02 0.20** –0.74* 0.14 –0.47 0.00 –0.05 –0.12 0.06** 0.04** 0.06** 0.34 –2.17** –0.97 NO2 NOx 0.00 –0.08 –0.05 –0.27 0.01 –0.06 14.66** 14.85** 1.62 1.73 2.12 2.35 0.00 –0.17 –1.98 –2.37 –0.01 –0.35 0.00 –0.01 0.07 –0.33 –0.01 –0.03 –0.02 –0.06 –0.03 –0.16 0.50 0.52 –0.06 –0.14 1.67 1.98 –0.05 –0.05 –2.19 –1.89 –2.26 –1.91 –0.02 –0.05 –0.01 –0.03 –0.01 –0.05 0.92 1.40 6.88 5.03 1.63 4.65 NO2 NOx 0.06 0.07* 0.17* 0.22** 0.04 0.06 –0.60 –1.15* 0.32 0.47 0.37 0.52 0.09* 0.14** 0.72** 0.71** 0.00 0.06 0.01 0.01 0.14 0.23 0.01 0.02* 0.01 0.02* 0.07 0.10* –0.54 –0.66* 0.05 0.03 –0.18 –0.43 –0.01 0.00 –0.02 –0.10 –0.03 –0.13 0.02* 0.03** 0.01 0.02 0.02* 0.02* –0.27 –0.07 –1.82** –2.31** 0.47 –0.89* (denoted with “S”); information presented in the web-based additional supplement has not been peer reviewed.] Two-pollutant models. Immediately after exposure, the associations for PNC at 11.2% (95% CI: 5.5, 17.0%) remained unchanged after adjustment for all other pollutants (Table 3; PNC row) and cancelled out the other significant association of EC(F) seen in the univariate model (Table 3; PNC col- umn). For the outdoor locations, PNC and Fe showed the most consistent associations in the two-pollutant models [see Supplemental Material, Table S2 (http://dx.doi.org/10.1289/ ehp.1104389)]. We could not study individual associations with PNC and Fe because they were highly correlated. Findings for 2 hr after exposure were very similar (see Strak et al. 2012, Table R4). PNC was most consistently associated with FENO in the full data set. In the outdoor-only mod- els, the consistent significant associations of PNC, coarse-fraction (C) EC [EC(C)], water- soluble Cu, and total Fe could not be further disentangled (see Strak et al. 2012, Table R5). The morning after exposure, associations were weaker than at previous time points (see Strak et al. 2012, Table R6). The most consis- tent associations were found for water-soluble Ni and V, which remained similar after adjust- ing for all the other pollutants. However, those associations were driven by one single influen- tial observation and decreased and became nonsignificant after excluding this observation. The water-soluble fractions of Ni and V were too highly correlated to study their individual associations with FENO. PNC associations at 7.3% (95% CI: 0.5, 14.1%) were less stable than at the first two time points, with mod- estly reduced nonsignificant effect estimates after adjusting for water-soluble Ni and NOx. The associations with water-soluble Ni and V were not present in the outdoor-only data set, even though their concentrations were not increased at the underground location (see Strak et al. 2012, Table R7). Associations between air pollution and lung function. Single-pollutant models. We observed significant associations of FVC and FEV1 with a range of pollutants includ- ing NOx, PNC, absorbance, EC, Fe, Cu, and water-soluble Ni. None of the exposure param- eters were associated with changes in PEF and FEF25–75 at any time point [see Supplemental Material , pp. 3–4 (http://dx.doi.org/10.1289/ ehp.1104389); see also Strak et al. 2012, Tables R2, R3]. Two-pollutant models. Immediately after exposure, fairly consistent associations with FVC were found for PNC, NO2, and water-soluble Ni (Table 4). In the outdoor- only models, we observed the most consistent associations for PNC and NOx, respectively, at –1.3% (95% CI: –2.4, –0.3%) and –2.4% 1187