Median nicotine concentration (μg/m3) in offices at baseline and 6, 12 and 24 months after the Spanish smoking law (January 2006)(samples repeated at the four measurements)
| Baseline median nicotine concentration (IQR) | 6-Month follow-up median nicotine concentration (IQR) | 12-Month follow-up median nicotine concentration (IQR) | 24-Month follow-up median nicotine concentration (IQR) | |
| Public administration | 0.21 (0.08–0.56) | 0.08 (0.01–0.20) | 0.07 (0.01–0.20) | 0.05 (0.01–0.12) |
| Local administration | 0.47 (0.17–1.13) | 0.20 (0.03–0.57) | 0.13 (0.06–0.20) | 0.10 (0.01–0.22) |
| Regional administration | 0.12 (0.06–0.41) | 0.10 (0.01–0.20) | 0.08 (0.01–0.21) | 0.04 (0.01–0.09) |
| National administration | 0.20 (0.06–0.56) | 0.06 (0.01–0.21) | 0.01 (0.01–0.09) | 0.03 (0.01–0.07) |
| Universities | 0.24 (0.08–0.67) | 0.06 (0.01–0.17) | 0.07 (0.01–0.16) | 0.08 (0.04–0.16) |
| Private sector | 0.40 (0.07–1.29) | 0.08 (0.01–0.20) | 0.01 (0.01–0.16) | 0.06 (0.01–0.16) |
| Small (<10 workers) | 0.41 (0.05–1.40) | 0.10 (0.01–0.22) | 0.06 (0.01–0.17) | 0.08 (0.01–0.40) |
| Medium (10–50 workers) | 0.39 (0.08–1.32) | 0.07 (0.01–0.18) | 0.01 (0.01–0.15) | 0.05 (0.01–0.12) |