Measurement of Offline Exhaled Nitric Oxide in a Study of Community Exposure to Air Pollution J.Q. Koenig,1 K. Jansen,1 T.F. Mar,1 T. Lumley,2 J. Kaufman,1 C.A. Trenga,1 J. Sullivan,1 L.-J.S. Liu,1 G.G. Shapiro,3 and T.V. Larson 4 1Department of Environmental Health, 2Department of Biostatistics, 3Department of Pediatrics, and 4Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
Abstract As part of a large panel study in Seattle, Washington, we measured levels of exhaled nitric oxide (eNO) in children's homes and fixed-site particulate matter with aerodynamic diameters of 2.5 µm or less (PM2.5) outside and inside the homes as well as personal PM2.5 during winter and spring sessions of 2000-2001. Nineteen subjects 6-13 years of age participated ; 9 of the 19 were on inhaled corticosteroid (ICS) therapy. Exhaled breath measurements were collected offline into a Mylar balloon for up to 10 consecutive days. Mean eNO values were 19.1 (SD ± 11.4) ppb in winter sessions and 12.5 ± 6.6 ppb in spring sessions. Fixed-site PM2.5 mean concentrations were 10.1 ± 5.7 µg/m3 outside homes and 13.3 ± 1.4 inside homes ; the personal PM2.5 mean was 13.4 ± 3.2 µg/m3. We used a linear mixed-effects model with random intercept and an interaction term for medications to test for within-subject-within-session associations between eNO and various PM2.5 values. We found a 10 µg/m3 increase in PM2.5 from the outdoor, indoor, personal, and central-site measurements that was associated with increases in eNO in all subjects at lag day zero. The effect was 4.3 ppb [95% confidence interval (CI) , 1.4-7.29] with the outdoor monitor, 4.2 ppb (95% CI, 1.02-7.4) for the indoor monitor, 4.5 ppb (95% CI, 1.02-7.9) with the personal monitor, and 3.8 ppb (95% CI, 1.2-6.4) for the central monitors. The interaction term for medication category (ICS users vs. nonusers) was significant in all analyses. These findings suggest that eNO can be used as an assessment tool in epidemiologic studies of health effects of air pollution. Key words: airway inflammation, asthma, children, exposure assessment, inhaled corticosteroids, nitric oxide, panel study, personal exposure, PM2.5. Environ Health Perspect 111:1625-1629 (2003) . doi:10.1289/ehp.6160 available via http://dx.doi.org/ [Online 12 June 2003] The full version of this article is available for free in HTML or PDF formats. |