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Table 5 Associations between health outcomes (uLTE4 and albuterol usage) and PM1.5 exposure events (increase of at least 5 or 10 μg/m3 within microenvironment) as measured by the personal monitor

From: Within-microenvironment exposure to particulate matter and health effects in children with asthma: a pilot study utilizing real-time personal monitoring with GPS interface

Micro-environment Exposure event increase Lag, days % Increase for exposure event (95 % CI)
Albuterol usage LTE4
Home 5μg/m3 0 −1.7 (−17.6, 17.2) 13.3 (−7.6,39.1)
1 11.0 (−10.1, 37.1) 7.4 (−16.0,37.2)
0-1 −1.2 (−17.3, 18.0) 4.1 (−11.5,22.5)
10μg/m3 0 10.3 (−6.5, 30.3) 17.7 (−4.8,45.6)
1 13.4 (−8.3, 40.2) −3.4 (−23.4,21.8)
0-1 7.6 (−7.6, 25.1) 9.5 (−8.5,31.2)
Transit 5μg/m3 0 9.7 (−5.9, 27.9) 24.0 (1.5,51.5)
1 17.6 (−6.9, 48.6) 17.2 (−3.9,43.1)
0-1 13.7 (−4.3, 35.2) 13.2 (−2.8,31.7)
10μg/m3 0 10.8 (−4.2, 28.2) 10.9 (−10.4,37.2)
1 6.3 (−15.5, 33.6) 8.7 (−12.7,35.2)
0-1 7.3 (−9.5, 27.2) 4.7 (−10.5,22.4)
School 5μg/m3 0 13.3 (−5.7, 36.0) 10.6 (−9.0,34.4)
1 5.9 (−13.2, 29.1) 2.7 (−16.5,26.4)
0-1 1.7 (−14.6, 21.1) 9.0 (−5.2,25.4)
10μg/m3 0 12.4 (−5.2, 33.2) 19.0 (−5.3,49.6)
1 3.1 (−19.3, 31.6) 0.6 (−19.8,26.3)
0-1 4.8 (−11.6, 24.3) 9.1 (−6.0,26.6)
  1. For 0–1 day lag, the indicator was ‘1’ if an event occurred on current or previous day, and ‘0’ otherwise; observations were weighted by the number of records used in the 0–1 variable (1 or 2 days). For Albuterol usage models, temperature and Friday indicator covariates were used; for uLTE4 models, temperature and cold indicator were used (the lag for cold was set as the same for the air pollution variable). 30 subjects were available for analysis; number of records used for model fits were: 114, 80 and 143 for 0, 1 and 0–1 day estimates for albuterol usage, respectively, and 80, 58 and 111 for uLTE4. For more detail, see the text