TY - JOUR T1 - P77 Children's exposure to airborne fine particulate matter at home and asthma outcomes JF - Thorax JO - Thorax SP - A109 LP - A110 DO - 10.1136/thx.2010.150979.28 VL - 65 IS - Suppl 4 AU - K Woods AU - A Apsley AU - S Semple AU - S W Turner Y1 - 2010/12/01 UR - http://thorax.bmj.com/content/65/Suppl_4/A109.3.abstract N2 - Objectives The relationship between indoor air exposure to fine particulate (PM2.5) and asthma symptoms in children is uncertain. The aim of the present study was to relate PM2.5 exposure to indices of asthma severity and control.Methods Children with asthma were recruited. Disease severity was determined by questionnaire and spirometry. Asthma control was assessed by 5-day peak flow variability and children's asthma control test (CACT) on the first and fifth day of peak flow testing. Concentrations of PM2.5 were measured over a 24-h period in the living room and the child's bedroom.Results 22 children were recruited, mean age 11.0 years. Across the 22 homes the median time weighted average (TWA) PM2.5 concentration (range) in the living room was 7.4 mg/m3 (2.0–150.0) and for the bedroom was 5.6 (3.1, 11.1) mg/m3 (p=0.04 for comparison with living room). As expected, there was a significantly higher mean TWA PM2.5 in the living rooms and bedrooms of the seven homes where smoking was reported; 22.0 mg/m3 for living rooms in smoking homes and 4.7 mg/m3 for non-smoking homes, p=0.001. There was a positive association between TWA PM2.5 in the living room and peak flow variability (r=0.51, p=0.027, see Abstract P77 Figure 1) and a negative association between TWA PM2.5 in the living room and CACT on day 5 (r=−0.48, p=0.037). TWA PM2.5 exposure was not related to indices of asthma severity including FEV1 and treatment. Peak PM2.5 concentration was not associated with any outcome.Abstract P77 Figure 1 Conclusions This small study suggests that even at relatively low concentrations, there is an exposure-response relationship between increasing indoor air PM2.5 concentrations, increased airway variability and poorer asthma control in children. ER -