The impact of exposure to indoor pollutants on allergy and lung inflammation among school children in Selangor, Malaysia: An evaluation using factor analysis

Abstract

A cross-sectional study of 470, 14-year-old students from 8 secondary schools located in sub-urban and urban areas in Hulu Langat district, Selangor, Malaysia was undertaken to determine the impact of atmospheric indoor air pollutants on atopy, asthma, respiratory symptoms and lung inflammation among school children. The students were surveyed using ISAAC and ECRHS questionnaires, their FeNO levels were measured and allergic skin prick tests were conducted. Active and passive sampling was used to measure the classroom indoor air concentration of NO2, CO2, formaldehyde, PM10, PM2.5, temperature and relative humidity. Linear mixed model, two-levels multiple logistic regression, PCA and SPC were applied to determine the complex relationship between respiratory symptoms, personal factors, FeNO levels and atmospheric indoor pollutants. 20.6% of students reported daytime breathlessness and 55.5% reported having rhinitis in the last 12 months. Atopy was prevalent in 57.7% of students, with predominant sensitization to Derp1 (51.9%) and Derf1 (47.9%) among doctor’s diagnosed asthmatic students. Indoor air pollutants in urban area schools were significantly higher than those in sub-urban areas (p < 0.001). There was a significant association between exposure to PM10 (OR = 2.66, 95% CI: 1.33-5.30) with skin allergy symptoms in the past 12 months. The PCA suggested that the most prominent factor associated with increasing FeNO levels was PM10, with 73.5% of the variation. SPC predicted the pattern of FeNO at an upper confidence limit (UCL) of 104.21 ppb with increasing PM10 concentration in the classroom (UCL = 40.23 μg m-3). Exposure to PM10 and PM2.5 significantly influenced the inflammation of the school children’s lungs. Moreover, there were associations between self-reported wheezing, daytime and nocturnal attack of breathlessness with doctor’s diagnosed asthma among school children. © The Author(s).