Study On The Relationships Between The Indoor Air Pollutants And Childhood Ashtma

ObjectiveTo investigate the association between indoor air pollutants and childhood asthma, screen the risk factors of asthma, and provide theoretical foundation for the prevention of asthma and protection of the vulnerable children.MethodA hospital based case-control study was conducted in Bejing. Cases (n=218) were children recruited at the asthma clinic in Children's Hospital and Capital Institute of Pediatrics who were diagnosed with asthma by paediatricians. Controls (n=205) consisted of children from the same age group without asthma were recruited in the same hospital. Information regarding the health status of the study children and the environmental status of their home was collected using a standardized questionnaire. In addition, serum concentration of total IgE, and several specific IgE were measured. Statisital analysis was then performed to explore the risk factors of asthma. Beside, indoor air concentration of VOCs, formaldehyde, nitrogen dioxide, and fine particulates were measured in the living room and bedroom of a subsample of the study. Then, one factor analysis and multiple logistic regressions were performed to explore the relationships between the air pollutants and asthma.Results1 The familily history of asthma or allergy is a risk factor for asthma, children whose parents have asthma or allergyy have a higher risk of having asthma (OR=3.210)2 Sensitization to dust mite and mold are risk factors for asthma, the OR of sensitization to dust mite and mold were 4.620, 4.596 respectively.3 ETS exposure was also a risk factor for asthma, children who were exposed to ETS have a higher risk of having asthma (OR=1.996).4 Concentrations of VOCs, formaldehyde and NO₂ in most families were lower than the limited values of indoor air quality standard. The exceeding rate of TVOC concentration in the homes of the cases and controls was 9.09% and 3.45% respectively, and the exceeding rate of formaldehyde concentration in the homes of the cases and controls was 3.03% and 3.33% respectively.5 Cases were exposed to significantly higher TVOC, benzene, toluene, xylene, styrene and C11 levels than controls (P<0.01).6 TVOC, xylene, and styrene appeared to be significant risk facors for asthma with the odds ratios of 5.478, 4.142, and 4.142 respectively.7 No significant relationships were found between formaldehyde, NO₂, PM_2.5 and asthma.ConclusionsFamilily history of asthma or allergy, sensitisation to dust mite and mold, exposure to ETS are risk factors for asthma. TVOC, xylene, and styrene are significantly related with childhood asthma. This study indicates the concentrations of VOCs lower than the limited values of indoor air quality standard may increase the risk of childhood asthma, thus the relative limited values of indoor air quality standard should be revised in order to protect both the healthy and the vulnerable children.