Concentration of Phthalate in Dorm Rooms and its Association with Asthma and Allergy

The dramatically increased prevalence rate of asthma and allergy among children was associated to phthalate indoor rooms in previous studies e.g. Swede DBH and Bulgarian ALLHOMES. China is a developing country with fewer allergies compared to western countries. Students' dorm rooms are more pollutant than home environment. A case-control study was carried out from May 2006 to April 2007 in Tianjin University campus, China. The concentrations of six kinds of phthalate esters in dorm rooms were measured and were associated to occupants' (college students') asthma and allergy. The health conditions of occupants were self-reported in the cross-sectional study prior to the present case-control study, based on which 205 controls and 143 cases were selected. Cases were those having at least two symptoms of asthma, rhinitis and eczema; while controls had none of such allergic symptoms. Project members inspected their dorm rooms (175 dorm rooms), measured physical parameters e.g. air temperature, relative humidity and CO2 concentration, and collected dusts from horizontal surface above the floor e.g. shelf, window/door frame. These dusts were used to analyze the six kinds of phthalate indoors (ug/g dust) by GC/FID method, i.e. DEP, DiBP, DBP, BBzP, DEHP and DiNP. The median concentration of DEP was 14.5 ug/g dust, DiBP 20.2, DBP 28.6, BBzP 26.2, DEHP 34.3, DiNP 25.1. Rooms with PVC frame window, had significantly higher concentrations of DEHP, BBzP, DBP, DiBP, DiNP in dust (p<0.05). All six phthalate esters had higher concentrations in buildings constructed after year 2000, though only DEHP and DiBP reached significance. DEHP, DiBP and DiNP were significantly higher in rooms with stone floor covering. Both for summer and winter air change rate measurements, a higher air change rate was associated with lower concentrations of phthalate esters. However, it was found that frequently cleaned rooms had higher contents of phthalates in dust, even though this trend was not statistically significant. There were no significant differences of phthalate concentrations among case and control groups. The adjusted odd ratios (AOR) of DBP to rhinitis was 5.03 (p<0.018). The association between BBzP, DEHP and allergy did not research significant level. The concentrations of phthalate in dorms were lower than in homes as a result of less chemical sources. However, the chemical and physical property of phthalate and its affecting mechanism on asthma and allergy need to be further studied.