Prevalence and risk factors of poor indoor air quality and sick house syndrome symptoms in Dubai

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The British University in Dubai (BUiD)
"Housing environment is a key determinant of health and wellbeing for individuals, communities, and public health at large. Recently, an increasing range of diseases related to poor Indoor Environmental Quality (IEQ) commonly referred to as Sick Building Syndrome (SBS) symptoms – or Sick House Syndrome (SHS) in case of housing related symptoms –which are evolving as a global concern. What exacerbate the concern regarding SHS is its’ being a product of intricate interactions between three multivariate factors involving the IEQ factors in addition to building and population characteristics. Due to that complexity; high levels of ambiguity and uncertainty enfold the associations between IEQ and SHS. Globally, previous research focused in investigating the associations between IEQ and health symptoms in offices more than houses. However, housing IEQ and its associated health risks is of growing concern because of the longer exposure to contaminants and its inclusion of vulnerable individuals. In the United Arab Emirates (UAE), poor indoor air quality (IAQ) in housing – which is one of the IEQ factors – is considered as the 2nd environmental health risk. However, few population-based researches were conducted regarding poor housing IEQ and its associations with SHS. None covered a sample including the different nationalities living in UAE. That is important in revealing more realistic results reflecting the present IEQ and SHS in UAE housing. Furthermore, the impact of many building variables on IEQ and SHS is under-researched by previous studies i.e. applied HVAC system, building age and type. Therefore, this research sought to respond to a number of questions aiming to: (1) Explore the IEQ conditions and prevalent SHS in Dubai housing; (2) Identify the risk factors affecting IAQ and SHS; (3) Investigate the impact of the applied heating, ventilation, and air conditioning (HVAC) system on IEQ and SHS; (4) Assess the sufficiency of provided AERs; and (5) Propose appropriate strategies to mitigate poor IEQ and SHS prevalence. The two major methods employed by this study were a cross-sectional survey and a field study. The survey collected data from 770 Dubai residents. The utilized questionnaire was adopted and adapted from the MM 040 NA questionnaire, EPA IEQ in addition to EPA IAQ and work environment questionnaire. A pilot survey covering 120 Dubai households was conducted to examine the reliability and validity of the proposed questionnaire and to develop it accordingly. SPSS Statistics Version 23 software was used for the survey analysis and it encompassed the conduct of principal component analysis (PCA) and multiple linear regression (MLR) models. Regarding the field study; it was conducted in the living hall of 60 Dubai household and it included measurements, questionnaire, and AERs calculations using CO2 steady-state method. Performed measurements were: (1) Continuous measurement of indoor PM2.5, PM10, CO, CO2, TVOC, RH, and T levels for 24 hours; (2) A single sample of indoor HCHO drawn for 30 minutes; and (3) A spot measurement of outdoor CO2, CO, TVOC, RH, and T levels. The survey results revealed that prevalent health symptoms experienced at least 1 – 3 days/week in Dubai households were ergonomic symptoms experienced by about 18% of Dubai households, general (17%), skin (17%), fatigue (17%), nose (17%), neurological (15%), cough (12%), eye (10%), throat (9%), chest symptoms (8%), and fever (5%). Prevalent SHS symptoms – occurred at least once a week and became better outdoors – were about 30%. The most prevalent IEQ conditions at least 1 – 3 days/week was dust and dirt experienced by about 29% then “Too quiet” (22%), “Too hot” (22%), “Too humid” (19%), “Too noisy” (19%), “Too cold” (17%), “Too glary” (13%), “Too dim” (14%), “Little air” (15%), “Too dry” (16%), and “Stuffy bad air” (14%). The most prevalent odors at least 1 – 3 days/week were “Fishy/food odors” reported by approximately 21%, “Body/cosmetics odors” (20%), “Tobacco smoke” (20%), “Incense smoke” (19%), “Chemicals odors” (7%), “Dampness odors” (6%), “Diesel/engine exhaust” (6%), “New carpets’ odors” (4%), and “Paint odors” (4%). Moreover, following is a summary characterizing measured indoor IEQ parameters and estimated AERs in the 60 Dubai households: • PM2.5 levels exceeded the 35µg/m3 limit (ASHRAE 2016) in all households. • PM10 levels exceeded the 150µg/m3 limit (DM 2016) in 88% of households. • TVOC levels exceeded the 300µg/m3 by DM (2016) in 67% of households. • CO2 levels exceeded the 800ppm limit (DM 2016) in 45% of households. • T range was not complying with DM (2016) requirements in all households while RH range was not complying with DM (2016) requirements in 60%. • Estimated AER insufficient as per (ASHRAE 2016) in 38% of households. • CO and HCHO levels were acceptable as per national and international standards. According to survey results; perceived IAQ discomfort was significantly associated with: perceived odors, Thermal, Lighting, and Noise comfort, dust allergy, age, migraine, other Africans, in addition to new wall covering. IAQ discomfort was positively associated with all above parameters except the new wall covering. Regarding the signicant associations with prevalent SHS symptoms; the population variables identified as risk factors that had positive association with prevalent SHS symptoms were: dust allergy, migraine, asthma, females, eczema, and other Arabs or MENA Nationals. The following list shows the building and IEQ variables identified as risk factors positively associated with prevalent SHS symptoms. Notably that no significant association was found between any of the three HVAC systems studied by this research with SHS symptoms as per the adjusted MLR models. • Dimness with all SHS symptoms. • Stuffy air, dust, dirt, paint odors, dampness odors, in addition to attached kitchen with Eye, Nose, Throat, and Chest symptoms. • High humidity, incense smoke, water leakage, in addition to Dubai Sector 1 with General, Ergonomic, Nervous, and Skin symptoms. The above results revealed the great opportunities in mitigating prevalent SHS symptoms in Dubai housing when controlling the identified risk factors. To achieve that, collaborative efforts are required from all related bodies i.e. governmental and academic institutions, building industry, and even occupants. Following are the major practical implications and recommendations that can be derived from findings of this research: • Developing related regulations by: o Mandating an appropriate exposure limit for indoor PM2.5 concentration. o Establishing rigorous policies to enforce compliance with mandated limits. o Establishing convenient policies to manage probable environmental risk of incense burning and new paints. o Incorporating the needs of atopic individuals and females in related policies. • Increasing public awareness about below risk factors and how to manage them: o The risk of having unacceptable indoor levels of PM2.5, PM10, TVOC, CO2, T, RH, and AERs that threatens a substantial number of Dubai housing. o The identified IEQ and building risk factors associated with SHS symptoms which were: indoor dimness, dust and dirt, stuffy air, paint odors, high humidity, water leakage, dampness odors, incense smoke, attached kitchens, and Dubai Sector 1. While population risk factors were: dust allergy, migraine, asthma, gender, eczema, and other Arabs or MENA Nationals. • Employing efficient management methods for the above identified risk factors i.e. indoor lighting solutions, moisture control methods, dust prevention strategies … etc. • Conducting further research to fill available theoretical gaps i.e. in-depth researches regarding identified risk factors exploring their sources and management methods. "
Indoor air pollution., Sick Building Syndrome (SBS), Sick House Syndrome (SHS), United Arab Emirates (UAE), Indoor Environmental Quality (IEQ), housing environment, Dubai housing