ABSTRACT

INDOOR AIR QUALITY (IAQ) IS A CRITICAL PUBLIC HEALTH CONCERN GIVEN THAT INDIVIDUALS SPEND APPROXIMATELY 90% OF THEIR TIME IN ENCLOSED ENVIRONMENTS. POOR IAQ HAS BEEN LINKED TO RESPIRATORY DISEASES, CARDIOVASCULAR CONDITIONS, AND COGNITIVE IMPAIRMENT, WHILE IMPROVEMENTS IN AIR QUALITY HAVE DEMONSTRATED MEASURABLE BENEFITS, INCLUDING ENHANCED WORKPLACE PRODUCTIVITY (2 TO 7 TIMES GREATER EFFICIENCY) AND REDUCED PREVALENCE OF ASTHMA AND ALLERGIES. THIS STUDY INVESTIGATES IAQ ACROSS DIVERSE OCCUPATIONAL SETTINGS IN MACAO, EMPLOYING A COMBINATION OF ENVIRONMENTAL SAMPLING AND THE U.S. ENVIRONMENTAL PROTECTION AGENCY (USEPA) EXPOSURE MODEL TO ASSESS HEALTH RISKS ASSOCIATED WITH PROLONGED INDOOR EXPOSURE.   FIELD SAMPLING WAS CONDUCTED IN FIVE REPRESENTATIVE WORKPLACES (RESTAURANTS, STUDENT DORMITORIES, AUTO REPAIR SHOPS, OFFICES, AND PARKING SECURITY ROOMS), AND PARTICULATE MATTER WAS COLLECTED FROM AIR CONDITIONING FILTERS TO DETECT HEAVY METAL CONTENT IN THE SAMPLES. SUBSEQUENTLY, WE APPLIED THE PMF MODEL TO ANALYZE THE POLLUTION SOURCES AND THE US EPA EXPOSURE MODEL TO ASSESS HEALTH RISKS AND EVALUATE THE CARCINOGENIC RISKS IN THE FIVE REPRESENTATIVE WORKPLACES. THE FORWARD MATRIX FACTORIZATION (PMF) MODEL IDENTIFIED SIX MAJOR POLLUTION SOURCES: TRAFFIC EMISSIONS (23.8%, ZN/SB), BUILDING MATERIALS (21.6%, AL/TI), COOKING ACTIVITIES (18.5%, NA/CA), CHEMICALS (15.2%, AG/B), ELECTRONIC DEVICES (12.3%, TL), AND OUTDOOR ACTIVITIES (8.6%, CO/NI). THE HEALTH RISK ASSESSMENT USING THE US ENVIRONMENTAL PROTECTION AGENCY (USEPA) EXPOSURE MODEL SHOWED THAT THE OVERALL NON-CARCINOGENIC RISK (HI = 6.16×10^-6) AND CARCINOGENIC RISK (6.57×10^-9) WERE BELOW THE SAFETY THRESHOLD, INDICATING THAT ITS DIRECT HEALTH HAZARD WAS MINIMAL. HOWEVER, NICKEL AND CHROMIUM WERE IDENTIFIED AS THE MAIN CONTRIBUTORS TO POTENTIAL LONG-TERM RISKS.THIS STUDY IS CURRENTLY ONLY A PRELIMINARY EXPLORATORY STUDY AND PROVIDES A BASIS FOR SUBSEQUENT RESEARCH.THESE FINDINGS UNDERSCORE THE NECESSITY FOR SITE-SPECIFIC IAQ MANAGEMENT STRATEGIES, SUCH AS ENHANCED MECHANICAL VENTILATION, AIR FILTRATION UPGRADES, AND OCCUPANCY REGULATIONS. THE STUDY PROVIDES POLICYMAKERS WITH EVIDENCE-BASED INSIGHTS TO MITIGATE HEALTH RISKS IN HIGH-EXPOSURE ENVIRONMENTS WHILE ESTABLISHING A FRAMEWORK FOR FUTURE IAQ MONITORING IN URBAN SETTINGS.