Association between air pollution and general outpatient clinic consultations for upper respiratory tract infections in Hong Kong

• Published in: PloS one 2014-01, Vol.9 (1), p.e86913
• Main Authors: Tam, Wilson W S, Wong, Tze Wai, Ng, Lorna, Wong, Samuel Y S, Kung, Kenny K L, Wong, Andromeda H S
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Air pollution; Air Pollution - adverse effects; Air pollution effects; Ambulatory care; Ambulatory care facilities; Ambulatory Care Facilities - statistics & numerical data; Analysis; Asthma; Biology; Clinics; Confidence intervals; Earth Sciences; Environmental Exposure - adverse effects; Environmental protection; Female; Health aspects; Health care; Hong Kong - epidemiology; Hospitals; Humans; Infection; Infections; Male; Medicine; Middle Aged; Morbidity; Mortality; Nitrogen dioxide; Outdoor air quality; Particulate matter; Patient admissions; Pollutants; Pollution; Pollution effects; Primary care; Public health; Referral and Consultation; Respiratory diseases; Respiratory tract; Respiratory tract diseases; Respiratory tract infection; Respiratory Tract Infections - epidemiology; Respiratory Tract Infections - etiology; Retrospective Studies; Risk assessment; Risk Factors; Short term; Sulfur; Sulfur dioxide; Time Factors; Time series; Viral infections
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0086913

Many studies have shown the adverse effects of air pollution on respiratory health, but few have examined the effects of air pollution on service utilisation in the primary care setting. The aim of this study was to examine the association between air pollution and the daily number of consultations due to upper respiratory tract infections (URTIs) in general outpatient clinics (GOPCs) in Hong Kong. Daily data on the numbers of consultations due to URTIs in GOPCs, the concentrations of major air pollutants, and the mean values of metrological variables were retrospectively collected over a 3-year period (2008-2010, inclusive). Generalised additive models were constructed to examine the association between air pollution and the daily number of consultations, and to derive the relative risks and 95% confidence intervals (95% CI) of GOPC consultations for a unit increase in the concentrations of air pollutants. The mean daily consultations due to URTIs in GOPCs ranged from 68.4 to 253.0 over the study period. The summary relative risks (and 95% CI) of daily consultations in all GOPCs for the air pollutants PM10, NO2, O3, and SO2 were 1.005 (1.002, 1.009), 1.010 (1.006, 1.013), 1.009 (1.006, 1.012), and 1.004 (1.000, 1.008) respectively, per 10 µg/m(3) increase in the concentration of each pollutant. Significant associations were found between the daily number of consultations due to URTIs in GOPCs and the concentrations of air pollutants, implying that air pollution incurs a substantial morbidity and increases the burden of primary health care services.