Effects of Particulate Matter on Respiratory Allergic Diseases Considering Meteorological Factors in Busan, Korea

Background: Ambient pollution has been associated with adverse respiratory health effects. Although meteorological variables have been known to impact on respiratory hospitalization, few studies have investigated the effects of ambient pollution considering temperature or humidity. Here, we identified the effects of ambient particulate matter for daily respiratory admissions considering meteorological factors.

Methods: We used daily hospital admissions for respiratory diseases in Busan from hospital records using the International Classication of Diseases (ICD-10) for the period 2007-2010. The respiratory allergic diseases used in our study are allergic rhinitis (J30) and asthma (J45-46). Age was categorized as group I (0-15), group II (16-64) and group III (≥ 65 yr). Hourly particulate matter < 10µm (PM₁₀) levels and particulate matter < 2.5µm (PM_2.5) levels were obtained from 19 monitoring stations in Busan, and collected by and made available from the Korean Ministry of Environment. The meteorological observation data in Busan provided by the Korean Meteorological Administration included temperature and relative humidity.

Results: The mean value of hospital admission for allergy rhinitis and asthma was 4.4±6.1 people and 3.3±3.3 people respectively. A daily-average value of PM₁₀ and PM_2.5 concentrations level was 49.6±20.5 µg/m³ and 24.2±10.9 µg/m³ respectively. The mean temperature was 15.1±7.9°C, relative humidity was 62.0±18.0%. Admission for allergic rhinitis was associated with increasing temperature anomaly (P=0.003) and decreasing relative humidity (P<0.001). When the relative humidity was constant, the increase in PM₁₀ levels was significantly associated with higher admission for allergic rhinitis. In asthma, hospitalization was correlated with decreasing relative humidity (P<0.001) and increasing PM₁₀ (P=0.008). Even after considering relative humidity, higher PM₁₀ levels still were associated with higher hospitalization rate. In subgroup analysis according to age, admission rate in group I and group III was more strongly affected by PM₁₀ levels than group II (IRR 7.4 and 6.4, respectively). Furthermore, it showed the association between higher PM_2.5 levels and admission for asthma, regardless of the effect of PM₁₀levels.

Conclusions: Particulate matter levels and meteorological factors have an effect on hospitalization for allergic rhinitis or asthma. After adjusting meteorological factors, PM₁₀ or PM_2.5 levels increase significantly admission rate for respiratory allergic diseases.