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Effects of ambient particulate matter on peak expiratory flow rates and respiratory symptoms of asthmatics during Asian dust periods in Korea
Author(s) -
PARK Jeong Woong,
LIM Young Hee,
KYUNG Sun Young,
AN Chang Hyeok,
LEE Sang Pyo,
JEONG Seong Hwan,
JU YoungSu
Publication year - 2005
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.2005.00728.x
Subject(s) - medicine , asthma , respiratory system , adverse effect , nitrogen dioxide , population , particulates , asian dust , ozone , bronchodilator , aerosol , environmental health , meteorology , ecology , physics , biology
Objective: Dust generating events frequently produce ambient dust particles that are less than 10 µm in diameter, and these have been linked to adverse effects in the general population. However, the evidence linking these particles to adverse effects on the airways of asthmatic individuals is limited. The objective of this study was to investigate the possible adverse effects of Asian dust events on the respiratory functions and symptoms of subjects with bronchial asthma. Methodology: From March to June 2002, individuals were enrolled who had been diagnosed as having asthma by bronchial challenge or by their bronchodilator response. The patients were divided into three groups according to asthma severity: mild, moderate and severe. Patients with other major disease states were excluded. Patients completed twice‐daily diaries monitoring PEF, respiratory symptoms, and daily activities. The daily and hourly mean levels of particulate matter <10 µm in diameter (PM 10 ), as well as nitrogen dioxide (NO 2 ), sulphur dioxide (SO 2 ), ozone (O 3 ) and carbon monoxide (CO) were measured at 10 monitoring sites in Incheon, Korea. Results: Dust events occurred 14 times during the study period. On dusty days there were increased levels of PM 10 , decreased levels of NO 2 and SO 2 , and no change in the CO levels, compared to the levels on control days. An increase in PM 10 concentration was associated with increases in PEF variability of >20% ( P < 0.05), more night‐time symptoms ( P < 0.05), and a decrease in the mean PEF ( P < 0.05), calculated by longitudinal data analysis. In contrast, there was no association between the PM 10 levels and bronchodilator inhaler use or daytime respiratory symptoms. Using a general additive Poisson regression model, a borderline association was noted between PM 10 and respiratory symptoms, with a relative risk of 1.05 (95% confidence interval (CI), 0.99–1.17). There was no association between the PM 10 concentrations and PEF measurements, with PEF variability of >20% between the morning and evening values and a relative risk of 1.05 (95% CI, 0.89–1.24) in all subjects. Conclusions: This study provides evidence that Asian dust events are impacting on the respiratory symptoms of subjects with bronchial asthma, and ambient air pollution, particularly elevated PM 10 , might be one of the aggravating factors.