Effects of airborne particulate matter on respiratory morbidity in asthmatic children.
BACKGROUND
The effects of airborne particulate matter (PM) are a major human health concern. In this panel study, we evaluated the acute effects of exposure to PM on peak expiratory flow (PEF) and wheezing in children.


METHODS
Daily PEF and wheezing were examined in 19 asthmatic children who were hospitalized in a suburban city in Japan for approximately 5 months. The concentrations of PM less than 2.5 mum in diameter (PM(2.5)) were monitored at a monitoring station proximal to the hospital. Moreover, PM(2.5) concentrations inside and outside the hospital were measured using the dust monitor with a laser diode (PM(2.5(LD))). The changes in PEF and wheezing associated with PM concentration were analyzed.


RESULTS
The changes in PEF in the morning and evening were significantly associated with increases in the average concentration of indoor PM(2.5(LD)) 24 h prior to measurement (-2.86 L/min [95%CI: -4.12, -1.61] and -3.59 L/min [95%CI: -4.99, -2.20] respectively, for 10-mug/m(3) increases). The change in PEF was also significantly associated with outdoor PM(2.5(LD)) concentrations, but the changes were smaller than those observed for indoor PM(2.5(LD)). Changes in PEF and concentration of stationary-site PM(2.5) were not associated. The prevalence of wheezing in the morning and evening were also significantly associated with indoor PM(2.5(LD)) concentrations (odds ratios = 1.014 [95%CI: 1.006, 1.023] and 1.025 [95%CI: 1.013, 1.038] respectively, for 10-microg/m(3) increases). Wheezing in the evening was significantly associated with outdoor PM(2.5(LD)) concentration. The effects of indoor and outdoor PM(2.5(LD)) remained significant even after adjusting for ambient nitrogen dioxide concentrations.


CONCLUSIONS
Indoor and outdoor PM(2.5(LD)) concentrations were associated with PEF and wheezing among asthmatic children. Indoor PM(2.5(LD)) had a more marked effect than outdoor PM(2.5(LD)) or stationary-site PM(2.5).
Ma
Lu
L
Department of Public Health, Hyogo College of Medicine, Japan.
Shima
Masayuki
M
Yoda
Yoshiko
Y
Yamamoto
Hirono
H
Nakai
Satoshi
S
Tamura
Kenji
K
Nitta
Hiroshi
H
Watanabe
Hiroko
H
Nishimuta
Toshiyuki
T
D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000009:adverse effects* / Q000032:analysis; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D006776:Hospitals, Pediatric; D006801:Humans; D019570:Inhalation Exposure; D007564:Japan / Q000453:epidemiology; D008297:Male; D008499:Medical Records; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D010366:Peak Expiratory Flow Rate; D015995:Prevalence; D012135:Respiratory Sounds / Q000503:physiopathology; D012189:Retrospective Studies; D013997:Time Factors
D000393:Air Pollutants; D052638:Particulate Matter