 this paper examines the associations between average daily particulate matter less than 10 microns in diameter ( pm10 ) and temperature with daily outpatient visits for respiratory disease including asthma , bronchitis , and upper respiratory illness in anchorage , alaska , where there are few industrial sources of air pollution . in anchorage , pm10 is composed primarily of earth crustal material and volcanic ash . 
 carbon monoxide is measured only during the winter months . 
 the number of outpatients visits for respiratory diagnoses during the period 1 may 1992 to 1 march 1994 were derived from medical insurance claims for state and municipal employees and their dependents covered by aetna insurance . 
 the data were filtered to reduce seasonal trends and serial autocorrelation and adjusted for day of the week . 
 the results show that an increase of 10 micrograms / m3 in pm10 resulted in a 3 - 6% increase in visits for asthma and a 1 - 3% increase in visits for upper respiratory diseases . 
 winter co concentrations were significantly associated with bronchitis and upper respiratory illness , but not with asthma . 
 winter co was highly correlated with automobile exhaust emissions . 
 these findings are consistent with the results of previous studies of particulate pollution in other urban areas and provide evidence that the coarse fraction of pm10 may affect the health of working people.imagesfigure 1 . 
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