Context: This case series reports the changes in the respiratory health of eight asthmatic subjects and the relationship with air quality associated with the October 2007 firestorm in San Diego County of California.
Case presentation: Participants were eight subjects with asthma enrolled in Asthma Clinical Research Network (ACRN) (NIH# U10-HL074218) studies at the University of California San Diego (UCSD), School of Medicine, who had study data collected immediately prior, during and 1 month after the 5-day firestorm in San Diego County. Air quality deteriorated to an extreme average of 71.5 mg/m(3) small particulate matter less than 2.5 μm (PM(2.5)) during the firestorm. Respiratory health data included morning and evening peak expiratory flow rates (PEFR), morning and evening Forced Expiratory Volume in one second (FEV(1)), rescue medication usage, and sputum eosinophils. Morning and evening PEFR and FEV(1) rates remained stable. The two subjects tested during the fires had elevated eosinophil counts and rescue medication usage was increased in five of the eight subjects.
Discussion: Pulmonary function test values were stable during the wildfires for all eight subjects but there was a statistically significant increase in rescue medication usage during the wildfires that correlated with PM(2.5) values. The two subjects tested during the fires showed increases in sputum eosinophil counts consistent with increased airways inflammation.
Relevance: These findings suggest that poor air quality associated with wildfires resulted in an increase in airways inflammation in these asthmatic subjects, but pulmonary function tests remained stable, possibly due to increased rescue medication usage. This is especially pertinent as there is an increase in incidence of wildfires this decade.