ASTHMA EXACERBATIONS DURING SANTA-ANA WINDS IN SOUTHERN CALIFORNIA

This study investigated the relationship between Santa Ana wind condit ions and visits for asthma at a southern California emergency departme nt. Visits to the emergency department for asthma were analyzed retros pectively to determine whether the incidence increased during Santa An a wind conditions. These northeasterly winds are common during fall an d winter in southern California and belong to a class known as Foehn w inds. They are characterized by gusty winds, decreased relative humidi ty, warm temperatures, and decreased levels of airborne pollutants. Du ring a 4-year period, we noted that emergency department visits for as thma increased (3.12 vs. 2.16 visits per day, P <0.0001) during Santa Ana winds compared with other weather conditions. Asthmatics presentin g during Santa Ana winds appeared to be more ill, as judged by higher admission rates (21.9 vs. 18.7%, P <0.05). These winds were also assoc iated with reduced particulate matter (PM10) counts (P <0.0001). Altho ugh the magnitude of the increase in emergency department visits was s mall, it occurred at a time when typical inciters of respiratory disea se should be minimal. An as yet unidentified factor associated with th ese winds may be a stimulant for some asthmatics. Similar wind pattern s in other localities might affect respiratory disease as well.