Acute effects of urban air pollution on respiratory emergency hospital admissions in the Canary Islands

In the cities of Las Palmas (L/P) de Gran Canaria and Santa Cruz (S/C) de Tenerife, Canary Islands, particulate matter is highly influenced by mineral dust because their proximity to the Sahara desert (PM_10–2.5 levels are higher than PM_2.5). In this context, the short-term association between different PM fractions and gaseous pollutants with emergency hospital admissions for all respiratory, chronic obstructive pulmonary disease (COPD) and asthma was analyzed, evaluating the potential independent effect of PM_10–2.5. A generalized additive model was fitted controlling for seasonal patterns and time varying confounders. Different lag structures, polynomial distributed lag models, and two-pollutant models were examined. Under Lag01, in S/C de Tenerife, a 10 μg/m³ increase in PM_2.5 and PM_10–2.5 was associated with a 5.1 % risk increase (95 % confidence interval [CI] 1.0 to 9.2) in all respiratory and with a 7.7 % increase (95 % CI 0.9 to 14.9) in COPD emergency admissions, respectively. In L/P de Gran Canaria, a positive association between PM_10–2.5, PM_2.5, and NO₂ with the increased risk of asthma hospitalization was found: 11.2 % (95 % CI 0.5 to 22.9), 21.9 % (95 % CI 6.9 to 39.0), and a 17.4 % (95 % CI 6.6 to 29.4), respectively. The overall findings suggest that in these cities, (1) PM_2.5, PM_10–2.5, and NO₂ are associated with the risk of emergency hospital admission for respiratory diseases; (2) there is no evidence of confounding for the associations observed; and (3) PM_10–2.5 may have an impact on public health.