Relationship between air quality and asthma-related emergency hospital admissions in Mexico City 2017–2019

Abstract

BackgroundPrevious studies found exposure to air pollution leads to exacerbations of asthma in paediatric and adult patients and increases asthma-related emergency hospital admissions (AREHA).MethodsAREHAs and levels of air pollutants (PM10, PM2.5and NO2) were obtained from Mexico City for the period 2017–2019. A time-series approach was used to explore the relationship between air pollutants and AREHA. Relative risks of AREHA were estimated using a negative binomial regression in young children (less than 5 years) and adults (greater than 18 years).ResultsThere was a positive association between AREHA and PM10, PM2.5and NO2in adults, which remained after mutual adjustment for these pollutants. The relative risk (RR) of admission in adults increased by 3% (95% CI 1% to 4%) for a 10 µg/m3increase in PM10, 1% (0.03% to 3%) for a 5 µg/m3increase in PM2.5and by 1% (0.06% to 2%) for a 5 µg/m3increase in NO2. In contrast, in young children, AREHAs were negatively associated with PM10after adjustment for NO2(RR 0.97 (0.95 to 0.99) for a 10 µg/m3and with NO2after adjustment for PM10and PM2.5(RR 0.98 (0.96 to 0.99) and 0.97 (0.96 to 0.99), respectively, for a 5 µg/m3increase in NO2). AREHAs in children were not associated with PM2.5after adjustment for NO2.ConclusionsAmbient air pollution, within the previous week, was associated with emergency hospital admissions for asthma to public hospitals in adults in Mexico City. The relationship in children was less consistent. Further work is needed to explore why differences between adults and children exist to inform appropriate interventions to benefit public health.