Abstract
Background: Asthma exacerbations, a common reason for Pediatric
Emergency Department (PED) referral, can be triggered by multiple
factors, including infections, air pollution and allergens. Lockdown
measures and other public health interventions during the SARS-CoV-2
pandemic determined radical changes to behavioral and social habits,
that were reflected by a reduction in the transmission of all
respiratory pathogens and in the emissions of relevant air pollution
anthropogenic sources.
Objective: This study aims to describe how restrictions during
SARS-CoV-2 pandemic impacted the PED referral for asthma exacerbations
and their potentially associated environmental triggers in densely
populated urban areas.
Methods: PED referrals for acute asthma from 2015 to 2020 were
compared to air pollution and pollen data. To this purpose, historical
daily concentration records of PM2.5,
PM10 (including specific chemical tracers), as well as
NO2, C6H6, tree, grass
and weed pollen were analyzed.
Results: In 2020, asthma-related PED referrals decreased up to
85%, compared to the average referral rate of the previous 5 years
(P <0.01). The drastic drop in PED referrals was
associated with a reduction of high-priority cases by 50-60%, unlike
PED referrals for overall diagnoses, showing a larger contribution for
severe outcomes. A concomitant diminished contribution of
traffic-related air pollution was shown.
Conclusions: The lower rate of asthma exacerbations in
childhood can be related to synergic interactions of the multiple
effects of lockdown measures which induced lower viral infection rates
and decreased exposure to outdoor allergens. The reduction of
traffic-related air pollution determined a weakening of inflammatory
properties of urban PM.