Long-term trends in urban NO2 concentrations and associated pediatric
asthma cases: estimates from global datasets
Abstract
Background: Combustion-related nitrogen dioxide (NO2) air pollution is
associated with pediatric asthma incidence. We estimated global surface
NO2 concentrations consistent with the Global Burden of Disease Study
for 1990-2019 at 1km resolution, and concentrations and attributable
pediatric asthma incidence trends in 13,189 cities from 2000-2019.
Methods: We scaled an existing surface annual average NO2 concentrations
dataset for 2010-2012 from a land use regression model (based on 5,220
NO2 monitors in 58 countries and land use variables) to other years
using NO2 column densities from satellite and reanalysis datasets. We
applied these concentrations to epidemiologically-derived
concentration-response factors, population, and baseline asthma rates to
estimate NO2-attributable pediatric asthma incidence. Findings: We
estimated that 1.85 million (95% uncertainty interval: 0.93 – 2.8
million) new pediatric asthma cases were attributable to NO2 globally in
2019, two-thirds of which occurred in urban areas. The fraction of
pediatric asthma incidence that is attributable to NO2 in urban areas
declined from 20% in 2000 to 16% in 2019. Urban attributable fractions
dropped in High-income (-41%), Latin America/Caribbean (-16%), Central
Europe, Eastern Europe, and Central Asia (-13%), and Southeast Asia,
East Asia, and Oceania (-6%), and rose in South Asia (+23%),
Sub-Saharan Africa (+11%), and North Africa and Middle East (+5%)
regions. The importance of NO2 concentrations, pediatric population
size, and asthma incidence rates in driving these changes differs
regionally. Interpretation: Despite improvements in some regions,
combustion-related NO2 pollution continues to be an important
contributor to pediatric asthma incidence globally, particularly in
cities. Funding: Health Effects Institute, NASA