Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2014 May 3;383(9928):1581-92.
doi: 10.1016/S0140-6736(14)60617-6.

Outdoor air pollution and asthma

Michael Guarnieri  1 , John R Balmes  2
Affiliations
Review

Outdoor air pollution and asthma

Michael Guarnieri et al. Lancet. .

Abstract

Traffic and power generation are the main sources of urban air pollution. The idea that outdoor air pollution can cause exacerbations of pre-existing asthma is supported by an evidence base that has been accumulating for several decades, with several studies suggesting a contribution to new-onset asthma as well. In this Series paper, we discuss the effects of particulate matter (PM), gaseous pollutants (ozone, nitrogen dioxide, and sulphur dioxide), and mixed traffic-related air pollution. We focus on clinical studies, both epidemiological and experimental, published in the previous 5 years. From a mechanistic perspective, air pollutants probably cause oxidative injury to the airways, leading to inflammation, remodelling, and increased risk of sensitisation. Although several pollutants have been linked to new-onset asthma, the strength of the evidence is variable. We also discuss clinical implications, policy issues, and research gaps relevant to air pollution and asthma.

PubMed Disclaimer

Conflict of interest statement

Declaration of interests

JRB is the Physician Member of the California Air Resources Board, the state agency with regulatory responsibility for air quality and climate change mitigation policies. MG declares that he has no competing interests.

Figures

Figure 1
Figure 1. Sources, transport, transformation, and fate of atmospheric pollutants
Reproduced from the US Climate Change Science Program. CFC=chlorofluorocarbon. CH4=methane. CO=carbon monoxide. CO2=carbon dioxide. N2O=nitrous oxide. NOx=nitrogen oxides.
Figure 2
Figure 2
Mechanistic framework for air pollution effects in asthma
Figure 3
Figure 3. Particulate matter size
Image modified with permission from the US Environmental Protection Agency.PM=particulate matter.
Figure 4
Figure 4
Compartmental deposition of particulate matter
Figure 5
Figure 5. National emissions of key air pollutants for USA, UK, and China with projections to 2030
(A) Nitrogen oxides. (B) Particulate matter with a diameter <2·5 μm. (C) Sulphur dioxide. Data from the GAINS Database.
See this image and copyright information in PMC

References

    1. Lim SS, Vos T, Flaxman AD, et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2012;380:2224–60. - PMC - PubMed
    1. Brauer M, Amann M, Burnett RT, et al. Exposure assessment for estimation of the global burden of disease attributable to outdoor air pollution. Environ Sci Technol. 2012;46:652–60. - PMC - PubMed
    1. Perez L, Declercq C, Iniguez C, et al. Chronic burden of near-roadway traffic pollution in 10 European cities (APHEKOM network) Eur Respir J. 2013;42:594–605. - PubMed
    1. Wong GWK, Chow CM. Childhood asthma epidemiology: insights from comparative studies of rural and urban populations. Pediatr Pulmonol. 2008;43:107–16. - PubMed
    1. Robinson CL, Baumann LM, Romero K, et al. Effect of urbanisation on asthma, allergy and airways inflammation in a developing country setting. Thorax. 2011;66:1051–57. - PMC - PubMed