Outdoor air pollution and asthma

Lancet. 2014 May 3;383(9928):1581-92. doi: 10.1016/S0140-6736(14)60617-6.


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.

Publication types

  • Review

MeSH terms

  • Air Pollutants / analysis
  • Air Pollutants / toxicity*
  • Air Pollution / adverse effects*
  • Air Pollution / analysis
  • Asthma / etiology*
  • Environmental Exposure / adverse effects
  • Gases / toxicity
  • Health Policy
  • Humans
  • Particulate Matter / analysis
  • Particulate Matter / toxicity
  • Risk Factors
  • Vehicle Emissions / analysis
  • Vehicle Emissions / toxicity


  • Air Pollutants
  • Gases
  • Particulate Matter
  • Vehicle Emissions