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Children face special risks from air pollution because their lungs are growing and because they are so active and breathe in a great deal of air.

Several studies have found air pollution linked to harm to children while they are still in the womb. A large study in California found that higher particle pollution levels increased the risk of preterm birth.5 Pregnant women exposed to even low levels of particle pollution had higher risk for preterm birth in a Boston study.6 Preterm births occurred more frequently when particle pollution spiked, as an Australian study found, even when they controlled for other risk factors.

Further evidence that cleaner air provides real benefits to children’s health came in a 2016 report from the same study exploring changes to 4,602 children’s respiratory symptoms such as coughing, congestion and phlegm. The study looked at the changes in these symptoms in three groups of children living in Southern California over different periods of time when air quality also differed (1993-2001, 1996-2004, and 2003-2012). As air quality improved, the children in the study suffered fewer bronchial symptoms whether they had asthma or not. In communities where the air quality improved the most, the children experienced even fewer symptoms.

So, does cleaning up the air really improve children’s health? In 2017, the researchers reviewed these long-term studies of children in Southern California and the impact of improvements in air quality on their health. They concluded that the 20 years of collected data provided strong evidence of the potential to improve children’s health by reducing some of the most common outdoor air pollutants.

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PM 2.5 refers to a category of particulate pollutant that is 2.5 microns or smaller in size. The average cross-section of a human hair is 50 microns. PM stands for “particulate matter.” The EPA and many health organizations categorize particulate matter by size because different size particles have different health effects. For instance, PM 10 particles (particles less than 10 microns in size) can irritate your nose and eyes, but fewer of these particles penetrate deep into your lungs, so they do not cause the same health problems that smaller micron particles can, although they do increase rates of respiratory disease 

PM 2.5 particles are complex because they can be made up of numerous types of chemicals and particles, and they can be partly liquid, as opposed to solid, like a common dust particle. Particulate pollutants that are entirely or partly made up of liquid droplets are known as an aerosol. Natural kinds of aerosols include dust, sea salt and volcanic ash, whereas man-made sources include factory and auto emissions, coal combustion and biomass burning for clearing land or farming.

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A 2013 assessment by WHO’s International Agency for Research on Cancer (IARC) concluded that outdoor air pollution is carcinogenic to humans, with the particulate matter component of air pollution most closely associated with increased cancer incidence, especially lung cancer.

The Board meets regularly, bringing together ministers from the health and environment sectors to address important issues in the WHO European Region.

Evidence published by WHO/Europe earlier this year, as part of the international project to review evidence on health aspects of air pollution (REVIHAAP), confirmed the importance of outdoor air pollution as a risk factor for health, and strengthened the causal link between fine particles (PM2.5) and cardiovascular and respiratory ill health. It also showed that long-term exposure to PM2.5 can trigger a range of problems, such as atherosclerosis, adverse birth outcomes and childhood respiratory diseases, and suggested possible links with neurological development, cognitive function and diabetes.

IARC’s recent classification provides indisputable evidence that air pollution is carcinogenic, and adds to the compelling evidence for taking action to improve air quality in order to reduce this important burden of disease in Europe.

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Ambient air pollution accounts for an estimated 4.2 million deaths per year due to stroke, heart disease, lung cancer and chronic respiratory diseases. Around 91% of the world’s population lives in places where air quality levels exceed WHO limits.

Exposure to high levels of air pollution can cause a variety of adverse health outcomes. It increases the risk of respiratory infections, heart disease, stroke and lung cancer.  Both short and long-term exposure to air pollutants have been associated with health impacts.  More severe impacts affect people who are already ill.  Children, the elderly and poor people are more susceptible.  The most health-harmful pollutants - closely associated with excessive premature mortality - are fine PM2.5 particles that penetrate deep into lung passageways.  

Although air quality in high-income countries has been generally improved over the last decades, the adverse health effects of particulate air pollution, even at relatively low levels, remain a global public health concern.

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