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The air we breathe is becoming increasingly poisoned and air pollution is now considered to be the world’s largest environmental health threat. It is estimated that nine out of 10 people now breathe polluted air, which contributes to seven million deaths each year.
Air pollution is hard to escape – it is all around us; just because there isn’t any visible smog that doesn’t mean the air is clean. Many cities and villages worldwide see toxic pollutants in the air exceed average annual values as recommended by the World Health Organization’s air quality guidelines.
Types of Air Pollution
There are a number of air pollutants with known or suspected harmful effects on human health; they can cause and exacerbate a number of diseases including asthma, cancers, pulmonary illnesses and heart disease. Pollutants include:
- Nitrogen dioxide, sulfur dioxide and ozone – produced by burning fossil fuels, these can irritate airways of the lungs, increasing the symptoms of those with lung disease. They are also known factors in causing asthma.
- Particulates – solid and liquid matter from fuel combustion. These can be carried deep into the lungs, causing inflammation and worsening heart and lung disease. Particulates smaller than 2.5 microns in size can penetrate the lungs and blood system, increasing the risk of heart and respiratory disease and lung cancer.
- Carbon monoxide – prevents the uptake of oxygen by the blood, reducing the supply of oxygen to the heart, especially in people suffering from heart disease.
In most areas, these pollutants are the result of combustion from space heating, power generation, and vehicle traffic.
There are two types of air pollution; ambient or outdoor pollution, and household or indoor pollution generated by household combustion of coal, wood, or kerosene, which is used for open fires or basic stoves in poorly ventilated spaces. Each type of air pollution can contribute to the other as air moves from inside a building to outside, and vice versa.
Outdoor workers – those in agriculture, construction, waste collection, and even traffic police – are most vulnerable to ambient air pollution, much of which has been classified as carcinogenic by the International Agency for Research on Cancer.
Household pollution kills four million people - mostly women and children - annually, particularly in Asia and Africa where polluting fuels are used every day for cooking, heating, and lighting.
Microscopic pollutants can slip past the body’s defenses towards the respiratory and circulatory system causing damage to the lungs, heart, and brain. Air pollution is the second leading cause of noncommunicable diseases and around a third of deaths from stroke, lung cancer, and heart disease can be attributed to air pollution. In some countries, such diseases can only be reduced by improving air quality.
When air pollutants are high, adults with existing heart conditions and adults and children with lung conditions are at an increased risk of becoming ill and needing treatment, while those with asthma may notice they need to use their reliever inhaler more. Older people are more likely to suffer from lung and heart conditions, and when air pollution levels are high, the general population may suffer from a sore or dry throat, sore eyes, or tickly cough.
Exposure to air pollution is linked to a wide range of adverse health outcomes in children including infant mortality, asthma, neurodevelopmental disorders and childhood cancers. Globally, 93% of children under 18 live with air pollution above the WHO’s guidelines, and is thought 14% of children aged 5-18 worldwide have asthma where air pollution is a contributing factor. It is a factor in half of all deaths from lower respiratory infections in children under five in lower-middle-income countries.
Air Pollution and Climate Change
The world is becoming hotter and more crowded, and humans are pumping out greater volumes of dirty emissions. Air pollution is closely linked to climate change; burning fossil fuels is the main driver of climate change and a major contributor to air pollution – efforts to lessen one can improve the other. Approximately one million lives worldwide a year could be saved by 2050 if the goals of the Paris Agreement – which aims to combat climate change – are met by reducing air pollution.
Air pollution is the greatest environmental risks to health, and climate change is the greatest public health threat of the 21st Century. Fossil fuels are the primary source of climate-warming emissions and health-damaging air pollution. Decreasing even short-lived climate pollutants can generate immediate benefits for health and slow climate change.
Sources and Further Reading