More than 90 per cent of exposure in the Middle East to the most harmful air pollutants is the result of human activity, not naturally occurring dust, according to a new study.
Researchers said that vehicles and fossil-fuel-powered industry, including power generation, were key sources of the smallest particulate matter (PM), which can cause potentially fatal illness.
Dust has long been seen as a major contributor to the region's pollution problems, but the findings indicate that it tends to be a source of larger and less harmful particulate matter.
"Previously it was assumed most of the particles that matter most for human health were natural," said Prof Jos Lelieveld, of the Max Planck Institute for Chemistry in Germany and The Cyprus Institute, who led the study.
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"Now we've found most are human induced. The potential for improving health related to air pollution is enormous."
The new study used data including measurements taken at sea across the Middle East over a two-month period in 2017.
By looking at the composition of particles and carrying out complex modelling, the scientists worked out what were the human and natural contributions to pollution of a given particle size.
Air pollution poses risk to health
A key finding was that anthropogenic or human sources were responsible, Prof Lelieveld said, for "more than 90 per cent" of exposure to PM2.5s, which are particles up to 2.5 microns in diameter.
PM2.5s are a significant health hazard because their small size means they can penetrate deep into the lungs and sometimes enter the bloodstream.
As well as causing short-term health effects, such as irritation to the eyes, nose, throat and lungs, and shortness of breath, they increase a person’s risk of developing serious conditions such as heart disease or lung cancer.
In some areas, such as deserts far away from towns and cities, naturally occurring dust may be responsible for a larger proportion of PM2.5s. But in urban settings, where people are concentrated, human activity, including vehicle use, plays the dominant role.
Naturally occurring dust tends to cause a greater amount of PM10 pollution, which consists of particles up to 10 microns in size.
Their larger size means these particles are more often trapped in the airways and therefore less likely to cause the most harmful health effects of pollution.
"They irritate the airways, they exacerbate asthma, [but] for the long-term health, the small particles are more relevant ― that's PM2.5," Prof Lelieveld said.
While some human-made pollution came from outside the region, including south-east Europe, he said most resulted from the burning of fossil fuels in the Middle East.
Almost all the region’s harmful gas pollution, including nitrogen dioxide and sulphur dioxide, is of human origin, Prof Lelieveld said.
According to figures published by the World Bank earlier this year, air pollution in the Mena region kills about 270,000 people a year.
Typical PM2.5 levels in the region are more than 10 times those recommended by the World Health Organisation.
Other researchers involved in the study came from King Abdullah University of Science and Technology and King Saud University, both in Saudi Arabia.
The Global Burden of Disease Survey 2017, created by the Institute for Health Metrics and Evaluation at the University of Washington, reported that the mean annual exposure to PM2.5s in the Arab world was 59 micrograms per cubic metre.
This compares with the world average of 46mcg per cubic metre.
The survey recorded a figure of 41mcg per cubic metre for the UAE.
A project that looked at anthropogenic sources of pollution in the country, the UAE Air Emissions Inventory Project, found that industry caused about two thirds of PM2.5s, while road vehicles caused about one fifth. In terms of harmful gases, traffic was the main source.
Clean energy investment
The UAE’s investments in clean energy, which avoids the particulate matter and greenhouse gases associated with fossil fuel power generation, have topped $40 billion.
There has been huge expansion in solar power capacity and the building of the four-reactor Barakah Nuclear Power Plant.
As reported in The National, earlier this month the authorities launched the UAE National Air Quality Agenda 2031 with the aim of reducing pollution levels.
Unveiled by the Ministry of Climate Change and Environment and including public and private sector organisations, the new strategy is aimed at providing cleaner air for all.
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