Lately, in parts of Europe, we have seen an increase in an almost apocalyptic-resembling phenomenon: the arrival of desert dust from the Sahara that coats everything in an orange haze. It has been occurring more frequently in the past several years, and this bizarre meteorological event has made news headlines as air quality warnings pop up in affected areas. What causes these events? What are the dangers of desert dust? Read on to learn more.
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The Sahara: a massive, diverse ecosystem
Named after the Arabic word ‘ṣaḥrā’ (meaning desert), the Sahara desert is the world’s largest hot desert spanning 9.2 million square kilometres (3.6 million square miles or 2.3 billion acres) across the northern African continent. To put its size in perspective, it measures just about the same size as China. It is home to many types of wildlife and is inhabited by about 2 million humans. The Sahara consists of various types of terrain like salt flats, mountains, and valleys, but it is, of course, most known for its vast expanses of sand. Some sand dunes in the Sahara can reach as high as 450 metres (1476 feet)2!
Desert dust defined
It helps to understand exactly what desert dust is to grasp the effects it has on our health. As defined by a 2019 study, desert dust is a mixture of particulate matter (PM) sourced from the surface of arid and semi-arid regions. In these areas, the soil quality is poor, meaning that its components are mostly made up of minerals4.
A major contributor to the increase of desert dust emission levels in the past century is our changing climate. Increased global temperatures are causing deserts to expand. Anthropogenic land use practices are also responsible for contributing to desert dust emissions. Some of these practices include agricultural expansion and livestock grazing, practices that contribute to desertification. The degree to which land use impacts desert dust emissions is debated but is estimated to be between 10 to 50% of the cause5.
Desert dust in Europe
With the Sahara located about 4000 kilometres (2480 miles) from Europe as the crow flies, it is hard to imagine that conditions there can impact us on an entirely separate continent. However, in areas of the Sahara where desert sand is loosely bound to the Earth’s surface, wind can blow desert dust up into the air where particles may be suspended for a week, sometimes longer. If wind conditions are right, airborne sand can then travel thousands of kilometres.
Desert dust can impact a wide variety of industries and aspects of daily life: weather, visibility, climate, human and plant health including agricultural crops, and can severely disturb our ability to produce solar-powered energy3.
The Copernicus Atmosphere Monitoring System (CAMS), implemented on behalf of the European Commission by the European Centre for Medium-Range Weather Forecasts (ECMWF), is the association responsible for reporting on the amount of dust in the atmosphere on both a regional and global scale. Among other things, CAMS aims to predict the level of disruption caused by desert dust by using a combination of satellite images and computer models. The following CAMS images show a daily timelapse of the evolution of desert dust as it approaches and makes contact with Europe.
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Richard Engelen, Deputy Head of CAMS, emphasises the gravity of Sahara sand on African and Mediterranean communities: ‘It gets into houses, into lungs, can close airports and roads, and with climate change potentially causing deserts to grow, desert dust in the atmosphere will only increase’3.
Desert dust creates particularly high levels of ambient total suspended particles (TSP) and PM10. The aforementioned 2019 study found that during a desert dust event, daily PM10 levels exceeded 1000 μg/m3 close to emission areas, but daily concentrations measured between 400–600 μg/m3 in surrounding communities influenced by dust transport. However, PM2.5 levels are also significantly higher than normal during desert dust atmospheric events, accounting for 4 to 35% of measured PM104.
Impact on health
A 2011 study analysed the effects of increased quantities of PM10 and PM2.5 due to desert dust on daily mortality in Rome, Italy. The heightened levels of PM from atmospheric desert sand events led to increased mortality from ‘natural, cardiac, cerebrovascular, and respiratory causes’. The increase in mortality was found to be between 2.64 and 12.65% during these atmospheric events with the highest impact being had on cardiac mortality6.
Dust storms have also been linked to an increase in bacterial loads. A 2015 study in Senegal showed an increase in bacterial meningitis as a result of desert dust events7. There have also been recorded examples of ‘dust-related disease’ in other parts of the world like ‘Valley Fever’, an infection found in the deserts of North America caused by the inhalation of fungal spores8.
It is not news that, regardless of its sources, particulate matter exposure has a significant effect on health. PM10 can impact our respiratory and cardiovascular health. It can also serve as a trigger for asthma attacks, allergies, and is an aggravation of other respiratory conditions like chronic obstructive pulmonary disease (COPD).
PM2.5 is largely considered to be the most dangerous form of PM. Measuring 2.5 microns or smaller, it can easily gain entry into our bodies through the respiratory system (inhalation). It then accesses other organs of the body like the heart and the brain, after which it dissolves in the bloodstream. PM2.5 causes a range of negative health effects as follows:
- Short-term (exposure of up to 24 hours): increased hospital admissions for heart and lung conditions, increased mortality, bronchitis, asthma attacks, breathing difficulties, and aggravation of existing conditions
- Long-term (exposure of months or years): premature death, pregnancy complications, stunted lung development for infants and children, increased risk of multiple types of cancer but especially lung cancer
The dangers of PM can impact anyone and everyone, but the groups that are most at-risk include pregnant women, children, the elderly, and immunocompromised individuals.
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Impacts on the environment
Unfortunately, once the desert dust has settled (literally), it must end up somewhere. Where does it go? Most desert sand that was once ambient ends up in bodies of water. Some of these nutrients help to fertilise the ocean and the Mediterranean Sea; however, in high quantities, it can severely impact coral reefs and aquatic life. Additionally, if desert dust is deposited on ice and snow, it accelerates melt since it reduces albedo (the amount of sun radiation reflected to the atmosphere)8.
Particulate matter plays an important role in environmental degradation and climate change. It leads to crop destruction, causes acid rain, and damages habitats for animals (who suffer the same negative PM-caused health effects that humans do) and plants. PM also both warms and cools the climate: certain air pollutants have more warming potential than CO2, whereas others like particulate sulphites can have a cooling effect9.
Put your health first during desert dust events with Eoleaf
We do not always have control over the atmospheric or meteorological events that occur outside our homes. However, we can control the amount of pollution that we breathe indoors.
Some helpful recommendations to protect you and your loved ones during periods of desert dust are:
- Stay indoors and seal your entryways
- Limit outdoor exertion and activities
- If you must go outdoors, wear a mask that protects your nose and mouth and wash your face and hair when you return home
- Keep your windows and doors closed
- Watch out for any negative health symptoms that may arise and seek treatment if necessary
An excellent complement to the above steps is to equip your home with an air purifier.
Eoleaf air purifiers all come equipped with 8 different filtration technologies that effectively combat particulate matter of all sizes. One of those technologies includes a HEPA-certified filter, meaning that our devices are guaranteed to remove 99.95% of particles of 0.01 microns or more from your breathing air.
Eoleaf products can protect you from many types of allergens (dust, dust mites, mould and its spores, and pet dander), germs (bacteria and viruses), and fine particle pollution. Put your health first with an Eoleaf air purifier when air pollution levels are unpredictable.
References
1 Victor, D., & Minder, R. (2022a, March 16). Saharan sands float north to Europe, coating cities with dust. The New York Times. https://www.nytimes.com/2022/03/16/world/europe/sahara-sandstorm-europe.html
2 Interesting facts about the Sahara Desert. Global Adventure Challenges. (n.d.). https://www.globaladventurechallenges.com/journal/facts-about-sahara-desert
3 Desert Dust Strikes Southern Europe. Copernicus Atmosphere Monitoring Service. (2020, May 21). https://atmosphere.copernicus.eu/desert-dust-strikes-southern-europe
4 Querol X, Tobías A, Pérez N, Karanasiou A, Amato F, Stafoggia M, Pérez García-Pando C, Ginoux P, Forastiere F, Gumy S, Mudu P, Alastuey A. Monitoring the impact of desert dust outbreaks for air quality for health studies. Environ Int. 2019 Sep;130:104867. doi: 10.1016/j.envint.2019.05.061. Epub 2019 Jun 14. PMID: 31207476; PMCID: PMC6686079.
5 Tegen I., Lacis A.A., Fung I. The influence of mineral aerosols from disturbed soils on the global radiation budget. Nature. 1996;380:419–422.
6 Mallone S, Stafoggia M, Faustini A, Gobbi GP, Marconi A, Forastiere F. Saharan dust and associations between particulate matter and daily mortality in Rome, Italy. Environ Health Perspect. 2011 Oct;119(10):1409-14. doi: 10.1289/ehp.1003026. PMID: 21970945; PMCID: PMC3230430.
7 Diokhane, A.M., Jenkins, G.S., Manga, N. et al. Linkages between observed, modeled Saharan dust loading and meningitis in Senegal during 2012 and 2013. Int J Biometeorol 60, 557–575 (2016). https://link.springer.com/article/10.1007/s00484-015-1051-5#citeas
8 What is desert dust and how does it change atmosphere and the air we breathe?. Copernicus Atmosphere Monitoring Service. (2022, May 10). https://atmosphere.copernicus.eu/what-saharan-dust-and-how-does-it-change-atmosphere-and-air-we-breathe
9 World Health Organization. (2023). Climate impacts of Air Pollution. World Health Organization. Retrieved April 20, 2023, from https://www.who.int/teams/environment-climate-change-and-health/air-quality-and-health/health-impacts/climate-impacts-of-air-pollution
