Earth Matters

Fine Particulate Maps With and Without Dust

June 23rd, 2015 by Adam Voiland

Fine particulate matter (PM2.5) for 2010-2012 with dust and sea salt included. Visualization by Josh Stevens. Data from van Donkelaar et al. 


Fine particulate matter (2.5) concentration for 2010-2012 without dust and sea salt included. Data from van Donkelaar et al.

If you saw our June 22 Image of the Day with global maps of fine particulate matter (PM2.5), you may have noticed large concentrations over the Sahara Desert and the Arabian Peninsula. With vast deserts in these areas, it’s not a surprise that the satellites detected so many particulates. Winds regularly send plumes of dust blowing over the region and even to Europe and the Americas.

However, it isn’t clear how damaging dust particles are to human health in comparison to other types of fine aerosol particles (such as those produced by burning fossil fuels or biomass burning). Several teams of epidemiologists have looked for associations between outbreaks of Saharan dust and health problems, but the results have been mixed. A literature review published in 2012 summarized the state of the science this way: “The association of fine particles PM2.5, with total or cause-specific mortality is not significant during Saharan dust intrusions. However, regarding coarser fractions PM10 and PM2.5-10, an explicit answer cannot be given. Some of the published studies state that they increase mortality during Sahara dust days while other studies find no association between mortality and PM10 or PM2.5-10. The main conclusion of this review is that health impacts of Saharan dust outbreaks needs to be further explored.”

Since dust is natural and may not have significant effects on human health, the team of Dalhousie University scientists who developed the global PM2.5 exposure maps prepared two versions of their data. One shows total PM2.5 concentration (top map above) globally; the other shows PM2.5 excluding contributions from dust and sea salt (bottom map). Notice how much less PM2.5 appears in northern Africa when dust is excluded.

To get a sense of how PM2.5 concentration (excluding dust and sea salt) has changed between 2000 and 2010, see the map below. Notice that while PM2.5 has decreased over North America and Europe, it has increased over Asia. To read more about what is driving these trends, read this story.  To learn more about the data used to create these maps, visit this website. 


Areas where PM2.5 concentration has increased between 1998 and 2012 are shown with shades of red. Decreases are shown with shades of blue. Data from van Donkelaar et al.


4 Responses to “Fine Particulate Maps With and Without Dust”

  1. Joseph Chepsoi says:

    The maps are informative, educative and interesting. Are there maps on aerosols and other pollutants? These maps can be useful for policy makers and development planners.

  2. Tonatiuh says:

    Would be useful to correlate with carbon monoxide and nitrogen oxides.

  3. Ainsley Veitch says:

    How easy it is to create high tech filtering system to capture the dangerous atomic particle in these gases is their a knowledge that can be created and freeze them with a form of cryonic way when capture and store for future study to create fuel for space craft……………. probably could amplify a centrifuge engine that only used in space to create pulusion movement and when enter the earth orbit it could transfer over to anti gravity amplify control system by magnetic repelling against un- aline poles but it would take a mathematical order to accurately cancelling out direction of movement ….did you get me am I thinking or not can you add to this problem or see where I go wrong.

  4. Dhanasekar says:

    I wonder how is the dust pollution from the deserts and fine particulates are corelated using stalellite images of optical density. what is the calculation.How this confirmed with wind direction and speed.Can some one reply