If fine particulate matter as a pollutant from industrial or natural sources (e.g. a desert) can be such a cause for concern in terms of (further) desertification as well as health impacts, is there a reason why there does not appear to be much action to control or solve it?

For instance - you will sometimes see construction sites required to use a canopy and/or water to localize the spread of fine particulate matter to a particular site, and forestation projects can serve to anchor some land in the face of advancing desert boundaries - but such applications seem limited in their enforcement.

What more could be done to control and combat fine particulate matter (and perhaps avoid warmer, drier countries and regions from becoming dust bowls)?

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    $\begingroup$ I think it's important to define what you mean by fine PM. Dust (e.g. from construction or deserts) is not categorically "fine", but is "coarse" instead. Also, you make it sound as if there are no controls for fine PM, but it is highly regulated in industry (at least in USA). Current science stresses the importance of ultra-fine PM (less than 1 ug/m3), and the EPA no longer cares much about PM10... PM2.5 being the currently regulated particulate size bin. $\endgroup$
    – f.thorpe
    Nov 12, 2014 at 22:28

1 Answer 1


There has been some considerable attention, it is not that factor that is hampering more coherent action, it is a lack of full understanding of the fine particulate matter itself - allow me to explain.

A lot of the reason why there has only been largely piecemeal approaches to combat Fine Particulate Matter, globally speaking, is due to the incomplete understanding of the aerosols and their dynamics themselves.

Having said that, there are different strategies to combat fine particulate matter (FPM). But, first, a definition - the United Nations Environment Program (UNEP) page Pollutants: Particulate matter (PM) states:

PM 2.5 refers to particles with a diameter of less than 2.5 microns. These are usually called fine particles and contain secondary aerosols, combustion particles and re-condensed organic metallic vapour, and acid components. Fine particles can reach all the way down to the alveoli in the lungs.

The inclusion of secondary aerosols, combustion particles (e.g. soot) and recondensed organo-metallic vapour can and does complicate attempts to mitigate the effects once released and would also complicate attempts to prevent the release.

It could be argued that the ultrafine fraction at 0.1 microns and less could be included under the FPM umbrella; however, as stated on the UNEP page, these are still the focus of extensive research.

There are several documents calling for the control and providing practical strategies by governmental organisations, one such document is the US EPA's Controlling Fine Particulate Matter Under the Clean Air Act: A Menu of Options (2006), in which it is acknowledged that

The chemistry and physics of PM2.5 formation in the atmosphere is incompletely understood.

also, in a practical sense,

In a perfect world, control-efficiency and cost-effectiveness data would be at hand; however, it is not consistently available.

and also in a scientific - practical sense:

there are important distinctions between filterable and condensable PM2.5. Further, some methods used to measure PM emissions reflect only the filterable components and, to exacerbate the problem, the filterable components vary depending on the test method used.

The first step in any attempts to mitigate the FPM content in the air is to monitor the sources, flow, composition etc of the particles. From the EPA document:

The importance of determining source apportionment for ambient PM2.5 in a specific area cannot be overstated; developing a cost-effective approach to controlling PM2.5 emissions sources requires an understanding of the relative contribution from local and regional sources. Adequate monitoring data are needed to provide insight into the composition of ambient PM2.5 in a given area.

A British document Fine Particulate Matter (PM2.5) in the United Kingdom (2012), states the reason why action is not happening fast enough reasonably well, with

The science underpinning the knowledge of PM2.5 is rapidly evolving and remains uncertain in many areas. There is a need for rapid translation into the policy arena of the newest results and understanding.

The uncertainty due to the varying compositions, which in turn affect how the particles move, how they interact with the surrounding environment suggests that 1 method would not be sufficient, and that more localised methods of control are necessary.

As you suggested, the importance of understanding FPM can not be understated, in epidemiological research Reduction in Fine Particulate Air Pollution and Mortality Extended Follow-up of the Harvard Six Cities Study (Laden et al. 2006), there have been found to be a drop in mortality corresponding to a drop in FPM concentrations.


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