Can dust pollution make you ill? The short answer is ‘yes’. The long answer is a bit more complicated: there are various ways in which dust pollution can make us ill. Particularly at threat, however, is our respiratory system. Although the respiratory system possesses multiple layers of defence against particulate matter (PM) pollution, repeated exposure to high PM rates makes one more vulnerable to various respiratory illnesses such as measles, influenza and even the novel Coronavirus.
In recent years the main element of dust pollution that has come under study for its link to respiratory illnesses is PM2.5. This is as it, out of our current categorisation schema for dust pollution, can enter our respiratory system with the greatest ease, and thus on average cause the most harm.
How can dust pollution make you ill?
It has become an established fact within the scientific community that high concentrations of airborne dust heightens the risk of contracting a respiratory illness. There are two main mechanisms which are postulated to be behind this association. The first flows from the the direct effects particulate matter has on your respiratory system, and the second from its airborne interaction with infectious material. We will go through each of them.
First of all, a dust particle can lodge itself in your nose, your mouth, your throat, and even your lungs. In doing this it will cause a physical impediment to the proper working of the respiratory system – if you inhale enough of them it can lead to serious complications, while constant exposure repeatedly engages the finite resources of your immune system. This latter possibility lowers the system’s capacity to effectively defend against infectious material, thereby heightening the likelihood of contracting a respiratory illness.
Thus, higher rates of airborne particulate matter can be used to explain higher illness infection rates. This we can call the passive means by which dust pollution can make you ill, and which we cover in our article on the long-term health effects of dust pollution.
But the physical impediment it can cause is not the whole story of its threat. Its presence in the air is also postulated to affect the respiratory illness infection rates. There are two ways dust pollution might cause this: either directly, with the dust particles acting as physical vehicles for the infectious microbes, or indirectly, as the proliferation of airborne particulate matter changes the diffusion rate of the microbial matter so that it remains airborne for a longer amount of time.
Either way, the higher the concentration of airborne particulate matter, the higher the likelihood of you inhaling infectious microbial matter, so the higher the likelihood in turn of you contracting said infection. This we can call the active means by which dust pollution can make you ill.
Particulate matter pollution therefore potentially poses a double threat. Not only can it create a physical blockade in your lungs or windpipe, lowering your immune response, but it could also facilitate the entrance of infectious microbial matter into our respiratory systems. Below we will look into the scientific literature looking into the second possibility.
Can dust pollution make you ill?
The correlation between dust pollution and influenza and influenza-like cases.
Using three-year’s data, our study suggested that human influenza cases were correlated to PM2.5 concentrations…
Liang et al, (2014), p. 7
One of the most important studies in recent times was undertaken in Beijing between 2008 and 2013. Researchers compared the air pollution data recorded from an air monitoring station found at the US Beijing Embassy with the amount of people who were recorded as being hospitalised due to influenza over the three year period from 2008-2011. This was one of the first studies to investigate comprehensively over an extended time period the relationship between the levels of dust pollution and the incident rate of influenza cases in Beijing, a city well known for its issues with air pollution.
All monthly measurements of the PM2.5 concentrations exceeded the standard of 35 micrograms per metres cubed – 81.21% of the days in the five year period reported values above the standard daily mean average. Specifically, and most conclusively pointing to the effect of dust on our getting ill, spikes recorded in the PM2.5 concentrations in the summers of 2009 and 2010 were followed 1-2 months after by corresponding spikes in the amount of influenza cases. In addition to this, a relatively low spike of PM2.5 concentrations in the summer of 2008 (attributed to air pollution measures taken during that summer’s Olympic Games) was paired with a correspondingly low spike in the influenza cases recorded.
The comparing of the two data sets led to a clear conclusion: the higher the rates of PM2.5, the higher the number of people hospitalised for influenza. This has been backed up by further studies carried out in China, such as Su et al (2019), who found a correlation between the rates of influenza-like illnesses and the atmospheric PM2.5 concentrations in Jinan.
Of course, this data doesn’t clear up whether dust only heightens the infection rate passively by lowering the immune system capabilities of the populace, or whether it actively increases the amount of infectious material inhaled. Further studies, however, have pointed towards the latter option as at least operating in tandem with the former.
They also help to assess whether the latter is directly caused by the dust, in the sense that the dust acts as a carrier of the virus into the respiratory system. or whether its increased presence only indirectly increases the amount of microbial matter inhaled through a changing of the atmospheric particle dynamics.
Can dust pollution make you ill?
The correlation between PM2.5 concentrations and the amount of atmospheric microbial matter
The data suggest that potential pathogen and antibiotic resistance burden increases with increasing pollution levels and that severe smog events promote the exposure…
Qin et al, (2020), p. 8
Evidence pointing towards the active pair of possibilities has been provided by a study looking into the microbiome of Beijing over a 6 month period between 2012 and 2013. In it, researchers compared the levels of PM2.5 and PM10 with the amounts of microbial matter found in the air.
They found that, the higher the particulate matter rates, the higher the amount of microbial matter found in the air. The levels of 72 microbes found in the air peaked just when the air pollution was at its worst (p. 5).
This provides support for the active pair of possibilities. If the increase in influenza cases were linked to the increased inhalation of infectious material, rather than a simple weakening of the populace’s respiratory systems’ defences, then one would expect to see a rise in the levels of infectious material paired with a rise in the airborne particulate matter. The study satisfied this expectation. This study, however, does not yet lend any weight to the direct role of dust in the increased inhalation of microbial matter, nor for its indirect role.
A further study from 2017 by Reche et al., however, provides evidence in support of the former, direct possibility. There the scientists presented results from dust-collecting instruments placed in the Sierra mountains in Spain. They first took samples of the air or water collected to measure the ‘free’ viral and bacterial matter, that matter not attached to any dust particles, and then treated a second lot of samples to a detaching procedure. This procedure then allowed a testing of the total microbial matter found in the sample, which, when the ‘free’ amount was subtracted, provided the amount of microbial matter present that was originally attached to the particulate matter.
Their results showed that that around 69% of the viruses deposited from the atmosphere onto their filters “were [likely] attached to dust or organic aggregates” (p. 1158). It seems, then, given this finding, that the increase in the rates of respiratory illnesses found in the former studies can be attributed not only to the heightened presence of particulate matter in the air, but directly to the particulate matter’s capacity to act as a vehicle for any microbial matter in the air.
Conclusion: can dust pollution make you ill?
A review of recent scientific studies provides a clear positive, if slightly complex, answer to our question: yes, dust pollution really can make you ill. Not only can it cause impediments to the proper working of one’s respiratory system through its physical blocking of one’s air passages, weakening the respiratory systems of those who inhale it, but it is also likely that it can act as a facilitator for the inhalation of any infectious material present in the air. This is as, the dustier the air, the more infested the air is with microbial matter. And the more microbial matter in the air, the likelier it is that one inhales enough of the matter sufficient to lead to infection.
This may be due to dust acting as a carrier for the infectious material, or just due to its increasing the density of the air, or both. Indeed, it seems most likely that the correlation between dust pollution levels and the incident rate of respiratory illness is likely to be best explained by a combination of all three possible factors mentioned, as all three are supported by independent evidence. This means that not only will a reduction of the dust levels both strengthen the local populace’s respiratory systems’ defences, but it will also lessen the likelihood of the inhalation of infectious microbial matter, and result in a reduction of the total airborne infectious material.
Sources
Liang et al., (2014). PM2.5 in Beijing – temporal pattern and its association with influenza. Environmental Health [online]. 13(102), 1-8. [Viewed 18.05.2020]. Available online: https://doi.org/10.1186/1476-069X-13-102
Qin et al., (2020). Longitudinal survey of microbiome associated with particulate matter in a megacity. Genome Biology [online]. 21(55), 1-11. [Viewed 18.05.2020]. Available online: https://doi.org/10.1186/s13059-020-01964-x
Reche et al., (2017). Deposition rates of viruses and bacteria above the atmospheric boundary layer. ISME J [online]. 12, 1154-1162. [Viewed 18.05.2020]. Available online: https://doi.org/10.1038/s41396-017-0042-4
Su et al., (2019). The short-term effects of air pollutants on influenza-like illness in Jinan, China. BMC Public Health [online]. 19(1319), 1-12. [Viewed 18.05.2020]. Available online: https://doi.org/10.1186/s12889-019-7607-2
Xing et al., (2016). The impact of PM2.5 on the human respiratory system. Journal of Thoracic Disease [online]. 8(1), 69-74. [Viewed 18.05.2020]. Available online: https://doi.org/10.3978/j.issn.2072-1439.2016.01.19
