Microplastics in our air ‘spiral the globe’ in a cycle of pollution, study finds
Samuel Greco
Microplastics in our air ‘spiral the globe’ in a cycle of pollution, study finds
CNN Article: https://www.cnn.com/2021/04/13/world/atmospheric-plastics-study-intl-hnk-scli-scn/index.html
Research Paper: https://www.pnas.org/doi/10.1073/pnas.2020719118#sec-3
Microplastics are a major source of aerosols and have been shown to have adverse effects on human health1. Of the plastic that is produced 12-18% ends up back in the environment due to poor governmental management as well as littering1. The problem with this is plastic does not simply decompose but rather breaks up into smaller and smaller pieces which eventually become airborne. It is estimated that 22 Gg (22,000 tons) are deposited through the US every year2.
In the paper by Brahney, Janice, et al. they discuss how they can use data of atmospheric microplastics along with modeling to identify trends in aerosols deposition, sources, and re-emissions throughout the US as well as the world. They report using “detailed deposition dataset available for the remote parts of the western United States in combination with a microplastics-enabled version of the Community Atmospheric Model (CAM) (41) to determine the most likely sources of atmospheric microplastics, their residence time in the atmosphere, and their accumulation areas.” What they discovered with this modeling is that road dust sources account for 84% of plastic deposition in the western US while ocean emissions, agricultural dusts, and population sources contributed 11, 5 and 0.4%, respectively. They also report when this model was turned to a global scale 99% of deposition came from oceans. Additionally, they state that the current deposition rates in land environments average at 10 mg ⋅ m−2 ⋅ year−1 however these rates could rise to 100 mg ⋅ m−2 ⋅ year−1 by 2050. Importantly, they state that the microplastic that is formed is not from the current year but rather from decades previously.
In an article published by Jessie Yeung of CNN they discuss this research article. I liked this article but I found it a little too concise. They state the data as it is stating how much microplastics are being deposited across the US each year as well as the different sources discussed in the paper. The article does a good job at noting that the microplastics are formed from older plastic sources and shows how coastal deposition is different than terrestrial deposition. However, the author does not at all mention the analytical and computational methods to receive this data which is a majority of this paper.
One thing I disliked about the article was the author choosing the largest numbers out of every dataset that was used. For example, when considering how much plastic ends up back in the environment the paper states it’s a range from 12-18% but the author only says 18%. This also occurs a second time with the time these aerosols stay airborne as they range from hours to a max of 6.5 days (which majority of these correspond to less than one day). Jessie does not talk about the size of different microplastics and how they relate to time spent in the atmosphere. The research paper itself is quite long as it goes into each computational model that is used. Coming from an organic background is it a little more difficult to understand the computational models but in terms of how it is written I would say it is very concise.
Overall, I would rate this article a 7/10. They present the data as it is which is good, but I would like to see more detail. They also fail to mention the difference between US deposition and global deposition. I generally feel there is a lack of depth with this article, and it reaches a more surface level that I would like to see. It is nice to see the author uses quotes that are not found in the paper showing the author of the research paper was interviewed for this article.
References
(1) Geyer, R.; Jambeck, J. R.; Law, K. L. Production, Use, and Fate of All Plastics Ever Made. Sci. Adv. 2017, 3 (7), e1700782. https://doi.org/10.1126/sciadv.1700782.
(2) Brahney, J.; Hallerud, M.; Heim, E.; Hahnenberger, M.; Sukumaran, S. Plastic Rain in Protected Areas of the United States. Science 2020, 368 (6496), 1257–1260. https://doi.org/10.1126/science.aaz5819.
I agree with you that the news article is pretty light on details, though I feel saying "up to x%' is a fine way to describe a range of possible values in most cases such as when saying up to 18% of plastic waste enters the environment. However, for the life time of airborne microplastics, I agree it would have been better to say the majority last for less than a day.
ReplyDeleteMy main gripe with the news article is that it doesn't really talk about the ocean much. Since microplastics come from mechanical actions on plastics, there is very few terrestrial sources of microplastics, mainly from road and traffic, with some wind and dust. The ocean on the other hand is a constant and huge source of mechanical action, which as the paper mentions causes it to be the largest source of microplastic aerosols. The only thing stopping ocean sourced microplastics from being the largest terrestrial deposition source is that oceans are massive and most ocean based microplastics end up back in the ocean. However, even the paper mentions that they are likely underestimating the amount of ocean sourced terrestrial depositions because their mountain stations were too far away from the cost. Once microplastics leave the ocean, it is likely they won't come back and will instead be pushed further and further inland. The article quotes the paper's call to action to get plastic out of the ocean at the end of the article, but never explains why that is so important.
I completely agree you Leo. With the data given and how it was aquried it is very diffucult to pin-point how much deposition is coming from the ocean. I think the article could of included data stating how the microplastics are formed rather than just saying they form over time.
DeleteGreat choice of topic and articles! I learned a lot about microplastics. I agree with your subpar rating of the CNN article. I wish that the CNN article had highlighted the contributions from road and braking and the ocean in comparison to cities. The article simply mentioned all of the sources but didn't draw attention to the percentages of contribution. If they included figure 1 from the journal article it would have been really clear. I really liked that figure and it helped me understand the breakdown of the contributions. The way the article writes about the contributions is very vague and doesn't tell the reader which is the most important. I think it is important to note that the journal article kept stating they suggest that there are stronger sources and deposition of plastic over the ocean than they were able to detect. I also think that the article should have emphasized that most of the study was related to and conducted in the U.S. The study did make efforts to expand to the global picture but most of the article focuses on the U.S. It is misleading to make most of the data out as global. I did like how the CNN article emphasized the importance of legacy microplastics which was a main point of the journal article. Overall the article didn't seem to hit all of the main points of the journal article which is why I agree with your assessment of 7/10.
ReplyDeleteI agree with you Emily. I think one of the more important aspects of the paper come from the fact that the mechanical motion is how microplastics are formed and that movement is always going to be greater when we look at wave action. Figure one is very helpful to see clearly the different breakdowns of microplastics. I do wish the article did include at least one of these figures from the paper.
DeleteWhen reading the PNAS publication’s descriptions of plastics getting into aerosols and following a cycle like some known biogeochemical cycles across the globe, I very quickly wondered how this would be described in the CNN article if at all. As someone new to this area of chemistry, I still find aerosols strange, and I imagined it may be a difficult thing to describe to the average CNN reader. But, I actually thought the CNN article did a really nice job talking about how the plastics get into the air. When I was comparing the descriptions between the article however, I found that the CNN author never used the word aerosol. The only time the word aerosol is used in the CNN article is in one quote from the PNAS publication. Do you think an aerosol is something difficult to describe to the average reader of CNN, or do you think they could have gone into more detail? Or was it a sufficient description without using the word aerosols? Curious on your thoughts!
ReplyDeleteAlso, just something I’m curious about, you mention how the PNAS publication talks about plastics in aerosols being from decades prior, how did they date the microplastics? Like some sort of carbon dating for plastic? Or are they just saying there must be some that old since the plastic is never decomposing? I was looking around for an explanation of this but either missed it or misunderstood.
Those are great questions Sarah. To the first point I think a general defintion of aersols would be very nice to include and I don't think it would be troublesome to the average CNN reader. I, like you, am also new to this area of chemistry. To the second point the paper references another research paper that states microplastics increase at 2-10 fold per decade. In terms of how they date this I also could not find a super clear cut answer but found that the UV levels as well as oxidation levels gives insight.
DeleteI actually slightly disagree with you rating for this CNN article. While it was simple I thought that it was able to thoroughly convey the main findings and concerns of the research paper. The main finding was that most of the microplastics in the global plastic cycle are from historical plastic sources, which the CNN article very clearly gets this across. They also share some of the important statistics without getting too bogged down with numbers where most readers would gloss over them.
ReplyDeleteI wasn't the biggest fan of them citing their own article when mentioning previous studies that had gone into research on the health effects of microplastics, and especially since after reading through that article I wasn't the biggest fan of how they presented the findings. Essentially saying multiple times that microplastics have shown no harmful effects on humans, before saying there isn't enough research on it to make claims... oof. But I like how the original CNN article backtracks a bit and clearly states that microplastics could be harmful for both the environment and human health, but more research needs to be done.
I think this news article did one thing that we tend not to see often: explain the mechanism behind the science. I really liked that they included how we get microplastics from tires, ocean waves, and agricultural processes. In my opinion, Yeung did a great job of explaining these mechanisms in an accessible way. One thing that I would have wanted to see alongside these explanations, however, were some statistics pulled from the article to help readers learn the relative prominence of each source of microplastics. The journal article had a lot of great figures (such as Fig. 4) that described the source contributions for different regions of the world. I think this would have been a good discussion point for the news article to help people relate to the data and see where microplastics come from in their part of the world.
ReplyDeleteAnother thing I noticed from the news article was that they didn't mention the models the researchers used in the journal article. The models provided very compelling data that was used to source these microplastics, and Yeung didn't discuss that aspect of the paper at all.
I would agree with your 7/10, since the CNN article could have been made stronger by adding more details about microplastic sources and the models used in the journal article.
I like you point Hailey on figure 4 as this is one I did really see useful when reading this paper. When I first read the article I thought the author talked about the mechanism behind the generation of microplastics because it is so relevent to the paper but now I realize this is something the article just missed. I do believe including the models would be vital but in terms of how this is done to a general audience would be difficult.
DeleteI agree that the CNN article is very concise, I don't think that this alone is a negative feature of the reporting. I think that considering the audience, this article is an effective introduction to the concept and potential impacts of microplastics, but its by no means a substantive summary of the Brahney paper. It seems to me that Yeung's goal was to use Brahney's publication as a grounded jumping off point to talk about microplastics in relatively broad terms, and I think she succeeded in that goal. The discussion of microplastics as an environmental concern began relatively recently, especially in more popular discourse. I have had many conversations with people in the past two years who were not even familiar with the term itself. For this reason, I think it was a wise choice to prioritize a more general discussion of microplastics to a specific report of Brahney's findings, so I don't mind that much of the methodology was overlooked. In general, Yeung gives a concise and understandable definition of microplastics, includes good quotes from the researchers to add context and ethos, and stresses the importance of this issue by introducing relevant health and environmental concerns. I think that this is the extent of the information that is important to the general public. I know you mentioned that the way Yeung published the data might exaggerate Brahney's findings, and I see your point, but I don't think the article misrepresents the data. Although the best way to report the amount of plastics that return to environment is by describing the range as 12-18%, Yeung does say that this number is "up to 18%" which makes it clear that this is the top end of the figure and not an average or some other value.
ReplyDeleteThat is a very interesting thought Hannah and I did not even consider this. I guess I assumed that the article should describe as much of the paper as possible or the parts of vital importance. I did not really consider the author just trying to get across the concept and impacts of microplastics and using the paper as more of a tool rather than the article being a summary. I think you are right in that aspect and that makes me look at this article with new eyes.
DeleteI agree with you that Yeung overlooks the methods of the paper. While I do not feel that popular media sources, such as CNN, needs to dive deep into the methods of a paper, I feel that it is important to at least allude to the methods so the reader has some grasp of what was done in the study. Given the complexity of the computational and analytical methods used in this paper, what level of details about the methods do you think could have helped readers understand the study better?
ReplyDeleteAdditionally, I agree with other commenters that the author does a great job summarizing the actual mechanisms by which microplastics form and enter our atmosphere, highlighting mechanisms such as waste clusters breaking down in the ocean and tire/road turbulence and friction generating and emitting microplastics. Do you think that Yeung would have had to remove some of these mechanistic details if she were to include information about the methods of the paper, or do you think both of these could have fit into this news article?
Finally, while I appreciate that Yeung provided the readers with a link to the original PNAS paper, I found it to be poor journalism to provide a link to another CNN article when claiming that microplastics have not been found to have health impacts on human (rather than providing a link to the WHO report that established these findings). Moreover, the author neglects to mention that the WHO report primarily focuses on the human health impacts of microplastics introduced to the body via water ingestion, and not those introduced from food consumption and air inhalation.
I agree that the article should have gone into greater depth on how each source of microplastics contributes to global levels, as it might have furthered their argument about the importance of keeping plastics out of the ocean. Additionally, as other commenters have mentioned, there are definitely figures in the paper that would have been helpful to present in the CNN article, particularly Fig. 1, which clearly lays out sources and contributions in a way that is easily parsed even when skimming. However, I do not feel that the article largely brushing over the methodology in Brahney's paper is necessarily a drawback. It told the reader when the data was collected, and what results were found, which is ultimately as much as most readers will be interested in and willing to learn. This article is not here to give a deep dive into the paper, if people wanted to know about the computational and analytical methods used, they could go read it themselves. Instead, the article aims to give big takeaways and convey potential environmental impacts shown by the research, and I think it does that very well while still resonating with a lay audience.
ReplyDeleteI thought you rating of the article was reasonable. I agree that the article is not very good and 7/10 is acceptable. I noticed you talked about the article contains quotes from the scientist in the study. I would also assume that those quote were attained through an interview. However, it is not. The article presents the quotes and then link another article. From further research, I found that the quotes were attained from an article from Cornel Chronicle. I am not fully sure if this article conducted the interview, but I would assume they did as they did not site any other sources for it. I believe that sourcing a quote from a secondary source very unreliable.
ReplyDeleteI found your blog post to be relatively well written. I enjoyed that your background information was collected from outside sources. I would have preferred a little bit more information in the background especially because you found two other sources. Specifically, you did not address the difference between oceanic and terrestrial aerosols. I am still a bit confused at why the oceanic aerosols are much higher. I think this would have been a good concept to address in the start of the blog post.
I agree with your assessment overall. I think it was excellent at highlighting the key takeaways from the PNAS publication, but could've included more findings from this study. While the use of direct quotes seems good at first, I feel it would be more efficient to use quotes for specific data points/conclusions, rather the broad statements that are mostly background information.
ReplyDeleteMost of the necessary background info was there, but I think a definition of what microplastics are and description of their diversity would be helpful. Yeung did a good job of highlighting the mechanical origin of microplastics, but with "microplastics" becoming a buzzword lately, I'd like to see a sentence that recenters on what they actually are (*this might've been in the ad video, but I was having issues playing it & I imagine others were also, so putting it in the article itself is preferable).
I don't think using the highest number of a range, e.g. the 6.5d residence time, is necessarily misleading (as long as there's an "up to" qualifier). There's definitely a fine line between fearmongering v.s. highlighting conservative estimates might to demonstrate the significance of a problem & enact legislation/change. Quoting the study for these values gives them credibility, but this could be strengthened by explaining that residence time is affected by particle size, for example.
One thing I found lacking in the CNN article was not just mentioning that this study used modeling, but a discussion of the discrepancies between their modeled values and observed values from other studies (which Brahney et al. addressed multiple times). It's important to include methods (at a very high level) to instill trust in science and also highlight the variety of methods out their with their limitations.
Nice work. I agree with the other commenters that some definitions of microplastics would be good but that the details about the sources of microplastics was a good inclusion by the author. I do think that this article was able to convey the overall message with a relevant and adequate level of detail for the average reader. As we talk frequently about in class, the average national reading level is of middle-school age, and so I think if more information about the methods utilized by the scientific paper would be burdensome. The article is very succinct and links to the paper, so I thought it was pretty good.
ReplyDeleteI think the small issues that other commenters are pointing to, such as the article mislinking the research and quotes to different sources, along with poor context on how the information has wider implications on the globe. Especially not involving the methods for a paper like this, these all accumulate to an article that feels somewhat lackluster. I'd have liked to seen a bit more background from the journalist themselves on the sources of the microplastics as well. Overall, good review.
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