Researchers Find Link Between Air Quality and Alzheimer's Disease

When it comes to human health, recent studies have suggested that not only the respiratory and cardiovascular systems are affected by air pollution, but the central nervous system could be affected as well. One disease of particular interest and relevance is dementia, in particular Alzheimer's Disease and Vascular Dementia, mainly because of the emotional and physical toll takes on patients and their families, and incidence is expected to triple in the next 40 years.    

This Yahoo! Finance Article tells us all about how a longterm (15 years) study was realised in Umea, Sweden where they related traffic-related air pollution to dementia incidences, to which they provided the following scientific article as their main resource: Environmental Health Perspective Article. 

Even though it may seem as though the Yahoo! Finance Article did a good job on summarising this paper's mayor findings, as one keeps reading it is noticeable that it becomes more of a "promotional stunt" than an informative article for the community. As one reaches the last 2-3 paragraphs of the Yahoo! article a company is mentioned, a product is introduced and the rest of the article just reads like a TV commercial for a household product (an air filter for your home). Which leads me to believe that the Yahoo! article was written with the purpose of "scaring people into buying their product" (it is a Yahoo! Finance article after all) or creating a bigger problem so that the public will buy their solution. 

Why did I use " " for that particular phrase? Because when you compare and contrast the Yahoo! and the EHP article, it is noticeable how the Yahoo! author only took the bits and pieces of that paper that would make their product more marketable. For example, the Yahoo! article mentioned a "direct link" to have been found in the study when in the Conclusions section of the paper they state that they [observed associations between the two and it should serve as strong indicator to pursue future studies]. Another example would be that they only propose one solution to this problem, which would be (yes, you guessed it!) buying their product. 

Also the Yahoo! article fails to mention a wide number of important information found in the paper such as: how each subject treated/considered, and how the exposure to the air pollution was quantified. In the paper, they took week long measurements of NO2 (which is a traffic pollution indicator) during a 6 month period and used those measurements and the area in which the participating cohort lived to run models to determine their exposure to this indicator substance. 

Overall, I thought that Yahoo! Finance had an interesting article when I started to read it but was very disappointed at the end. However, that paper was so interesting to me that I had to share it here. Also similar types of studies have been done in Mexico.

China Exports Pollution to U.S.

Interconnecting economies across the world has many benefits regarding job production, infrastructure, and revenue/profit. An unfortunate consequence of a global trade market that has recently received attention by the media is the intercontinental movement of air pollution. A negative consequence of such interconnected economies has been analyzed regarding China's exporting infrastructure with the U.S as highlighted in an article in the New York Times (NYT). A report in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) recently analyzed the movement of pollutant emissions from Chinese emissions. These emissions are largely a result  of the the manufacturing of goods in China for foreign consumption.

The New York Times highlights that companies in the U.S. decide to outsource manufacturing to other countries, namely China, for various reasons including the avoidance of the additional emissions of air pollution associated with large manufacturing plants; the true effect of this strategy is commented on by one of the authors of the PNAS article:

"outsourcing production to China does not always relieve consumers in the United States - or for that matter many countries in the Northern Hemisphere - from the environmental impacts of air pollution."

The NYT article highlights that although there is intercontinental movement of air pollution from China to the US (fig 1), the net reduction of manufacturing in the U.S. does mean cleaner air in the American East. This is easily understood by considering that the movement of pollution approaches the U.S. from the West, leaving the highest concentrations of pollution in the Western half of the U.S. Since the population density is much higher in the Eastern regions of the U.S., this results in decrease of average air pollution when considering the entire country.

The NYT article also highlights that the amount of air pollution in the Western U.S. resulting from emissions from China is a small fraction compared to the amount produced by sources in the U.S. including traffic and domestic industries.

Figure 1. Simulated maximum percentage of Chinese EEE (emissions embodied in export) to daily mean US surface pollution for (A) sulfate, (B) ozone, (C) black carbon (BC), and (D) CO (carbon monoxide).

To better understand how manufacturing goods for export has affected China and the US, consider that in 2006, 36% of anthropogenic sulfur dioxide, 27% of nitrogen oxides, 22% of carbon monoxide, and 17% of black carbon were emitted in China as a result of the manufacturing of goods for export. For each of these pollutants, 21% were a result of China-U.S. trade. Atmospheric modeling showed that export-related Chinese pollution contributed 3 - 10% of annual mean surface sulfate concentrations and 0.5 - 1.5% of ozone over the Western U.S. in 2006 (fig 2). This extra pollution has averaged to one extra day or more of noncompliance with U.S. ozone standard in Los Angeles and even much of the Eastern states.

Figure 2.  Simulated percentage contribution of surface air pollution in 2006 from Chinese EEE for (A) sulfate, (B) ozone, (C) black carbon (BC), and (D) CO (carbon monoxide).

Overall, the NYT article did an excellent job of covering the key points that the PNAS article discussed. The modeling done by the authors was just that, a model, and the NYT article did not make broad assumptions on the data presented. The NYT article also did a great job of highlighting that manufacturing of exported goods is not only harmful to the U.S. but also to regions east of China, a topic that is not discussed as much in the PNAS article. I believe this was a good example of popular media bringing a pressing issue to light using scientific data from a peer-reviewed source.

Air Pollution Is Responsible For 3.3 Million Deaths Every Year

An article in the Huffington Post, written by Seth Borenstein, discusses a new study that suggests 3.3 million people a year are being killed by air pollution and that the death total could double by 2050. The journal article published in Nature Letters that Borenstein is referring to titled, "The contribution of outdoor air pollution sources to premature mortality on a global scale,"  was written on a study performed by J. Lelieveld at the Max Plank Insitute and in collaboration with The Cyprus Institute, Harvard School of Public Health and King Saud University.

In his article, Borenstein discusses some of the different important contributions to outdoor air pollution related deaths worldwide, highlighting agriculture, power plants and traffic emissions. Borenstein comments on how the agricultural death number (664,100 deaths worldwide) was surprising, both to him and Lelieveld. However Borenstein then continues on by explaining how ammonia form fertilizer and animal waste from farms can enter the atmosphere and react with nitrates and sulfates to produce smog.

Table 1 shows the current estimated death toll caused from outdoor air pollution and the projected 2050 estimates, showing the expected increases in the number of deaths (Lelieveld et al, 2015).

While Borenstein does a nice job of explaining the overall study, he does fail to mention that Lelieveld does admit that while biomass combustion and soil dust particles were not observed to influence mortality, there were few cities these particles were measured with any consistency. Also, using the atmospheric model ECHAM5/MESSy,  the estimated deaths caused by outdoor air pollution was indeed 3.3 million, but Borenstein failed to report the confidence interval associated with this. The estimated was reported in the journal article as 3.3 million, with a 95% confidence interval of 1.61-4.81 million. When discussing human death toll, this seems to be an important component to include.


Overall,  I found that Borenstein did manage to capture the main points of the journal article. He was able to keep the science behind the atmospheric chemistry in simplified terms. He even reported both positive and negative comments associated with the study, which is important when communicating science to the public.

Link to Huffington Post Article
Link to Air Pollution Study

Around the world most modern cites with economic grown the air quality is typically getting worse due to anthropogenic pollutants. Among the most notable are nitrogen oxides specifically NO2. The bulk of these pollutants are made by automobiles, industrial and power generation processes. There is one region where this is not the case-- The Middle East.  Many of the areas where there has been war, have seen a decrease in pollution. The Quartz article says that this decrease in pollution in certain areas is due to the displacement of refugees, and not due to changes in environmental policy.

Image taken from journal article

A) 2005-2010 B)2010-2014

The article being cited within the news article obtained data using satellites owned by NASA, as well as a Dutch satellite to determine Tropospheric Vertical Column Densities (TVCD) by detecting scattered solar UV and visible radiation. The colors displayed on the map represent an increase (red) or decrease (blue) of pollution over a given time period.  The values given in the journal article are not converted to Dobson units. Instead the scale used is in 10^15 molecules/cm^2. This is because the observed values were an order of magnitude less than a Dobson unit.

The article does not go in to large detail with the science. This is not a surprise, as I would assume most of the general public have no concept of what a Dobson unit. The article also only displays the figure that shows the change in TVCD, and not the initial  values or overall averages. The article only mentions the decreases seen due to war, and neglects how in Lebanon there has been an increase in pollution. Also neglected were the trends relating changes in GDP and pollution. Greece has had an economic slowdown. Iran had sanctions placed against them. Neither of which are mentioned in the news article. The news article also states that in decrease in pollution is not due to policy changes, which is mostly true. With Kuwait being the exception. Overall I think that the Quartz article did not due a great job of presenting all of the data found, and is only using data that is convenient to present.

News article

qz.com/487165/the-only-region-in-asia-where-air-pollution-is-declining-is-the-middle-east/

journal article

http://advances.sciencemag.org/content/1/7/e1500498.full-text.pdf+html

Ozone Is Making Flowers Smell Different to Bees

Volatile organic compounds (VOC) are chemical markers used by bacteria and plants for various reasons. Of particular note is the ability of these VOCs to attract bees to flowers to promote pollination. Like many organic molecules these have been proposed to be susceptible to degradation in the presence of ozone. The article Ozone Is Making Flowers Smell Different to Bees published on Smithsonian.com summarizes a recent article published in New Phytologist. 

More interesting to look at than an experimental apparatus

The article from Smithsonian.com retains most of the core information from the original paper even making a note to cite the initial study along side its summary. VOCs from black mustard plants were subjected to various amounts of ozone and the composition of the mixture was analyzed by mass spectroscopy. The initial study found up to a 30% decrease in certain VOCs upon exposure to ozone. This decrease was most pronounced at higher exposure to ozone going from 0, 80, and 120ppb ozone and as the distance increased from the source of VOCs 1.5, 3, and 4.5m. In particular the molecules anisaldehyde, p-cymene, phenol, and various monoterpenes were found to decrease upon exposure ozone. The exact decrease of each was related to the rate at which each reacts with ozone. Benzaldhyde was found to have increased by about 15%. The particular chemicals are generalized as "scent molecules" in the Smithsonian article. 

The Smithsonian article adequately summarized the behavioral studies that followed where in single bees were introduced to an environment with an artificial flower scented with ozone treated VOCs and non treated VOCs. As one might expect the bees preferred the non treated VOCs. The Smithsonian article summarizes this nicely while sparing us what constitutes a bee "touching" a flower.

The Smithsonian article ends by explaining the sources of ozone, citing several articles that imply growing industrial nations such as China and migration of greenhouse gases between continents is responsible for these changes. The article however makes which a big misunderstanding here. This paper does not suggest their experimental results are actually occurring to any significant amount on wild flowers. The paper's conclusions are based solely on experiments conducted in a laboratory without any studies down on natural systems. 

Overall the Smithsonian article does a great job at summarizing the original paper's techniques and results without going into extensive technical detail. It however extends the conclusions of this paper to systems beyond the scope of is reasonable for the the current research presented. 

Smithsonian Article

New Phytologist Paper

Unexpected Levels of CCl4 in Atmosphere

The ozone layer in the stratosphere serves to filter harmful UV radiation, enabling life on the surface of Earth to thrive.  The depletion of the ozone layer in the stratosphere caused great alarm in the scientific community when it was discovered in the 1980s, as increased UV exposure poses a risk to organisms.  The Montreal Protocol was enacted in 1987 as an international protocol intended to reduce the use of ozone depleting substances, namely chloroflourocarbons (CFCs).¹  The Montreal Protocol is largely considered a success as the production of most CFCs has ceased and the ozone layer is recovering.

An article published in the Huffington Post describes an unexpected caveat to the general success of the Montreal Protocol.²  The article states that 39 kilotons of CCl₄ (an ozone depleting chemical) are still being produced every year.  The quantity of CCl₄ is unexpected given reports that the chemical stopped being emitted in 2007.  Though the source of CCl₄ is unknown, the article concludes with the prediction that the ozone layer can make a complete recovery if the levels of ozone depleting chemicals continue to decline.

The Huffington Post article is discussing a study published in Geophysical Research Letters, which describes the slower than expected decline of CCl₄ levels in the atmosphere.³  The authors use NASA’s 3-D GEOS Chemistry Climate Model to predict changes in levels of CCl₄ in the atmosphere accounting for the changing rate of photolysis, soil and ocean sinks, and stratosphere-troposphere mixing.  The results of the models show an inter-hemispheric gradient of CCl₄ more consistent with a mean lifetime of 35-years (as opposed to the previously thought 25 year lifetime), and an approximate global CCl₄ emission of 39 kilotons/year.  

The most important issue, and what both articles highlight well, is the unexpected presence of CCl₄ in the atmosphere, and the threat this chemical poses to the ozone layer.  One major shortcoming of the Huffington Post article is the failure to mention explicitly that though there are unexpected levels of CCl₄, overall levels are still decreasing at a rate of ~1%/year (as opposed to the predicted 4%/year.)  Additionally, the article cites the lead author, Qing Liang, in her conclusion that it is “apparent there are either unidentified industrial leakages, large emissions from contaminated sites, or unknown CCl₄ sources."2  This statement is not included in the Geophysical Research Letters paper.  The Huffington Post article also fails to reference the suspected lifespan of CCl₄ of 35 years as opposed to 25 years.  This is mentioned in the video that accompanies the article, but I think it is a mistake to not include this in the writing.

Overall, I think the Huffington Post article and Geophysical Research Letters agree relatively well in that they both stress the unexpected levels of CCl₄.  However, because the Huffington Post article doesn’t write about the fact that the levels of CCl₄ are still decreasing, the longer estimated lifespan of CCl₄, and stresses the unknown and possible “industrial” source of the unexpected emissions, I believe the threat and potential malicious source of CCl₄ emissions are oversold.

Link to Huffington Post article

Link to GeophysicalResearch Letters article

1. Montreal Protocol on Substances that Deplete the Ozone Layer. (n.d.). Australian Government (Department of the Environment).  Retrieved September 19, 2015.

2. Boehrer, K. (2014, August 23). Ozone-Depleting Compound Found In Unexpected Concentrations Despite Ban. Huffington Post. Retrieved September 19, 2015.

3. Liang, Q., P. A. Newman, J. S. Daniel, S. Reimann, B. D. Hall, G. Dutton, and L. J. M. Kuijpers (2014). Constraining the carbon tetrachloride (CCl4) budget using its global trend and inter-hemispheric gradient. Geophysical Research Letters, 41, 5307–5315, doi:10.1002/2014GL060754.

Example Post from 2014 (Michael Manning's)

This is an example blog post from last year that current MPH student Michael Manning presented...

Microplastic beads can be found in common household products such as facial washes and exfoliants and have been the subject of many recent scientific studies. These fine particles can be washed down the drain, pass through waste water treatment facilites and accumulate in water supplies such as the Great Lakes. It is hypothesized that these particles can have a negative impact on wildlife. And so, over the past few years, organizations such as the Great Lakes and St. Lawrence Cities Initiative have worked to regulate the use of these particles.

A recent article published online in Vice News addresses the growing concern over the accumulation of plastic microbeads in the Great Lakes. This article explains current efforts to regulate these particles by state and local governments. The Vice article also explains how the pollution of these microbeads will harm the Great Lakes environment and its wildlife surroundings.

In order to explain the levels of plastics in the Great Lakes, the article cites a study by scientists at the State University of New York – Fredonia and the 5 Gyres Institute in California. This study documents the levels of microplastics in the surface water of the Great Lakes. Samples were taken by trawling Lake Superior, Lake Huron and Lake Erie. overall, 21 data points were taken.  

The Vice article does a good job of citing the study to explain that there are these substances in the lakes, and that they can come from household products. Unfortunately though, this is the only part of the article that is backed up by cited scientific research.

The article makes several claims about the impact of these microbeads, and although they might make sense, and may be factually accurate, the article does not cite any science to support these claims. One argument is that once these microbeads enter the waterways, they begin to absorb pollutants and carry them to the lakes. It is also asserted that, because these beads can be the size of fish eggs, they may enter the food chain and cause harm to wildlife through biomagnification. Neither of these claims are cited with peer reviewed scientific evidence and so I am hesitant to accept them as fact. 

All in all, the Vice article does a good job of explaining the issue of microbeads in the Great Lakes. They accurately explain the study that was done and make factual claims about the products that contain microplastics. Unfortunately, while seemingly attempting to increase the importance of this issue, the authors make claims that are not explained through peer reviewed scientific articles. Because of this, I would give this article a 6/10.

Link to Vice News Article

Link to Marine Pollution Study

Link to Marine Pollution Study (With MGet It)