Long-term PM2.5 Exposure and Neurological Hospital Admissions in the Northeastern United States

by Thy Annie Nguyen

Many prior studies have suggested that particulate matter (PM) exposure may induce an inflammatory response that leads to neurodegenerative diseases and cognitive decline. PM has been known to carry heavy metals, induce free radicals, and contain carcinogens. Especially with PM2.5 (particulate matter ≤ 2.5 μm) being small enough to potentially cross the blood brain barrier, it is worth studying how these aerial pollutants may affect neurological health. In a study from 1999 to 2010 in the northeastern United States, Kioumourtzoglou et al. (2016) found a correlation between long-term exposure in dense, urban cities that produced large quantities of PM2.5 and accelerated disease progression in Alzheimer’s Disease (AD), Parkinson’s Disease (PD), and dementia. Approximately 9.8 million residents in 50 cities were surveyed while air pollution data was collected from the EPA’s Air Quality System Database. Although the design of the study prohibited an analysis of the role of PM2.5 in disease onset, researchers were able to measure the effects PM2.5 concentrations had on the current population of neurological patients who had already exhibited the onset of disease. Continue reading

China Enters the Climate Change World

by Jason Yi

In early 2017, journalist Edward Wong wrote an article that analyzed China’s stance on climate change. Earlier, Donald J. Trump made the statement that climate change is a “hoax” produced by China and expressed his desire to leave the global Paris Agreement which takes the initiative in reducing greenhouse gas emissions. Wong mentions that in previous years under president Obama’s term, America pressured China to supply accurate annual coal consumption data. However, with Trump’s desire to withdraw from the Paris Agreement, Wong believes that China will quickly lose its current aspiration to provide such accurate information. In the past, China has only submitted two coal consumption estimates for the years 1994 and 2005 while other nations have submitted three or more. Furthermore, on the previous census, China’s coal powered energy use was 12–14% higher than the last estimate and in these censuses, it was evident that there existed consistent differences between provincial and national levels. Continue reading

Pathophysiological Effects of Particulate Matter Air Pollution on the Central Nervous System

by Thy Annie Nguyen

Human activities have severely impacted air quality. Whereas cardiovascular disease and respiratory conditions have been the main concern in assessing the adverse effects of air pollution, neurological impacts are recently being studied and are equally important. Wright and Ding (2016) review the many adverse effects of particulate matter (PM) exposure and the implications of increased air pollution in highly urbanized communities. From short-term insults to long-term diseases, it was found that PM from air pollution was a direct cause of a myriad neurological diseases as well as increasing mortality and cardiovascular morbidity. PM air pollution consists of “metals, dust, various organic compounds, and microorganisms suspended within aerosolized droplets.” When inhaled, ultrafine PM is small enough to cross blood and mucous barriers, travelling to the brain and other parts of the central nervous system. As ultrafine PM enters these sites, they may directly cause insults on neurological systems through inflammation, inhibiting blood flow, decreased brain volume, increases oxidative stress, and much more. For example, long-term exposure to ultrafine PM has been shown to lead to vascular conditions such as hypertension and atherosclerosis. In addition, blockages in blood vessel in the brain have been strongly associated with increased likelihoods of stroke. Continue reading

Identifying Suitable Trees For Urban Heat Management In Face Of Global Warming

by Deniz Korman

Global ambient temperatures keep rising year by year, and urban areas specifically experience higher temperatures compared to rural areas due to lower vegetation coverage and increased emissions. An effective strategy to counteract this problem is to expand green spaces and improve urban forestry. However, it is important to ensure that the greenery that we integrate into our cities can withstand changing climate conditions as ambient temperatures keep increasing at a rate faster than ever. Lanza and Stone (2016) focus on how global warming has affected the climate conditions around 20 highly populated metropolitan areas in USA, and the impact that this has had on present tree species. Continue reading

The Responsibility to Regulate the Emissions of Our Airlines

by JP Kiefer

The governing body responsible for regulating greenhouse gas emissions in aircraft, the International Civil Aviation Organization, has not passed any significant greenhouse gas regulation over the past fourteen years despite the industry’s contributions to climate change. Liu (2011), recognizes that there may be some technical reasons the ICAO has chosen not to do so, but ultimately states that the ICAO would be the proper organization to implement regulation if not for political issues within its leadership. Continue reading

Changes in Measuring Air Quality in California

by Emily Segal

Particulate Matter (PM) is an air pollutant that when large enough can be seen as soot or smoke, and when small enough, can only be observed using an electron microscope. Particles less than 2.5 micrometers in diameter (PM2.5) are especially dangerous because they can be inhaled into the respiratory system and can lodge in the lungs. Scientists have been studying the quantity of particulate matter in the air for a while, but between 1988 and 2013, the system for monitoring this air pollutant underwent many changes. Essentially, the old way of measuring PM2.5, through traditional filter sampling, was replaced by the more effective method of using Beta Attenuation Monitors (BAM). It is important to have a monitoring network that operates frequently and in many areas because this data can then be compared to data from various hospitals in order to draw conclusions about the connections between PM2.5 concentrations and health consequences. Additionally, the real-time nature of BAM can help make short-term forecasts for air qualities in different regions. This was not possible previously because traditional filter sampling had many delays caused by transporting, conditioning, and weighting filters before any conclusions about the actual PM2.5 measurement could be made. Continue reading

Just How Much Methane is Released in California?

by Emil Morhardt

On the occasional foggy day in Claremont, one can be nearly bowled over by the smell of dairy farms—not a smell that mixes well with the usual orange blossom/eucalyptus fragrance permeating the campus of the Claremont Colleges. The smell is wafting over from the eastern South Coast Air Basin (SoCAB), which, along with California’s Central Valley is the focus of a new top-down estimate of methane emissions by Yuyan Cui  and colleagues at NOAA and the University of Colorado in Boulder, Harvard University, and the University of Michigan. Top-down estimates are based on measurements of methane made from above—in this case by aircraft—rather than based on ground-based considerations, such as counting the number of dairy cows and multiplying by how much methane each is thought to produce. One object of the study was to provide data for use by the State of California in attempting to assure that statewide greenhouse gas emissions not exceed 1990 levels by 2020. The study used some fancy inverse modeling to trace the concentrations measured aloft to their sources, and to calculate that total emission levels. The results corroborated those of several other recent studies, showing that twice as much methane is being emitted than was estimated by the USEPA in 2005, something on the order of 426 Gg (Gigagrams, millions of kilograms) per year. In the eastern SoCAB it, sure enough, is coming from the dairy cattle. In the western SoCAB, where there aren’t any, it comes from landfills, wells, and other un-described point sources. Continue reading

Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security

Atmospheric pollutants such as carbon dioxide, black carbon, and methane contribute to degrading air quality, global warming, and negative health impacts.  Although there currently exist over 400 emission control measures, no research has been done comparing these measures with each other and their effect over long periods of time.  Shindell et al (2012) examined a number of these control measures using projection models to see the effects of these measures based on a projection of the future, and compared results between the control measures.  Using various models the authors calculated projections for future temperatures based on each emission control measure and the impacts of measures on climate, agriculture, health and economic valuation.  The results of the models showed that the measures could reduce global mean temperature increase over the next few decades and could reduce crop yield losses, premature deaths, and ice cap melting.  Although the tested models do not deal with carbon dioxide emissions (a larger long term contributor to global warming than methane or black carbon as it persists longer in the environment), the authors of this paper hope that the widespread benefits of their studied measures will help convince policymakers to adopt these measures.-Anthony Li
Shindell D., Kuylenstierna J. C. I., Vignati E., van Dingenen R., Amann M., Klimont Z., Anenberg S. C., Muller N., Janssens-Maenhout G., Raes F., Schwartz J., Faluvegi G., Pozzoli L., Kupiainen K., Hoglund-Isaksson L., Emberson L., Streets D., Ramanathan V., Hicks K., Oanh N. T. K., Milly G., Williams M., Demkine V., Fowler D. 2012. Simultaneously mitigating near-term climate change and improving human health and food security.  Science 335, 183

The researchers used the International Institute for Applied Systems Analysis Greenhouse Gas and Air Pollution Interactions and Synergies (IIASA GAINS) model and selected 14 pollution control measures out of its 400 that focused on mitigating climate change, enhancing air quality, reducing methane, and technical and regulatory measures referred to as black carbon measures.  Technical measures included removing diesel vehicles, biomass stoves, brick kilns, and coke ovens, while regulatory measures included bans on particular pollution sources and providing modern heating and cooking technologies. The IIASA GAINS model estimates worldwide emissions reductions of particulate and gaseous species based on real-world data and subsequent measures that have already been applied.  The selected pollution control measures were then applied to a projection of future atmospheric composition based on energy and fuel projections, regional and global livestock projections, and all presently agreed upon emission-related policies, which was all provided by the International Energy Agency.  The projection was set at multiple scenarios, using combinations of measures or individual measures and seeing their subsequent effects.  Emissions from these scenarios were also used with the ECHAM5-HAMMOZ and GISS-PUCCINI composition models to calculate the impacts on atmospheric concentrations and radiative forcing, both of which could add to uncertainty in the temperature predictions.  Once the projections were completed, the authors then analyzed the separate packages of measures based on physical impacts (including avoided warming, avoided crop yield losses, and avoided premature deaths) and valuation per metric ton as calculated by the value of a statistical life.
The authors found that of the projected measures, the scenario where all methane, black carbon, and carbon dioxide control measures are used had the lowest increase in temperature.  The methane with all the black carbon measures scenario and the carbon dioxide measure scenario both came in with the second lowest increase, followed by the methane and black carbon technical measures scenario and the methane measures only scenario.  The ECHAM and GISS models calculated a negative forcing for all the measures.  Analyzing the individual packages of the measure’s effects show that methane control measures resulted in the most avoided warming, most avoided annual crop yield loss, and highest value in climate and crops of US dollars per metric ton of methane.  The black carbon technical measures had the highest amount of annual avoided premature deaths and highest value in health at US dollars per metric ton of methane.
The researchers found that the measures were capable of substantially reducing the global mean temperature.  Specifically, they targeted the black carbon measures and said the results showed how these measures can be used to reduce drought risk in Southern Europe and the Sahel while reversing shifting monsoon patterns in South Asia.  In terms of agriculture, the methane and black carbon technical measures showed great reduction in crop yield loss, while the black carbon regulatory measures had minimal impact.  Health impacts were vastly improved upon with both of the black carbon measures, as black carbon contains particles smaller than 2.5 micrometers which are much more damaging to health than ground level methane is. 

Only a small fraction of air quality measures currently implemented provide substantial mitigation against global warming.  However, the methane and black carbon emissions reduction measures studied in this paper show that these measures could have global and regional impacts on climate, as well as human health and agriculture.  The authors of this paper hope that the measures benefitting not only climate change but also health and agriculture will help motivate policies to put them into practice.