Improving the Heat Island Effect Through Green Roofs

Rachel Nurnberger- Environmental Science

David Pacheco- Building & Construction Technology 

Zac Wannamaker- Natural Resource Conservation

Green roofs add a beautiful shade of natural green to a dull urban environment.

New York City’s struggle with the urban heat island effect is no secret. The issue has seen a growing amount of concern in recent years due to the increase in hospitalizations and deaths caused by extreme city temperatures (Calma, 2018). This increase in inhabitant health issues has lead NYC to seek resolution to the issue through heat island mitigation programs. Continue Reading

Green Roofs: Saving the Air and Saving Lives

Nicholas Lanni: Animal Science

Cole Payne: Building and Construction Technologies

Ben Lasky: Geology

Buzzing from the alarm clock’s warning ushers in the start of a new day. Avoiding the seductive snooze button, you roll out of bed and begin your morning preparations. Between the alertness of being awake and the daze of sleep, you slowly waddle to the dark bathroom to brush your teeth and wash off the last bit the previous night’s trance in the shower. Drying off, you begin to suit up for today’s task, whether its another day at school or a demanding shift on the job. Sizzling fragrant coffee provides the final jolt needed to get you on your way. Nearly walking out the door you almost forget something: your face mask. Leaving the safety of your climate-controlled home and venturing outdoors without it would be foolish. Indeed, taking deep breaths of unfiltered air is very unhealthy and dangerous. Continue Reading

Reducing Cows Environmental Impact

Bessie producing methane

Andreas Aluia- Forestry

Sean Davenport- Environmental Science

Haley Goulet- Animal Science

Picture this. Miles of rolling green fields sprawled out in front of you, dappled in hundreds and hundreds of black and white cows. Their heads low as they graze the young grasses covered in early morning dew. Behind you the farmer is preparing the barns for the cows return in the afternoon. Each breath of air making you feel renewed with the peace and clean air of the countryside. But how clean is it?

 

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Assessing and Combating the Enteric Methane Contributions of Ruminants

Authors: Melissa Bonaccorso (Natural Resource Conservation); Morgane Golan (Animal Science, Pre-Vet); Ben Phaneuf (Building Construction Technology)

In a new effort to better quantify the methane emitted by livestock, researchers are utilizing methane-collecting backpacks on cows.

Most of us have the best intentions when making decisions at the grocery store – we often try to choose what is best for our health, and many of us have environmentalism in mind, as well. It can be difficult to know what is best, and all the contradictory information out there can leave us frustrated and confused. It seems that every few months there is a new set of rules for how we are supposed to eat: vegan, vegetarian, antibiotic-free, gluten-free, cage-free, GMO-free; and when it comes to beef, grass-fed is now all the rage. Unfortunately, if environmental sustainability is your motive, grass-fed beef actually does more harm than good. Ruminants such as cattle, sheep, and goats, are animals that are able to subsist on plant matter because they have a stomach compartment, the rumen, in which microorganisms digest these cellulose products. However, this form of digestion, known as enteric fermentation, comes at a cost. The microbial ecosystem of the rumen generates methane as a byproduct of this fermentation, in a process called ruminal methanogenesis (Lassey 2006). Methane (CH4) is a greenhouse gas, and is of critical importance because it has a global warming effect that is 28-36 times that of carbon dioxide (EPA). Nearly half of all human-caused methane emissions come from agriculture, and livestock contributes nearly 70% of CH4 emissions from the agricultural sector (Vergé et al. 2008, p.132; Lassey, 2006; Wysocka-Czubaszek 2018). In the context of the US specifically, methane accounts for 10% of our total greenhouse gas emissions, and 26% of these methane emissions comes from enteric fermentation – the second-highest portion next to natural gas and petroleum systems (EPA). While its concentration in the atmosphere is much lower than that of CO2, methane is 20 times more effective at trapping heat than carbon dioxide is, and has the potential to contribute 18% of the total expected global warming up to the year 2050, next to carbon dioxide’s 50%  (Milich, 1999). Thus, while CO2 tends to get the most public attention for its contributions to climate change, methane is a much more potent greenhouse gas, which calls for more significant consideration.

An average of 30 million animals per year are slaughtered for the beef industry in the US, and an average of 2 million animals, with an additional 3.4 billion pounds of beef, are imported to the US from Canada annually (ERS, 2015). In addition, about 9 million milk cows are active in the US in 2016 alone (statista.com). In all, approximately 20 billion pounds of beef is consumed in the US each year, accounting for approximately half of the American dietary carbon footprint (Waite, 2018). The amount of CH4 emissions from ruminants in 2016 was equivalent to 170 million metric tons of CO2 (Center for Sustainable Systems, 2018). To put these numbers into context, the effect of greenhouse gas emissions produced by annual US beef consumption is equivalent to that which would result from a car driving around the entire Earth 22,000 times (space.com; ewg.org). In response to the severity of methane output via enteric fermentation, the scientific community has become increasingly concerned with identifying resolutions that are considerate of productivity within the agricultural sector, as well as environmental efficiency.

Significant enteric methane production, and the overall increasing trend in GHG emissions by the beef and dairy industries, are symptomatic of a high demands for livestock products (Place, 2016). Many environmentalists and animal-rights activists advocate for a drastic decrease in or even total elimination of beef and dairy consumption in the American diet. Reduction in meat and dairy consumption is certainly linked to a lower personal environmental impact: the greenhouse gas emissions associated with the average meat-eater’s diet are about 1.5 to 2 times those of vegetarians and vegans, respectively (Scarborough, et al. 2014). But most people are resistant to altering their diet in such a radical way, due to a plethora of social and physical barriers; global demand for meat products is actually increasing at a rate faster than land availability can accommodate (Kwan, 2011; Jenkins, 2004; Verge, 2008). In fact, demand for beef and dairy products in the US is expected to increase 70% within the next 36 years (Place, 2016). Although veganism and vegetarianism can help reduce total greenhouse gas emissions, we simply cannot rely on everyone to adopt these lifestyles if we are to make significant changes with haste. In addition, campaigns to reduce meat consumption pose a threat to cattle farmers’ incomes. Harsh restrictions on the beef and dairy industries, or campaigns to reduce the consumption of these products across the nation and world, are both insufficient and would also pose a threat to those whose livelihoods depend on these industries. For these reasons, research teams including veterinarians, environmental specialists and other invested individuals, are collaborating to identify strategies for reducing ruminal methane emissions, without harming invested parties. To minimize the impact of ruminal methane emissions without negatively affecting animal welfare and the livelihoods of stakeholders, we propose the integration of dietary supplements into ruminal feed to naturally inhibit methanogenesis.

One of the most promising methods of reducing ruminal methanogenesis without posing a threat to the industry or the animals is through supplementation of the animals’ diets. Since feed efficiency and methane production are intrinsically linked, ruminants reared on cellulose-based diet, such as those destined to become the beloved “grass-fed” beef, will produce more methane, and for a longer time than they might otherwise, since the cellulose-based diet is not conducive to optimal growth of the animals (Tirado-Estrada et al., 2018). Experts in the field have acknowledged that completely altering the diet of every ruminant on earth is not feasible: grain-based diets can be costly and are often inaccessible (Tirado-Estrada et. al., 2018). It is possible and cost-effective, however, to improve the digestibility of the livestock diet by replacing some of the fiber content with protein-rich concentrates, while still utilizing the typical pasture-based diet. Increasing the digestibility of the diet of dairy and beef cattle can reduce methane emissions in two ways: first, by helping these cows reach market weight sooner, thereby limiting the amount of methane that each cow can produce throughout its life, and second, by inhibiting the process of methanogenesis in the rumen. Any compound with a high protein/low fiber content would be a fine contender for the improvement of the ruminal diet, but those that are naturally sourced, readily available and less costly are most ideal for the animals, the environment, and stakeholders. An excellent option which meets this criteria has been identified: mangosteen peel powder (MSP). Mangosteen peel powder, or Garcinia mangostana, is very highly regarded among animal nutritionists, because it does not negatively affect the crucial microbial populations of the rumen, but can reduce the population of methanogens, the microorganisms most responsible for methane production, by up to 50% in a safe manner (Polyorach et. al., 2016). The utilization of MSP in feed has been found to significantly reduce methane production between 10-25% (Wanapat et al. 2015; Manasri et al 2012; Polyorach et al. 2016). Aside from reducing the population of methanogens, protein-rich plant concentrates present in mangosteen peels, called saponins and tannins, have also been found to minimize the growth and activity of methane-producing protozoa in the rumen, without inhibiting their function entirely (Wallace et al, 2002, Patra 2011). Supplementing the diet with naturally derived plant compounds such as this effectively reduces methane production, and does so without causing significant consequences to the animal’s microbial system or putting the animal at risk for ruminal disease (Patra, 2010).

Dietary additives are already widely used to supplement cattle feed, which makes further supplementation feasible once high-protein supplements, like MSP, are made readily available in the national market. For example, Rumensin is a feed additive that has been used in the cattle industry for over 4 decades (Greenfield et al., 2000). The active ingredient in Rumensin is a coccidiostat, meaning that it is an antibiotic specifically geared at killing coccidiosis bacteria in the animal body. Rumensin is an attractive product because of its prevention and control of disease, as well as its capacity to improve feed efficiency by 4% (“Data on Dairy Science”, 2012). Because of the traction and popularity associated with this feed supplement, which improves productivity while also combating a severe public health crisis, there is potential for MSP to be utilized in a similar manner, with the intent to mitigate the impending public health crisis of climate change.

In anticipation of concerns among farmers and other food animal industry leaders that dietary supplementation would be too costly, it is important to emphasize that methane reduction and productivity are not mutually exclusive; in fact, quite the opposite is true. Dietary manipulation, as a means by which to decrease methane emissions, may also have the attractive quality of improving feed efficiency and animal productivity (Lovett et al., 2003). Protein rich, plant-based supplements are capable of improving milk production and composition, daily weight gain, and feed conversion efficiency (Khan et al., 2015). In other words, with the use of dietary supplements, animals can be brought to their goal weight more quickly while producing higher-quality meat. The inclusion of such methane-inhibiting concentrates has been found to correspond directly with more rapid animal development and increased body weight while potentially reducing enteric methane by up to 40% (Benchaar et. al., 2001, Lovett et al., 2003). The investment in dietary supplements may therefore ultimately result in money saved that would otherwise be spent on longer rearing times to get animals to their goal weight. The inclusion of protein-rich plant concentrates also has the potential to not only decrease enteric methane production but also increase the fat content in milk when included in the diets of dairy cows (Tirado-Estrada et. al., 2018). Integration of protein-dense supplements into the diet may be the most feasible option for increasing productivity while decreasing enteric methane production by dairy and beef cattle. For this reason, dietary supplementation of this sort is considered the most appealing and cost-effective option to motivate farmers to adopt more sustainable practices (Patra, 2010).

In order to effectively address

 

 

 

 

 

 

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Green Weed, Green Planet

Tyler Clements (Environmental Science), Rudy Marek (Geology), Mitch Maslanka (Natural Resource Conservation), Olivia Santamaria (Horticulture)

In 1996, California voted to become the first state to legalize marijuana for medical use. Fast forward to today, and the legalization of marijuana is now a seemingly unstoppable movement that is sweeping across the United States. With recreational and medicinal use being rapidly legalized all over the country, 29 states have already legalized marijuana medicinally and 9 have recreationally (Robinson, Berk, & Gould, 2018, para. 2). From the start of California legalizing marijuana, this new industry with seemingly endless potential was given the green light to begin at the commercial level. As of 2017, the industry has grown from $6.73 billion to $9.7 billion in North America (Borchardt, 2017, para. 1; Robinson, 2018, para. 6; Zhang, 2017, para. 2). The entrepreneurs of the country began to think of ways to create and expand a marijuana based business and one of the most important aspects of this process was how the marijuana itself was going to be grown. Continue Reading

Green roofs: an analysis on air pollution removal and policy implementation

 

In October 1948, a thick cloud of air pollution formed above the industrial town of Donora, Pennsylvania. It lingered for five days, killed 20 people and induced sickness in 43% of the town (Environmental Protection Agency, 2007). Pollution poses a serious threat to our environment and health. Nearly one-quarter of the people in the U.S. live in areas with unhealthy short-term levels of particle pollution, and roughly one in ten people live where there are unhealthful levels year-round (American Lung Association, 2010). Air pollution is of particular concern to public health as it is the cause of hazards including upper respiratory irritation, chronic respiratory irritation, heart disease, lung cancer, and chronic bronchitis (Kampa & Castanas, 2008). The most common health-related impacts from air pollution are increased occurrences of respiratory illnesses such as asthma and a greater incidence of cardiovascular disease (Pope, Bates & Raizenne, 1995). Urban environments struggle heavily with air pollution due to the large amount of factories and vehicles that are major sources of air pollutants that accumulate so much that they become a hazard to human health. In Canada, the Ontario Medical Association found air pollution to result in 9,500 premature deaths per year (OMA, 2008) and estimates increased costs of healthcare up to $506.64 million and lost productivity of up to $374.18 as a result of air pollution (OMA, 2005). Conditions will only worsen as pollution grows with population, traffic, industrialization and energy use (Mayer, 1999). There are many pollutants in the air of an urban environment, though particulate matter (PM10), ozone (O₃), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂) are among the most serious to human health (World Health Organization, 2016).

Particulate matter that appears in urban environments is made up of sulfate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water that exist in the air from human activities such as combustion of fossil fuels, vehicles, and factory emissions. According to The World Health Organization (WHO), the limit for PM10 is 50 μg/m3 annual mean. This represents how much particulate matter is allowed in the air annually by law. Chronic exposure to particles contributes to the risk of developing cardiovascular, respiratory diseases, and lung cancer (WHO, 2017).  In countries of Europe that have concentrations of PM above guideline levels, it is estimated that average life expectancy is 8.6 months lower than it would be if PM exposure from human sources was regulated (WHO, 2017).

NO2 is most commonly formed from anthropogenic burning of fuel (heating, power generation, and engines in vehicles/ships). The limit for nitrogen dioxide is 40 μg/m3 annual mean. Epidemiological studies have shown that symptoms of bronchitis in asthmatic children increased in association with long-term exposure to NO2 and at short-term concentrations above 200 μg/m3, NO2 is a toxic gas which causes significant inflammation of the airways (WHO, 2017). Reduced lung function growth is also linked to NO2 at higher concentrations currently measured in Europe and the US. The US EPA (1998) also focuses on the danger of NO2 by stating that Nitrogen oxides (NOx) resulting from combustion of fossil fuels can form ground level ozone that causes respiratory problems, premature deaths, and reductions in crop yields. (EPA, 1998).

Ozone at ground level, not to be confused with the ozone layer in the upper atmosphere, is formed from vehicle and factory emissions and emissions from solvents and industry. The legal amount that is allowed in cities is 100 μg/m3 8-hour mean, which means that by law over 8 hours concentrations of ozone cannot exceed 100 μg per cubic meter of air. In some cases, chemicals like nitrogen oxides (NOx) react with sunlight and also contribute to forms of ozone. The limit for ozone is 100 μg/m3 8-hour mean and once this threshold is passed, O3 can cause breathing problems, trigger asthma, reduce lung function and cause lung diseases (WHO, 2017). The American Lung Association (2007) reported that annually, over 3,700 premature deaths in the United States (premature death is a death that occurs before a person reaches their expected age) can occur as a result of a 10 parts per billion (ppb) increase in O3 levels (ALA, 2007). Bell (2004) found that increased mortality rates in 95 urban areas within the US are linked to elevated levels in ozone, with one of these urban areas being Chicago, where ALA (2007) found over 2 million people at increased risk for health problems resulting from short-term exposure to O3 and particulate matters (ALA, 2007; Bell, 2004).

SO2 is a colourless gas with a sharp odour that is produced from the burning of sulfur-containing fossil fuels (coal/oil) for heating residences, generating power, and motor vehicles along with the smelting (extraction by melting) of mineral ores that contain sulfur. The limit for sulfur dioxide is 20 μg/m3 24-hour mean and this means that air in cities will contain on average 20 μg per cubic meter over the span of 24 hours. When the limit is exceeded, SO2 can affect the respiratory system, lung functioning, and cause irritated eyes. Evidence shows that the effects of sulfur dioxide are felt very quickly and most people would feel the worst symptoms of coughing, wheezing, shortness of breath, or a tight feeling around the chest in 10 or 15 minutes after breathing it in (S02, 2005). Inflammation of the respiratory tract causes coughing, mucus secretion, aggravation of asthma and chronic bronchitis and makes people more prone to infections of the respiratory tract (WHO, 2017).

One policy the U.S. government has in place to control pollution levels is the Clean Air Act (CAA) of 1970 (majorly revised in 1977 and 1990). The CAA’s purpose is to reduce air pollution and its harmful effects by setting limits on pollution. This Act requires states to meet specific air quality standards regarding six common pollutants: particulate matter, ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead (EPA, 2017b). The Act contains specific provisions to address hazardous or toxic air pollutants, acid rain, chemical emissions that deplete the ozone layer, and regional haze (EPA, 2017b). The six “criteria” air pollutants are regulated based primarily on human health and secondarily on environmental criteria.

The CAA improved the environment which in turn improved the economy and human health. In the 45 years following the installation of the CAA, national emissions of the six common pollutants dropped an average of 70% while gross domestic product grew by 246% (EPA, 2017c). Forty-one areas that previously had unhealthy carbon monoxide levels in 1991 now meet the health-based national air quality standard. In 1990 alone, pollution reductions under the Act prevented 205,000 early deaths, 10.4 million lost I.Q. points in children due to lead exposure, and a multitude of other health effects (Environmental Protection Agency, 2017d). Despite massive improvements in air quality since CAA took effect, millions of Americans still live in areas with pollution levels exceeding the limits (EPA, 2007). Those who struggle to meet CAA air quality standards may find green roofs a useful tool to bring pollutant levels down.

In response to rising air pollutants, people are considering transforming city rooftops into green roofs to mitigate the problem. A green roof is a layer of vegetation installed on top of a roof, either flat or slightly sloped (National Park Service, 2017). The high amount of rooftop space in urban cities creates an opportunity for green roofs to be implemented on a large scale. Roofs represent 21–26% of urban areas and 40–50% of their impermeable areas (Wong, 2005; Dunnett & Kingsbury, 2004). These spaces typically have much unused surface area that could be repurposed to combat the aforementioned effects of harmful air pollutants, a green roof’s main purpose. The plants that compose the roof are able to take up compounds through their natural processes respiration and photosynthesis, which remove the pollutants from the air and improve its quality.WHO has guidelines for the limits of the primary air pollutants that must not be exceeded in urban environments. Green roofs will help keep the levels of PM10 at 50 μg/m3 annual mean, nitrogen dioxide at 40 μg/m3 annual mean, ozone at 100 μg/m3 8-hour mean, and the concentrations of sulfur dioxide in the air of urban environments at 20 μg/m3 24-hour mean.

Literature surrounding green roofs agrees on their impact of particulate matter removal (Speak, Rothwell, Lindley & Smith, 2012; Currie & Bass, 2008; Rowe, 2011; City of Los Angeles, 2005; Yang, Yu & Gong, 2008; Jayasooriya, Ng, Muthukumaran & Perera, 2017). The range of particulate that is annually reduced by a green roof is 0.42–3.21 g/m2 over 500,000 square meters of rooftops (Speak et al, 2012). Rowe (2011) performed a study where 2000 m2 of uncut grass were planted on a green roof. It was estimated that the green roof could remove up to 4000 kg of particulate matter. In a simulation where green roofs were built over 198,000 square meters of roofs in Chicago, 234.5 kg of particulate matter would be removed by green roofs in one year (Yang et al., 2008).  Yang et. al (2008) also did a study where the concentrations of acidic gaseous pollutants and particulate matters on a 4000 m2 roof in Singapore are measured before and after the installation of a green roof. Research found that the levels of particulate matter was reduced by 6% in the air above the roof after installation of the green roof (Yang et al., 2008). Jayasooriya et al. (2017) state that green roofs annually remove 1.53 g/m2 PM10  (Jayasooriya et al., 2017).Currie and Bass (2008) state that green roofs have the potential to reduce annual amounts of PM10 by .89–9.21 g/m2 (grams per square meter) over 486,000-2,430,000 square meters of green roof coverage in Toronto (Currie & Bass, 2008). Jayasooriya et al. (2017) states that green roofs annually remove 1.53 g/m2 PM10 (Jayasooriya et al., 2017). Another study on green roof remediation in Los Angeles (LA) puts these numbers of removed particulate matter into context. The city of LA found one square meter of green roof able to remove approximately 0.1 kg of particulate matter per year and if a gasoline powered vehicle were to release .01 grams of pm per mile of travel and drive 10,000 miles per year, then the vehicle would emit 100 grams per year (.01 kg/year) and therefore, one square foot of green roof would reduce the pollution of this theoretical car for the whole year (City of Los Angeles, 2005). According to the literature, the annual range of particulate matter reduced by green roofs fall between .42 g/m2 and 9.21 g/m2 (Speak et al., 2012; Currie & Bass, 2008; Rowe, 2011; City of Los Angeles, 2005; Yang et al., 2008; Jayasooriya et al., 2017).

Currie and Bass (2008) state that green roofs have the potential to reduce annual amounts of NO2 by 0.6–2.55 g/m2. Yang et. al (2008) found that if green roofs were built over 198,000 square meters of roofs in Chicago, 452.25 kg of nitrogen dioxide would be removed by green roofs in one year. Rosenfeld, Akbari, Romm, and Pomerantz (2008) calculated that emissions from coal fired power plants to the air could be reduced by 350 tons of NOx per day in Los Angeles by implementing green roofs. This value of energy saved from the installation of green roofs relates to a 10% reduction in the causes of smog to the city of Los Angeles, with an active NOx trade program, and results in a savings of one million dollars per day (Akbari, Pomerantz & Taha, 2001; Rosenfeld et al.,1998;  Clark, Talbot, Bulkley & Adriaens, 2005) estimate that if 20% of all industrial and commercial roof surfaces in Detroit, MI, were traditional extensive sedum green roofs, over 800,000 kg per year of NO2 , 0.5% of that area’s emissions, can be removed. Yang et. al (2008) states that green roofs annually remove 2.33–3.57 g/m2, NO2 in an urban environment. Jayasooriya et al. (2017) states that green roofs annually remove .37 g/m2 NO2. In a study done in Singapore, 21% of nitrous acid, a byproduct of nitrogen dioxide, was reduced directly above a green roof (Rowe, 2011). One study implementing green roofs in Kansas City, MO, used by the EPA, estimated that by 2020, green roofs would reduce 1800 pounds (816 kg) of NOx (EPA, 2016). After reviewing the literature, it is found that a green roof can reduce a range of 0.37-3.57 g/m2 (Currie & Bass, 2008; Yang et. al., 2008; Jayasooriya et al., 2017; Rosenfeld et al., 2008) Clark, Adriaens, and Talbot (2008) reported that green roofs yield an annual benefit of $0.45–$1.70 per m2 ($0.04–$0.16 per square foot) in terms of nitrogen oxide uptake. Clark et al. (2005) estimates that NOx reduction from a 2000 ft2 green roof would provide an annual benefit of $895–$3392, resulting in the green roof being 24.5-40.2% cheaper than a conventional roof without vegetation.

Currie and Bass (2008) state that green roofs have the potential to reduce annual amounts of O3 by 1.2–3.58 g/m2. Yang et al. (2008) state green roofs have the potential to annually reduce 4.49–7.17 g/m2 O3 and in their simulation of Chicago, green roofs were built over 198,000 square meters of roofs, the results were measured over the course of just one year, with 871 kg of O3 removed by green roofs. Jayasooriya et al. (2017) state that green roofs annually remove 1.24 g/m2 O3 . Since ozone is formed by the reaction of sunlight with pollutants such as nitrogen oxides (NOx), green house reduction in nitrogen oxides also reduce concentrations of ozone in the urban environment. According to the literature, the annual range of ozone reduced by green roofs fall between 1.2 g/m2 and and 7.17 g/m2 (Currie & Bass, 2008; Yang et. al., 2008; Jayasooriya et al., 2017).

Yang et. al (2008) found that if green roofs were built over 198,000 square meters of roofs in Chicago, 117.25 kg of sulfur dioxide would be removed by green roofs in one year. Currie and Bass (2008) state that green roofs have the potential to reduce annual amounts of SO2 by 0.2–0.84 g/m2. Yang et al. (2008) state that green roofs annually remove 0.65–1.01 g/m2 SO2. Jayasooriya et al. (2017) state that green roofs annually remove 0.1 g/m2 SO2. In a study done in Singapore, 37% of sulfur dioxide was reduced directly above a green roof (Rowe, 2011). One study implementing green roofs in Kansas City, MO, used by the EPA, estimated that by 2020, green roofs would reduce 2600 pounds (1179.34 kg ) of SO2 (EPA, 2016). In one field study, the concentrations of acidic gaseous pollutants and particulate matters on a 4000 m2 roof in Singapore are measured before and after the installation of a green roof. Research found that the levels of SO2 were reduced by 37% in the air above the roof after installation of the green roof (Yang et al., 2008). After reviewing the literature, it is found that a green roof can reduce a range of 0.10-1.01 g/m2 (Currie & Bass, 2008; Yang et al., 2008; Jayasooriya et al., 2017; Rowe, 2011, EPA, 2016)

As an example of the costs of building a green roof in a U.S. city, the installation costs to install green roofs on every roof in Chicago were estimated to be $35.2 billion (Yang et al., 2008). This brings up a high cost of green roofs that deters many cities from considering installation. The EPA projected in 2009 that extensive green roof installation costs, which were ranging from $15-$20/sq. foot should drop to $8-$15/sq. foot as installations increased, and soil substrate and plants became more available (EPA, 2009). Not everyone considers green roofs for their own homes, however, with the amount of pollution removed and human health improvements and the inherent existent pollution in cities, green roofs are critical to pollution removal in urban environments and should therefore be installed. In fact, having a green roof reduces more pollution in an urban environment than simply not having one at all. Agra, Klein, Vasl, Kadas, and Blaustein (2017) compared green roofs to other roofs of buildings with no vegetation at all (control roofs) and found that the control roofs had a CO2 concentration 50 cm above the ground of almost 375 ppm while the three types of green roofs in the study ranged from maintaining concentrations of 365-370 ppm of CO2 50 centimeters above surface (Figure 1). With green roofs being confirmed to be more effective With costs of green roofs accounted for and their associated improvement of human health via reduction in air pollution, green roofs can become even more desirable with the inclusion of governmental incentives/policies for cost reduction.

Seeing cost as one of the main obstacles standing in the way of green roofs, we urge government action to alleviate this issue. The U.S. government must make green roof installation less expensive through an incentive system. Funding should be granted to all major U.S. cities for the installation of green roofs. Depending on design, plant type, and climate conditions the price of green roof construction typically ranges from $15-20 per square foot, though the EPA projects that extensive green roof installation costs should drop to $8-$15/sq. foot as installations increase, and soil substrate and plants became more available (EPA, 2009). The U.S. Government should offer $10 per square foot of green roof for commercial, residential, and private properties. In target areas where pollution is most concentrated, the government should offer $15 per square foot. This proposal makes the initial up-front cost of green roofs more feasible, if not directly profitable.

Green roofs become more attainable and widespread with the help of government incentives, as shown by successful policies in Washington D.C. Currently, Washington D.C. has over 3 million square feet of green roof (Department of Energy & Environment, 2017a). The district set a goal that by 2020, 20% of its buildings will have green roofs. In 2006, the D.C. Department of Energy and Environment (DOEE) launched the “RiverSmart Rooftops Green Roof Rebate Program” to give grants that encourage the installation of green roofs on private property. The grants offer $10 per square foot and up to $15 per square foot if the building is in target watersheds. With no cap on project size, all properties are eligible including residential buildings. To encourage small buildings to install green roofs as well, the program gives funds to offset costs of structural assessments to buildings of under 2,500 square feet (DOEE, 2017a). This incentive plays a large role in the growth in green roof installation per year in D.C. In 2005, building owners installed 0 square feet of green roof as compared to 104,068 sq feet of green roof installed in 2006, the first year of this initiative (DOEE, 2017b). In 2015, D.C. implemented a whopping 712,493 square feet of green roof. Though there is some variation, there is a general increase in total green roof area in Washington D.C. (DOEE, 2017c). An incentive program similar to this on the federal level would increase the total area of green roofs on a broader scale.

Installing green roofs in urban environments is cost-effective. They reduce the amount of pollution in air, improve the health of people living in urban cities, and can be less expensive to install with the implementation of governmental incentives & policies. If all rooftops in Chicago were covered with intensive green roofs, a projected 2046.89 metric tons of pollutants would be removed (Yang et al., 2008).

When discussing the green roofs ability to improve human health, the concentrations of pollutants most commonly discussed in the literature are O3, SO2, particulate matter, and NOx   (Agra, 2017; Clark et al., 2005, 2008; Rowe, 2011; City of Los Angeles, 2006; Rosenfeld, 1998; EPA, 1998) By installing green roofs, the four main pollutants would decrease in concentration enough to create improvements in human health and economic benefits in the reduction of human mortality.  Worker productivity and health is improved along the way, as employees that have a view of nature scenery were less stressed, had lower blood pressure, reported fewer illnesses, and experienced greater job satisfaction (Kaplan et al., 1988; Ulrich, 1984).

The cost-benefit analyses discussed how implementing green roofs would result in savings of a million dollars a day from decreased air conditioning, an overall annual benefit of $895–3392 for each 2000 ft2 green roof, and a reduction in the particulate emissions of one car for a whole year per square meter of green roof. Green roof financial incentives in Washington D.C. greatly increased the total area of green roofs in the area (DOEE, 2017b). An incentive program paired with indirect incentives would be successful if emulated on a federal level. The U.S. has proven that federal environmental policies can be effective as show by the Clean Air Act (EPA, 2015).

Even though green roofs cost 2-3 times as much as a bare roof to install, government incentives can alleviate these costs to bring installation prices down. With the upfront costs lowered, we can reap the benefits of financial, health, and environmental pay-off by green roofs.

AUTHORS

Matas Rudzinskas – Environmental Science

Aaron Lutz – Turf Grass Science

Tara McElhinney- Natural Resource Conservation

 

REFERENCES

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What the Frack? Fracking Threatens the Environment With Methane Leakage

(University of Michigan, 2013)

Wellsboro, a rural Pennsylvania town of roughly 3,200 residents, wasn’t doing very well economically (Hurdle 2010). Local farms were heavily in debt, motels frequently had occupancy under 40% outside of the tourism season, and many residents earned $12,000 less each year than the state average (Hurdle 2010). All of that started to change in 2008, when farmers started to receive checks of $375,000 or more, catapulting them back into financial solvency (Hurdle 2010). Then the railroad started to pick up, breaking out of more than 20 years of stagnation and doubling its yearly revenue (Hurdle 2010). Following the increase in rail traffic was a similar increase in traffic on the roads, so much so that residents were concerned the roads wouldn’t be able to take it (Hurdle 2010). Motels regularly filled up during the normally quiet winter and other businesses saw a similar increase in customers (Hurdle 2010). What could have caused an economically insignificant town like Wellsboro to experience such a reversal of fortunes? The answer was simple: fracking.

“Fracking”, a common nickname for hydraulic fracturing, is a relatively new form of unconventional gas production (EPA 2017). By injecting a solution of water and various additives into a wellbore at high pressure, surrounding rock formations are fractured, allowing trapped oil or natural gas to escape (EPA 2017, Allen et al., 2013, p. 17768). Once the initial injection is complete, the naturally pressurized gas flows back to the wellbore (EPA 2017). With the gas comes some of the injected fluid, which may now contain naturally occurring materials such as brines, metals, radionuclides, and hydrocarbons (EPA 2017). This returning liquid is known as “flowback”, and is a waste product that is collected for recycling or disposal (EPA 2017). The flowback is contained to prevent the aforementioned materials and some of the methane gas from escaping into the environment (Allen et al., 2013, p. 17769). After the flowback is dealt with, the natural gas escaping from the wellbore can be captured and later sold. Fracking has allowed the extraction of gas from previously inaccessible rock formations such as tight sandstone, shale, and some coal beds (EPA 2017). Wellbores can be vertically drilled hundreds or thousands of feet underground, and can include additional horizontal drillings that extend thousands of feet to help reach the gas dispersed throughout the rock formations (EPA 2017).

Fracking is only a problem insofar as it is an imperfect solution to a larger issue. That larger issue is how to generate energy without further increasing our contribution to climate change. This desire for cleaner fuel sources has made natural gas more attractive, and the increased demand has been met by wider use of fracking. The demand is so great that 91 to 273 additional wells have to be drilled every year just to maintain current production of natural gas (Stephenson et al., 2011, p. 10760). The economic and environmental benefits provided by fracking have been the driving force behind the increased popularity of fracking.

Fracking provides many two main economic benefits: creating jobs and economically producing natural gas. From 2007 to 2012, employment in the U.S. private sector grew by a measly 1%, while the oil and natural gas sector grew by a whopping 40% (U.S. EIA, 2013). This amounted to a total of 725,000 jobs nationwide, cutting unemployment by half a percent during the recession (Reuters, 2015). Most of these jobs were created near where the gas was extracted, at a rate of roughly 2.5 jobs per million dollars of gas extracted (Reuters, 2015). The majority of these jobs were within 100 miles of new natural gas production, with some directly involved in producing the gas, and some indirectly assisting (Reuters, 2015, U.S. EIA, 2013). Jobs for drilling wells increased only marginally, with most of the overall increase being in the areas of extraction and support (U.S. EIA, 2013). As shown by the data, fracking has a significant impact on employment, making it a promising source of energy.

The increased production of natural gas caused by fracking has had many positive economic effects. One of the most stunning effects is that the U.S. now produces 97% of its natural gas needs (U.S. EIA, 2017). This has resulted in net imports of natural gas declining by roughly 3 trillion cubic feet from 2005 to 2016 (U.S. EIA, 2017). In fact, the U.S. is expected to export as much as 7 trillion cubic feet of natural gas per year by 2025 (Sieminski, 2014). For now, the natural gas produced by the U.S. is used domestically, mostly for power generation and in the industrial sector (Sieminski, 2014). This is particularly visible in the Northeastern United States, where electricity generation from natural gas has increased by more than 10 million kWh in Pennsylvania, New York, and New Jersey (U.S. EIA, 2017). With domestic natural gas prices in 2017 being almost universally lower than they were in 2011 (U.S. EIA, 2017), it’s only logical that bulk users of fuel like power plants would switch to take advantage of the sudden windfall. While normally the decrease in operating costs for power plants caused by fracking would be solely of benefit to the economy, this also benefits the environment.

Prices of natural gas in the U.S. are heavily dependent on how much gas can be extracted from shale formations economically (U.S. EIA, 2012). In 2005, near the start of the fracking boom, natural gas prices began to decline rapidly (U.S. EIA, 2012). This trend continued into 2016, with prices plummeting to half of what they were in 2011 (U.S. EIA, 2012). There can be no doubt that fracking is responsible for the current glut of natural gas, with two locations exemplifying this; The Barnett shale in Texas and the Marcellus shale in the Northeast United States. The trends in these areas are mirrored across the U.S., with natural gas from shale and tight formations making up at least 50% of national natural gas production in 2010 (Sieminski, 2014). In Texas horizontal drilling in the Barnett shale has exploded from less than 400 wells in 2004 to over 10,000 by 2010 (U.S. EIA, 2011). These horizontal wells are responsible for roughly 90% of the natural gas production of the entire Barnett shale, despite only making up 70% of productive wells in the region (U.S. EIA, 2011). In the Northeast U.S. the Marcellus shale has provided so much cheap gas that power plants have increased their use of natural gas by 20%, making natural gas responsible for 41% of power generation in the region by 2016 (U.S. EIA, 2017). This has mostly come at the expense of coal, which in New York and Connecticut has seen a 90% decline from 2006 levels (U.S. EIA, 2017). In addition to the increased availability of natural gas, environmental policies such as tax credits and mandates to reduce CO2 emissions have made natural gas increasingly attractive compared to coal (U.S. EIA, 2017). Despite prices in 2012 being 30% lower than the previous year, the only coal that increased in production was high-sulfur coal that is compatible with CO2 reducing scrubbers (U.S. EIA, 2013). Similarly, in 2012 cheap natural gas was so abundant that carbon dioxide emissions from coal burned for power generation decreased to levels not seen since 1984 (U.S. EIA, 2013). While electricity sales declined by only 1% nationally from 2006 to 2016, total CO2 emissions from energy generation fell by roughly 10% (U.S. EIA, 2013, U.S. EIA, 2017). This is due to the fact that the main component of natural gas is methane (CH4) (Teasdale et al., 2014), and methane releases roughly 50% as much carbon as coal when burned (U.S. EIA, 2017). By replacing carbon intensive coal with cleaner natural gas in the energy sector, less total carbon has been emitted despite overall production remaining roughly the same (U.S. EIA, 2013, U.S. EIA, 2017). In 2015 when emissions from coal and natural gas in the energy sector were nearly equal, natural gas produced 80% more electricity than coal, clearly cementing natural gas as the less carbon intense fuel (U.S. EIA, 2017). By providing more energy at a similar or even lesser cost to coal, natural gas is paving the way for an energy-secure future with less carbon emissions.

While natural gas has been shown to cause less carbon dioxide emissions than the coal it is replacing, it brings with it a new problem, that of methane leakage.  Methane emissions are a concern because methane is a particularly potent greenhouse gas.  Greenhouse gases are gases that trap heat in the atmosphere, contributing to climate change. The overall impact each gas has on global climate change depends on the the amount of time it stays in the atmosphere, overall quantity of it in the atmosphere, and how strongly it absorbs energy (EPA, 2017). Using these factors, greenhouse gases are compared using a unit of measurement known as the Global Warming Potential (GWP) (Forster, 2007., p. 210). GWP is standardized to be comparative to carbon dioxide, so a gas with a GWP of 2 has twice the effects of an identical amount of carbon dioxide when released into the atmosphere (Forster, 2007., p. 210). The GWP of methane is 72 for a period of 20 years, and 21-25 for a period of 100 years (Forster, 2007., p. 212), so we can see it has a much larger impact on trapping heat than carbon dioxide. While methane only has a lifetime of 12 years, the indirect effects it can have on other compounds allow it to do damage long after its initial release (Forster, 2007., p. 212). With natural gas and petroleum systems making up the largest energy-related methane emissions source in the U.S., something needs to be done to control their emissions (EPA, 2017).  

For overall emissions coming from fracking, Allen et al. (2013) found that natural gas production emits about 2.3×1012 grams of methane, which comprises of 0.42% of gross gas production (Allen et al., 2013, p. 17772).  Of the total emissions, Omara et al. (2016) compared methane emission rates from conventional (vertical drilling for reservoirs that have high permeability) and unconventional (horizontal drilling for low-permeability sources, such as shale) natural gas extraction wells.  The authors found that unconventional wells (850 to 9.29×104 g/h) generally emitted higher amounts of CH4 than conventional wells (20 to 4480 kg/h) (Omara et al., 2016, 2102).  Considering natural gas’s comparatively massive GWP, total leakage from fracking systems must be less than 3.2% to have net environmental benefits over coal, a notoriously dirty fuel (Alvarez et al., 2012, p. 6437). Consensus in scientific literature shows that fracking in the United States has leakage rates between 3% and 17%, meaning we have likely already passed the point where natural gas provides benefits (Caulton et al., 2015, pg. 6240, Jiang et al., 2011, p. 7, Karion et al., 2013, p. 4396).  Coupling the rise in demand of fracking with the rapid decrease of well productivity after the first year (Stephenson et al., 2011, p. 10760), new wells are constantly needing to be drilled.  This means methane emissions from fracking will continue to increase, and we will continue to stray further from the environmental benefits fracking was originally thought to have if nothing is done about these emissions (Schneising et al., 2014).

Fracking can be broken into four phases: pre-production, drilling, fracturing, and well completion (Jiang et al., 2011).  Of all the stages, well completion has the greatest methane emissions.  During this process, methane can be emitted through flowback, the recovery of the liquids, if it is not sent to emission control devices (Allen et al., 2013, p. 17769).  Allen et al. (2013) measured a range of about 1.0×104 grams to 1.7×107 grams in methane emissions, with a mean of 1.7×106 grams.  Emissions this high should be addressed.

Further compounding the problem is the fact that inventory estimates of methane leaks are almost universally undervalued (Goetz et al., 2015, Caulton et al. 2015). This is partially due to the difficulty of locating the sources of these leaks (Teasdale et al., 2014). Having official estimates of leakage rates chronically lower than actual rates presents a false picture to the public, making continued fracking seem more viable than it may actually be. More than with almost any other energy source, accurately measuring leak rates and continuously working to reduce them is a critical part of making fracking an economically and environmentally viable energy source. Because of these higher emissions, many environmentalists believe fracking should be gotten rid of altogether.  However, as mentioned previously, when fracking is done right with technology controlling its methane emissions, it has the potential to be a more environmentally friendly source of energy than coal by emitting less carbon dioxide (U.S. EIA, 2013, U.S. EIA, 2017).  This, and the fact that it provides jobs (Reuters, 2015, U.S. EIA, 2013) and lowers the cost of natural gas (U.S. EIA, 2012) is enough reason as to why we should not disregard fracking.

There needs to be solution to fracking’s methane emissions, so that it can meet its potential as an energy source.  Allen et al. (2013) measured methane emissions significantly lower than the EPA’s measurements from the national emissions inventory because 67% of the wells that were in the study sent methane to control devices rather than releasing it to the atmosphere, which brought their emissions significantly down (p. 17770).  One of the most efficient methods to stop the problem of methane leakage from a fracking site is the vapor recovery unit, better known as VRU. VRUs work with the storage tanks, which store emissions from flowback, on a franking site. Storage tanks on fracking sites without VRUs vent approximately 21 billion cubic feet of gas per year (Harvey, 2012). The storage tanks are used to store the natural gas that has been collected throughout the fracking process. VRUs work to remove methane vapors that build up in the tank. Without VRUs methane can be get lost in the atmosphere when the gas is added to the tank, and when the gas is being removed from the tank (Harvey, 2012). The VRU system works by analyzing the pressure in the tank and when it reaches a set point the gas goes through a gas vent line and into the VRU machine .Within the VRU machine the gas is filtered through a scrubber where the liquid trapped is returned to the liquid pipeline system or to the tanks, and the methane recovered is pumped into gas lines (Changnet, 2008).

VRUs may be the answer to the methane leakage problem, as they can capture up to 95% of methane that would have leaked into the atmosphere from the storage tanks of a fracking site that does not use one (Harvey, 2012). The gas company Encana has a site in Wyoming that installed a VRU in order to reduce methane emissions. The VRU machine has shown to reduce 80% emissions in the past four years (Sider, 2014).

Using this machine will not only reduce most of the methane released, it could also save gas companies thousands of dollars in the long run. The methane gas that is filtered into the VRU can potentially be harvested and used for profit.  Anadarko Petroleum Corporation reported that at peak capacity their VRU were able to capture 25 million cubic feet of gas per day. At this rate the company was able to make $18,262 off the VRU alone in one year (Harvey, 2012). Gas companies that are using VRU systems have reported that they have been extremely beneficial when it comes to the payback. The gas producing company ConocoPhilips had installed a VRU system onto 9 tank batteries on one of their sites. This in total cost the company $712,500, however it did not take long for that money to be worth the investment. In just four months the VRU were able to bring the company enough profit to refund this payment. After that every month the VRU brought the company $189,000 (Harvey, 2012).

In 1970, Congress passed the Clean Air Act of 1970, which mandates reductions in various harmful volatile organic compounds (VOC). The act covers many aspects of VOC emissions, but fracking sites continue to emit methane which is harmful to the environment. This brings us to our proposal. If the EPA implemented stricter regulations on methane emissions in the Clean Air Act, companies would be forced to adopt various technologies, VRUs being one of them, in order to meet EPA regulations. In turn, the nation could stay away from relying on coal while minimizing harm to the environment from fracking. Methane emissions from fracking are indeed an issue, and something needs to be done to reduce them.

Certain drilling sites in Montana, Colorado, and Utah have already adopted this technology (EPA, 2014). This is the result of competition between fracking companies who aim to make their sites less harmful to air quality (Biello, 2010). In fact, mandatory Stage I and Stage II vapor recovery systems are a direct result of the Clean Air Act. These systems can be found at gasoline dispensing facilities (GDF), known to all of us simply as the gas stations that dot various roadways. Whenever gasoline is transported or pumped from one container to another, VOCs naturally escape into the atmosphere. Since GDFs can be found in many locations, harmful amounts of VOCs can be emitted into the atmosphere due to the frequency of oil tankers delivering fuel to GDFs and consumers refueling their automobiles. Stage I vapor recovery systems refer to when oil tankers deliver gasoline to various GDFs, and Stage II refers to when consumers refuel their automobiles. When consumers refuel their automobiles at GDFs, VOCs that would normally escape into the atmosphere are returned to the underground gas reservoirs at these GDFs. When oil tankers refill these reservoirs, the trapped VOCs are returned to the oil tankers (PEI, 2017). These regulations have invariably had an incredible impact on VOC emissions in the following years. The EPA shows that since 1970, VOC emissions have dropped from approximately 12 grams per vehicle mile travelled, to 2 (EPA, 2017). This shows that on a federal level, technology can be successfully and widely adopted in order to improve air quality at the expense of energy companies. If it can be done for petroleum, why can’t it be done for natural gas?

In order to reduce humanity’s impact on climate change, we should take the necessary steps to reduce GHG emissions.  While hydraulic fracturing is not the largest source of methane emissions, any chance to reduce emissions should be taken advantage of. There are a wide variety of ways one could reduce emissions from fracking, but not all of them are realistic. Flaring is already a common practice in the industry, but why burn off a useful gas when you can harness its potential? When a solution such as VRUs is readily available, why not utilize it?  They have a high efficiency of reducing emissions, and provide an opportunity for companies to profit from the captured methane.  We see VRUs already being implemented at certain sites across the country, and government-mandated implementation of vapor recovery technology is already present in gas stations, so it seems reasonable to do the same for fracking sites. And with the ever growing need for energy in our industry-driven world, and a steadily decreasing amount of natural gas, shouldn’t we harness all that we can, and protect our world while we’re at it?

AUTHORS

Hillary Wilcox – Animal Science Major

Mikhaela Flynn- Environmental Science Major

Sean Mulvaney – Natural Resource Conservation Major

Winsten Chen- Natural Resource Conservation Major

 

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Green the Heat

 

Image result for green roofs

Green roof in city (Klinkenborg, 2009).

 

Tall buildings consisting of dark roofs and roads with black asphalt remove much of the vegetation that used to thrive there. It is now evident that these changes in the landscape caused severe environmental challenges. Urban areas became vulnerable to the impacts of climate change and the rapid expansion of the population only worsened the cause because of the demand for new accommodation made it normal to ignore existing problems. According to the U.S Census Bureau, 62.7 percent of the U.S. population now live in urban areas (“U.S. Cities are Home to 62.7% of the U.S. Population but Comprise 3.5% of Land Area”, 2015). Many of the environmental challenges in urban areas can be seen in forms of temperatures rising, worsening the urban heat island effect, and pollution from the release of CO2 into the atmosphere. All causing major health threats to citizens living in these areas and more sadly affecting children and the elderly who in many cases were diagnosed with heat related illnesses. Continue Reading

The Importance of Being Green: Green Roofs Help Urban Inhabitants Breathe Easier

 

Green roofs have become a popular amenity in cities as city dwellers seek environmentally friendly places to work, live and breathe.

 

Rachel Eckenreiter, Animal Science

Justin Esiason, Environmental Science

Patrick Meehan, Building Construction Technology

 

     As the sun rises in Beijing, the workforce can be seen flowing into the arteries of the city to start the day. The streets steadily fill with people, some whizzing by on bicycles, others on foot as the sun fights through toxic haze and dust. A father and daughter navigate through the dense crowd, completely unfamiliar with the language spoken around them and written on street signs, the young girl quickly glances around her, confused and overwhelmed. Faces of many sizes, ages and shapes glide by, most clad in white medical masks. Her eye catches something they’ve seen before: the welcoming sign of their hotel.  The bright and quiet lobby is cool and clean as they head toward the elevator. Once in the room, she wastes no time and heads straight for the bathroom sink, with the sensation that her face is covered in grime as if she had worked in a dry dirt field all day. After washing her face, she glances down to find that the pristine white hand towel had turned mostly dark grey and brown. Although their stay in China was only three weeks long, it was enough time to recognize that the city of Beijing had a major air pollution problem. (Rachel Eckenreiter, Personal Communication, April 6, 2017). Continue Reading