Plot 1: Air Pollution Emissions in the United States

https://jmwiggins.shinyapps.io/Pollution/

Air pollution has drastic impacts on people’s life quality and life expectancies. It is associated with heart attacks, asthma attacks, premature mortality, and numerous other long-term health consequences. Some pollutants have more serious impact on human health than others. Particulate matter 2.5, or PM2.5, is one of the most harmful pollutants. These are tiny particles that can go deep into the lungs and bloodstream. It enters the atmosphere by being either directly emitted from sources, such as factories, or formed in the atmosphere by chemical reactions. The main gases that are part of this secondary process are sulfur dioxide and nitrogen oxides. While the presence of these pollutants lead to dangerous living conditions locally, they also have implications for environmental conditions globally.

Air pollution peaked in 1970 and has been generally decreasing since then. This is in part due to the Clean Air Act, which passed in 1970. This created new emission standards, with greener impacts such as forcing factories to emit less pollution. While this has been a great shift in our country’s environmental quality, there are lasting affects to the rise in pollution. Pollution in the atmosphere contributes to the greenhouse gas effect. This means that pollution in the atmosphere works to trap heat near Earth’s surface. Even if all pollution emissions stopped right now, they would not go away quickly. Some gases, like carbon dioxide, have atmospheric residence times of hundreds of years.

Additionally, not all countries are decreasing their emissions. The environmental actions of a country can affect the entire world.

Plot 2: Air pollution emissions globally

As shown in the plot, there is not a lot of movement at first. Then, in the 1900s, the amount of emissions shoots up across the continents. Most continents decreased their emissions. Asia’s emissions continue to rise. This is in part due to the large populations held in that region, which means more energy consumption and production.

Due to the increase and presence of global emissions, the Earth is experiencing widespread warming because to the greenhouse gas effect. Everybody on Earth is impacted by these changes in our climate, whether directly or indirectly. However, some groups of people have a disproportionate share of the burden of consequences. This leads to vulnerable groups experiencing higher rates of illness. These warming patterns create unsafe conditions for people, making them vulnerable to heat-related illnesses—which can be deadly.

Ozone is formed in the troposphere by the chemical reaction of nitrogen oxide, volatile organic compounds (VOCs), and solar radiation. Due to the increase in both nitrogen oxide and VOCs in the environment, ozone is increasingly common close to the surface. Smog develops from the formation of ozone at ground level. The ingredients needed in this process make it a feedback loop. Heat is needed, in the form of solar radiation, leading to high levels of ozone being more likely to form in warmer temperatures. Global warming, in part due to increased ground-level ozone, makes it easier for ozone to form. Thus, keeping the cycle.

Plot 3: Ozone

Ozone is harmful to life on Earth when it is close to the surface. In the stratosphere, about 12 miles above the surface, it is helpful in protecting the surface from the sun’s radiation. However, at ground level it is extremely detrimental, both to the Earth’s ability to regulate its temperature and to the health of people and other life. The surplus of ozone created from greenhouse gases has led to a decrease in air quality in many regions of the world.

People of color are disproportionately impacted by the presence of ozone. Many census tracts with the highest proportions of people of color have higher amounts of ozone. The area of high point density on the right side of the graph is very concerning.

Ozone can lead to immediate breathing problems for people living in an area with high amounts of ozone. This can manifest as shortness of breath or respiratory infections. Along with short-term impacts, there are many long-term risks. This includes increased metabolic disorders, nervous system issues, reproductive issues, and even cardiovascular mortality.

The uneven distribution of ozone across census tracts in Brooklyn coupled with its severe health risks indicate an urgency for equitable environmental solutions, particularly as the climate continues to change.

Plot 4: Brooklyn, NY’s temperature over time

The average daily temperature in Brooklyn has increased over time between the two time periods of 1954-1986 and 1987-2022. While it seems to be a small difference, a temperature change of even one degree Fahrenheit has drastic impacts on Earth’s climate.

Even locally, heat waves would be more extreme, rainstorms would be more intense, and sea levels would rise. This puts vulnerable people in particular in a lot of danger.

People living in cities are greatly impacted by increases in temperature due to the urban heat island effect. Places with a lot of structures and infrastructure absorb and re-emit the sun’s heat much more than natural landscapes. Urban areas that lack greenery and have an abundance of these structures can be 7 degrees Fahrenheit warmer than outlying areas. In some instances, it can get even hotter.

In urban heat islands, there is an influx in air conditioning usage, which can exacerbate negative air quality conditions with the increase in energy demand. This is just one example of another feedback loop that leads to poor environmental quality.

Different groups of people have varying levels of vulnerability to heat-related illnesses. Populations with low-income are at a greater risk. They are more likely to lack air conditioning and live in poor housing conditions. It can also be more difficult for them to find cooler shelters during extreme heat. Other sensitive populations include older adults, young children, people who work outdoors, and people in poor health.

A strategy to combat the heat island effect and protect vulnerable populations is increasing tree density. Trees and vegetation shade surfaces and deflect solar radiation from the sun. This can have a dramatic effect on the surface temperature of an area.

Plot 5: Trees and temperature in D.C.

https://jmwiggins.shinyapps.io/Trees_DC/

This shiny app depicts tree cover and the temperature difference from the urban area mean temperature, by census blocks in D.C. The temperature differences variable represents how much each block group fell above and below the urban area temperature mean. Positive values (red) indicate block groups that are hotter than average. Negative values (white) indicate block groups that are cooler than average. The tree canopy variable represents the percentage of each block group’s area that is tree canopy.

The relationship between tree cover and temperature is stark. The areas with few trees have high comparative temperatures. The block groups that have a higher amount of tree canopy tend to be cooler in temperature than the urban area mean. This is a perfect example of the urban heat island effect and it emphasizes how important trees are to a city’s ability to regulate its temperature.

Think about how different it feels to walk down a street with no trees, compared to walking down a road with a lot of shade from trees. Now, imagine living in an area that has few trees for consecutive blocks. This is particularly dangerous in cities that have a lot of pedestrians because there are so many people experiencing the extreme urban heat. New York City is an example of a city with many walkers. The city is oriented toward walking and public transportation. This is great for the environment! However, good environmental conditions for pedestrians are critical to ensure safety.

Plot 6: Breakdown of commuting

The proportion of people walking to work in Brooklyn is much larger than in the entire United States. In fact, it is about four times as large. The other major difference in this breakdown is that the majority of people take public transportation to work in Brooklyn, while that is the fourth common method across the United States. The vast majority of people drive to work. This comparison provides a standard to compare Brooklyn to.

While many people take public transportation to work in Brooklyn, a lot of those routes require people to walk somewhere first. For example, having to walk to a bus stop or subway station. This leads to a higher proportion of people having to be outside in the sun significantly more than the rest of the United States. A lot of people drive to work in the United States, whether that is alone or carpooling. This can serve as an individual shelter from heat, compared to traveling on foot to work.
This is especially dangerous in cities with a lack of trees, due to the urban heat island effect.

Plot 7: Map of trees in Brooklyn, NY

Tree distribution is New York city is not even. Some areas have an abundance of trees while others suffer from low tree density. The eastern part of Brooklyn has lower density while the center has higher tree density. Brooklyn is a very urbanized borough and is extremely susceptible to the heat island effect. Based on the relationship between trees and surface temperature that was explored in the map of DC, it is reasonable to expect that the eastern part of Brooklyn with low tree density will be warmer than areas in the center with higher tree density.

As a result, people in the areas in the east may be more vulnerable to heat-related illnesses.
Different areas of Brooklyn have vastly different demographic characteristics—it is a very diverse place. It is important to examine if particular groups of people tend to have decreased environmental quality compared to others. If these populations are identified, programs can be implemented to improve their situation, such as planting more trees to help mitigate heat stress on health.

Plot 8: Distribution of trees by race

The average count of trees per person is highest in census tracts that have a majority of white people. This data is normalized by the population, so it is not a matter of census tracts having a higher population of people with more trees. Census tracts with a population of majority Asian people have the lowest number of trees per person, on average.

This indicates that white people have a disproportionately bigger share of the trees in Brooklyn, NY, while census tracts with a majority population of people of color lack trees. These bars should be similar across races.

Of course, a census tract that has a majority race of white does not mean that every person in the census tract is white. However, there is a significant difference between them in this visualization which indicates that there is likely a relationship.

These results have some concerning implications. Majority white census tracts typically have more tree cover, and thus, made shade and cooler temperatures in warm seasons. People of color do not have as many trees available in their neighborhoods to keep themselves cool. This increases vulnerability to heat-related illnesses, putting the people in these areas in danger.

Given that higher temperatures can lead to a multitude of health consequences, census tracts that have a majority of people of color are most at risk of serious illnesses.

While the disparities of environmental quality for racial groups is a large part of the investigations of environmental justice, there are additional demographic characteristics that are important to examine.

Plot 9: Distribution of trees by housing unit ownership

New York City is a big renting city. There are much more housing units being rented than that are owned. This sets the number of trees per housing unit into context and suggests the proportion of the population in Brooklyn that rents versus owns their housing unit. There is a higher number of trees per housing unit for census tracts that have a majority of owned units, on average.

Owning property can be very difficult to do because it is very expensive—particularly in New York City. Additionally, a lot of people who own housing units received them as they were passed down through generations. People that do not have generational wealth are less likely to receive a housing unit through their family.

The mismatch in distribution of trees between areas of high and low ownership is indicative that a large portion of the abundance of people renting in Brooklyn may not have adequate tree cover. It is also suggestive of a relationship between income and tree distribution.

Plot 10: Relationship of education attainment, income, and trees

This visualization indicates that there may be a relationship between education attainment level, income, and the number of trees in a census tract. This data shows the average number of trees and the average median income by census tracts of each education level that is the most common attainment level.

Based on these points, there seems to be a positive relationship between the number of trees and median income. Additionally, the number of trees generally increases the higher the most common education attainment level is.

Plot 11: Map of trees per acre with race and income in Brooklyn, NY

https://jmwiggins.shinyapps.io/TreeShiny/

This map shows the distribution of trees in Brooklyn, New York. Based on the previous visualizations, it is important to explore these characteristics more deeply and analyze the spatial aspect of it.
Filtering the percentage of people of color to the higher end, the map narrows down to the east side of Brooklyn. This area has more census tracts with lower tree density than the rest of Brooklyn. Filtering the income shows a similar result. The areas of census tracts with lower tree densities are what is left.

These areas are places that will likely become much warmer than the rest of Brooklyn on hot days. This also means that these people will be at a higher risk of illness.

These distributions are one of the many examples of the disproportionate environmental burdens that marginalized communities face, particularly as the Earth experiences climate change. Inadequate tree density is a challenge that can be improved with proper planning and work. The first step is identifying locations of need through spatial, quantitative, and qualitative analysis.

Increasing tree density in areas with vulnerable populations is a solution that would not only benefit residents, but also the Earth.