Introduction
When given the choice to explore a health-related topic through the creation of an atlas, I decided to explore further on one of the conditions that has affected myself and its relationships with a few environmental factors. Asthma is a chronic respiratory condition that affects the airways, causing inflammation and narrowing, which leads to symptoms such as wheezing, shortness of breath, coughing and chest tightness. While the exact cause of asthma is not fully understood, several factors can contribute to its development. These include, but are not limited to, genetic factors, environmental triggers, allergies, and respiratory infections. This atlas will focus on the United States and explore a few environmental factors such as the Air Quality Index (AQI), CO2 emissions, and cigarette use among adults.
Maps
Asthma Prevalence
Percent of Adult Population with Asthma in the Contiguous U.S. by State (CDC, 2017)
Above is a choropleth map made using R, illustrating the asthma prevalence in the U.S. by state in 2017. This 2017 data is retrieved from the Centers for Disease Control and Prevention (CDC). From this map we see that asthma is more prevalent in the northeast and northwest corners of the United States. States with darker shades of red indicates this higher prevalence. This pattern seen in the asthma prevalence data does not seem to correlate heavily with the other maps exploring air quality and pollution, but instead correlates more to the map showing cigarette use.
Mean AQI
Mean Air Quality Index for the Contiguous U.S. by State (EPA, 2017)
This is a choropleth map created using R to illustrate the average air quality index (AQI) values of each state in 2017. Data used for this map is retrieved from the United States Environmental Protection Agency (EPA). As you can see, California clearly has the highest AQI value, which means the worst overall average air quality in 2017. However, asthma was not very prevalent in California relative to the other states. The AQI of the states on the east coast are generally quite low, although asthma is more prevalent is some of those areas.
Transportation CO2 Emissions
Transportation CO2 Emissions of the Contiguous U.S. by State (BTS, 2017)
Here is a choropleth map made in R displaying the CO2 emissions by transportation in the United States by state in 2017. The data is retrieved from the Bureau of Transportation Statistics (BTS). From the map, we see that high emissions are concentrated in Texas, California, and some states to the east. This pattern of emissions shows a mostly opposite trend to the Asthma Prevalence map. In Texas and California, the percentage of population with asthma was relatively low, yet their CO2 emissions are relatively high.
Industrial CO2 Emissions
Industrial CO2 Emissions of the Contiguous U.S. by State (BTS, 2017)
Above is a choropleth map created in R that demonstrates the industrial CO2 emissions by state in the United States in 2017. The data here is retrieved from the Bureau of Transportation Statistics (BTS). Similar to the Transportation CO2 Emissions map, we see that Texas, California, and some states to the east has higher emissions relative to other states of the Unites States. It represents the same general pattern, which is in opposition to the pattern proposed by the Asthma Prevalence map.
Cigarette Use
Cigarette Use by Adults in the U.S. by State (BFRSS, 2019)
*note: leaflet data may disappear when resizing window while viewing other maps, please adjust window size to reload.
Here is a choropleth map made with Leaflet illustrating the cigarette use by adults in the United States by state in 2019. The data is retrieved from USA Facts, who got their data from the CDC’s Behavioral Risk Factor Surveillance System (BFRSS). Here we can see a higher level of cigarette usage in the eastern interior states of the United States as well as in the northeast corner. The pattern presented by this map indicates a clearer correlation with the Asthma Prevalence map than the other maps explored within this atlas.
Analysis
First, as a basis for comparison, the asthma prevalence in the United States in 2017 is mapped out in a choropleth map. The prevalence of asthma is shown as a percentage of the population with asthma which puts the data on a common scale, making it easier to grasp immediately. A red sequential color scheme is used to fit into the conventions health maps typically use. Darker shades of red indicate a higher percentage of population with asthma as it tends to grab attention more than the lighter shades.
Looking at the mean AQI for the United States in 2017, it demonstrates an interesting point and leads to a pattern which does not align with what is observed in the Asthma Prevalence map. California has the highest average AQI, which means that the air quality is quite poor relative to the rest of the country. However, asthma prevalence in California is, in fact, lower than most other states. As air pollution can trigger asthma symptoms or exacerbate existing asthma, the point demonstrated by this map is rather fascinating. This happens to be a running theme in the two maps exploring transportation and industrial CO2 emissions.
Although the cause of asthma is complex and involving various factors, CO2 emissions is likely to lead to environmental changes that increase the prevalence of asthma on affected populations. CO2 emissions are often accompanied by the release of other pollutants, such as nitrogen oxides, sulfur oxides, and particulate matter. These pollutants can worsen air quality and contribute to the development and exacerbation of asthma. With this in mind, the patterns presented by both the Transportation CO2 Emissions map and the Industrial CO2 Emissions map becomes intriguing.
Both the transportation and industrial CO2 emissions are highly concentrated in California and Texas, as well as some other states on the east coast. As the Asthma Prevalence map indicates, however, prevalence in both California and Texas are relative low. Also, this evidence directly contradicts the general knowledge of the impacts and relationships between CO2 emissions and asthma. Both maps use a yellow and brown sequential color scheme to display the level of emissions with darker shades of brown signifying higher emission levels.
Finally, the Cigarette Use map presents a different relationship that matches the distribution seen in the Asthma Prevalence map. States on the east coast have higher levels of cigarette use among adults compared to the west coast, with California being in one of the lowest categories. Despite having high AQI and CO2 emissions, California has a relatively low prevalence of asthma and low cigarette use among adults. This observation suggests cigarette use might have more of a direct impact on asthma prevalence than the other environmental factors explored in this atlas.
Conclusion
Environmental factors such as the AQI, CO2 emissions, and cigarette use all have a varying degree of impact on the prevalence of asthma. While the air quality and CO2 emissions did not correlate heavily with the asthma prevalence data, the cigarette use among adults suggested a possible correlation. Air quality and CO2 emissions are factors that are significant drivers of climate change which can ultimately affect the distribution and prevalence of allergens that in turn impact asthma prevalence. However, these factors are indirect in comparison to the choice an individual makes to use cigarettes. Using cigarettes is a choice that directly affects the health of our body system and the relationships presented in this atlas unintentionally highlights the consequence of these choices.
Resources
- United States Census Bureau. (2022). US States Shapefile. Cartographic Boundary Files [Shapefile]. Retrieved from here
- CDC. (2017). Asthma Prevalence Data. Asthma Prevalence [table]. Retrieved from here
- CDC. (2019). Cigarette Use Among Adults. State Tobacco Activities Tracking and Evaluation (STATE) System [table]. Retrieved from here
- Bureau of Transportation Statistics (BTS). (2017). Energy Consumption and CO2 Emissions. State Transportation Statistics [table]. Retrieved from here
- Environmental Protection Agency (EPA). (2017). Mean AQI. USA Facts [table]. Retrieved from here