Using large air pollution data sets in introductory agriculture, biology, and environmental classes
Justin Pruneski, Rich Rosecrance, Rob Swanson, Bruce Wiggins
Part A. Overview
Summary: Our goal is to create a case study module to investigate EPA air pollution data, while identifying key components of the process that can be applied to other data sets for further case investigations
Target audience: First-year college students (with suggestions for adding material for more advanced courses). Some Excel skills assumed.
Objectives:
Instructor will be able to:
● Identify potential sources of data for students to explore
● Facilitate student exploration of prior knowledge and interests
● Guide students use of helpful resources and data sources
Students will be able to:
● Summarize the central issues of the case
● Develop a question that can be answered with big data
● Identify and access large data sets
● Use Microsoft Excel to manipulate data and perform statistical analysis
● Use Microsoft Excel to make graphs and charts to visualize data
● Use data generated to support or refute their hypotheses
● Communicate their results and persuade their peers
Part B. Classroom instructions
General Structure of the lesson (each of these are expanded below)
Phase I
1. Introduce the Case - Students read the case and get (hopefully) get invested in the topic
2. Recognize Potential Issues - Students reread to clear up confusion and extract more info
3. Identify Major Themes - Students brainstorm what the case is about
4. Pose Specific Questions - Students brainstorm what they know about the topic and what they want to know
Example: analysis of ozone data from EPA
Phase II
5. Obtain Additional Resources - Students explore what type of resource they need to address their questions and try to find them
6. Define Problems - Students refine their questions
7. Design and Conduct Scientific Investigations - Students use available resources to collect and analyze data to address their questions
Phase III
8. Produce Materials to Support Conclusions - Students communicate the research of their investigation to the class and try to persuade them that their conclusions are valid
Specific Structure of the Lesson
Phase I. Problem Posing: Analyzing the Case
1. Introduce the case: Begin by providing a copy of the case to individuals or by projecting the case for the group. Next, ask a student volunteer to read the case out loud while the others read along silently. This gets everyone "on the same page" and is a surprisingly productive case-learning method. Reading aloud lets students know that they will be verbally involved in this process. Plan on 2 minutes for this step, and it can be done in small groups or by the whole class.
Example Case
Why is Gramma wheezing?
Gramma Neevers came in from the sweltering heat, collapsed into a kitchen chair, wheezing. They had just spent a full day touring the sites in Washington D.C. Her son, Bert, bustled in after her, worried.
“Gramma, if your breathing gets any worse, we may have to get you to a doctor. Even if it gets better, I’m not so sure we should go see the fireworks tonight.”
Gramma shook her head stubbornly. “Now Bert, I didn’t come to visit you to miss the Fourth of July fireworks. I think it’s this heat… it’s got to be over a hundred degrees out. I just don’t have these problems back in Aroostook County.”
Bert shook his head, “I don’t see how temperature has anything to do with it, Gramma.”
Stacey, Bert’s wife, walked into the kitchen and gave Gramma a quick hug, “I think she’s right, Bert. At the hospital, we usually see more people with breathing problems when it gets really hot. I overheard one of the doctors say that it has something to do with ozone.”
“I don’t know, Stacey,” said Bert, doubtful, “it could be a lot of other things.”
“Hrm”, thought Gramma Neevers, pulling out her smartphone, “These two chowderheads don’t know a darn thing. I need to get some facts!”
2. Recognize Potential Issues: Ask students to spend 2-3 minutes silently reading the case again. This time they should be noting words or phrases that seem to be important to understanding what the case is about. If students have a printed copy of the case, they might underline these phrases. Otherwise, they might jot down ideas and questions about these phrases.
3. Identify Major Themes: Initially, it is helpful to think about the case as a whole and see what underlying themes students identify. Ask the class to consider the question: "What is this case about?" Then take 5-7 answers from the class. Don't be surprised at the variety of themes associated with the case! This step, while brief, alerts students to the complexity of the case.
4. Pose Specific Questions: A productive way to generate questions is to ask students to use a chart listing what they know and what they need to know. If students are working in a group (recommended), this might be done as a group discussion. One student could record for the group while questions, facts and issues are raised (10-15 minutes of class time, possibly less, should suffice). A brief, whole class discussion of identified questions allows the instructor to assess prior knowledge and enables students to hear each others' ideas. The Know/Need to Know method usually leads to a long list of questions, and there will not be time to pursue them all.
Example: Somewhere on this list, someone might have thought to look at measures in ozone concentration. This will be the entry into the big data demonstration. Here are some student instructions for examining the data from the first case.
You will be comparing the ozone concentrations in two locations: Washington DC, and Aroostook County, Maine. You will download the daily ozone concentrations (in parts per million (ppm), from the EPA’s web site.
Part 1. Downloading the Data
1. Open your browser and go to the EPA’s AirData site:http://www.epa.gov/airquality/airdata/.
2. Click on the ‘Download Data’ link, then click ‘Download Daily Data’.
3. For the Pollutant, select “Ozone”.
4. For the Year, select “2011”.
5. For the County, select “ME-Aroostook”.
6. For the Monitor Site, select “230031100”.
7. For Exceptional Events, select “Include Exceptional Events”.
8. Click ‘Get Data’, then click ‘Download CSV (spreadsheet)’. Save the downloaded file to your computer with a filename “Aroostook_O3_2011”.
9. Repeat steps 5-8, but substitute “DC-District of Columbia” for the County and “110010043” for the Monitor Site. Name this second file “DC_O3_2011”.
Part 2. Exploring the Data
1. Open the “DC_O3_2011” spreadsheet. There are many columns of data, but we will focus on just two of them for now. Column A (“Date”) is the date the measurement was taken, and Column D (“Daily Max 8-hour Ozone Concentration”) is the highest ozone concentration (in ppm) during a given 8-hour period.
2. Now graph your data. Make a scatterplot of ozone concentration vs. date. What is the highest ozone concentration? When did the highest ozone concentrations occur? What is the general shape of the graph? How many days exceeded the Federal standard?
3. Repeat steps 1-3 for the “Aroostook _O3_2011” spreadsheet. Which location has the higher ozone levels? Do the graphs look the same?
Part 3. Student Exploration
1. Work with your team to ask more advanced questions.
2. Questions could include:
--How do air pollution concentrations change over time (e.g. 1980 vs 2012--google motion chart)?
--How does city size affect air pollution levels?
--Globally, how does air pollution from cities of similar size vary (e.g. Bangkok, Manilla)?
--How do weather events affect air pollution levels (e.g. temperature, sunlight, solar radiation, wind)?
--How does tourism affect air pollution levels (ie. new orleans during mardi gras, or D.C. for the 4th of July)?
--What is the relationship between vehicle numbers and air pollution levels?
3. After you have asked a question, formulate a hypothesis that might answer/explain your question. Then download the necessary data to test your hypothesis. Write a short description of your results and how well they relate to your hypothesis. Discuss your results with the class.
Phase II. Problem Solving: Investigating the Questions
5. Obtain Additional Resources: No matter what type of question learners pose, it is likely they will use additional resources to help them develop a reasonable answer. Resources may include textbooks; other library materials; results of computer simulations; results of lab or field research; articles from professional journals or popular press, data sets, maps, emails, websites or other electronically based resources; pamphlets from organizations; interviews with experts; information from museum exhibits, etc. Ask students to list 3-4 potential resources as they wrap up the case analysis. Extended informational research may be assigned independently. The instructor may decide to make some resources available by putting them on reserve in the library, bringing them to the classroom, or creating a web page with some relevant links.
Example: There are many potential resources students can use to answer their questions, but for this exercise, it may be helpful to direct them towards free online sources of data. A list of some of these are at the end of the exercise.
6. Define Problems: Students will better define problems and frame specific questions to investigate as they learn more about the case. At this point it will be important for them to consult with others, most likely members of their group or other classmates. Talking about ideas and plans with peers is an important step in refining problems. This can lead to different perspectives that might help shape good research problems. Such conversation and collaboration is a hallmark of the work of scientists.
7. Design and Conduct Scientific Investigations: Students are encouraged to use available laboratory, field or computer tools and resources. Scientists often begin by synthesizing pieces of existing information into a new theoretical framework (work which may be accompanied by repeated experimental designs as was done by Watson and Crick in modeling DNA). Students might locate or generate data sets, conduct interviews, as well as gather ideas from their reading, library research, and from laboratory and field activities. The instructor may play an active role here by introducing specific lab activities, equipment, or methodologies, or by introducing students to simulations, datasets or modeling programs that relate to key questions raised by the case. It is up to the instructor to decide how open-ended he or she wishes the investigations to be.
Example For this investigation students will not be able to perform actual laboratory or field experiments. Instead, students will find authentic scientific data, manipulate it, and analyze it to create evidence supporting or refuting their hypothesis.
Phase III. Peer Persuasion: Supporting Methods and Reasoning
8. Produce Materials to Support Conclusions: Before learners are ready to present their conclusions, ask them to identify multiple ways for others to view and review their work. The group should consider their preferences as both presenters and reviewers. Traditionally we ask for term papers or lab reports, but the possibilities for alternative supporting materials are vast: posters (scientific, public service, etc.), videos, booklets, pamphlets for the general public, consulting reports, artwork, designs for new technology, scientific publications, newspaper stories, editorials, or new case studies for example. When students review each others products they can engage in the kind of discussion and possible controversy about differing methods and results that is common in scientific discourse.
Part C. Instructors Resources
1. AirData website resources
--Interactive mapper-students can locate individual monitoring stations, and download station-specific data.
--Concentration plot-provides quick graphs of concentration versus time.
--Explore the site for more.
2. Air Quality Standards.
The standards listed in Title 40 of the Code of Federal Regulations Part 50.
Pollutant / Type / Standard / Averaging TimeSO2 / Primary / 0.14 ppm (365 μg/m3) / 24-hour
SO2 / Primary / 0.030 ppm (80 μg/m³) / annual
SO2 / Secondary / 0.5 ppm (1,300 μg/m³) / 3-hour
PM10 / Primary and Secondary / 150 μg/m³ / 24-hour
PM2.5 / Primary and Secondary / 35 μg/m³ / 24-hour
PM2.5 / Primary and Secondary / 15 μg/m³ / annual
CO / Primary / 35 ppm (40 mg/m³) / 1-hour
CO / Primary / 9 ppm (10 mg/m³) / 8-hour
O3 / Primary and Secondary / 0.12 ppm (235 μg/m³) / 1-hour
O3 / Primary and Secondary / 0.075 ppm (150 μg/m³) / 8-hour
NO2 / Primary and Secondary / 0.053 ppm (100 μg/m³) / annual
Pb / Primary and Secondary / 0.15 μg/m³ / Rolling 3 months
3. Students may want to explore:
● The link between forest fires or other exceptional events and ozone. See this website: www.epa.gov/airnow/2011conference/forecasting/Murphey.ppt.
● The relationship between weather conditions and air pollution levels. See later on for a more detailed example. See for one source of weather data.
● The effect of city size or population on air pollution levels.
● The effect of the number of vehicles on air pollution, or the amount of pollution produced from vehicles in different eras.
● Data for motor vehicle registrations per capita, from Gapminder USA
● Change in pollutant concentrations over time (This could be visualized using google motion chart, a gadget within Google Docs).
● Comparing different pollutants (EPA site has data on CO, Pb, NO2, Ozone, PM10, PM2.5, and SO2).
● The effects of air pollution on particular health conditions (ex. asthma, lung cancer). Asthma measures: http://www.cdc.gov/asthma/brfss/2010/brfssdata.htm.
● Are certain areas over/under the EPA standards (daily, monthly, yearly average). What is the right standard?
● Comparison of US cities to other cities around the world (ex. Mexico City).
● If students are interested in the effect of elevation, they can google elevation data for the particular cities/locations they are interested in.
● Type and amount of energy use. Data available from the U.S. Census Bureau, in Excel format http://www.census.gov/compendia/statab/cats/energy_utilities/electricity.html.
● Agricultural data. Data for total acreage of farm land, from Gapminder USA Data for a number of different agricultural measures from the U.S. Census Bureau, in Excel Format http://www.census.gov/compendia/statab/cats/agriculture/crops.html
Part D. References
The format and much of the instruction language for this case study was taken from “Starting Point: Teaching Entry level Geoscience” website, specifically the “How to Use Investigative Cases with Examples” webpage http://serc.carleton.edu/introgeo/icbl/how.html accessed 6/20/12
Anderson, W.; G.J. Prescott, S. Packham, J. Mullins, M. Brookes, and A. Seaton (2001). "Asthma admissions and thunderstorms: a study of pollen, fungal spores, rainfall, and ozone". QJM: an International Journal of Medicine (Oxford Journals) 94 (8): 429–433. DOI:10.1093/qjmed/94.8.429. PMID 11493720
Health Aspects of Air Pollution with Particulate Matter, Ozone and Nitrogen Dioxide. Report on a WHO Working Group, Bonn, Germany 13–15 January 2003