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Is Your Bus Exhausting? Stevens Institute of Technology

 

TEACHERS: Weather's Role

Objectives
Students will be able to:
  • collect and analyze data for a high ground level ozone day and a low ground level ozone day
  • make comparisons and determinations about ozone levels utilizing graphing skills
  • learn that ground level ozone may be abundant when VOCs, NOx, and intense sunlight are present

Materials

 

Background:

Ground level ozone is formed by chemical reactions between volatile organic compounds (VOCs), also known as hydrocarbons and oxides of nitrogen (NOx) in the presence of sunlight. NOx and VOCs are known as the chief "precursors" of ozone. These compounds react in the presence of sunlight to produce ozone. These gaseous compounds mix like a thin soup in the atmosphere, and when they are exposed to sunlight, ozone is formed. Due to the nature of these reactions, ozone concentrations can reach unhealthful levels when the weather is hot and sunny with little or no wind. As a result, ground level ozone pollution, or smog, is mainly a daytime problem during summer months.

Large industrial areas and cities with heavy summer traffic are the main contributors to ozone formation. When temperatures are high and the movement of air is limited, ozone can accumulate to unhealthy levels.

What is considered to be an unhealthy level? The EPA has established a general index to guide citizens in planning driving and outdoor activities during the ozone season. The Air Quality Index, or AQI, is a scale used to report ground level ozone and other common pollutants in the air. The higher the AQI value, the greater the health concern. A specific color has been assigned to each AQI category. The color scheme can help to quickly determine if air pollutants are reaching unhealthy levels.

EPA Air Quality Guide for Ozone

  • Good Air Quality Index 0-50 (Green)
    • Partly sunny to cloudy skies or rain
    • Temperatures in mid-70s to low 80s
    • Windy
    • No health impacts are expected when air quality is in this range.
       
  • Moderate Air Quality Index 51-100 (Yellow)
    • Partly cloudy to sunny skies
    • Temperatures in upper 70s to mid-80s
    • Light to moderate winds
    • Unusually sensitive people should consider limiting prolonged outdoor exertion.
       
  • Unhealthy-Sensitive Groups Air Quality Index 101 150 (Orange)
    • Sunny skies
    • Temperatures in high 80s to 90s
    • Light winds
    • Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.
       
  • Unhealthy (more people affected) Air Quality Index 151-200 (Red)
    • Sunny skies
    • Increasing humidity
    • Temperatures in high 80s to 90s
    • Little to no wind
    • Active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion.
       
  • Very Unhealthy (Alert) - Air Quality Index 201-300 (Purple)
    • Hazy, hot and humid
    • Temperatures in 90s and above
    • Little or no wind
    • Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion.
       
  • Hazardous  (Alert) - Air Quality Index > 300 (Brown)
    • Health warnings of emergency conditions.
    • The entire population is more likely to be affected.

In areas where ground level ozone has the potential to reach unhealthy levels, Ozone Action Day programs have been established. An Ozone Action Day program is a voluntary initiative by government, environmental groups, and business leaders working with the general public to take extra action to prevent air pollution when high ozone levels are predicted. Because ground level ozone forms under certain weather conditions, a regional team of meteorologists can predict days when ground level ozone concentrations may exceed health standards. These are generally hot, sunny days with little or no wind.

Ozone Action Days can be declared by the state environmental protection agencies if exceptionally high concentrations of ground level ozone are predicted. Awareness of such high levels of ground level ozone allows citizens to take measures to help reduce the amount of ozone or smog.

In this lesson, the students will analyze the same type of data that the meteorologists use to determine the formation of ground level ozone.

 

Procedure:

PART 1: Gather the Data

  1. Take out your copy, or access the Air Quality Guide for Ozone in another browser window.
  2. From the list below, click on the link of the closest city. Locate the city on the map and watch the animation several times. Also mark the location of the city on the map of Connecticut.
Bridgeport, CT New Haven, CT Hartford, CT Groton, CT
  1. Determine the AQI Color of the city for every hour listed and enter the data into the table on your Student Worksheet (hit the escape key to stop the animation at the specified time and refresh/reload button on your browser to reinitiate the animation).
Date and Location:
Time AQI Color Air Quality Max. AQI
Value
 Temperature
(oC
or oF)
Wind Speed (kmh or mph)
ex. 8:00
Green
Good
50
25.7 ºC
8.4 km/h
10:00          
12:00          
14:00          
  1. Write in the corresponding Air Quality condition (Good, Moderate, etc.) and Maximum AQI value (0-50, 51-100, etc.). This information can be found on the Air Quality Guide for Ozone.
  2. In another browser window (CTR+N) or tab (CTRL+T), or another computer, obtain the weather data for the city selected above. Access the Weather Underground site, by clicking the city
    • IMPORTANT: Scroll down to read the hourly data
Bridgeport, CT New Haven, CT Hartford, CT Groton, CT
  1. Determine the Temperature (either oC or oF) and Wind Speed (either kmh or mph) for every hour listed in the table and enter the data in the table in you Student Worksheet.
  2. Make the following three bar graphs using the data in your table (ask your teacher for assistance if you are unsure how to make the graphs).
    1. Ozone (Max. AQI) v. Time
    2. Temperature v. Time
    3. Wind Speed v. Time

PART 2: Analyze the Data
After you have completed the graphs, use the data in the table and the graphs to answer the questions on the Student Worksheet.

 

Assessment

  1. For homework, the students will repeat the procedure, steps 1 - 7, but use the following links to look at examples of low ground level ozone days. The students should obtain another copy of the Student Worksheet and use the following links to complete the homework assignment:

    AIRNow
Bridgeport, CT New Haven, CT Hartford, CT Groton, CT

Weather Underground

Bridgeport, CT New Haven, CT Hartford, CT Groton, CT
  1. The student responses to the questions on the Student Worksheet(s) can provide insight as to student understanding of the topic.

Implementation Tips
This introductory lesson actually uses archived images, which will offer greater flexibility to prepare for the lesson if you are expecting network failure, or cannot get into the computer lab.

The second portion of the lesson may be completed without using a computer.

If there are not enough computers for students, you could:
  • create small working groups
  • project the images and weather data for the class using an LCD projector
  • arrange to take your class or small group of students to the Internet access computer on a regular basis for data collection
  • collaborate with the Computer Teacher

If the network is slow or not working, you could:
  • print the images and weather data on overheads and use the overhead project to project the images for the class
  • print and/or photocopy the images and weather data, enough for small student working groups
  • save the images to disk

Notes
Please refer to the Graphing Tips and Examples for assistance.

Graphing Cloud Cover/Conditions (Sunlight) - optional
This graph is optional and increases the complexity of the lesson. To graph Cloud Cover versus Time, use the chart below. The chart lists various sky conditions (terminology may be subjective) with a numerical value associated with each condition to ease the students' ability to graph the data.

The Cloud Cover data, gathered from the Weather Underground site, specifically, the "Conditions" column, refers to the Cloud Cover visible in the sky. Cloud Cover is often judged by the scale below and expressed in one of four terms, Clear, Scattered, Broken, and Overcast. For graphing purposes, the terms need to be expressed with a numerical value. In addition to explaining the conversion to your students, it may be necessary to point out that the amount of cloud cover has a direct relationship with the amount of sunlight, and the amount of sunlight has a relationship with the amount of ground level ozone generated during the day.
Cloud Cover/Conditions % Cloud Cover
Clear 0% > 10%
Scattered (includes Partly Cloudy) 10% - 50%
Broken (includes Mostly Cloudy) 50% - 90%
Overcast 90% +

 


 
 
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