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Teacher Resource Manual

Unit: Air Pollution and Visibility

Grade Level: 4

The Clean Air Campaign is pleased to provide Georgia standards-based air quality unit plans for the 4th through 8th grades. We hope that you will implement the all lessons in this 4th grade unit and offer your feedback. Teacher input and suggestions will be reviewed and incorporated into all future updates of lessons in this unit. We look forward to hearing from you at .

This lesson is part of a series of instructional units developed by The Clean Air Campaign® in partnership with the Georgia Department of Natural Resources, Environmental Protection Division, Air Protection Branch, the Georgia Tech Center for Education Integrating Science, Mathematics and Computing (CEISMC), and the Atlanta Bicycle Campaign. The units were developed with input from teachers in the Atlanta Public Schools, Clayton County Schools, Cobb County Schools, Decatur City Schools, DeKalb County Schools, Fulton County Schools, Henry County Schools, Marietta City Schools, Rockdale County Schools, and several private schools. Their suggestions and comments were valuable.

The units are designed to inform students in grades 4-8 about air quality issues in metro Atlanta and Georgia, including issues related to science, health, and human behavior. The units utilize readily available resources, web-based resources, and print resources to teach air quality concepts. For more information about The Clean Air Campaign®, log onto

Grade Level / Unit Topic / Lesson Titles
4 / Air Pollution and Visibility /
  • Hazy Days
  • Monitoring Air Pollution

5 / Air Quality and Transportation /
  • The Six Infamous Air Pollutants
  • Traffic Jams
  • Green Vehicles

6 / Electricity and Air Pollution /
  • Air Pollution and Electrical Energy Production
  • Air Pollution and Light Bulbs

7 / All Choked Up: Air Pollution and the Respiratory System /
  • Every Breath You Take
  • Lung Power and Air Pollution

8 /
Air Pollution and Earth Science
  • Ozone: The Good, the Bad, and the Ugly
  • Heat Islands

The instructional units can be integrated into existing content lessons. They can easily replace an existing activity. Therefore, issues relating to air quality can be woven throughout the curriculum for an entire semester or school year. This allows the teacher to focus on Quality Core Curriculum standards that must be taught at each grade level without having to find extra time in the curriculum to focus on air quality issues. Lessons can be accessed through the Georgia Learning Connections (GLC) ( and The Online Guide to Environmental Education in Georgia ( The Clean Air Campaign®, ( and the Georgia Tech CEISMC ( web sites.

Technology Integration

The units integrate technology based on standards suggested by the International Society of Technology Education (ISTE). Therefore, web resources are used extensively throughout most of the lessons. If web access is limited, students may use library resources (books, encyclopedias, or journals) to gather information on specific topics. Print sources may be available from several government agencies, including the United States Environmental Protection Agency and the Georgia Department of Natural Resources.

The 4th Grade Unit

This unit explores the relationships between air pollution, particulate matter, and visibility. It explores how air quality is monitored in Georgia.

There are two lessons in the unit as follows:

  1. Hazy Days - In this lesson, students will examine a picture of the Atlanta skyline on a clear and hazy day and offer observations and conjectures related to what they are seeing. Then students will examine substances of various particle sizes, such as rock salt, regular table salt, flour, sand, and confectioner’s sugar. This exploration of very small particles, that are still large enough to be seen by the human eye, will assist the students in thinking about particles that are too small to be seen by the human eye and yet contribute to air pollution, particularly related to visibility and respiratory issues.
  2. Monitoring Air Pollution – In this lesson, students will conduct an experiment using sticky tape and index cards to collect evidence of particulate matter around their schools. They will make predictions about where they think they will collect the most particulate matter, and then they will conduct their experiment and analyze their data to see if their predictions were accurate. Through this, they will also learn about variables and controls. Just as the students placed index cards with sticky tape around the school to collect particulate or monitor the amount of particulate, the state puts more sophisticated instrumentation around the state, Air Monitoring Stations, to collect data on several air pollution factors, including particulate. So the student index cards with sticky tape are a small scientific model of the more sophisticated instrumentation. A note on cluster sampling: It is important that you select the squares (quadrants) that you are going to examine prior to beginning the experiment. This is so that students won’t be inclined to pick the dirtiest squares on any one card afterward, which would introduce statistical bias into the analysis of the data.

Unit Resources

Transparency Masters

Transparency masters in the forms of PowerPoint presentations or Word documents are included. These can be presented in class or pre-printed on transparencies. The masters are in color. If no color printer is available, items in color can be shaded in with color transparency markers prior to the start of class.

  1. Hazy Days
  2. Monitoring Air Quality in Georgia
  3. Photo of the Atlanta Skyline


In addition to the websites used in the unit, others may be useful. They are:

- Ozone map archives of United States can be found on this site. Students will also be able to get a sense of the circulation of ozone around the Southeast.

- This EPA website includes weather forecasting information linked to air quality.

- A website for kids sponsored by the United States Environmental Protection Agency.


The Clean Air Campaign® has a free speakers bureau. Requests for speakers can be made through its Web site,

Georgia’s Air Pollution Problem

(Adapted from 2005)

Smog is a mixture of air pollutants, some that can be seen or smelled, and others that cannot. In Georgia, the two most important pollutants that threaten human health are ground-level ozone and particle pollution.

Across Georgia, 28 counties or parts of counties are classified by the U.S. EPA as nonattainment areas for either ground-level ozone, particle pollution, or both. This includes 20+ counties in metro Atlanta, as well as areas surrounding Macon,Rome and Chattanooga.

Nonattainment status means that for many days air pollution levels are likely to exceed federal and state limits. Poor air quality poses risks to human health, threatens our economic prosperity, and is detrimental to the environment. Air pollution is a year-round problem in Georgia.

Ground-level ozone, a primary component of smog, is created from a recipe of oxides of nitrogen (NOx) and volatile organic compounds (VOCs or hydrocarbons) cooked by sunlight and high temperatures. It is formed in the atmosphere when days are warm and there is a lot of sunlight. That is why we see more smog in the summer “smog season”, from May 1 – September 30. When combined with particulate matter and other pollutants, smog is formed.

Sources of smog include:

  • Nitrogen Oxides (NOx) come almost entirely from man-made sources: combustion of fuels in cars and trucks, coal-fired power plants, industrial boilers and gas-powered engines such as lawnmowers and leaf blowers.
  • Volatile organic compounds (VOCs) are vapors that emanate from paint and print shops, gas stations, dry cleaners, lawn chemicals, and from combustion engines, such as those in cars and trucks, boats and diesel locomotives. Trees also emit VOCs.
  • Particle pollution, or particulate matter (PM), consists of a mixture of extremely small solids and liquid droplets that typically includes aerosols and fine solids, such as dust and soot. Sources include all types of combustion, including vehicle exhaust, power plants, wood burning, construction activity and agriculture.

The Air Quality Index

(Adapted from 2004)

A key tool for communicating about outdoor air quality is the Air Quality Index, or AQI. The AQI is an index for both reporting daily air quality and for forecasting the next day’s air quality. It tells you how clean or polluted the air is, and indicates what health effects may occur within a few hours or days after breathing polluted air. The Environmental Protection Agency (EPA) and the Georgia Environmental Protection Division (EPD) use the AQI to provide the public with timely and easy-to-understand information on local air quality and related health issues.

The EPA focuses on six major air pollutants, called criteria pollutants, regulated by the Clean Air Act: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, lead, and nitrogen dioxide. For each of these pollutants, the Environmental Protection Agency (EPA) has established national air quality standards to protect against harmful health effects.

The AQI for ozone concentrations range from 0 to 500. The higher the AQI value, the greater the level of air pollution and its associated health risks. For example, an AQI value of 50 represents good air quality, while an AQI value higher than 300 represents hazardous air quality.

An AQI value of 100 generally corresponds to the national air quality standard for the pollutant, which is the level the EPA, has established to protect public health. So, AQI values below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is considered to be unhealthy—at first for certain sensitive groups of people, then for everyone as the AQI values increase.

The AQI Index also uses colors to indicate air quality and health concerns related to air quality. The chart below provides additional information about the AQI. Real time Air Quality Index data for Atlanta can be found at

What these numbers mean
0-50 / CODE GREEN:
Good / The air quality is good and you can engage in outdoor physical activity without health concerns.
51-100 / CODE YELLOW:
Moderate / At this level the air is probably safe for most people. However, some people are unusually sensitive and react to ozone in this range, especially at the higher levels (in the 80s and 90s). People with heart and lung diseases such as asthma, and children, are especially susceptible. People in these categories, or people who develop symptoms when they exercise at "yellow" ozone levels, should consider avoiding prolonged outdoor exertion during the late afternoon or early evening when the ozone is at its highest.
101-150 / CODE ORANGE: Unhealthy for Sensitive Groups / In this range the outdoor air is more likely to be unhealthy for more people. Children, people who are sensitive to ozone, and people with heart or lung disease should limit prolonged outdoor exertion during the late afternoon or early evening when ozone levels are highest.
151-200 / CODE RED:
(Smog alert) / In this range even more people will be affected by ozone. Most people should restrict their outdoor exertion to morning or late evening hours when the ozone is low, to avoid high ozone exposures.
201-300 / CODE PURPLE:
Very Unhealthy
(Smog alert) / In this range even more people will be affected by ozone. Most people should restrict their outdoor exertion to morning or late evening hours when the ozone is low, to avoid high ozone exposures.
(Smog alert) / Everyone should avoid all outdoor exertion.


The Air Protection Branch of the Georgia Environmental Protection Division is responsible for protecting Georgia’s air quality through the regulation of emissions from industrial and mobile sources. The Ambient Monitoring Program (AMP) maintains a large statewide network of monitors measuring the ambient (outdoor) air for approximately 170 pollutants including ozone, lead, particulate matter, oxides of nitrogen, sulfur dioxide, carbon monoxide, hazardous air pollutants and compounds that aid in smog formation. The program also uses meteorological data to better understand the influence of meteorology on air quality and then reports the air quality index (AQI) for metro Atlanta, Savannah, Columbus, Augusta, the north Georgia mountains, Macon, Brunswick and central Georgia areas. AMP also issues year-round smog alert forecasts for a twenty county area in and around Atlanta.

Air Pollution and Visibility

(Adapted from 2004)

On certain days of the year, when we look at the Atlanta skyline, we do not have a clear view of all of the buildings. A white or brown haze hangs in the air and distorts the view. This haze is unnatural. It is caused by human created air pollution, often carried by the wind hundreds of miles from where it originated. Because of this haze, people in Atlanta are not able to see as far as they normally would if the haze was not present. It is estimated that the typical visual range in the eastern U.S. is 15 to 30 miles, or about one-third of what it would be without human made air pollution.

Haze is caused by fine particles that scatter and absorb light before that light reaches the observer. As the number of fine particles increases, more light is absorbed and scattered, resulting in less clarity, color, and visual range. Five types of fine particles contribute to haze: sulfates, nitrates, organic carbon, elemental carbon, and crustal material. The importance of each type of particle varies across the U.S. and from season to season. Details on each particle type are provided below:

  • Sulfate particles form in the air from sulfur dioxide gas. Most of this gas is released from coal-burning power plants and other industrial sources, such as smelters, industrial boilers, and oil refineries. Sulfates are the largest contributor to haze in the eastern U.S. due to the region's large number of coal-fired power plants. In humid environments, sulfate particles grow rapidly to a size that is very efficient at scattering light, thereby exacerbating the problem in the East.
  • Organic carbon particles are emitted directly into the air and also form there as a reaction of various gaseous hydrocarbons. Sources of direct and indirect organic carbon particles include vehicle exhaust, vehicle refueling, solvent evaporation (e.g., paints), food cooking, and various commercial and industrial sources. Gaseous hydrocarbons are also emitted naturally from trees and from fires, but these sources have only a small effect on overall visibility.
  • Nitrate particles form in the air from nitrogen oxide gases. These gases are released from virtually all combustion activities, especially those involving cars, trucks, off-road engines (e.g., construction equipment, lawn mowers, and boats), power plants, and other industrial sources. Like sulfates, nitrates scatter more light in humid environments.
  • Elemental carbon particles are very similar to soot. They are smaller than most other particles and tend to absorb rather than scatter light. The "brown clouds" often seen in urban areas and in mountain valleys can largely be attributed to elemental carbon. These particles are emitted directly into the air from virtually all combustion activities, but are especially prevalent in diesel exhaust and smoke from the burning of wood and wastes.
  • Crustal material is very similar to dust. It enters the air from dirt roads, fields, and other open spaces as a result of wind, traffic, and other surface activities. Whereas other types of particles come from the condensation and growth of microscopic particles and gasses, crustal material is the result of the crushing and grinding of larger, earth-born material. Because it is difficult to reduce this material to microscopic sizes, crustal material tends to be larger than other particles and falls from the air sooner, contributing less to the overall effect of haze.

Some of the pollutants that form haze have been linked to serious health effects and environmental damage. Exposure to fine particles in the air have been linked with increased respiratory illness, decreased lung function, and premature death. In addition, sulfate and nitrate particles contribute to acid rain, which can damage forests, reduce fish populations, and erode buildings, historical monuments, and even car paint.

To reduce haze we must reduce emissions of haze-forming pollutants across broad areas of the country. Cars, trucks, and industries are much cleaner than they were in the past, and several programs are in place to maintain this progress over the next several years. Nonetheless, these programs by themselves are unlikely to restore visibility to their original pre-haze conditions.