Air Quality Lesson 4 : How Can We Monitor Air Quality?

How Can We Monitor Air Quality?

Subject/Target Grade

Science/Middle School (7-9)


Two 45-50 minute periods,  about three days apart – Classroom,  school grounds, home, outdoors

Materials per class

•     1 air freshener spray bottle or other odor source (lemon, onion)

•     fan

•     hole punch

•     stapler

•     spray bottle with water

•     Great Lakes Airshed  (map from Lesson 3)

•     Ozone Monitors in Michigan

(transparency master)

•     Particle Pollution (PM2.5 ) Monitoring Network (transparency master)

•     Types of Particle Pollution (transparency master)

(transparency master)

•     Particles in the Air (transparency master)

per small group

•     thermometer (different kind for each group)

•     4” x 6” white index card

•     clear adhesive tape

•     ruler

•     scissors

•     string (about 24”/monitor)

•     microscope or magnifiers

•     ozone paper

•     plastic bag

•     particle counting grid (transparency) • What’s in the Air? (student resource) • How Can We Monitor Air Pollution? (student activity)

per student

•     color conversion chart (Schoenbein Scale)

Materials to make ozone paper

•     250 mL beaker

•     corn starch

•     potassium iodide

•     distilled water

•     stirring rod

•     hot plate

•     small paint brush

•     glass plate

•     filter      paper

•     safety glasses

How Can 

We Monitor  Air Quality?

Lesson Overview

Students learn about the gases and particles that make up the air and explore different ways that we can monitor pollutants. Students monitor particle and ozone pollution around their school/homes using homemade monitors.

Students answer these essential questions: What types of things pollute the air and how can we detect them?  How can we monitor particle pollution and ozone levels in our community?

This lesson includes an Enhancement Activity that delves deeper into the use of biomonitors (living things) such as lichens and milkweeds in air pollution studies.


Students will be able to:

1.      Recognize the importance of air pollution monitoring stations.

2.      Explain how a particle collector and ozone paper can  be used to monitor pollution.

3.      Compare the particle and ozone levels in different locations.

4.      Infer possible sources of the particle and ozone pollution.

Lesson 4 


Michigan Grade Level Content Expectations:

Middle School:

MS-ESS3-4. Construct an argument supported by evidence for how increases in human population and per-capital consumption of natural resources impact Earth's systems. 

MS-ESS3-3. Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.

High School:

HS-ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those relationships are being modified due to human activity.

HS-LS2-7. Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.

HS-ETS1-3. Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including costs, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts. 

Advance Preparation

1.      Draw a diagram of your classroom on the board.

2.      Prepare a large chart similar to that on the student datasheet to track class data.

Prepare the grid for particle counting by transferring the teacher template to a transparency. Cut a strip for each group of students.

Background Information

Air quality monitoring throughout the airshed is an important tool to determine if all areas of Michigan and individual companies are in compliance with air quality standards for criteria pollutants. Monitoring is also done to measure levels of toxic air contaminants and to detect acid deposition.

Lesson 4

4.      Prepare ozone test strips according to the directions below. You may want to do this as a demonstration or have upper level students prepare the strips for you.

Making Ozone Test Strips (Schoenbein Paper): a.  In a 250-mL beaker, add 1-1/4 teaspoon of

cornstarch to 100 mL distilled water.

b.      Heat the mixture until it gels and then

remove it from the heat source. 

c.       Add 1/4 teaspoon potassium iodide and stir well. Cool solution.

d.      Lay      a          piece    of         filter    paper   on        a          glass    plate    and      carefully            brush   paste    onto     the       filter    paper. 

e.       Turn     the       filter    paper   over     and      do        the       same    on the other side. Try to apply paste as uniformly as possible. Wash hands after applying the mixture!  Potassium iodide  can cause minor skin irritation.

f.        Set the paper in a dark place (not near a  copy machine) to dry. A low temperature (110-120oC) drying oven may be used.

g.      Cut      the       filter    paper   into      1-inch  strips    and      place in a plastic bag or glass jar (out of direct sunlight) for storage.

5.      Review the Lichen andMilkweed PowerPoint presentations if you are going to do enhancements. You may want to collect some local lichen and milkweed leaf samples to bring in to show the students. Fact sheets containing additional information about particle pollution, ozone pollution, milkweed, and monarchs can be found on your MEECS Air Quality CD.

Monitoring stations are found throughout the State with the most monitors in the Detroit area. Frequency of monitoring varies from continuous readings to discrete sampling events.The Michigan Air Quality Monitoring Program consists of the operation of federally mandated National Air Monitoring Stations (NAMS),

State and Local Air Monitoring Sites (SLAMS), Special Purpose Monitoring Stations (SPMS), local governments, and industries. The National Atmospheric Deposition Program/National Trends Network(NADP/NTN)is a nationwide network of precipitation monitoring sites. Real-time web cameras to monitor visibility are set up in National Parks and other locations.

Although modern Michigan monitoring networks date back to 1956, Dr. R.C. Kedzie, a meteorologist at Michigan Agricultural College, used Schoenbein paper to monitor ozone twice a day between 1871 and 1882. Christian Friedrich Schoenbein discovered ozone in 1839 and developed a way to measure it by using starch, water, and potassium iodide. Today, the ozone test paper he developed is known as Schoenbein paper. The paper changes color when ozone is present because ozone oxidizes potassium iodide to form potassium hydroxide and iodine. The iodine then reacts with starch to produce a blue color.

1.      2KI + O3 + H2O  g  2KOH + O2 + I2

2.      I2  +  starch  g blue color

Ozone paper is sensitive to high humidity and will work best when humidity levels are low. Thus, the test may be inconclusive if humidity is high and/ or ozone levels are low. The Schoenbein method does have some interferences because it measures oxidants rather than ozone itself. However, ozone is usually the main oxidant measured. When corrected for humidity, Kedzie’s data show that ozone levels at that time followed patterns similar to those of today. Ozone levels peaked in the summer months and fell in the winter months (Linvill, Hooker, and Olson, 1980).

Ambient air monitoring is a requirement for the State Implementation Plan (SIP) that is designed to accomplish air quality goals. Air quality measurements are used to demonstrate the attainment status with regard to National Ambient Air Quality Standards (NAAQS) for carbon monoxide, lead, nitrogen dioxide, ozone, particles, and sulfur dioxide. Individual companies may have requirements in their air permits for monitoring  their smokestacks.

Monitoring for air toxics happens in a few selected areas of Michigan. An important air toxic is mercury. Mercury concentrations in air are usually low, but when mercury enters water, biological processes transform it to a highly toxic form  (methyl        mercury)          that      can       build    up        in         fish      and animals            that      eat       fish.     People are       exposed           to         mercury           primarily          by eating  fish.    

Acid deposition monitoring sites are part of a national monitoring network. “Clean” or unpolluted rain is slightly acidic, pH of 5.5 to 5.6, because carbon dioxide and water in the air react to form carbonic acid, a weak acid. However, in some parts of the United States, the average pH of rain is between 4.2 and 4.4. Most of the acid in “acid rain” (or more accurately, acid precipitation) comes from two kinds of air pollutants—sulfur dioxide (SO2) and nitrogen oxides (NOX). These are emitted primarily from utility and smelter “smokestacks” and automobile, truck, and bus exhausts, but they also come from burning wood.

One of the most basic forms of air pollution, haze, degrades visibility in many American cities and scenic areas, including national parks. A few locations in Michigan have web cameras to monitor visibility (haze). Haze-forming particle pollution comes from a variety of human-produced sources such as combustion from vehicles, power plants, fuel burning, and fugitive dust. Natural sources include      windblown      dust     and soot     from    wildfires.         In         the atmosphere, sulfur dioxide (SO2) and nitrogen oxides (NOX)      are transformed     into      fine      particles           of sulfates and nitrates. These and other particles scatter and absorb light, which impairs visibility and contributes to haze. Typical visual range in the Western United States is 60 to 90 miles, which is about half of what it would be without humanproduced pollution. In most of the Eastern United States, the visual range is 15 to 30 miles, which is about one-third of the natural visual range.

Lesson 4 

Biomonitoring for air pollution damage to lichens and plants such as milkweeds is done by organizations such as the National Park Service and the Wisconsin Department of Natural Resources. This type of monitoring uses plants and animals to assess the impact of air pollution.

An interesting result of monitoring is that a “fingerprint”      of         the       types    of         particles,          air toxics,  and trace metals can be used to track origins and dispersion of pollution. For instance, certain pesticides used only in the Southern states have found their way to Lake Superior by way of air masses. Atmospheric deposition of these contaminants happens when gases and particles are captured in precipitation (wet deposition), pollutants are bound in particulate matter (dry deposition), and gases are absorbed in water.

There are ways to monitor indoor air pollution. Radon surveys in homes and buildings using radon test kits have been done in Michigan. In one survey, approximately 12% of the homes (one in eight homes) had radon levels higher then the U.S. EPA’s action level. Some people have carbon monoxide detectors in their homes to detect emissions from their combustion appliances.

Many questions need to be asked before starting a monitoring program. The most basic question is, “What are       we       trying   to         find     out?”   This     leads    to:

•       WHY? (objectives, problems addressed)

•       WHERE? (locations)

•       WHEN? (frequency and duration)

•       HOW? (sampling techniques, tests, equipment, observations)

Procedures need to be in place to make sure that the data are collected in a consistent manner (a quality assurance plan) and standardized data sheets will make data management easier.


Linvill, D., W. Hooker and B. Olson. (1980). “Ozone in Michigan’s Environment 1876–1880.” Monthly Weather Review 108(11): 1883–1891.

Michigan Department of Environmental Quality. 

Air Quality Division. Michigan’s Air. Retrieved 

June 20, 2005, from

University Corporation for Atmospheric Research. 

Making and Using Schoenbein Paper. Retrieved August 25, 2005, from


How do contaminants in the air move? Cut up a lemon or onion, open a container of vanilla extract (a point source of air “pollution”), or spray some air freshener. Students will act as air monitoring instruments. Each “instrument” will raise a hand when an odor is detected. Assign two students to be “technicians.” Have one technician time how long it takes for all of

What can we conclude about the movement of air molecules? [Molecules disperse outwards from the source and they move relatively quickly.] Show the map of the Great Lakes Airshed from Lesson 3 to illustrate this on a larger scale. The concentric rings indicate how long it may take air from various regions to reach the Great Lakes, but it also could be interpreted as how long it may take for air in the Great Lakes region to disperse elsewhere.

1.    Track the movement of air pollution with this

U.S.         Environmental     Protection              Agency. Office     of Air and Radiation. Retrieved June 20, 2005, from What would happen if a fan were placed between the students and the odor producing substance? Using a fan, blow the odor molecules away from the students and then towards the students. Ask them to think about prevailing winds in Michigan (west, northwest, and southwest) and how that would affect the movement of air. Relate this to the Great Lakes Airshed map. 

Air pollution from industrial centers in Chicago, Illinois, Gary, Indiana, and Milwaukee, Wisconsin can travel to West Michigan. Air pollution from the Detroit area can impact Canada.

2.      Introduce air quality monitoring.

How can we tell if air quality is getting better or worse? Write suggestions on the board. Develop the idea that air quality monitoring might help answer this question.

What does monitoring involve? To introduce monitoring concepts by example, divide the class into groups and give each group a thermometer. Different kinds of thermometers would work best. Tell them that their task is to monitor the air temperature in the room and post their answers on the board. Consider their results noting that there was no standard procedure for when and where to monitor, different thermometers were used, and probably only one reading was taken. To get the best results, monitoring should involve long-term data collection, standardized equipment and procedures, and replication of measurements.

Note: If students need a review of the pollutants that they will be monitoring, have them read the article, What’s in the Air? and complete the activity page. There are additional resources on the MEECS Air Quality CD related to air quality monitoring such as a biomonitoring enhancement lesson.

3.      Make air quality monitors.

Can we make our own air monitoring devices? Provide students with the materials for the monitoring devices and a copy of How Can We Monitor Air Pollution? Students should be able to construct their particle collectors with minimal guidance.

Give each student an ozone strip to be attached to the particle pollution detector. Keep the ozone strips in a plastic bag until they are used. If the collectors are going to be taken home, provide a plastic bag for transportation and caution students to be careful not to crush or contaminate their monitors.

4.      Place the air quality monitors.

Is there a pattern to where monitors in Michigan are located? Use the Ozone Monitors in Michigan and Particle Monitoring Network transparencies to show the location of air monitors in Michigan. It should be evident that rural areas do not have as many monitors since they do not have the levels of pollution found in urban areas.

Where should we place the air quality strips?

Use the questions in the How Can We Monitor Air Pollution? student activity pages to guide placement. Have students list on their data sheet possible places to put their monitors—either outdoors or indoors.

During the winter months, outdoor ozone collection may not give good results since levels are low. Higher readings are more likely between May and early October. Indoor ozone sources include electrostatic air cleaners, photocopiers, laser printers, brush-type electrical motors (such as sewing machines), and ozone generators in hot tubs.

Particle pollution is complex as shown in Types of Particle Pollution transparency. Outdoor particle      pollution          levels   are       influenced       by        a variety of factors such as weather conditions, combustion levels (e.g., burning), vehicle emissions (e.g., school buses), and dust production (e.g., dry unpaved roads). Indoor particle pollution sites include wood shops, metalworking sites, ventilation systems, wood stoves,      fireplaces,        cigarettes,        combustion      appliances, and entry areas with door mats.

As shown in the Particles in the Air transparency, the particles of interest for air quality (PM2.5 and PM10) are very small. Combustion products and the other particle types mentioned fall in the range of 10 microns or less.

Students should choose different areas to place their monitors to provide the most diverse class data. One particle collector and ozone monitor should remain unused for a control.

Safety Note:  Caution students not to place their air quality collectors too close to combustion sources such as candles or stoves       (as        this      is          a          fire       hazard).

Note:  Make sure students expose their ozone strips for only 8 hours or less during the day. Take the ozone paper off the monitor and store it in the plastic bag. The particle collectors can be left out for several days, but they should not

5.   Analyze pollution levels. What was the level of ozone? What was the pattern of particles as shown on your collector? Have the students bring their air quality monitors back to class and complete the student data sheet, How Can We Monitor Air Quality? Use the questions in their student pages to direct the analysis of their results. If information about the relative humidity is available, actual levels of ozone can be estimated (see the Advanced Interpretation of Schoenbein Paper teacher resource for the conversion chart using humidity). A color conversion chart for the ozone paper can be found with the Air Quality unit materials or online from the Center for Excellence and Equity in Education ( colorscale.html).

Review all of the results as a class, stressing the “why, when, where, and how” of monitoring. Point out that monitoring helps to determine trends and to alert us to when pollutant levels are high.

be exposed to rain. Have students take outside monitors down during periods of rain or snow and place them in a plastic bag during these times. Remind students to record on their datasheet what time they took their monitor down and when they put it back up.

Note: In the next lesson, students learn to    use       Internet           resources         to         find            actual   outdoor levels of particle pollution and ozone. U.S. EPA’s AIRNow web site ( provides archived information that can be used to compare with the monitored particle pollution and ozone levels.

Assessment Options

1.   Tell students that they have $600,000 for new air monitors for the state of Michigan. Each monitoring station costs $100,000. Have them determine what they would like to monitor, where they would like the stations to be, and what    they     hope    to         find     out       from    their monitoring network.

Criteria                     Apprentice





Monitor was not correctly made.

Monitor was basically correct with a few modifications.

Monitor was successfully constructed.

Monitor was carefully constructed  exactly according to directions.



No rationale was given for the placement of  the monitor.

Some thought was given to the location for monitoring.

Monitor location takes into account ozone and particle levels.

Monitor location relates directly to ozone and particle levels.

Recording Results

In Table 1, no weather information was collected.

In Table 1, some weather information  was collected.

Table 1 was completely filled    out.

Table 1 was completely and correctly            filled    out in detail.



Did not provide an adequate interpretation of the ozone paper.

Provided an interpretation but did not compare with the control.

Correctly  interpreted the  color of the ozone paper and made  a comparison to  the control.

Correctly  interpreted the color and provided a thorough explanation.



Did not provide an average  number of  particles or observations.

Attempted to calculate the average number of particles and made some observations.

Calculated the average number of particles and made reasonable observations.

Calculated the average number of particles correctly and made detailed observations.

Scoring of Classroom Assessment

2.   Evaluate the air monitoring activity using the rubric below.

Adaptations/Extensions/ Enhancements

1.      An enhancement lesson on the MEECS Air Quality CD explores the use of biomonitors such as lichens and milkweeds to determine air pollution levels. Students identify different types of lichens in different areas and measure the percentage of lichen coverage on trees to determine how pollution is affecting the lichens in their area. Students measure the level of ozone damage to milkweed plants found in their community.

2.      Have students follow trends in visibility and relate them to weather conditions and pollution levels. This could be done by viewing haze cameras on the Internet or by setting up a visual air quality site (see Additional Resources and the MEECS Air Quality CD).

3.      Hold a contest for the best design and testing of other types of particle pollution detectors. Design suggestions are an index card or glass slide with a thin layer of petroleum jelly, a jar with       sticky      tape     around the       perimeter,        and      filter paper. With proper supervision, use detectors to monitor particles in vehicle exhaust.

4.      Create a “Particle Reference Library” by making slides of different kinds of particle pollution such as pollen, dust, and sand. Your reference slides can then be used to identify particles from student particle collectors.

5.      Ask students to test other methods of measuring ozone such as tracking deterioration of a rubber thread, and using a ZikuaTM (a test card optical reader) or an Eco Badge® (a compact, easy to use test card) produced by Vistanomics ( Note: Mention of these commercial products does not constitute endorsement.

6.      Encourage students to monitor acid rain and ozone following the protocols from the Global Learning      and      Observations   to         Benefit the

Environment (GLOBE) program on the MEECS

Air Quality CD or at the GLOBE web site ( Compare your data to student monitoring data from throughout the world. Particles in rainwater can be studied by filtering  the      water   and      examining        the       filter    paper when it is dry.

Assign students to monitor your classroom for radon and carbon monoxide. Detection devices may be available from your local health department        and      the       fire       department.

Additional Resources

Biomonitoring of Air Quality Using Plants 

This World Health Organization monograph reviews comprehensively the existing literature  on biological monitoring of air quality with plants. This review includes consideration of all plant species that are currently, or have a potential of, being used as bioindicators of air pollution.  Mulgrew, A. and P. Williams. (2000). Biomonitoring of Air Quality Using Plants. Retrieved  July 9, 2018, from whocc_hygiene_report_10.pdf

Chem Matters

ChemMatters is a quarterly magazine for high school chemistry students published by the American

Chemical Society. Sample issues are available online. The September 2002 issue describes NASA’s  Aura mission to observe and monitor the atmosphere. There is also an activity about measuring  ozone with Schoenbein paper. The September 2001 issue has several articles relating to ozone.  American Chemical Society. (2011). Chem Matters. Retrieved July 9, 2018 from

Educational Materials on Visibility Science and Regulations 

These are some introductory and educational materials on visibility science, issues, and laws and regulations. See an animation of how visibility changes with atmospheric conditions and download background material on visibility. Interagency Monitoring of Protected Visual Environments.  Educational Material on Visibility Science and Regulations. Retrieved July 9, 2018, from

Global Learning and Observations to Benefit the Environment (GLOBE

GLOBE is a worldwide student environmental monitoring program that links students to scientists. Measurements are taken in five general categories: atmosphere, soils, hydrology, land cover, and phenology. Students put their data on the GLOBE web site that is available for anyone to use. Global Learning and Observations to Benefit the Environment (GLOBE). Retrieved June 4, 2011, from http://

Global Ozone Project

In the Global Ozone (GO3) Project middle and high school students throughout the world are  measuring ground-level ozone on a continuous basis and uploading their data to an overlay in Google Earth. Measurements are made with high accuracy using sophisticated ozone monitors installed and maintained by the students and calibrated on a frequent basis using a transfer standard. GO3 students throughout the world are building the first global database for ground-level ozone. GO3 Foundation. (2011). Global Ozone Project. Retrieved June 4, 2011, from

Hands on the Land

Hands on the Land (HOL) is a network of field classrooms stretching across America from Alaska to Florida. HOL is sponsored by Partners in Resource Education, a collaboration of five Federal agencies, a non-profit foundation, schools, and other private sector partners. (2011). Hands On the Land

Retrieved June 4, 2011, from

Haze Cameras

Midwest Hazecam brings you live pictures and corresponding air quality conditions from scenic urban and rural locations in the upper Midwest. With Midwest Hazecam, you can literally see the effects of air pollution on visibility. The National Park Service also has web cams ( WebCams/index.cfm) as do many local sites in Michigan. Midwest Hazecam. Retrieved June 4, 2011,  from

History of Ozone. The Schoenbein Period, 1839-1868.

This paper in the Bulletin of the History of Chemistry describes Christian Schoenbein’s work on ozone beginning with its discovery in 1839. The first analytical instrument for ozone analysis was Schoenbein’s nose. His starch-iodide test was commercially available as a kit. Rubin, M. (2001). The History of Ozone. The Schoenbein Period, 1839-1868. Bull. Hist. Chem. 26(1): 40-56. Retrieved June 4, 2011, from

Lichens, Tardigrades (water bears), and Sulfur Dioxide

The PathFinder Science Network is a community of people interested in doing science research. There is no cost for registration but it is necessary to complete the simple registration, which is required to upload collaborative project data and/or publish student research work. Research on lichens and some very small organisms living on them can be used to assess atmospheric levels of sulfur dioxide, SO2. PathFinder

Science. Lichens, Tardigrades, and SO2. Retrieved June 4, 2011, from

Milkweed Monitoring

Lots of information on milkweed monitoring from the Wisconsin Department of Natural Resources.

The biomonitoring enhancement lesson was adapted from resources from this page as well as the

Wisconsin DNR milkweed biomonitoring kit. Wisconsin Department of Natural Resources. Milkweed Monitoring Project. Retrieved June 4, 2011, from milkweedmonitoring.htm

Recognition of Air Pollution Injury to Vegetation: A Pictorial Atlas

This reference discusses major air pollutants and their effects; the discussion is illustrated with more than

150 photographs. Flager, R.. (Ed.). (1998). Recognition of Air Pollution Injury to Vegetation: A Pictorial

Atlas. Pittsburgh, PA: Air & Waste Management Association


This site describes visibility impairment caused by air pollution in the United States. One of the  most basic forms of air pollution, haze, degrades visibility in many American cities and scenic areas.

Pictures and descriptions of haze in national parks and wilderness areas are included. United States Environmental Protection Agency. (2009). Visibility. Retrieved July 9, 2018, from

Download: Advanced_Interpretation_of_Schoenbein_Paper_Teacher_Resource.pdf

Download: How_Can_We_Monitor_Air_Pollution_Student_Activity.pdf

Download: Ozone_Monitors_in_Michigan_Transparency_Master_VpuDZZc.pdf

Download: Particle_Counting_Grid_Transparency_Master.pdf

Download: Particle_Pollution_Monitoring_Network_Transparency_Master_XIvjO1u.pdf

Download: Particles_in_the_Air_Transparency_Master_0XI0i2q.pdf

Download: Types_of_Particle_Pollution_Transparency_Master_fKRhqpj.pdf

Download: Whats_in_the_Air_Student_Resource__Activity.pdf

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