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Help needed: Ozone testing

Posted: Mon Jul 30, 2018 9:25 am
by lakshu_s
I wanted to explore if the concentration of outdoor ozone would decrease as you moved further away from a highway? I am testing, "If I place an ozone strip far away from the highway then the concentration of ozone on that strip will be less than a strip placed close to the highway".

I need your guidance please as always.

For this experiment I wanted Eco badge test cards and Colormetric chart. Please let me know where I would get these both. I saw in Amazon some products. But can you suggest please.

Correct me if I am wrong. We place the test cards in one location for 1 hour, and then compare the change of color in ozone strip vs colormetric chart and record the amount of ozone in parts per billion right? sorry i am new to Eco badge test cards. So not sure how to measure ozone amount. Can you tell me how to measure please.

Also I am planning to select two highways in my location. We are in St.louis. So selecting I170 and I64. I am planning to place 2 cards in 2 different locations close to highway and another 2 cards far from highways (probably near residential area) and check on the amount of ozone. Similarly, I am planning to repeat for another highway too. Does this seem correct to you? Any further thoughts on enhancing this experiment for getting better results.

Looking forward for your support.


Re: Help needed: Ozone testing

Posted: Tue Jul 31, 2018 7:30 pm
by LeungWilley
Hi Lakshu,
This sounds like a great experiment!

I am sorry to say that the eco badge kit that you mentioned in the post doesn't appear to be readily available any more.

You might want to consider something like this:

This item will give you both the test cards and the Colormetric chart. Please do note that you only need to expose these cards to the ambient air that you are measuring for 10 minutes. You will then compare strip to the chart and this will give you a range of reading. For the one shown in the links, the ranges are <less than 90, 90 to 150, 150 to 210, and greater than 210 micrograms ozone per cubic meter of air. (For Ozone, 1 ppb = 1.97 µg/m3 so you will need to convert these results to Parts Per Billion,ppb)

For this experiment, there are a couple of items that you will want to watch out for:
1. These test strips will only work under certain environmental condition such as % humidity. (Please refer to the directions for these tests strips). You will want to make sure to record these data (temperature, %RH, time of days, etc...) along with your test strip results to be sure that the data is valid.
2. In regards to the locations and the test, you have a very good idea / setup. The only suggestion I have is that you might want to repeat this experiment during different time of the day. For example, morning rush hour, mid-day, evening rush hour, etc...
3. You might also want to add a "control" area for testing so that you have data to show the accuracy of these test strips.

Finally, as a point of comparison, you may want to look at the ozone data from the EPA.

It looks the EPA have 2 monitoring station near St. Louis, one near I-70 (Hyde Park) and one near East St. Louis (I-64). It could be interesting to see how your data compares.

Best of Luck with your experiment!

Re: Help needed: Ozone testing

Posted: Wed Aug 01, 2018 9:14 am
by lakshu_s
Thanks so much Willey. This really helps to start with. I will first go step by step and please guide me as I progress for any questions. This area is new to me and I have study a lot to start with. Let me ask my mom to order the strips by this week.


Re: Help needed: Ozone testing

Posted: Wed Aug 01, 2018 1:36 pm
by lakshu_s
Hi Willey,
I went over all project details. I have some clarifications. Can you please help me out.

1. I am planning to consider the below variables:
Location((directions are relative to highway), Distance from Highway in feet, Temp C, Amount of Sunlight, Wind direction (from), wind speed in km/hr, Ozone ppb.
Please let me know if you think any additional variables are required?

2. Also you mentioned in your email that control variable is required. Can you give me an idea which location we can have as control.

3. In your email, you mentioned about looking at ozone data from the EPA. ... y-monitors

Can you please help me which link I have to go to from the above link. There are so many links in this page :?

4. You mentioned about 2 monitoring stations. Do I need to compare EPA of these 2 stations vs what i get. Can you help me to find Ozone from these 2 stations?


Re: Help needed: Ozone testing

Posted: Wed Aug 01, 2018 6:20 pm
by LeungWilley
Hi Lakshu,
It sounds like you are off to a very good start!

In regards to your question:
1. The list of variables looks good. I would suggest caution on a few of them though. Since you are using the ozone test strip, please note that you will not be getting a direct ozone ppb reading. In fact, you will be getting a range that's defined by the color chart. I would also be careful about the sunlight measurement. You may need to build something called a Pyranometer in order to do this measurement. Taking one step back, have you determined a hypothesis and how these variables will be used in the testing of this hypothesis? This usually helps me figure out if I have all the variables covered.

2. In regards to the control, this could be a room inside your home where the ozone level is fairly constant. The idea here is that the test strip should give you consistent results at this location so that you can have confidence about what it is telling you in the field.

3. Sorry about this. I should have been more clear in the last post. Here are the steps to look at the ozone data from the EPA Air Data Map:
Step 3A. At the website, please click on the graphic on the right hand of the page that says "Click to launch Air Data Map App," this should bring up a map of the United States behind a splash screen.

Step 3B. Once you close the splash screen, in the address bar on the left hand side of the page, type in St. Louis, MO, USA and the map should zoom into St. Louis.

Step 3C. Now, on the upper right hand side of the page, click on the left button (the one that looks like 3 sheets of paper stack on top of each other) , this will allow you to turn on the different stations that EPA uses to monitor air data. Select the box that says Ozone - Active and you should see 2 purple pin dropped on the map.

Step 3D. When you left-click on the pin, you can see the station information as well as the data that the stations have collected (Both annual data and daily data) . All of these data are in csv format that you can open with Excel or Google Spreadsheet. These data are just for comparison purposes only and it's entirely up to you to decide whether you want to use them.

I have attached a screenshot so that you can see what the screen should look like. (You can also adjust the base map, i.e. the button with 4 sheets of paper, to change the map to something that may be easier to read)

Good Luck and please post again if you have any other questions.

Re: Help needed: Ozone testing

Posted: Thu Aug 02, 2018 12:54 pm
by lakshu_s
Thanks so much Mr.Willey for your quick responses. It is really helping me a good start. But long way to go.
Regarding your questions:
1. I am planning hypothesis something as : If I place an ozone strip far away from the highway then the concentration of ozone on that strip will be less than a strip placed close to the highway. But of course once i decide dependent/independent variables i will modify the hypothesis accordingly.
In my list of variables I am including the amount of sunlight for which I am planning to record as clear/sunny/partly cloudy. Does that seem right? You mentioned about Pyranometer to do this measurement. Instead can we just record as clear/sunny/partly cloudy and keep them as constant.
so in my project Temperature, Amount of Sunlight, Wind speed, Wind direction will be constant variables.
Please correct me if I am wrong.

2. I get the point about control variable. Thanks.

3. I got good understanding about how to look at the ozone data from EPA map. I downloaded daily parameters. My question is which column corresponds to Ozone concentration? I guess it should be observation count or observation percentage. Can you please confirm on this. I see units of measure is either in ppb or ppm.

4. Also I was doing some research of converting micrograms ozone per cubic meter to ppb.
My question is : In Ozone strips we will be seeing 4 ranges. So for example if we get range of 90 to 150 what is the exact value we should record on our chart. I am sad eco badge kit is no longer :( .
you also mentioned 1 ppb = 1.97 µg/m3 . Can you please explain for one range so i will get better understanding.

Thanks again for all your time.

Re: Help needed: Ozone testing

Posted: Thu Aug 02, 2018 7:22 pm
by LeungWilley
Hi Lakshu,
No problem. Glad I am able to help.

Let's go through each of your responses:
1. Absolutely. You can use clear/sunny/partly cloudy as the amount of sun light during the time of data collection. I was not sure how you were planning to use that information (i.e. if you were planning on looking at chemical equations) which was why I asked about your hypothesis for this experiment. Based on your description, I feel that what you have listed will work fine.

2. Great!

3. I believe column U "Arithmetic Mean" is the ozone concentration in ppm. The observation count, I believe, is the number of sample that the machine took during the 1 hour window and the observation percentage is the percent of successful measurement.

4. Ok, I will try my best to explain it. The unit on this test strip is µg/m3 and it measures micrograms of gaseous pollutant per cubic meter of ambient air. At the product description part of the Amazon link:,

you will see the following conversion in the last sentence:
90 micrograms per meter cube ---> 0.0451 ppm.
150 micrograms per meter cube---> 0.0752 ppm.
210 micrograms per meter cube ---> 0.105 ppm

So, at the standard condition (20C, 1ATM), the number on the color strip is roughly 2 times the number in ppb. (1 ppm = 1000ppb so if you multiply 0.0451 *1000, you will have 45.1 ppb. So 90µg/m3 = 45.1 ppb)

So, for the range 90 - 150 µg/m3, it is 45.1 - 75 ppb. This would be the results of your test strip.

I hope that helps! Good luck and please post again if you have other questions.

Re: Help needed: Ozone testing

Posted: Mon Aug 06, 2018 2:42 pm
by lakshu_s
Thanks again for your time Mr.Willey.

I understood your responses from 1-3. Please find below my clarifications.

1. On 4th, I have a question. I understood about the conversion from µg/m3 to ppb. Thanks so much.
You mentioned for the range 90 - 150 µg/m3, it is 45.1 - 75 ppb.
My question is: As part of this experiment I am planning to record the ozone concentration vs distance in feet from highway.
In that case I would need to record correct ozone concentration right?
For example: Let us take for distance from highway is 300 feet and we are getting ozone concentration range as 45.1 - 75 ppb, then what I should consider while graphing. If it is exact measurement, then it would be easy for me to plot the graph. Please suggest.

2. Also can you suggest how to calculate distance. I guess from google maps we can calculate the larger distances between 2 locations.
But for shorter distance if I am selecting random place near highway which exactly don't have address, then how do you think I should record? Can I take approximate distance by using the foot steps?

Also once I select the locations I will share with you. I am planning to start my experiment in next 2 weeks.

Thanks again.

Re: Help needed: Ozone testing

Posted: Mon Aug 06, 2018 6:42 pm
by LeungWilley
Hi Lakshu,
Good Questions! In regards to:
1. Unfortunately, given the limitation of the test strips, I think all we can do is to categorize each band as a category. For example, let's say that 0 to 45 ppb is "low", 45 -75ppb would be "medium",. etc... Then, using this scale on a graph or map, you can show the different bands vs. the distance from the highway. If you want to go with more precise ozone measurements, we may need to reconsider the test strip and go with something like an ozone meter.

These are very expensive to purchase but you may be able to rent / borrow them from a local university. You will probably need to get your teacher involved to borrow the equipment though. Here's a link for one of the university that I believe is near St. Louis with this kind of program:

2. In regards to calculating distance, I think google map (right click on the map and select measure distance) is your best bet. For location that does not have an address, I would suggest recording the GPS coordinates (there are a number of apps for your phone that can give you this info). Once you have these coordinates, you can enter them back into google map and measure the distance.

Hope that helps! Good Luck!

Re: Help needed: Ozone testing

Posted: Wed Aug 08, 2018 2:33 pm
by lakshu_s
Thanks again for your responses Mr.Willey.

Please find below my questions in regards to your previous email.

1. I guess it is best to consider as low, medium and high categorization for each range.
In that case, my thoughts are to plot for distance from highway vs the range and plot them as bar graph. Let me know your thoughts please if bar graph is good option.
I am planning to take the readings for each highways (I64 and I70 in st.louis). For each highway, I am planning to select 2 locations near highway , 2 locations little farther from highway and 2 locations farthest from highway and record the ozone concentration for them. I am planning to plot individual graph one for I64 and one for I70 and see if that supports my hypothesis. Does this sound correct?

2. I got the idea of using GPS coordinates. Thanks for your help.

3. I have another clarification: Since we are keeping temperature as constant variable, do you think it should be always same temperature for all the scenarios or if the temperature should be constant for each location in the highway? Also time is constant variable. Do I need to record the ozone levels at the same time of each day? how does this work.
Can I just keep Date, Time, Temperature, Amount of sunlight, Wind direction, Wind speed constant for each location? Also I am including Ozone strips brand as constant.

4. Can you please give me some background on how to calculate wind direction from and Wind speed in km/hr?

Thanks again for your time.

Re: Help needed: Ozone testing

Posted: Thu Aug 09, 2018 9:57 am
by LeungWilley
Hi Lakshu,
Great questions! Let's try to tackle each one below.
1. I am not sure bar graph is the best option to display the data for this experiment. Just as a suggestion, you may want to consider flipping the axis that you described. - (i.e. the concentration of ozone (y-axis) vs. Distance from the highway source (x-axis). With this setup, I think a line graph or a scatter plot would help demonstrate the relationship of ozone vs. Distance from highway more clearly. Also, with this kind of setup, you can put both set of data on the same graph.

3. I don't think we can say that temperature is going to be constant since we won't have any control over the weather. (Similarly, time, amount of sunlight, wind direction will all be changing during the day so they are not constant either). The best that we can do is record all of these variables and see if we find other relationships to enhance your hypothesis. For example, let's say on a windy day, can you see how much further the ozone travel or does it dissipate more quickly? What is the effect on the amount of sunlight in ozone level? (Lower or higher on cloudy day?) Unfortunately, all of these variables are one of the big challenges of all field experiment.

4. For wind direction, I think a wind sock and a compass is probably your best bet. In terms of wind speed, please google "anemometer". There are a lot of instruction on YouTube on how to build one and use it to measure wind speed.

Good luck and please post again if there's anything else we can help with.

Re: Help needed: Ozone testing

Posted: Wed Aug 15, 2018 11:52 am
by lakshu_s
Hi Mr.Willey,

Thanks so much for your answers. Sorry it took me long to make some further research. Also I am back to school. I have some clarifications after going through your responses.

1. Regarding the graph, if I understood correctly, I am going to consider Distance from Highway(in feet) in X-axis and Ozone concentration in ppb in Y-axis. Sure I will plot as line graph or scatter plot.
My question: Since I am going to consider two different highways, I was planning to plot 2 different graphs one for I-64 and another for I-70 and compare both to make sure my hypothesis is correct (If I place an ozone strip far away from the highway then the concentration of ozone on that strip will be less than a strip placed close to the highway). Please correct me if you think otherwise.

2. As you mentioned, instead of taking other factors as constants in my experiment, I will record the temperature,wind speed, wind directions as other factors that impacts the ozone concentration. Also I will make sure the temperature stays more or less constant on each of the day I experiment, so on day it is not extremely cold or hot compared to other day. Does that sound correct?
So IV is: Distance from Highway(in feet)
DV: Ozone concentration in ppb
Constants: I will make sure to record ozone at the same time on each day . Amount of sunlight I will make sure as clear/sunny.

Modifying the hypothesis including these factors will further make this experiment complicated. So I would like to stick to what I thought. But I am really confused on constants.

3. For wind direction and wind speed, I found Underground Weather Internet site to record them. Is that correct.


Re: Help needed: Ozone testing

Posted: Fri Aug 17, 2018 1:19 pm
by LeungWilley
Hi Lakshu,
Hope the start of your new school year is going well! Sorry for the delayed response. I was travelling and just got to this post now.

Going through you responses:
1. Ok, I think your "two-graph" approach sounds reasonable. The one thing I would watch out for is that your hypothesis is basically stating that the primary source for ozone are the vehicles on the highways. With this in mind, you may want to select your test location based on some of the traffic data or traffic speed (since more traffic = typically slower speed). Here's are several sources for this type of information:

2. I am sorry about this. I may have confused you with my response in the previous post. The weather (sunlight, wind direction, time, traffic, etc..) are all "controlled variables." (constant variables)
Please take a look at this link:
(These are also called "constant variable" - sorry, I was not familiar with that term until I read up on that link.) Finally, I agree with your IV and DV.

3. Absolutely, weather underground is a very good resource for this. The only thing that I would suggest is that you select test locations that are near the weather stations that's providing you this data if at all possible. Parts of city can sometime have their own mini-weather system (I am not sure if this is the case in St. Louis but is an definite observable effect in New York, Boston, Chicago, etc...)

Hope this helps! Best of luck with your experiments!

Re: Help needed: Ozone testing

Posted: Mon Aug 20, 2018 2:28 pm
by lakshu_s
Hi Mr.Willey,

Np. Thanks for your time. I will go over the links sent by you and let you know if any questions.

I have real confusion on the variables.

For IV and DV I am clear.

[color=#0000FF]In my previous experiment last year, where my hypothesis is "If Carbon dioxide concentration levels from different sources (Normal Air (natural surrounding air), Air from lungs, and Car Exhaust) are compared for the temperature variation, then the rate at which the temperature of the air cools down in one hour will be slowest for Car Exhaust (which has the highest Carbon dioxide concentration level) compared to that of the other two sources."
My variables are:
Independent Variables: Carbon dioxide Concentrations of different Sources (Normal Air, Air from lungs, Car Exhaust)
Dependent Variables: Rate of Temperature Variation (in degrees Celsius) in one hour
Constants: Environmental location, Initial temperature of the air in the tank (32.4 degrees Celsius), Type of the soil (black soil), Amount of the soil at the base of the tank (4 cups), Volume of the tank (1 gallon)

Controlled Variables: Normal Air[/color]

Similar to that in my current experiment, I am confused on constants and controlled variables.
I am guessing the constants and controlled variables are as below:

Constants: Time, Amount of Sunlight, Type/Brand of Ozone strip

Controlled Variables: Ozone concentration at home, Temperature, Wind speed, Wind direction

Please correct me if I am wrong.


Re: Help needed: Ozone testing

Posted: Tue Aug 21, 2018 1:55 am
by LeungWilley
Hi Lakshu,
I think you pretty much got it. The only changes that I would suggest you to consider is that "Ozone concentration at home" is a constant instead of a controlled variable. (I would also suggest moving "Amount of Sunlight" to Controlled Variable as well)

To put it another way, "Controlled Variables" have a direct and immediate impact on the DV. While you are trying to minimize the impact of these "Controlled Variables" by trying to keep them as constant as possible, it is not always within your control. Constants are always "fixed" in the experiment. (For example: Time = 10 minutes for every measurement, Type / Brand of Strip, etc...)

Hope this helps! Good Luck!