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From Lot To Spot Carbon Dioxide Mapping Project


Background
Lennox is an unincorporated neighborhood within Los Angeles county. As it is bracketed by both the 105 and 405 freeways, lacks significant green space, and is directly east of Los Angeles International airport, it is known to have elevated levels of air pollution. As a way of engaging some members of the community with these issues From Lot To Spot (FLTS), in partnership with YouthBuild Charter, had a class of high school students take readings of the atmospheric concentration of carbon dioxide at five sites near their school.
Carbon dioxide gas, in of itself, is relatively harmless to human health. It was measured for two reasons. First, it is typically found in the presence of other pollutants, such as nitrous oxides and particulate matter, and is therefor a good proxy for other air quality metrics. Second, it is straightforward to measure with off the shelf hardware by high school students with minimal levels of training.

Training and procedures
As part of a classroom activity students were introduced to the issues of air quality and urban planning by members of FLTS on May 20th, 2014. The second half of the activity consisted of an introduction to using handheld carbon dioxide monitors and dataloggers from Pasco, as well as the data taking procedure. The procedure used for this project is as follows:
1. Before taking data at a given site run through a calibration with the monitor. This is done by sealing the sensor in a plastic jar and waiting for the reading to stabilize before exposing the sensor to the open air.
2. For a given device take a reading of CO2 levels.3. At intervals of about a minute retake the the CO2 level until five readings are taken.4. Calculate the average reading. This is the device average.5. Calculate the difference between the highest and lowest reading to calculate the range. This is the device range.6. Percent variability will be range/average. The larger this value the less reliable the data is from each monitor. This is the device variability.7. Repeat the calculations for the average, range, and variability, but using the average values for each monitor as your data set. This will give the group average, range, and variability.
Data collection
About fifteen high school students, over the course of an afternoon on May 22nd, 2014, used four different monitors to capture carbon dioxide levels in the vicinity of their school. These results were recorded on paper, then transcribed to an online spreadsheet and mapped. The maps below are color coded such that concentration increases from red to violet, and that spot size increases with the relativity variability of the data taken at that location. This means that a violet spot has a higher concentration than a blue spot, which in turn has a higher concentration than a red spot. The larger the spot the more variable the data was at that location. This could be due to calibration issues between devices as well as rapid movement of air with varying levels of carbon dioxide over a given area. It was noted on numerous occasions that the carbon dioxide level would rise quickly within twenty seconds of a plane flying overhead a testing location.

Maps and data
Device 1
Device 2
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Map2.png
Device 3
Device 4
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Averaged Map
Source Data
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Source Data
Interactive Map

View LennoxCO2Sites in a full screen map



Preliminary analysis
The final map represents 100 data points collected over the span of a few hours. While further data taking would be needed to draw stronger conclusions there are a few notable results which can be gathered from the averaged map and data. One, all of the sites reported levels of carbon dioxide above the background level of 400ppm. Two, there is a general trend towards carbon dioxide levels increasing as one goes under the flight path running east northeast from the runways at LAX. Three, the relative variability tends to increase with the average level of carbon dioxide concentrations. This relative variability would most likely be countered with taking data over a longer interval in order to average out the effects of the periodic spiking of exhaust gases from descending planes.

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