Air Quality Lab: Data Analysis and Correlation of NO2, O3 and OX Concentrations in Toronto

Data Analysis

1.    Record the numbers of the days (e.g. 1 to 7) in the file name of your winter dataset.

2.    Include your formatted timeseries showing the concentrations of NO2, O3 and OX over seven days in the winter. 
Please upload either a PDF or a JPEG of your graph. 

3.    What is the mean and standard deviation of O3, NO2 and OX in your winter dataset?     

4.    Which of the three species calculated (O3, NO2 and OX) had the smallest relative standard deviation in your winter dataset? Does this observation make chemical sense? Explain you reasoning.

5.    Include the correlation plot for NO2 and O3 for your winter dataset. Be sure to include the equation for the trendline and the R2 value on the plot.
Please upload either a PDF or a JPEG of your graph.

6.    Are NO2 and O3 positively correlated, negatively correlated, or not well correlated in the winter dataset? Does the direction of the correlation (positive or negative or lack of correlation) in the winter dataset make sense given the background chemistry you know about these pollutants from the introduction? Explain your reasoning.

7.    Does the direction of the correlation (positive or negative or lack of correlation) in the winter dataset make sense given the background chemistry you know about these pollutants from the introduction? Explain your reasoning.

8.    Is it possible to confidently extrapolate the linear regression of the correlation plot (meaning extend your line) beyond the data plotted? Can the lines extend past the axes (into negative values)? Why or why not? Explain your reasoning.

9.    Record the numbers of the days (e.g. 1 to 7) in the file name of your summer dataset.

10. nclude your formatted timeseries showing the concentrations of NO2, O3 and OX over seven days in the summer.
Please upload either a PDF or a JPEG of your graph.

11.    Looking at your summer dataset only, do O3 and NO2 show the diurnal (meaning changes that happen over one day) trend that was discussed in the introductory video? Explain your answer.

12.  What is the mean and standard deviation of O3, NO2 and OX in your summer dataset?
      

13.    Include the correlation plot for NO2 and O3 for your summer dataset. Be sure to include the equation for the trendline and the R2 value on the plot.
Please upload either a PDF or a JPEG of your graph.

Correlation Plots

14.    In Ontario we are legislated by two separate air quality standards related to the concentration of O3: The Ontario 1-hour Ambient Air Quality Criterion (OAAQC) of 80 ppb and the Canadian 8-hour Ambient Air Quality Standard (CAAQS) of 63 ppb.
What is the highest concentration of O3 observed in either of your datasets? Does this concentration exceed the 1-hour limit of 80 ppb under the OAAQC? 

15.    What is the highest 8-hour mean O3 concentration in either of your datasets?  Does the highest 8-hour mean value exceed the limit of 63 ppb under the CAAQS? 

16.    Thinking about chemical exposure and the health risks of poor air quality, does it make sense that the 8-hour CAAQS regulation is lower than the 1-hour OAAQC regulation?  Explain your answer.

 

17.    For the highest ozone concentration observed in your datasets,  which you identified in question 15, how many molecules of ozone would you inhale in a typical adult breath of 500 mL? (Assume a total ambient pressure of 1.0 atm and a temperature of 37 oC in the lungs)
Show your work by either writing out your approach in the textbox or inserting a photo or image.

Concentrations of OX tend to be higher in the summer and lower in the winter. Use the plots and statistics you have generated thus far to comment on whether this trend was apparent in your data?

 

18.    Concentrations of OX tend to be higher in the summer and lower in the winter. Use the plots and statistics you have generated thus far to comment on whether this trend was apparent in your data?

19.    Concentrations of OX tend to be more variable in the summer than the winter. Use the plots and statistics you have generated thus far to comment on whether this trend was apparent in your data?

 

Increased concentrations of volatile organic compounds (VOCs) can result in increased production of ground-level ozone. In the spring and summer trees are a major source of natural VOCs and isoprene (C5H8, structure at the beginning of the equation below below) is one of the major chemicals emitted by them. The overall reaction of isoprene with O2 in the atmosphere is shown below. If trees in the City of Toronto emit approximately 200 moles of isoprene per hour in the summer, how many moles of ozone are potentially formed from this source each hour? (Note that OH in the equation below is the hydroxyl radical, an important atmospheric oxidant, not hydroxide).

22.    The relationship between NO2 and O3 described by reactions [1] and [3] in the introduction is an oversimplification of the complicated chemistry taking place in the atmosphere. The more chemistry taking place in the atmosphere overall, the more NO2 and O3 will deviate from this simplified relationship. Compare the data you generated for both the summer and winter datasets and comment on which season sees more additional chemistry. Does this make chemical sense?

 

23.    The data you have been discussing so far is from Toronto, visit this site where you will find air quality data from 2018 from across Canada.  Explore a few locations and see if you can find a rural spot on the map whose air quality is clearly not affected by the type of local vehicular emissions described in the introductory video of this lab.  

Provide the following:
1.    Name and NAPS number of the sampling location you choose.
2.    A screenshot of the plot of O3, NO2 and OX from the location you choose that demonstrates why you feel this is a rural location.  You can download a picture of the plot by hovering your cursor over the plot and selecting the camera icon (see the top righthand of the example plot from Calgary, AB below).
3.    An explanation of how the observed concentrations of O3 and NO2 indicate to you this is a rural location.