Valuing the Benefits of Ecosystem Services Generated by the Reed Canyon Restoration Project: 1999-2009
Appendix D: Materials, Methods, and Data Collected for NO2 sampling
This study followed the sampling method prescribed by Palmes et al., with modifications suggested by Mavko (PSU). This sampling method was refined by Caleb Arata (Reed ’11).
The tubes - 3 tubes at each sampling site with one tube that remained capped as a control - were left at locations around Reed Campus from 4:00PM on November 22, 2009 and then collected at 10:30AM on December 11, 2009. This amounted to approximately a 2-and-a-half week deployment period. The tubes were typically placed at heights ranging from 0.5m to 2.0m on tree branches.
Only 18 sites survived the sampling period. There was presumably human interference in removing the tubes. There was also interference from wildlife. (It appeared as if as small animal has taken to chewing the caps off the tubes - rendering the set-up null.)
The tubes were then reacted with a reagent solution and the concentration of NO2 was analyzed using a spectrophotometer and a calibration curve. Multiple absorbance readings were taken of each tube. The computed [NO2], with the GPS coordinates of the sampling sites, is as follows:
Table 2: Atmospheric concentrations of nitrogen dioxide (ppb) at eighteen sampling sites around the Reed Campus.
|
Sampling sitea |
Canyon |
GPS coordinates (W,N)b |
elevation (ft) |
[NO2] (ppb)c |
|
1 |
No |
45.48092,-122.62707 |
123 |
10.5055 |
|
2 |
No |
45.48146,-122.62710 |
123 |
11.19916 |
|
3 |
Yes |
45.48154,-122.62660 |
121 |
7.906351 |
|
4 |
Yes |
45.48190,-122.62627 |
151 |
9.50991 |
|
5 |
Yes |
45.48239,-122.62521 |
145 |
10.67892 |
|
6 |
Yes |
45.48239,-122.62716 |
132 |
10.82785 |
|
7 |
No |
45.48266,-122.63091 |
141 |
12.74355 |
|
8 |
Yes |
45.48354,-122.63417 |
111 |
12.63134 |
|
9 |
No |
45.48459,-122.63497 |
97 |
16.50151 |
|
10 |
Yes |
45.48454,-122.63746 |
83 |
14.87959 |
|
11 |
Yes |
45.48235,-122.63709 |
58 |
14.51032 |
|
12 |
No |
45.48157,-122.63188 |
105 |
14.70414 |
|
13 |
Yes |
45.48207,-122.63381 |
145 |
11.57454 |
|
14 |
Yes |
45.48224,-122.63309 |
78 |
9.061077 |
|
15 |
No |
45.48196,-122.63538 |
90 |
14.54704 |
|
16 |
No |
45.47930,-122.62969 |
142 |
13.14342 |
|
17 |
No |
45.48129,-122.62993 |
154 |
14.20226 |
|
18 |
No |
45.48148,-122.62951 |
141 |
12.75375 |
a Sampling sites were selected randomly in an effort to create a distributive range of data inside and outside the canyon
bGPS coordinates and elevation measured using a GPS; the coordinates used a WGS84 datum.
cNO2 concentrations calculated by converting absorbance readings measured by a spectrophotometer; the absorbance readings are dependent on concentration of dissolved NO2 and duration of tube’s exposure.
Mean NO2 concentration in the canyon (11.29 ppb) was significantly lower than the mean NO2 concentration outside the canyon (13.37 ppb) (ANOVA, F=4.5506, df=1,17, P < 0.0487).
There is not a significant relationship between NO2 concentration and elevation (ANOVA, F=2.2180, df=1,17, P < 0.1559), and there is not a significant relationship between sampling site location and elevation i.e. there was a random distribution of elevations inside and outside the canyon (ANOVA, F=0.5736, df=1,17, P < 0.4958).