APPENDIX B.4.
SIMILARITY BETWEEN MEASURED CONCENTRATIONS
CLUSTER ANALYSIS
EVALUATION OF THE
MONITORING NETWORK OF
AIR QUALITY IN BAJA CALIFORNIA
APPENDIX B.4
APPENDIX B.4.
SIMILARITY BETWEEN MEASURED
CONCENTRATIONS. CLUSTER ANALYSIS
This section shows the results of the Cluster analysis to the records of concentrations in the BC
monitoring network for the years 2005, 2006 and 2007. No subsequent years have been included
because they present a great lack of information.
Cluster Analysis is a data analysis technique that allows to solve classification problems. Its objective
is to sort objects, in our case Monitoring Stations, in groups (or clusters) so that the degree of
association/similarity between members of the same cluster is stronger than the degree of
association/similarity between members of different clusters. Cluster analysis is a method to discover
associations and data structures that are not obvious a priori but can be useful once they are found.
A hierarchical analysis was performed between groups with the Pearson correlation method.
B.4.1 ROSARITO-TIJUANA-TECATE REGION
Figure B.4.1 shows the average concentrations by season for the years 2005 to 2007, recorded by the
monitoring stations of the Tijuana-Rosarito-Tecate region. From this figure stands out the great
similarity between the levels registered in the stations Playas and Rosarito, and also can be seen the
same behavior in the recorded concentrations of all the stations, except for Tecate.
Location of the stations in Rosarito-Tijuana-Tecate region
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APPENDIX B.4
FIGURE B.4.1 AVERAGE OF RECORDED CONCENTRATIONS BY SEASON FOR THE YEARS 2005 TO 2007 IN THE
MONITORING STATIONS OF ROSARITO-TIJUANA-TECATE.REGION.
Figures B.4.2 to B.4.6, show the proximity matrices and dendrograms of the group of stations in the
region of Tijuana-Rosarito-Tecate, for the pollutants O3, NOx, NO, NO2 and CO, respectively. The
records of the average concentrations of the stations were compared to each other, using the same
pollutant with the method of hierarchical cluster between groups with Pearson correlation, in order
to compare the behavior of the registers of concentrations of the monitoring stations.
From these figures, a high correlation can be seen between the average concentrations reported by
the stations Playas and Rosarito.
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APPENDIX B.4
OZONE (O3)
PROXIMITY MATRIX
CASE
1: Rosarito
2: Playas
3: La Mesa
4: ITT
CORRELATION BETWEEN VECTORS OF VALUES
1: Rosarito
2: Playas
3: La Mesa
4: ITT
1.000
0.978
0.928
0.974
0.978
1.000
0.946
0.984
0.928
0.946
1.000
0.975
0.974
0.984
0.975
1.000
This is a similarity matrix
FIGURE B.4.2 PROXIMITY MATRIX AND DENDROGRAM OF O3 CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE ROSARITO-TIJUANA-TECATE.REGION.
NITROGEN OXIDES (NOx)
PROXIMITY MATRIX
CASE
1: Rosarito
2: Playas
3: La Mesa
4: ITT
CORRELATION BETWEEN VECTORS OF VALUES
1: Rosarito
2: Playas
3: La Mesa
4: ITT
1.000
0.981
0.980
0.993
0.981
1.000
0.985
0.982
0.980
0.985
1.000
0.991
0.993
0.982
0.991
1.000
This is a similarity matrix
FIGURE B.4.3 PROXIMITY MATRIX AND DENDROGRAM OF NOX CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE ROSARITO-TIJUANA-TECATE.REGION.
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APPENDIX B.4
NITROGEN OXIDE (NO)
PROXIMITY MATRIX
CASE
1: Rosarito
2: Playas
3: La Mesa
4: ITT
CORRELATION BETWEEN VECTORS OF VALUES
1: Rosarito
2: Playas
3: La Mesa
4: ITT
1.000
0.978
0.974
0.983
0.978
1.000
0.979
0.958
0.974
0.979
1.000
0.981
0.983
0.958
0.981
1.000
This is a similarity matrix
FIGURE B.4.4 PROXIMITY MATRIX AND DENDROGRAM OF NO CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE ROSARITO-TIJUANA-TECATE.REGION.
NITROGEN DIOXIDE (NO2)
PROXIMITY MATRIX
CASE
1: Rosarito
2: Playas
3: La Mesa
4: ITT
CORRELATION BETWEEN VECTORS OF VALUES
1: Rosarito
2: Playas
3: La Mesa
4: ITT
1.000
0.978
0.928
0.974
0.978
1.000
0.946
0.984
0.928
0.946
1.000
0.975
0.974
0.984
0.975
1.000
This is a similarity matrix
FIGURE B.4.5 PROXIMITY MATRIX AND DENDROGRAM OF NO2 CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE ROSARITO-TIJUANA-TECATE.REGION.
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APPENDIX B.4
CARBON MONOXIDE (CO)
PROXIMITY MATRIX
CASE
1: Rosarito
2: Playas
3: La Mesa
4: ITT
CORRELATION BETWEEN VECTORS OF VALUES
1: Rosarito
2: Playas
3: La Mesa
4: ITT
1.000
0.931
0.947
0.927
0.931
1.000
0.967
0.847
0.947
0.967
1.000
0.917
0.927
0.847
0.917
1.000
This is a similarity matrix
FIGURE B.4.6 PROXIMITY MATRIX AND DENDROGRAM OF CO CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE ROSARITO-TIJUANA-TECATE.REGION.
B.4.2 MEXICALI REGION
Figure B.4.7 shows the concentrations recorded by the monitoring stations of the Mexicali region.
From this figure stands out the great similarity between the levels registered in the stations UABCITM and between UABC-COBACH; being the registers of the Campestre station different from the
rest of the stations.
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246
APPENDIX B.4
FIGURE B.4.7 AVERAGE OF RECORDED CONCENTRATIONS BY SEASON FOR THE YEARS 2005 TO 2007 IN THE
MONITORING STATIONS OF MEXICALI REGION.
Figures B.4.8 to B.4.12, show the proximity matrices and dendrograms of the group of stations in the
region of Mexicali, for the pollutants O3, NOx, NO, NO2 y CO, respectively. The records of the
average concentrations of the stations were compared to each other, using the same pollutant with
the method of hierarchical cluster between groups with Pearson correlation, in order to compare the
behavior of the registers of concentrations of the monitoring stations.
From these figures, a high correlation can be seen between the average concentrations reported by
the stations ITM-UABC.
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APPENDIX B.4
OZONE (O3)
PROXIMITY MATRIX
CASE
1: ITM
2: COBACH
3: UABC
4: Campestre
CORRELATION BETWEEN VECTORS OF VALUES
1: ITM
2: COBACH
3: UABC
4: Campestre
1.000
0.458
0.867
0.032
0.458
1.000
0.769
0.654
0.867
0.769
1.000
0.287
0.032
0.654
0.287
1.000
This is a similarity matrix
FIGURE B.4.8 PROXIMITY MATRIX AND DENDROGRAM OF O3 CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE MEXICALI.REGION.
NITROGEN OXIDES (NOx)
PROXIMITY MATRIX
CASE
1: ITM
2: COBACH
3: UABC
4: Campestre
CORRELATION BETWEEN VECTORS OF VALUES
1: ITM
2: COBACH
3: UABC
4: Campestre
1.000
0.969
0.997
0.947
0.969
1.000
0.978
0.902
0.997
0.978
1.000
0.959
0.947
0.902
0.959
1.000
This is a similarity matrix
FIGURE B.4.9 PROXIMITY MATRIX AND DENDROGRAM OF NOX CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE MEXICALI.REGION.
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APPENDIX B.4
NITROGEN OXIDE (NO)
PROXIMITY MATRIX
CASE
1: ITM
2: COBACH
3: UABC
4: Campestre
CORRELATION BETWEEN VECTORS OF VALUES
1: ITM
2: COBACH
3: UABC
4: Campestre
1.000
0.756
0.937
0.753
0.756
1.000
0.933
0.879
0.937
0.933
1.000
0.884
0.753
0.879
0.884
1.000
This is a similarity matrix
FIGURE B.4.10 PROXIMITY MATRIX AND DENDROGRAM OF NO CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE MEXICALI.REGION.
NITROGEN DIOXIDE (NO2)
PROXIMITY MATRIX
CASE
1: ITM
2: COBACH
3: UABC
4: Campestre
CORRELATION BETWEEN VECTORS OF VALUES
1: ITM
2: COBACH
3: UABC
4: Campestre
1.000
0.984
0.997
0.903
0.984
1.000
0.974
0.873
0.997
0.974
1.000
0.920
0.903
0.873
0.920
1.000
This is a similarity matrix
FIGURE B.4.11 PROXIMITY MATRIX AND DENDROGRAM OF NO2 CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE MEXICALI.REGION.
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APPENDIX B.4
CARBON MONOXIDE (CO)
PROXIMITY MATRIX
CASE
1: ITM
2: COBACH
3: UABC
4: Campestre
CORRELATION BETWEEN VECTORS OF VALUES
1: ITM
2: COBACH
3: UABC
4: Campestre
1.000
0.784
0.805
0.685
0.784
1.000
0.864
0.848
0.805
0.864
1.000
0.892
0.685
0.848
0.892
1.000
This is a similarity matrix
FIGURE B.4.12 PROXIMITY MATRIX AND DENDROGRAM OF CO CONCENTRATIONS REGISTERED BY THE MONITORING
STATIONS IN THE MEXICALI REGION.
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