interaction of pm 2.5 in the san joqauin valley. introduction ▪ determine the relationship of pm...
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Interaction of PM 2.5 in theSan Joqauin Valley
Introduction
▪ Determine the relationship of PM 2.5 concentrations between three cities located in the San Joqauin Valley.
▪ The cities analyzed included: Fresno, Hanford and Bakersfield
▪ Daily PM 2.5 concentrations [µg/m³] from the California Environmental Protection Agency database was analyzed.
▪ Statistical Analysis Performed: Chi Squared Test, Pearson Correlation, Bootstrap Correlation, Least Squares Regression, Reduced Major Axis Regression, Principle Component Regression
▪ Vehicular emissions
▪ Diesel soot and chemical fumes from oil production
▪ Burning of coal for electricity
▪ Wood burning stoves / furnaces
▪ Chemical reactions of gases
▪ Pollution carried by prevailing winds
PM 2.5 Sources
Chi Squared Test -95% Confidence
▪ Null Hypothesis: The data sets are normally distributed
Location Chi_2 Chi_Calculated Null Hypothesis
Bakersfield 27.58 195.18 reject
Hanford 27.58 142.21 reject
Fresno 27.58 199 reject
0 5 10 15 20 25 30 35 40 45 500
100
200
Bakersfield
0 10 20 30 40 50 60 700
100
200
Hanford
San Joquain Valley Distributions
0 10 20 30 40 50 60 70 800
100
200
Fresno
Correlation and Regression Analysis
Pearson Correlation: 0.2738P-Value = .0100
Pearson Correlation: 0.3161P-Value = .0153
Pearson Correlation: 0.6873P-Value = .0123
0 5 10 15 20 25 30 35 40 45 50-10
0
10
20
30
40
50
60
70
80
90
Bakersfield [µg/m³]
Fre
sn
o [
µg
/m³]
PM 2.5 Concentration Correlation
PM 2.5 Data
Least SquarePrinciple Component
Major Reduced Axis
0 5 10 15 20 25 30 35 40 45 500
10
20
30
40
50
60
70
Bakersfield [µg/m³]
Ha
nfo
rd [
µg
/m³]
PM 2.5 Concentration Correlation
PM 2.5 Data
Least SquarePrinciple Component
Major Reduced Axis
0 10 20 30 40 50 60 70 800
10
20
30
40
50
60
70
Fresno [µg/m³]
Ha
nfo
rd [
µg
/m³]
PM 2.5 Concentration Correlation
PM 2.5 Data
Least SquarePrinciple Component
Major Reduced Axis
Bootstrap Test of Correlation Coefficient
Average Correlation Coefficient r computed using
the mean function yields:Location r- value
Bakersfield 0.2731Hanford 0.3193Fresno 0.6877
Which is in agreement with the Pearson
Correlation results:Location r- valueBakersfield 0.2738
Hanford 0.3161Fresno 0.6873
0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
200
400
Bakersfield-Fresno
0.2 0.25 0.3 0.35 0.4 0.45 0.50
200
400
Bakersfield-Hanford
Bootstrap:Correlation Coefficients
0.6 0.62 0.64 0.66 0.68 0.7 0.72 0.74 0.76 0.78 0.80
200
400
Fresno-Hanford
Conclusion▪ All three cities are not normally distributed however they all were
positively skewed
▪ Hanford- Fresno showed the greatest correlation of PM 2.5 followed by Hanford-Bakersfield
▪ Bootstrap Method results were in agreement with the Pearson Correlation results
▪ P-Values for all three cities were less than 0.05. The correlation is therefore considered statistically significant
Questions???