Short reports
ScienceAsia (): 341-345 |doi:
10.2306/scienceasia1513-1874...341
Estimation of missing values in air pollution data using single imputation techniques
Mohamed Noor Noraziana,*, Yahaya Ahmad Shukric, Ramli Nor Azamc, Abdullah Mohd Mustafa Al Bakrib
ABSTRACT: Air pollution data obtained using automated machines often contain missing values which can cause bias due to systematic differences between observed and unobserved data. We used interpolation and mean imputation techniques to replace simulated missing values from annual hourly monitoring data for PM10. The most effective method for generating the missing data points was to replace each missing value with the mean of the two data points before and after the missing value. This approach was referred to as the mean-before-after method.
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| a |
School of Environmental Engineering, Malaysia University of Perlis, Pejabat Pos Besar, 01007 Kangar, Perlis, Malaysia |
| b |
School of Material Engineering, Malaysia University of Perlis, Pejabat Pos Besar, 01007 Kangar, Perlis, Malaysia |
| c |
School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang, Malaysia |
* Corresponding author, E-mail: norazian@unimap.edu.my
Received 29 Oct 2007, Accepted 17 Jun 2008
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