5.1. GAM vs UK: Mapping Spatial Variability of NO2

This is an array of figures that articulate the spatial variability of Seoul's mean NO₂ by each period. Each figure represents a month, and there is a comparison of GAM and UK and an aggregated time series of top, middle, and bottom. The dark green and dark red represents the lowest and highest areas from the average concentration.

For the entire period, the highest values from the mean are mostly situated in the southeast of Seoul (Seongnam) that are at least 4-15ppb higher than the other area. This area is seemed to have been consistently high due to the overflowing number of vehicles from the Kyeongbu Highway (National Highway NO.1) that integrated many small highways that lead to Seoul. The largest range between the highest area (SE Seoul) and lowest area(NW and N Seoul) was roughly at 30ppb during December 2013-January 2014. The second higehest area is the CBD of Seoul. The distibution only differed in February 2014 where the concentration is the lowest in the north and tends to increase as it goes towards the south.

Overall, apart from the first 10 days in December 2013, the spatial variability of both methods turned out to be similar and the boundaries were smoother from the GAM method.

August 2013

Mean (ppb)

	GAM_mean	UK_mean
Aug1	22.668	22.951
Aug2	19.311	19.406
Aug3	24.731	24.929

September 2013

Mean (ppb)

	GAM_mean	UK_mean
Sep1	24.421	24.414
Sep2	27.788	27.975
Sep3	24.578	24.654

December 2013

Mean (ppb)

	GAM_mean	UK_mean
Dec1	42.688	42.897
Dec2	34.675	34.857
Dec3	41.941	42.015

January 2014

Mean (ppb)

	GAM_mean	UK_mean
Jan1	38.239	38.33
Jan2	39.458	39.3
Jan3	41.452	41.7

February 2014

Mean (ppb)

	GAM_mean	UK_mean
Feb1	25.174	25.485
Feb2	34.461	34.953
Feb3	52.319	52.923