The Evolution of Temporal and Spatial Patterns of Carbon Monoxide Concentrations in the Metropolitan Area of Sao Paulo, Brazil

Table 2

Best fit and exponential fit trend lines and coefficient of determination () for the monthly average CO concentration time series of each station from 1996 to 2013. For the exponential fit, is the CO concentration (ppm) and is time (month).

Station	Group	Series length (year)	Best fit	-best fit (%)	Exponential fit	–exponential (%)	value	Decreasing (−)/increasing (+) rate (%)
SP1	1	17	Logarithm	76		76	0.0	−0.6
SP3	1	17	Logarithm	39		31	0.0	−0.3
SP4	1	17	Logarithm	87		84	0.0	−0.6
SP6	1	17	Logarithm	77		73	0.0	−0.5
SP7	1	14	Logarithm	76		76	0.0	−0.7
SP12	1	17	Logarithm	27		26	0.0	−0.3
SC	1	17	Logarithm	44		44	0.0	−0.3
OS	1	17	Second-degree polynomial	70		68	0.0	−0.4
SP5	2	8,5	Second-degree polynomial	23		19	0.0	−0.5
SAC	2	11,5	Second-degree polynomial	23		16	0.0	−0.3
SP8	3	11,8	Exponential	18		18	0.03	−0.3
TS	3	9	Exponential	20		20	0.03	−0.5
SP2	4	7,8	Second-degree polynomial	12		8	0.02	−0.3
SP9	4	6	Exponential	6		6	0.07	+0.3
SP10	4	6,5	Third-degree polynomial	24		14	0.12	−0.7
SAP	4	4	Second-degree polynomial	6		5	0.26	−0.2