Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Table 1

Annual variation rates of O₃ and other air pollutants from satellite observations over three periods (2005–2011, 2012–2016, and 2005–2016) in the NCP.

		2005–2011	2012–2016	2005–2016
O3	Variation rate (DU·yr^−1)	0.55 ± 0.20	−0.16 ± 0.23	0.36 ± 0.09
	r^2	0.60	0.14	0.63
NO2	Variation rate (10^15 molec·cm^−2·yr^−1)	0.25 ± 0.05	−0.45 ± 0.11	−0.02 ± 0.05
	r^2	0.85	0.85	0.01
HCHO	Variation rate (10^15 molec·cm^−2·yr^−1)	0.24 ± 0.11	−0.19 ± 0.32	0.05 ± 0.07
	r^2	0.49	0.11	0.05
CO	Variation rate (10^18 molec·cm^−2·yr^−1)	−0.03 ± 0.03	−0.05 ± 0.05	−0.02 ± 0.01
	r^2	0.15	0.24	0.26
SO2	Variation rate (DU·yr^−1)	0.01 ± 0.02	−0.05 ± 0.00	−0.03 ± 0.01
	r^2	0.06	0.99	0.50