295
300
305
310
315
320
325
330
335
1979
1984
1989
1994
1999
2004
2009
2014
N
2 O mole fration / ppb
Time / yr
Annually Mean Nitrous Oxide Concentrations (1979-2017)
c
d
-20
80
180
280
380
480
580
1979
1984
1989
1994
1999
2004
2009
2014
CFCs mole fraction / ppt
Time/yr
Annually Mean CFCs Concentrations (1979-2017)
HCFC-22
CFC-11
CFC-12
HFC-134a
Air Pollution and Climate Change: Sustainability,
Restoration, and Ethical Implications, Fig. 4 Global
average changes of greenhouse gases abundances. (a) The
Keeling Curve (1958–2019.02). (b) Global average
concentrations of methane (1979–2017). (c) Global average
concentrations of nitrous oxide (1979–2017). (d) Global
average concentrations of CFCs and HCFCs (1979–2017).
((b, c, d) Dataset from NOAA/ESRL/GMD, 2019 [165])
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Air Pollution and Climate Change: Sustainability, Restoration, and Ethical Implications