Earth Science & Climate Change, San Francisco, 28 -30 July 2014
Potential Controls on Trends in Background Concentrations of
Hg in the Northeastern US
Huiting MaoDepartment of Chemistry
State University of New YorkCollege of Environmental Science and Forestry
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
Thompson Farm – TF, Durham, NH, sea levelPack Monadnock – PM, Pack Monadnock, NH, 700 aslHuntington Wildlife Forest – HWF, Adirondacks, NY, 510 m asl
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10
Hg
o A
no
ma
ly (pp
qv)
-40
-20
0
20
40
1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10
Hg
O
An
om
aly (p
pq
v)
-40
-20
0
20
40Thompson Farm
Pack Monadnock
Huntington
1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14
25
th p
erce
ntile
an
om
aly H
go
(pp
qv)-50
0
50
100
3.8±0.9 ppqv yr-1 Mace Head: 3.1±1.1 ppqv yr-1 Ebinghaus et al. (2011)
Cape Point South Africa3.8±0.6 ppqv yr-1, Slemr et al. (2011)
Canadian mid-latitude sites ~2.6 – 3.9 ppqv yr-1 Cole et al. (2013)
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
Pack Monadnock
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Rate
of C
ha
ng
e (p
pq
v yr-1
)
-16
-14
-12
-10
-8
-6
-4
-2
0
Thompson Farm
Huntington
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Rate o
f Ch
an
ge (p
pq
v yr-1
)
-20
-10
0
10
20
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Rate o
f Ch
ang
e (pp
qv yr
-1)
-6
-4
-2
0
2
4
6
• In colder months the trends were more associated with anthropogenic emission reductions;
• In warmer months other sources/sinks and processes became more significant and even predominant.
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
1/1/06 7/1/06 1/1/07 7/1/07 1/1/08 7/1/08 1/1/09 7/1/09 1/1/10 7/1/10
Hg
o (p
pq
v)
100
150
200
250 HWFTFPMHWFTFPM
HWF: -1.8 ± 3.4 ppqv yr-1
TF: -0.8 ± 1.9 ppqv yr-1
PM: -3.6 ± 1.4 ppqv mon-1
For the overlapping period February 2006 – August 2010
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
Hg0 MMAs corresponding to 75th percentile CO mixing ratios at TF and PM
1/1/03 1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11
Hg
o A
no
ma
ly (pp
qv)
-40
-20
0
20
40 a) TF
1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11
Hg
o A
no
maly (p
pq
v)
-40
-20
0
20
40 b) PM
1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14
95th percentile an
oma
ly Hg
o (pp
qv)
-100
0
100
200
300 c) HWF95th percentile Hg0 MMAs at HWF
4.8±0.7 ppqv yr-1
2.0±0.8 ppqv yr-1
3.5±1.3 ppqv yr-1
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
Figure 6.
PM GEM in Polluted Air Masses (CO>75th percentile)
TF (CO> 75th percentile)
HWF (95th percentile)
For TF, other sources/processes in warmer months could overtake anthropogenic influence.
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10
Hg
o A
no
ma
ly (pp
qv)
-40
-20
0
20
40
1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10
Hg
O
An
om
aly (p
pq
v)
-40
-20
0
20
40Thompson Farm
Pack Monadnock
Huntington
1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14
25
th p
erce
ntile
an
om
aly H
go
(pp
qv)
-50
0
50
100
Background Concentrations
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
1/1/03 1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11
Hg
o A
no
maly (p
pq
v)
-20
0
20
40
60a) TF
1/1/06 7/1/06 1/1/07 7/1/07 1/1/08 7/1/08 1/1/09 7/1/09 1/1/10 7/1/10 1/1/11
Hg
o A
no
maly (p
pq
v)
-100
0
100
200
300
400c) HWF
1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 H
go
An
om
aly (pp
qv)
-20
-10
0
10
20
30
40
50b) PM
2.1 ± 0.6 ppqv yr-1
1.6 ± 0.6 ppqv yr-1
22 ±6 ppqv yr-1
Anthropogenic Contribution
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
1/1/02 1/1/03 1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11
Hg
o A
no
maly (p
pq
v)
-40
-20
0
20
40
Pre
cipita
tion
(mm
)
0
100
200
300
400
500
1/1/02 1/1/03 1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11
Hg
o A
no
ma
ly (pp
qv)
-80
-40
0
40
80
Pre
cipita
tion
(mm
)
0
50
100
150
200
250
HWF
TF Background GEM vs. Precipitation
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
TF Wet Deposition
Lombard et al., 2011, acp
Earth Science & Climate Change, San Francisco, 28 -30 July 2014
Acknowledgments
This study was funded by NSF AGS 1141713 and EPA STAR 83521501