Asset Details
Do you wish to reserve the book?
Chemical feedbacks weaken the wintertime response of particulate sulfate and nitrate to emissions reductions over the eastern United States
Hey, we have placed the reservation for you!
By the way, why not check out events that you can attend while you pick your title.
Oops! Something went wrong.
Looks like we were not able to place the reservation. Kindly try again later.
Are you sure you want to remove the book from the shelf?
Chemical feedbacks weaken the wintertime response of particulate sulfate and nitrate to emissions reductions over the eastern United States
Do you wish to request the book?
Chemical feedbacks weaken the wintertime response of particulate sulfate and nitrate to emissions reductions over the eastern United States
Please be aware that the book you have requested cannot be checked out. If you would like to checkout this book, you can reserve another copy
We have requested the book for you!
Your request is successful and it will be processed during the Library working hours. Please check the status of your request in My Requests.
Oops! Something went wrong.
Looks like we were not able to place your request. Kindly try again later.
Journal Article
Chemical feedbacks weaken the wintertime response of particulate sulfate and nitrate to emissions reductions over the eastern United States
2018
Overview
Sulfate (
SO
4
2
−
) and nitrate (
NO
3
−
) account for half of the fine particulate matter mass over the eastern United States. Their wintertime concentrations have changed little in the past decade despite considerable precursor emissions reductions. The reasons for this have remained unclear because detailed observations to constrain the wintertime gas–particle chemical system have been lacking. We use extensive airborne observations over the eastern United States from the 2015 Wintertime Investigation of Transport, Emissions, and Reactivity (WINTER) campaign; ground-based observations; and the GEOS-Chem chemical transport model to determine the controls on winter
SO
4
2
−
and
NO
3
−
. GEOS-Chem reproduces observed
SO
4
2
−
−
NO
3
−
−
NH
4
+
particulate concentrations (2.45 μg sm-3) and composition (
SO
4
2
−
: 47%;
NO
3
−
: 32%;
NH
4
+
: 21%) during WINTER. Only 18% of SO₂ emissions were regionally oxidized to
SO
4
2
−
during WINTER, limited by low [H₂O₂] and [OH]. Relatively acidic fine particulates (pH∼1.3) allow 45% of nitrate to partition to the particle phase. Using GEOS-Chem, we examine the impact of the 58% decrease in winter SO₂ emissions from 2007 to 2015 and find that the H₂O₂ limitation on SO₂ oxidation weakened, which increased the fraction of SO₂ emissions oxidizing to
SO
4
2
−
. Simultaneously, NOx emissions decreased by 35%, but the modeled
NO
3
−
particle fraction increased as fine particle acidity decreased. These feedbacks resulted in a 40% decrease of modeled [
SO
4
2
−
] and no change in [
NO
3
−
], as observed. Wintertime [
SO
4
2
−
and [
NO
3
−
] are expected to change slowly between 2015 and 2023, unless SO₂ and NOx emissions decrease faster in the future than in the recent past.
Publisher
National Academy of Sciences
Subject
