Airborne Organic Toxins
in Anchorage Ambient & Indoor Air

Will Changes in Gasoline Composition
Affect Toxics Levels?
(study updates)
Air Quality Program
Municipality of Anchorage
Dr. Mary Ellen Gordian
UAA
Why monitoring airborne organic toxics?
• In 1996 study, benzene level in
Anchorage homes (attached garage) was
5-times higher than homes in lower 48
• Alaska gasoline has higher benzene content
(roughly 5%) than gasoline in lower 48
• EPA’s new regulation: max benzene content
in gasoline < 1.3 % by July 2012
Lower benzene levels in indoor & ambient air ?
Any effects on other toxics like other VOCs, PAHs ?
Benzene emissions (lbs/day)
Estimated and Projected Anchorage Bowl
Benzene Emissions from Motor Vehicles with and
without I/M
2500
"Extra emissions" due to revocation of I/M
Emissions with I/M
2000
new rule
1500
Assume I/M is discontinued in 2012
and benzene content in gasoline
drops from 5.1% to 1.3% in same
1000
500
0
1996
2007
2009
2011
2013
2015
Year
2017
2019
2021
2023
Study Methods (Oct 2008 – Oct 2009)
VOC in gasoline
Regular & premium grades were collected from 12 – 20
selected gas stations in Anchorage, bi-monthly for 6 times
VOC in indoor air
Selected 509 homes with attached garage
Passive organic-vapor monitoring badges were exposed
to indoor air for a week
VOC & PAH in ambient air
24-hour air samples were collected for VOC & PAH
once every 6 days at Airport Heights
(residential area near Merrill Field Airport)
Annual mean conc. in gasoline, indoor & ambient air
VOC types
Gasoline
(%)
Indoor air
(ppbv)
Ambient
air (ppbv)
Benzene
5.1
4.7
1.06
Ethylbenzene
2.6
1.3
0.19
Toluene
18.4
12.8
1.85
Xylenes
14.4
5.8
0.87
Total BETX
40.5
24.6
3.96
4-7 times higher inside homes
Seasonal changes in ambient VOC & PAH
8
Benzene (ppbv)
7
6
More air toxins in
winter!!
5
4
3
2
Annual mean
1
3
Total PAH (ng/ m )
0
10/1
800
12/1
1/31
4/2
6/2
8/2
10/2
Date
700
What about
median?
600
500
400
300
200
Annual mean
100
0
10/1
12/1
2008
1/31
4/2
2009
6/2
8/2
10/2
Anchorage’s ranking in the Nation (2008-2009)
Source: EPA database (2008)
Rank
1
2
3
What about
4
comparing to
other residential 5
monitoring sites in6
winter cities? 7
Instead of
8
comparing with 9
EPA’s Superfund
10
areas? Anchorage
may be #1 for all11
County
Buncombe Co
Jefferson Co
Erie Co
Erie Co
Erie Co
Jefferson Co
Harris Co
Paulding Co
Anchorage
Gregg Co
Harris Co
....
categories…
City
Asheville
Steubenville
Tonawanda
Tonawanda
Tonawanda
Port Arthur
Galena Park
Yorkville
Anchorage
Near Longview
Houston
Mean Benzene
State conc. (ppbv)
NC
3.68
OH
2.63
NY
2.59
NY
2.50
NY
2.02
TX
1.88
TX
1.12
GA
1.07
AK
1.06
TX
1.02
TX
0.99
100
267
Nat’l Ranking
of Other VOC
Seattle
Minneapolis
King Co
Hennepin Co
WA
MN
0.33
0.17
Anchorage
Seattle
Minneapolis
Ethylbenzene
7
40
247
Toluene
2
122
232
Xylene
7
37
214
Benzene ranking #3-5 --- Tonawanda, NY
Source: Clean air coalition of western New York (www.cacwny.org/site.html)
Other locations that made TOP 10 for 3 categories:
•High-volume traffic
Azusa, Los Angels co, CA.
•Heavy industrial area
Burbank, Los Angels co, CA
•Trucking/train hub
Elizabeth, NJ
•Large facility of chemical company
280
78
78
Trucking &
cargo hub
95
Newark Int’l
Airport