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 GordianUAA

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 ?

Estimated and Projected Anchorage Bowl Benzene Emissions from Motor Vehicles with and

without I/M

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1996 2007 2009 2011 2013 2015 2017 2019 2021 2023

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"Extra emissions" due to revocation of I/M

Emissions with I/M

Assume I/M is discontinued in 2012 and benzene content in gasoline drops from 5.1% to 1.3% in same

Year

new rule

VOC in gasolineRegular & premium grades were collected from 12 – 20 selected gas stations in Anchorage, bi-monthly for 6 times

Study Methods (Oct 2008 – Oct 2009)

VOC & PAH in ambient air24-hour air samples were collected for VOC & PAH once every 6 days at Airport Heights (residential area near Merrill Field Airport)

VOC in indoor airSelected 509 homes with attached garage Passive organic-vapor monitoring badges were exposed to indoor air for a week

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

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10/1 12/1 1/31 4/2 6/2 8/2 10/2

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10/1 12/1 1/31 4/2 6/2 8/2 10/2

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Seasonal changes in ambient VOC & PAH

More air toxins in winter!!

20092008

Annual mean

Annual mean

What about median?

Anchorage’s ranking in the Nation (2008-2009)

....

Source: EPA database (2008)

Rank City County StateMean Benzene conc. (ppbv)

1 Asheville Buncombe Co NC 3.682 Steubenville Jefferson Co OH 2.633 Tonawanda Erie Co NY 2.594 Tonawanda Erie Co NY 2.505 Tonawanda Erie Co NY 2.026 Port Arthur Jefferson Co TX 1.887 Galena Park Harris Co TX 1.128 Yorkville Paulding Co GA 1.079 Anchorage Anchorage AK 1.06

10 Near Longview Gregg Co TX 1.0211 Houston Harris Co TX 0.99

100 Seattle King Co WA 0.33267 Minneapolis Hennepin Co MN 0.17

Anchorage Seattle Minneapolis

Ethylbenzene 7 40 247

Toluene 2 122 232

Xylene 7 37 214

Nat’l Ranking of Other VOC

What about comparing to

other residential monitoring sites in

winter cities? Instead of

comparing with EPA’s Superfund

areas? Anchorage may be #1 for all

categories…

Source: Clean air coalition of western New York (www.cacwny.org/site.html)

Benzene ranking #3-5 --- Tonawanda, NY

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280

Newark Int’l Airport

Trucking & Trucking & cargo hubcargo hub

Other locations that made TOP 10 for 3 categories:

Azusa, Los Angels co, CA.

Burbank, Los Angels co, CA

Elizabeth, NJ

•High-volume traffic•Heavy industrial area •Trucking/train hub•Large facility of chemical company

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