NFII 4BFRCROMBIE 

OOVE ~:Y-l 

Mr. Jared Blumenfeld 

Regional Administrator 

U.S. EPA, Region IX 

75 Hawthorne Street 

EXECUTIVE CH A MBERS 

HO ~OLULU 

May 19,2011 

jii;;;J;~~t SUBJECT: Recommended Designation for the Newly Promulgated 1-Hour Federal 

Sulfur Dioxide (S02) National Ambient Air Quality Standard (NAAQS) 

Pursuant to Section 1 07(d)(1) of the Clean Air Act, I am recommending that all counties 

in the State of Hawaii be designated as unclassifiable. The U.S. Environmental 

Protection Agency (EPA) requires that attainment determinations be made using both 

monitored and modeled data. Although the Department of Health (DOH) has monitored 

S02 data from seven ambient air monitoring stations, modeling was not conducted but 

will be performed in accordance with the recently Issued modeling guidance. 

A summary of the 2008 to 201 o S02 data collected at all monitoring stations is 

presented in Attachment I. Exceedances of the 1-hour S02 standard on the island of 

Hawaii are due to emissions from the ongoing Kilauea volcano eruption and have been 

flagged accordingly in EPA's Air Quality System (AQS). Documentations have been 

submitted to EPA for concurrence with excluding the flagged data as exceptional 

events. There have been no exceedances of the 1-hour S02 standard on the island of 

Oahu, where the majority of anthropogenic sources are located. 

We look forward to working with EPA, Region IX, on the final S02 designation. If you 

have any questions, please contact Mr. Wilfred Nagamine of the DOH, Clean Air 

Branch, at (808) 586·4200. 

Attachment 

c: Deborah Jordan. Director, Air Division (AIR-1 ). U.S. Environmental Protection 

Agency, Air Division 

Gwen Yoshimura, Air Quality Analysis Office (AIR-7), U.S. Environmental 

Protection Agency 
DATE ~ :>o f l.'() 1 1 

ACTION .I~ CQPifD (.f) 

RA / IRA 

ORA I ORA 

I/ A.IR AIR 

CEO CEO 

MTS UTS 

OPA (B 

ORC ORC 

#RJ«) "RIND 

SCfO SCR) 

t*m r-sn: ~Mat WA1a 

II ~d.;~ 
State of Hawaii 

Attachment 1: Designation Recommendation of the 1-Hour S02 NMOS 

ATTACHMENT I 

State of Hawaii 

Designation Recommendation of the 1-Hour Sulfur Dioxide (502) National 

Ambient Air Quality Standard (NAAQS) 

I. Recommendation 

As detailed in this document. it is recommended that all counties in the State of 

Hawaii be initially designated as unclassifiable for the 1-hour S02 NAAQ8. Without 

the modeled 802 component, the state cannot make a definitive determination of 

attainment or non-attainment. 

During the most recent complete data years of 2008 to 2010, there were seven S02 

monitoring stations in the state. Three S02 monitors were located in the City and 

County of Honolulu, which encompasses the island of Oahu and is the only 

Metropolitan Statistical Area (M8A) in the state. Four S02 monitors were located in 

Hawaii County for the monitoring of volcanic emissions. No 802 monitoring was 

conducted in the rest of the state which includes the Counties of Kauai {islands of 

Kauai and Niihau), Kalawao (Kalaupapa), and Maui {islands of Maui, Molokai, lanai 

and Kahoolawe). 

II. Basis for the Recommendation 

The U.S. Environmental Protection Agency (EPA) revised the primary health-based 

S02 NAAQS by establishing a new 1-hour S02 standard effective June 2, 201 0. 

Pursuant to the Federal Clean Air Act 107(d) (1), states are required to make 

attainment, nonattainment, or unclassifiable recommendations one year after 

promulgation of a new standard. 

To determine compliance with the new 1-hour 802 NMOS, EPA is requiring a 

hybrid approach using both monitored and modeled data. However, timely guidance 

in conducting large-scaled refined modeling for 802 was not provided and in 

absence of modeled data the state can only recommend an unclassifiable 

designation. 

Using monitoring data, the 1-hour 802 standard is attained when the three year 

average of the gglh percentile of the daily maximum 1-hour average at each moni1or 

does not exceed 75 parts per billion (ppb). In 2008 to 2010, all three monitors in the 

Honolulu MSA showed no violations of the standard. The ambient air stations on 

the island of Hawaii were established to monitor the impact of 802 emissions from 

the Kilauea volcano. Although the four monitors showed exceedances of the 1-hour 

standard, the data from these stations were flagged as being due to a natural event. 

The state has submitted the required exceptional events documentations to EPA 
State of Hawaii 

Attachment 1: Designation Recommendation of the 1-Hour S02 NAAOS 

Region 9 providing the causal relationship between the active volcano and the S02 

exceedances. With the data excluded, all stations on the island of Hawaii would be 

in compliance with the standard. 

Therefore, although none of the Honolulu M8A 802 monitors violated the standard, 

the area is unclassifiable because of the absence of large-scaled refined modeling. 

There were exceedances of the standard in Hawaii County but the area is 

unclassitiable because the data is due to a natural event awaiting exclusion 

concurrence by EPA and there is a lack of modeling data. The rest of the state 

(Kauai, Maui, and Kalawao Counties) is unclassifiable because there was no 802 

monitoring or modeling conducted. 

Ill. Data Exclusion Due to a Natural Event 

The S02 ambient air monitoring stations on the island of Hawaii were established to 

monitor impacts from volcanic emissions. The Kilauea volcano has been erupting 

continuously since 1983 emitting on average 2,000 tons per day of 802. In March 

2.008, a second vent opened at the summit causing an increase of S02 up to 9,000 

tons per day at one point. The Hilo and Mountain View stations were established to 

monitor 802 during southerly winds; the Pahala and Kana stations were established 

to monitor 802 during the prevalent northeasterty winds. 

All hour1y data of 75 ppb and greater from these stations have been flagged with the 

AQ8 code "AS" for volcanic eruption. Quarterly exceptional events documentations 

have been submitted to EPA Region 9 for concurrence with the flags for data 

exclusion. 

In the 2008 national emissions Inventory, S02 emissions from anthropogenic 

sources in Hawaii County were 73 percent less than in the City and County of 

Honolulu. This equated to 5,257 annual tons of 802 emitted in Hawaii County 

compared to 19,678 tons emitted in the City and County of Honolulu from point, 

area, on-road, and off-road sources. However, 802 emissions from biogenic 

sources were attributed entirely to the volcano at 961 ,366 annual tons in Hawaii 

County compared to zero tons in all other counties. The volcano is clearly the single 

largest 802 emitter in the state. 

IV. 2008 to 201 0 1-Hour SO~ NAAQS Compliance Data 

The following table presents the 991h percentile values and the 3-year average from 

2008 to 2010 at the three stations in the City and County of Honolulu and the four 

stations on the island of Hawaii. The three year average ggltl percentile of the daily 

maximum 1-hour 802 values is the metric that detennines atta.inment of the 

standard. All daily maximum values 75 ppb and above collected from the stations 

on the island of Hawaii were excluded from consideration. 

There was no S02 monitoring in Kauai and Maui counties. 
State of Hawaii 

Attachment 1: Designation Recommendation of the 1-Hour 802 NAAOS 

Station 2008 2009 2010 3-~ear average 

99th percentile 99th percentile 99111 percentile 99 percentiles 

City & County of Honolulu 

Honolulu (150031001) 11 15 13 13.0 

Kapolei ( 15003001 0) 16 9 18 14.3 

VVestBeach (150030011) 13 15 12 13.3 

Hawaii County 

Hllo (15001 1006) 51 53 56 54.0 

Kona (15001 1012) 67 49 60 58.7 

Pahala (1 5001 2016) 72 74 70 72.0 

Mt. V1ew (150012017) 58 64 57 59.7 

The Mt V1ew stat1on was closed m Octob-er2010 and moved to a new location. The 2010 data yaar 

represents 3 quarters of complete data.