## Technical Report



# Analysis of April 12-13, 2003

Kansas City Ozone

Exceedances

18 Febr uary 2004

Prepared by:

Bret A. Anderson

Michael F. Davis

Air Technica l Analysis Group

United States Environme n tal Protection Agency Region 7

901 N. 5 th Street

Kansas City, KS 66101

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# Table of Contents

1. INT R O D U C TIO N

............................................................................................................... ................................... 3

2. CLI M ATI C CH AR A C TERISTI CS

.................................................................................................... ................... 7

2.1 METEOROLOGI CAL ANAL YSIS

................................................................................................... .............. 14

2. 2 L A G R A N G IA N P A RTI C LE M O DEL I NG A NAL Y S IS

................................................................................ 15

3. AI R QU A L ITY C H A R ACTE R IZ ATION

............................................................................................... .......... 19

3. 1 E X P L O R ATIO N O F T H E C A U S E O F E X CEE D A NCES

.............................................................................. 20

3. 1. 1 CLIM A T OLOGI CA L EFFECT S ON MO NITO RIN G DAT A

................................................................... 20

3. 1. 2 CO -O C C U R R EN CE OF G A SEO U S POLL UTA N TS RELAT E D TO CO M B USTIO N S O UR CES A N D

THE EFFEC T ON OZ ON E CO NCE NT RATI O N S

............................................................................................. .. 24

3. 1. 3 CO -O C C U R R EN CE OF P ARTI C ULATE POL L UTANTS RELATED TO COMB USTION

SOU R C ES

........................................................................................................................ .......................................... 28

4. P M 2.5 SOU RCE APP O R T ION M ENT AN ALY S IS

........................................................................................... 32

5. C O N C LU S I ONS

................................................................................................................ ................................... 37

6. REFE RENCES......

...... ............ ...... ............ ...... ............ ...... ............ ...... ............ ...... .......... ..39

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 i

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EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 ii

## 1. Introduction

On April 12 and 13, 2003, three m onitors (hereafte r referred to as Liberty, W a tkins Mill,

and Rocky Creek) in the Kansas City ozone m o nitoring network recorded values in

excess of the 0.084 ppm 8-hour average dail y m a xim u m ozone national ambient air

quality standard (NAAQS). On July 8, 2003, the USEPA Region VII received a request

from the Missouri Departm e nt of Nat u ral Re sources (MDNR) to “flag” the data due to

the occu rren ce of large s cale ag ricu ltural burn i ng that occurred in central and southern

Kansas and north central Oklahom a.

The guideline docum ent that provides nationa l guidance for flagging am bient air quality

data influenced by exceptiona l even ts is, “Guid e line on the I d entif ica tion and Use of Air

Quality Data Affected by Exception a l Events ” (EPA-450/4-86-007), July 1986. This

guideline defines the term “exceptional event” as an event th at is no t exp ected to recu r

routinely at a given location, or that is possibly uncontrollabl e or unrealistic to control

through the SIP process. In addi tion, for air quality data to be flagged as influenced by

an exception al even t, a clear relations hip be tween the even t an d the elevated air quality

m easure m ent m u st be established.

A qualita tiv e descr i ptio n of the eve n ts and cond itions surrou nding the ag ricu ltur a l f i r e s

provided by the Kansas Departm e nt of Health and Environment indi cates that due to

severe drought conditions persistent in that region, a burn ban had been placed by the

Kansas Fire Marshal’s O ffice. Just prior to April 10, 2003, a sm all yet sufficient am ount

of precipitation was received that allowed the lo c a l f i re of f i cials to tem p orarily lif t the

burn ban. Seizing upon this narrow window of opportunity, m a ny in the local farm ing

community initiated their burning of the tall gra ss prairie, resulting in a spa t e of fires ov er

sm all period of tim e. In summary, it wa s the con t ention of the MDNR that the larg e

quantity of em issions resulting from these fire s over the short period of tim e were the

prim ary cause of the exceedances m easured in Kansas City.

Figures 1a and 1b dem o nstrate the rapid change in active burns as de te cte d by sate llite

. On April 9, 2003 (Figure 1a) there were few act ive burns over the region detectable by

satellite. By April 11, 2003 (F igure 1b) active burn signature s were detected over m u ch

of Kansas and north central Oklahom a , signi fying the rapid onset of the agricu ltu ral

burning in the Flint Hills Region. High resoluti on satellite im agery and therm a l analysis

taken on April 11, 2003 (Figure 1c) provides a glim pse at the spat ial extent of these fires

and the resultant sm oke plum e. Smoke can be seen in the visible im agery extending as

far north as the Iowa-Minnesota border em anating from the fires in Kansas and

Oklahom a. Nor m al range m a nage m e nt practice d i cta t es that range burning occur in the

Flint Hills region over a period of tim e characterized as “late spring”. T h is correlates

norm a lly with a period of weeks between m i d-March through early May. The burn ban

that was in effect prior to April 10, 2003 prevented range m a nagers from perform i ng any

early spring burns. Therefore, when the burn ban was lifted, a very large area of

grassland was ignited simultaneously.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 3

### In the initial review of th e reques t su bm itte d by the State, EP A Region VII te chnic a l staf f

concluded that the lim ited data provided in support of the original request was

insuf f i cient to estab lish c a usality be tween th e quantity of em i ssi ons from agricultural

burning and the April 20 03 ozone ex ceedance s. However, one com p elling fact was, that

in twenty plus years of ozone m onitoring in Ka nsas City, no values in excess of an 8-hour

average of 0.084 ppm have been observed in the month of April. Therefore, solely on the

m e rit of the unusual nature of observing ozone values uncharacteristic for that portion of

the ozone m onitoring season, m e teorological an d air quality monitoring staff from EPA

Region VII undertook a two m onth data analysis effort to characterize air quality and

clim atic conditions of that period in order to elucidate what conditions likely gave rise to

the events of April 12 and 13, 2003.

The inform ation con t ain e d herein is a summ ary of that effort. Section 2 of this docum ent

describes the clim atic patterns norm a lly observe d in April and the synoptic characteristics

of the April 12-13, 2003 tim e fra m e. Secti on 3 describes the regional air quality

characteristics during th at tim e period, and Section 4 details the resu lts o f a recepto r

modeling study undertaken to augment the air quality characterizations analyzed in

Section 3.

This analysis provides clear causal linkage between the high level of em issions produced

by the exceptional geographic exte nt of the burning that occurre d in the F lint Hills reg i on

over a two day period and the elevated ozone m e a s urem ents in Kansas City on April 12

and 13, 2003.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 4Figure 1a. MODIS Ac tive Fire D e t e ct ion fo r A p ril 9, 20 03

.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 5Fi gure 1b

. M O DIS Ac ti ve Fi re Dete ction for April 11, 2003.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 6Fig u re 1 c . Hi g h reso lutio n v i sible satellite imag ery from April 11

, 200 3.



## 2. Climatic Characteristics

In the summer of 2003, EPA Region VII m odeli ng staff undertook a data analysis ef fort

to characterize the nature of Kansas City clim atology during ozone m onitoring season.

The study had two m a jor focuses. The first wa s to assist in the developm ent of a more

com p rehensive understanding of the m e teor ological and clim atic conditions norm a lly

associated w ith elevated ozone in Kansas Cit y. T h is is often referred to as conceptual

model developm ent. The second focus was to test the application of relatively new

statistical methodologies designed to facilitate clim atic cla ssif i cation and determ ine their

efficacy for selection of candidate ep isode s for future pho toch em ical studies. Two

m e thodologies, one based upon classification of backward air trajectories, and the other

based upon multivariate analys is of surface and u pper air m e teorolog ical data. Ozon e

data was stratified with the identified synoptic patterns to provide an understanding of the

air quality characterist ics associated with each w eathe r pattern type.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 7

### The results of the clim atological study conc luded that one m a jor clim atic type or

“cluster” accounts for almost 82% of a ll ozon e ex ceedance d a ys in Kansas City

(Anderson, 2003). The pattern, referred to as C1 in the report, is m o st prevalent during

the m onths of June, July, and August with 82.5% of all instances of th is pattern occurring

in these three m onths (Anderson, 2003). Only 2 instances of this pa ttern occurred in the

month of April during th e study period. C1 is characterized by the presence of the classic

anticyclonic system over the Eastern and Sout heastern United Stat es and m e teorological

conditions local to the Kansas City area are typified by high tem p eratures, light southerly

winds, and high incom i ng solar radiation – all of which are conditions m o st favorable for

ozone form a tion as identified by m a ny previous studies. Of five other exceedance days

between 2000-2002 that fell outsi de of the C1 pattern, the second highest frequency was

two exceedance days th at fell in to th e C5 patte rn . The C5 pattern is ch aracterized by the

absence of strong synoptic scale system s ove r the Central United States, often tim es

seeing weak anticy c lonic system s located to th e south of Kansas City an d the pres en ce of

a stationary front situated to the north of Kansas Cit y. Resultant m e teorological

conditions s how light wind speed co nditions at the surface with le ss coherence to the

horizontal structure of the flow field. The C5 pattern occu rs most f r equently in the

months of April and May, with just over 50% of the instances of this pattern occurring in

those two months. However, th e tw o exceedance days that were associated with the C5

pattern occurred in the months of August and Septem ber.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 8Figure 2. Typical synoptic meteor o logic a l char acteris t ics for C1 patt ern. C1 patte rn as soci ate d with

westward e x te nsion of quasi

- perm anent pressure featur e kn own as Be rmuda Hi gh. C1 p a ttern

char acteriz e d by light south erly fl ow at s u rface

, hi gh te mperatures

, and hi gh inc o m i ng s o lar

radi a t i o n. T h e C 1 p a t t ern a ccoun ts fo r ov er 3 2 % of al l da ys of oz one moni t o ri n g se aso n , an d 82 % of

summer days (Anders on, 2003).

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 9Fi gure 3. C1 oz one c o ncen t r ati o ns s t ati s ti cs by m o nt h. C1 p a t t ern c o nsi s ten t l y e x hi bi ts hi gh oz on e

concentr ations acr o ss all m o nths e x cept October in comparis on with other synoptic regimes

. C1

accounts for 82 % of all oz one exceedance s in Kans as City (Anders on, 2003).

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 10-2 -1

. 5

-1 -0

. 5

0 0.5

1 1.5

21-Apr16-Apr1-May16-May31-May15-Jun30-Jun15-Jul30-Jul14-Aug29-Aug13-Sep28-Sep13-Oct28-Oct

Figure 4. Dail y me an time s eries f o r o z o n e sea s o n s 200 0- 200 2 of st anda rdized principa l co mpo n ent

score ass o ciated with the Li berty m o nitor i ng site , K a n s as Cit y , MO ( A nders on , 2003).



### Another m u ltiva r ia te statistical analy s is was used to asses s th e norm a l ozone trend in

Kansas City for this study as well. T h is phase of the Kansas City Ozone Clim atology

Study utilized principal com ponents analysis (PCA) to analyze both the spatial and

tem poral characteristics of va riations in ozone concentratio ns. The tim e series of PC

Scores for the Liberty monitoring site (see Fi gure 4), can be plotted to show the normal

ozone concentration during the ozone m onito ring season. According to Anderson (2003),

the seasonal trend of ozone concentrations begins with below norm a l concentrations

during the month of April continuing th rough the m i ddle of M a y when the ozone

concentratio ns reach v a lues equivalent to th e seasonal m ean value. Peak values are

norm a lly observed in the m i ddle of July and re turn to seasonal m ean values by the m i ddle

of Septem be r. This analysis is im portant in th a t it is anoth e r s t atis tic al too l that e l ucid a t es

the norm a l trend in ozone patterns in Ka nsas City. The sm oot hed ozone pattern

represented by the solid line in Figure 5 shows that typical ozone concentrations are well

below the seasonal m ean value in the m onth of April and do not approach seasonal m ean

values un til the m i ddle of May. As a result, the P C A tim e series dem onstrate th at th e

ozone concentrations observed at the Ca ss County, MO m onitoring sites on April 12-13,

2003 are well above the average 8-hour ozone concentration for the equivalent tim e

period. A value of 93 ppb, 8-hour concentr ation as observed on April 12, 2003 would

have a standard deviation of two-three tim es greater than th e ozone seaso n al m ean value,

and is well beyond any single day that has been recorded for the m onth of April.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 11F i g u re 5

. Typica l C5 sy no ptic p a ttern. C5 patter n char acteriz e d by the abs e nce of strong s y noptic

features

, ofte n resulting in calm or light wind sp eeds at the sur f ace, mode r a te daytime tem p eratures

and i n sol a ti on

. Domi n a n t e a rl y seas on p a ttern

.



### The results form the basis of our understanding of nor m a l ozone clim atological

characteristics for the Kansas City area for the month of April and also f o r what is

typically ob served on ozone exceedance days. In summary, the highes t o z one

concentratio ns are as sociated with th e C1 (summertim e anticyclonic) pattern, and this

pattern also accounts for the vast m a jor ity of ozo n e exceedan ce days (29 of 34

exceedance days from 2000 – 2000 or 82% all exceedance d a ys). Of all 633 days of the

study period, only two instances of the C1 pattern occurred in the m onth of April. W ith

this understanding of the frequenc y of occurrence of the C1 pa ttern in the early period of

the ozone m onitoring season, it was highly unus ual to observe such an extrem e ozone

event in the month of April. Days in April were most ev enly distributed among patterns

C4-C6, which also exhibit strong seasonality, be ing m o st prevalent in the early and late

months of the ozone m o nitoring seaso n. Of the fi ve rem a ining exceedance days, ozon e

stratification placed two exceedance days in th e C5 patter n, and the remainder in C2, C4,

and C6.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 12Fi gure 6. C 5 s u mmar y oz on e st ati s ti cs by mo nt h

. C5 do mina n t in Ap ril a n d May p erio d , a c co un t i n g

for 50 % of the instances of this clus ter in these months

. Note that me dian oz one c o ncentr ati o n for

C5 pa ttern in mo nth o f April is 48 ppb, wi th ma ximum value for C5 pattern in April being 65 ppb.



### Having established a basis for normal ozone cl im atology for the m onth of April and also

for ozone ex ceedance d a ys in Kansas City, the an alysis p r ocedures of Anderson (200 3)

were reapplied to the April 2003 period to co m p a r e conditions for this period with the

results of our the previous study. Specifical ly for the exceedance days of April 12 and

13, 2003, each day fell into the C5 p a ttern. Fro m the basis of clim atic norm s , the

occurrence of the C5 pattern dur ing this period of the year is reasonable, as over 22% of

instan ces of this pa tte rn norm a lly occur in the month April. However, re call the

discussion of the results of the analysis when 8-hour ozone concentrations are stratified

by m e teorological pattern, we find an entirely different situation. W h ile it is routine for

the C5 pattern to occur in the m onth of April, on the basis of statistical analysis we w ould

not expect to observe an y exceedances under th is pattern in A p ril. The su mmary

statistics for the daily m a xim u m 8-hour aver age concentration distribution for the C5

pattern in A p ril show that the m e dian oz one concentration is approxim a tely 48 ppb, and

the m a xi m u m observed concentration of the C5 pattern in A p ril is approxim ately 65 ppb

(see Figure 4). The occurrence of a 93 ppb 8-hour average observation on April 12,

2003 would be statistically cla ssified as an extreme obser vation well outside the norm a l

distr i bution f o r this pa tte rn in th e m o nth of April. Likewise, using sim p le probability

statistics, the proba bility of an ex ceedance occu rring during any period of the ozone

monitoring season under the C5 pattern is at m a ximum 0.3% (Anderson, 2003).

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 13

## 2.1 Met e orological Analysis

The clim atological analysis results describe d in S ection 2.0 of this docum ent indicated

that the April 12 – 13, 2003 period w e re both classi fied as a type C5 pattern, typified by

the pres ence of weak synoptic sys t em s, usually an ticyclones p o sition e d to the south of the

Kansas City area with a frontal system, usually a stationary front, lo cated to the north of

the Kansas City.

Surface synoptic ch arts for the April 12 a nd 13, 2003 period confirm the high degree of

sim ilarity to the m ean conditions of the C5 classification. On April 12, 2003 (see Figure

6), an anticy clonic system was located just to the southeast of the Ka nsas City area with a

stationary front just to the north of Kans as City. On April 13, 2003 (see Figure 7) an

anticyclonic system previously located over North Dakota app e ars to h a ve m i grated to

the eas t and was position e d over Mic h igan. At the sam e time, a low pres sure sys t em

started to developed on the leeside of th e Rocky Mountains over Montana and North

Dakota with a trailing trough. The twofold effect of the m i gration of the anticyclone and

for m ation of the leeside cyclone created a so utherly flow in advance of the developing

low and front, and also the retr ograd e of the statio na ry front located to the north of the

Kansas City area.

Fi gure 7. S u r f ace sy no pti c char t f o r Apri l 12 , 20 0 3

. A n al ysi s v a l i d a t 06 0 0 L S T

.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 14

### The additive effect of these synoptic change s likely played a s i gnifican t ro le in lim itin g

the disp ers i v e capacity of the atm o sphere sign if ica n tly. Fir s t, the presen ce of the

anticyclonic system over South Central Miss ouri on April 12, 2003 likely resulted in very

light and less coherent windf ields over W e stern Missouri and Eastern K a nsas near the

core of the system . The result likely would contribute to near sta gnation over this region

on that day. The retrograde of the stationa ry front from the April 12-13, 2003 tim e fram e

back across Missouri compounde d this by serving as a bl ocking m echanism to any

norm a l zonal flow (west-east) wind flow pattern.

Fi gure 8 a

. Su rface sy no pti c char t for A p r i l 13, 2 0 0 3

. A n al ysi s v a l i d f o r 06 0 0 L S T

.



## 2.2 Lag r angian Particle Modeling Analysis

In order to test th is hypo thesis, it was necessa ry to run dispersion sim u lations to sim u late

the effect of the cum u lative effect of th e presen ce of the anticy c lonic syste m and the

retrograde of the stationary front with hypot hetical em issions in the general geographic

location where th e Flin t Hills fires o ccurr ed during the April 10-13, 2003 tim efra m e . The

Pennsylvania State/National Ce nter for At m o spheric Res earch (NCAR) nonhydrostatic

num e rical m e teorological m odel MM5 was run for the period of April 9 – 13, 2003. The

MM5 sim u lation was run in a two-w a y nest ed configuration with 36 km and 12 km

dom a ins. MM5 was initializ ed with 3DAn al and SfcAnal data from the ETA m odel

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 15

### available from NCAR. The MM5 solution wa s then processed to extract wind and other

therm odynam i c infor m a tion necessary to drive the lagrangian particle dispersion m odel

(LPDM) FLEXPART.

The results from the for w ard lagrangian sim u lation confirm the hypothesis (see Figure

8b). In three days tim e starting on Apr il 9, 2003, the m a jority of the hypothetical

em issions of the sim u lated Flint Hills fi res had not progressed beyond the border of

Missour i. T h is age of th e air m a ss in this s i m u lation is ind i ca ted by the c o lor of the

particles, with older particle s exhibiting the warm er colors of orange, red, and purple.

From the for w ard sim u lation, we can see that em issions that would have been three days

old were still present within the Eastern Miss ouri region. The effect of the retrograde of

the stationary front can also be observed in th is simulation. T h e stra tification of particles

along the northwest-southeast ax is shown in Figure 8b is actu ally the blocking effect due

to wind directional difference on the both sides of the front. Therefore, the northeastward

move m e nt of the particles is se verely restricted b y the pres en ce of the front. As the front

continued to retrograde back across Missouri, many of the em issions that had been

transported f a rther north and east are actually being transpo r ted back tow a rds the Kan s as

City area, ad ding to th e already accu mulati ng em issions from the Flin t Hills fires.

As long as only linear processes are consider ed, it is possible to reverse a dispersion

problem simply by running a LPDM backward in tim e. This is referred to as inverse

lagrangian particle m odeling. In analogy to forward sim u lations we m a y call the particle

cloud produced by a backward sim u lation a ‘‘re troplum e’’. Essentially, a large num ber of

particles is releas ed at a recep tor and transp o r ted backward in tim e. Then the resid e nce

tim e of all particle s, nor m a lized by the tota l number of released particles, can be

determ ined on a uniform grid. The residence tim e in a particular grid cell is proportional

to the con t r i bution a sou r ce with un it streng th in this ce ll would m a ke to the m i xing ratio

at the recep tor. From here, it also po ssible to con s truct a spa t ial plo t which delineates the

regional extent of areas which the air m a ss pa ssed over prior to arri ving at the receptor

location. This is often referred to as an “influence function.” This technique was utilized

for the Liberty m onitoring site. Using the FLEXPART LPDM, the wind fields were

reversed for the sam e study period as describe d for the forward sim u lation. The resultant

“retroplum e” delin eates the areal ex tent in wh ich an air m a ss passed over prior to arriving

at the L i berty m onitor. Therefore, we are able to m o re accu rately judge potential so urce

regions of influence. As shown in Figure 8c, th e retrop lum e for the Lib e rty m onitor at 0Z

on April 11, 2003 clearly shows that the areas of eastern and central Kansas and north

central Oklahom a were the m o st likely area s at a regiona l lev e l tha t inf l ue nced the

Liberty m onitor i ng site. Utilization o f this t echn i que conf irms that these r e gions and the

burning activities with in each likely reach ed the Clay County m onitoring sites and

influenced the ozone values therein.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 16Fig u re 8 b . Ti me series o f FLE X PAR T a n a l y s is fo r the time perio d April 8 – 13 , 2003

. Col o r c o ding of particles re presents age of particle from release tim e . E a ch c o lor

represents a delta of twelve hours

.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 17Fi gure 8c. In verse l agr an gi an m o del a n al ysi s f o r L i bert y, MO Oz one Mo ni t o r. A n a l ysi s v a l i d at 0 Z

1 1 April 20 03

.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 18

## 3. Air Quality Characterization

The table b e low summarizes h i sto r ical eigh t-hour m a xi m u m values m easured during the

month of April for the past twenty y e ars at the Libert y, Missouri m onitoring location

(Site ID 29-047-0005).

Year Monthly

High

(ppm) Date

1982 0.062 4/24/1982

1983 0.073 4/26/1983

1984 0.051 4/5/1984

1985 0.060 4/19/1985

1986 0.072 4/11/1986

1987 0.063 4/25/1987

1988 0.077 4/13/1988

1989 0.068 4/22/1989

1990 0.064 4/8/1990

1991 0.076 4/16/1991

1992 0.053 4/30/1992

1993 0.071 4/10/1993

1994 0.079 4/24/1994

1995 0.070 4/8/1995

1996 0.071 4/24/1996

1997 0.074 4/18/1997

1998 0.072 4/23/1998

1999 0.075 4/7/1999

2000 0.064 4/28/2000

2001 0.074 4/29/2001

2002 0.067 4/14/2002

Mean

Valu e

‘82-‘02 0.068

Std. Dev.

‘82-‘02 0.0075

2003 0.093 4/12/2003

T a bl e 1: Hi st ori c al 8- ho ur Ma xi mum Oz one C o ncen tr ati o ns at t h e L i berty Si te



### The highest 8-hour m a ximum value m easured during the twenty-year period between

1982 and 2002 is 0.079 ppm

. The mean value of the ‘82-‘02 monitoring data is 0.068

ppm and the standard deviation is 0.0075. Hence, the April 2003 m a ximum 8-hour ozone

value of 0.093 is m o re than three standard devi ations greater than the m ean value for the

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 19

### ‘82-‘02 tim e fra m e. The m a xi m u m value m easur ed in 2003 is clearly not representative

of the m ean historical maxim u m 8-hour oz one concentration m e asured at the Liberty

monitoring site location in Ap ril. The ozone m o nitoring da ta for calendar year 2003 has

been validated by review of the Missouri De partm e nt of Natural Resources’ quality

assuranc e re cords and on -sit e assessm e nt of monitoring equipm ent operations. This

review confirm s that the data are valid and accurate.



## 3.1 Exploration of the Cause of Exceed ances

If air m onitoring data are validated an d accu rate, y e t not repres entative of typical

conditions, an exam ination of the atmos pheric and pollution s ource conditions under

which the data were m easured is undertaken to d e term ine the cause. For monitoring data

to be flagged as an unus ual or an ex ceptio n a l ev ent, the con d itions that cause th e

monitored value m u st have a low likelihood of recurrence.

There were multiple inte rrelated, bu t distin ctly se parate events that o ccur r e d

sim u ltaneously from April 9 through Apr il 16, 2003 that severely im pacted ozone

for m ation at the Liberty, MO m onitor and also affected m onitors acro ss th e entire s t ate of

Missouri. E ach of these events, when cons idered individually would not necessarily

cause an exceedance of the 8-hour ozone sta ndard to occur. When the events occur

sim u ltaneously, however, the cum u lative effect resulted in an exceptionally high 8-hour

ozone value to be m easured on April 12, 2003 in Liberty, Missouri and an unusual April

ozone episode to occur across eastern Kans as an d across the State of Mis s ouri which

caused exceedances of the 8-hour average daily m a xi m u m ozone national am bient air

quality standard (NAAQS) to be measured at three m onitoring locations in the Kansas

City ozone monitoring network on April 12 and 13, 2003.



## 3.1.1 Climatological Effect s on Monitoring Dat a

Previous sections of this re port discussed the regional scale clim atological conditions that

were in place during the period under consid eration. The conditions du rin g the period

from April 12-13, 2003 are characterized as pred om inantly stagnant w ith little vertical

m i xing, coupled with a stationary front that was moving in a retrograde f a shion from east

to west. The net effect of the m e teorology in play during this tim e period was to establish

a large stagnant airm ass with a boundary ge nerally located along the Mississippi River

valley. This frontal boundary prevented the ve n tilation of p o llutants f r o m this spatia l

dom a in.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 20Fi gure 9. S k e w -T L o g P Di agr am Up per Ai r C h ar t for T o pek a , KS

. An al ysi s v a l i d f o r 12 UT C ( 0 6 0 0

LST) 12 A p ril 20 03

.



### Upper atm o spheric charts taken from the T opeka National Weather Service site for 0600

LST on April 12 and 13, 2003 (Figures 9 and 10 respectively) provide greater clarity

regard ing th e loca l sta t e of th e atm o s phere on these days. The red line represents the

vertical tem p eratu r e lap s e rate and b l ue rep r esents dew point tem p erature lapse rates.

Figures 9 and 10 depict the typi c a l n o cturna l inv e rsion that u s ually develops shortly after

dusk and continues until the next m o rning wh en daytim e heating finally breaks up this

inversion. However, what we find of significant im portance on these days is the strength

of the noctural inversion and its shallow dept h. On both days, the tem p e r ature increased

10 ° - 15 ° C over the first 300 – 400 m e ters of the atm o sphere, creating a very strong yet

shallow inversion. W h ile a statistical com p ar ison of the strength of nocturnal inversions

is beyond the scope of this analysis, base d upon our experiences with such data, we

believe that these inversions are considerab ly stronger than w ould norm a lly be observed.

Com b ined with light, almost incoherent winds a t the su rf ace , this would result in the

trapping and buildup of ground based em issions during the night into early m o rning

hours.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 21Figure 10. Skew-T Log P Diagra m Upp er Air Ch art f

o r T o pek a , K S

. An alysis v a lid f o r 1 2 UTC 13

A p ril 200 3.



### An exa m ination of the raw hourly ozone m onitoring data across the spatial dom ain from

east-central Kansas, acro ss to the Mis s issipp i River follows. Hourly ozone values are

displayed because they can be readily co rrelated with the prevailing m e teorological

conditions and other gaseous and particulat e pollutant species, which are collected

sim u ltaneously across the spatial dom a in under study.

For com p arative pu rposes, first cons ider the ozone m onitoring data collected at the Cedar

Bluff, Kansas m onitoring location (Figure 11). T h is m onitoring site is s i tuated in a ru ral

location and is unim p acted by either the st agnant air m a ss or the com bustion products

present in th e atm o sphere across eas tern Kans as a nd Missour i f r om the Flint Hills f i res

(recall F i gure 1). W h en exam ining the data from the Cedar B l uff m onitor, you observe a

pattern which is typical of rural back ground ozone m onitoring locations with low

m a xi m u m values and a flat daily profile acro ss the tim e period from April 7 – 15. Hourly

ozone concentrations are observed to cycle up and down around the 0.02 ppm line on a

daily basis, consistent w ith da ylight and night tim e hours. (N ote: In all graphs presented,

the x-axis grid intercepts on the graphic correlate with th e m i dnight hour on the specified

day)

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 22Figure 11: Ce dar Bluff Oz one Data



### The data presented in Figure 12 clea rly illus t ra te s th e effect of a large s t agnant airmass on

am bient air ozone concentrations across east-Ce ntral Kansas and all of Missouri. Recall

the m odeling analysis presented in Figure 8b which depicted the extent of airm ass

stagnation during the five day period from Ap ril 8-13 which essentially trapped em issions

and em ission by-products across eastern Kansas and the entire State of Missouri. Note

that during the period of April 7 and 8, there is little app a ren t corre lation b e tween the

monitoring locations east of Cedar Bluff. By April 9, however, the m onitoring sites

respond in the sam e m a nner across a very larg e spatial dom ain. This indicates that all

monitoring sites were equally affected by ozone sim u ltaneously, which could only occur

under regional scale stagnation c onditions. It is also instru ctive to observe that that

monitoring s ites which are closer to the easte rn edge of the dom a in (Kansas City area)

trend h i gher in absolu te c oncentr ation

. Fi nally, note how all monitoring sites east of

Cedar Bluff trend upward in concen tration from April 10 through the 13 th 

### and then trend

down afterward. This is also due to the large scale stagnation present and lack of

ventilation which would norm a lly allow the poll utant rich atmosphere to be diluted or

transpo r ted f u rther to th e east.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 23Fi gure 1 2 : Ho url y oz one acr o ss the sp ati a l dom a i n

. No t e : Ced a r B l uf f D a t a at b o t t o m



## 3.1.2 C o -occurrence o f Gaseous Pollut a nt s Related to

Combustion Sources and the Effect on Ozone

Concentrations

In addition to a large-scale ozone event, a dditional pollutants were m easured across th e

affected spatial dom ain that led to th e c onclusion that a signif i cant com b ustion source

was im pacting the entire area. Specif ically, the c o inciden ce o f sim u ltaneo u s

m easure m ent of Carbon Monoxide (CO), par ticulate m a tter less than or equal to 2.5

m i crons in aerodynam i c diam eter (P M 2. 5) 

### , Nitric Oxide (NO), and Nitrogen Dioxide

(NO 2 

### ) are all attributed to sm oke produci ng combustion sources. Figures 13, 14, 15, and

16 illus t r a te clea r cor r ela tion be twee n these po llu tants. Unf o r t unate ly, not all am bient air

monitoring stations are equipped with m onitors for all the criteria pollutants. The data

presented illustrate the presence of smoke e m issions across the entire spa tia l dom ain.

W ith background ozone concentrations alrea dy elevated across the eastern State of

Kansas and all of Missouri due to a lack of atm o s pheric m i xing and dispersion, the

conditions in the Kansas City area were ripe for ozone form a tion due to the presence of

fresh em issions of nitric oxide and other ozone precursors from the la rge scale bu rnin g of

biom ass occurring in the Flint Hills region of eastern Kansas.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 24

### While the chem istry of ozone production is com p lex, the m a in features are well

estab lished and can be s u mm arized as follows . Nitric oxide (NO) introduced into the

atm o sphere reacts rapidly with O 3 

### to for m nitrogen dioxide (NO 2 

### , reaction 1). NO 2 

### can

efficiently absorb sunlight and photo-dissoci ate to yield oxygen atom s (O) and NO (R2).

These oxygen atom s in turn will reac t rap i dly with m o lecular oxygen (O 2 

### ) to reproduce

O 3 

### (R3; M represents a third m o lecule su ch as molecular oxygen or nitrogen (N 2 

### ) tha t

absorbs th e excess en erg y released in this r eac tio n, thereby s t abiliz ing the newly for m ed

O 3 

### m o lecule).

R1) NO + O 3 

### ¤ NO 2 

### + O 2 

### R2) NO 2 

### + h 4 (280< 2 < 430nm ) ¤ NO + O

R3) O + O 2 

### + M ¤ O 3 

### + M

Ozone is removed from the atm o sphere through several proce sses, including both

gaseous and aqueous chem ical reactions, and deposition to the ground. In polluted

atm o spheres, during th e nighttim e , R2 ceases to o ccur sin ce it is driv en by sunlight.

Consequently, R1 can dom inate nighttim e reactio ns lead ing to a com p lete rem oval of

ozone when sufficient NO is present. This process is dubbed NO

x 

### scavenging. In rural

areas, NO concentration s are gen e rally t oo low to scavenge ozone appreciably. NO

x 

### scavenging can also occur during the day tim e where NO concentrations are high.

Therefore, ozone levels experienced during the day depend on the relative am ounts of

different pollutants in the atm o sphere avai lable to contribute to the photochem ical

reaction, which in turn determ ines which of the chem ical reactions are driving ozone

chem istry at a particular tim e.

The set of equations presented above repr esent the m o st basic and lea s t c o m p lex

equilibrium conditions for form ation of ozone. Other, m o re com p lex, but well

estab lished reactions tha t provide add itio n a l ozon e for m ation potential inc l ude the

interaction between volatile organic co m pounds, hydroxy radicals, carbon m onoxide, and

ultraviolet radiation (sunlight). The pres ence of these additional ozone precursor

m a terials in the atm o sphere is confirm e d by highly correlated concentrations of carbon

monoxide with nitric oxide in W i chita, Kansas (F igure 13).

The m onitoring data f r o m the W i chita site shows a classic profile of fresh com bustion

source pollutants im pacting the m on itoring site with CO, NO, and NO 2 

### concentr ation s

rising and falling sim u ltaneously. The reason the em issions are class i fied as fresh is d u e

to the dom inance of the nitric oxide signal. Nitric oxide is a highly reactive ozone

precurso r du ring day ligh t hours and an active ozone scaveng e r during n i ghttim e hours.

The W i chita data se t ref l ect th is behavior quite w e ll with ozone concentrations dropping

to near zero in the presence of excess NO dur ing the night while, during daytim e hours,

ozone concentrations rise as NO is c onsum ed in the photochem i cal reaction.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 25Fi gure 1 3 : Wi chi t a He al th Dept . ga seo u s pol l u t a n t d a t a



### The data f r o m the JFK site (Figu r e 1 4 ) show si milar, but significantl y different behavior.

Once again, the data are correlated with sm oke em issions, but this site has continuous

ozone, NO, and PM 2. 5 

### monitors. Th is site illustra te s the relationship betw een NO and

fine particulate sm oke concentrations due to the high correlation betw een peak values of

NO (ppm ) and PM 2. 5 

### ( 3 g/m 3 

### ) over the tim e series. The only im portant difference in this

data se t is th at the corr elati on ceases to exist as excess NO is consum ed in the atm o sphere

during conversion to NO 2 

### and subsequently, ozone. Note the y-axis scale of figure 13,

where the m a xim u m NO concentrations m easured in W i chita during this tim e fra m e were

in the 70 ppb range, the available N O for conve rsion to ozone at this m o nitoring location

was in the range of 220-270 ppb, yet ozone concen trations at the JFK site did not exceed

the ozone standard, largely due to the excess reactive NO in the atm o sphere titrating out

available ozone. Observe that ozone concen trations drop to zero during the nighttim e

hours on April 10-12 with very high exce ss NO still present in the atm o sphere.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 26Figure 1 4 : J F K M o ni torin g Site D a t a



### The data from the Liberty m onitoring site (Fi gure 15) also illustrate sim ilar but different

behavior. A t the Libert y m onitoring site, the NO/NO 2 

### ratios are rev e rsed where the

prevalent ox ide of nitrog en presen t is NO 2 

### . The prevalence of NO 2 

### and the lack of

m easured NO is a clear indicato r that phot ochem i cal oxid a tio n of NO has taken place to

for m excess ozone at this site. The L i bert y m onitoring site is located approxim a tely

twenty m iles directly north east of the JFK location, which is sufficiently downwind under

the prevailing stable m e teor ological conditions for photoche m i cal for m a tion of ozone to

occur. Note the correlation of NO peaks on April 10 and 11 between the JFK and Liberty

sites. Th ey occur dur ing the sam e tim e , yet NO concentrations at Liberty are

substantially dim i nished due to ozone for m a tion. Observe also, the lack of NO signal at

the Liberty monito ring site on the 12 th 

### , accom p anied by elevated NO 2 

### and high ozone

concentratio ns that carry over in to th e 13 th 

### . This effect is not s een anywhere else in the

ozone-m onitoring network becaus e all of th e available NO for excess ozon e for m ation

has been co nsum ed in the photochem i cal reaction.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 27Figure 1 5 : Li bert y Mo nitor i ng Da ta



## 3.1.3 C o -occurrence o f Particulate Pollut a nt s Related to

Combustion Sources

In addition to gaseous pollutant m o nitors, th e national air m onitoring network consists of

monitors for particles, both fine (PM 2. 5 

### ) and coarse (PM 10 

### ). The fine particle sam p ling

network also has a subset of site s th at collec t PM 2. 5 

### sam p les for chem ical speciation

analysis. Data from the speciation sam p ling network can be very us eful to characterize

em ission sources and their po tential to im pact pollutant conc entra tions. Sam p les

collected by the chem ical speci ation network represent a 24- ho ur average concentration

instead of the hourly averages reported by the ga seous pollutant network. There were six

monitoring s ites in oper a ti on sim u ltaneously on April 12 which can be used to

characterize the origin of fine particle pollution on that day.

Figure 16 provides the profile of chem ically speciated PM 2. 5 

### across eastern Kansas an d

the state of Missouri. Virtually all chem ical species m easured respond equally and

sim u ltaneously acro ss th e entire domain with th e exception of the to tal f i n e particle mass

and the carbon fraction data. Total mass is ch aracterized as th e sum of the m a ss of all

chem ical species p r esen t, the data in dicate that the highes t mass concen trations were

m easured on the western side of the monito ring network and trended downward on April

12 as distan ce increases to the east.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 28Figure 16: P M 2.5 Chemic a l Speci ati o n Profile for April 12



### The prevalence of organic carbon collected on A p ril 12 clearly indicates that a

com bustion source is the prim ary contributor to fine particle m a ss. In order to

characterize the type of com bustion source, an a l y s is of the m e tal sp ecie s d a ta m u st be

undertaken (Figure 17).

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 29Fi gure 1 7 : P M 2

. 5 Speci ate d Me t a l s Pr ofi l e on Apri l 12



### The prim ary m e tal species of interest is pot assium as displayed in Figure 18. On April

12 th 

### , potass i um is elevated across th e entire m o nitoring netw ork in a m a nner sim ilar to

the organic carbon and the calcium distributions. On all other days in the tim e series,

concentrations are low and well grouped.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 30Figure 18: Speciated PM 2.5 Potassium Time Series



### In order to further elucidate the relationship betw een fine pa r t icle chem ical spec ies and

potential pollutant sources the PM 2. 5 

### m a jor constituents and trace m e tal sp ecies d a ta are

analyzed u s ing positiv e m a trix f actoriza tion in th e next se ctio n.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 31

## 4. PM 2.5 

## Source Apportionment Analysis

Che m ic al com position data for fine and particles coll ected at JFK PM 2. 5 speciati on site in Kansas

City , KS was analy zed using positive m a trix fact orization (PMF). T h e objective was to identify

the possible particle source s contributing mass at the s a m p ling site. PMF uses est i m ate s of the

error in the d a ta to provide optim u m data point scaling and perm its a better treatment of m i ssing

and below-detection-lim it values. It also applies th e n on-negativit y constraints to the factors.

Seven possibl e source facto r s were obtained from the fine particle data set and have been

identified as possible aerosol sources for the fine pa rticles. They are: (1) m o tor vehicles des c ri bed

b y the hi gh c oncentrations of organic carbon (OC) and elem ental carbon (EC) with som e soil dust

co m ponents, (2) biom ass burning which is typified b y high co ncentrations of OC, EC and K, with

presence of s o il dust, (3) unidentified com bustion source chara c teri zed by OC, SO 4 , S, Cu, Z n

, and Pb, (4) a possible second t ype of bi o m ass si gnature, characterized b y OC and K, (5) soil

factor represented b y Al, S i , Ca, Ti and F e , (6) S-factor (secondary sulfate) which is likel y to

represent coal power plant em issions, and (7) N-f actor (secondary nitrate) which is likely to

represent m o r e distant co mbustion em iss i ons dur ing the winter and spring m onths when the

formation pot ential for amm oniu m nitrate is the greatest.

0 20 0 40 0 60 0 80 0 10 00 12 00 14 00NH4NO3SO4ECOCAlAtBrCaClCuFePbMgMnNiKSeSiNaStSTiVZn 0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0. 9

Figure 19a. Source profile for F a ctor 1.



### Fortunately, the PM 2. 5 

### speciation network was operati onal on April 12, 2003, coinciding

with the first day of the exceedances in Kans as City. Three so urce profiles exhibited a

rather strong signal on A p ril 12, 2003. Factors 1, 5, and 7 exhibited the strongest signals.

Factor 1 is characterized by the presence of high OC/EC loading with sm aller am ounts of

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 32

### Al, Ca, Fe, K, and Si. High OC and K are usually indicative of biom ass burning. T h e

presence of the Al, Ca, Fe, and Si are soil dus t components. Factor 5 is sim ilar with the

high OC/EC loadings, w ith lesser amounts of K, Al, Fe, and Zn. Upon initial

investigation, both profiles share sim ilar charac ter i stics and are thus somewhat dif f i cult to

interpret decisively. A lite rature search of possible s ource profiles was conducted and

results of the Kansas City PMF analysis com p ared to published literature. It was

concluded that the Factor 1 pr ofile was m o re likely due to biom ass burning and Factor 5

more like l y associa t ed w ith m o tor vehicle s with a sm all road dust com p onent. I t is

im portant to note that there is a high degree of uncertainty, based largely upon the human

interpretation and com p a r ison of known profiles, in the results of this analysis. Factor 1

(Figure 19a) displayed a lower OC to EC ratio in com p arison to Factor 5 (Figure 19b).

An exam ple f r om the lite ratur e sea r c h (Figur e 20 ) indicate s that the lowe r OC/EC ratio

and larger K contribution is associated w ith biom ass burning. The higher OC/EC ratio

com b ined with the Fe, Al, and Zn in Factor 5 are more consistent with the mobile sour ce

signatures w ith reentrained road dust. On April 12, 2003 the strength of these two factors

were 4 and 6 tim es higher than normal (Factors 1 and 5 re spectively, see Figures 19c and

19d).

Each factor score is the highest of the two year dataset, and is consis tent in tha t , while the

inte rpre tatio n what the p o ssible f a c t o r s rep r esen t can be som e what uncertain, the strength

of these factors clearly indicate the characte ristcs of a com b ustion sou r ce present in th e

dataset on April 12, 2003. The combination of high OC with K, Al, Ca, Fe, and Si

confirm the presence of the biom ass burning on April 12, 2003. The higher loadings due

to the p r esen ce of the trace elem ents more commonly associated with so ils are th eorized

to be due, in part, to the nature of th e burning activity conducted in Kansas and

Oklahom a. Most literature surrounding sour ce profiles for biom ass burning refer m o re to

wood burning activity than to m o st other sour ces of biom ass com bus tion. Prairie fires,

by their natu re, burn clos er to the lan d surface than com bustion from wild fires (fores t) or

dom e stic wood burning. It is ou r theory that the convective heat from the burning of the

tall grass prairie lik ely en trains a sm all am ount of soil from either the land surface or so il

present on the vegetation and is carried aloft and transp orted downwind. This would

account for the presence of a soil signature in concert the with biom ass signature

observed in Factor 1. D u e to the confirm a ti on of the presence of a large biom ass burn

concurrent with the April 12 sam p ling date, we are reasonably confident in our analysis

that this signature likely re presents to biom ass burning.

Factor 5 is more difficult to interpret, both in term s of id entification and in understanding

the tim i ng of the presence of the factor stre ngth, especially on April 12. In our judgm e nt,

Factor 5 was m o st likely attr ibutable to m obile so urce ac tiv ity than to o t he r possib l e

profiles. Curiously, the streng th of the factor on April 12 is n o t consis ten t with our

understanding of m obile source activity, both in term s of di ur nal, weekly, and seasonal

activity patterns. April 12, 2003 landed on a Saturday, which would m ean that normal

weekend tra f f i c patterns f o r Kansas City lik ely would have occurr ed. Weekend traffic

patterns are norm a lly lighter th an weekdays. This difficulty is also com pounded by the

fact that April 12, 2003 was during the Easter weekend period. Traffic patterns would

have likely been lighter duri ng this period in comparison to other norm a l weekends. As

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 33

### such, the strength of the factor does not com port well with our understanding of the

expected influence of traffic patterns and, as a result, we are not able to provide a

confident judgm e nt on the actual nature of th e source represented by Factor 5. Initial

sensitivities were conducted to de term ine if the Factor 5 soluti on was an artifact of either

too m a ny or too few factors selected for the in itial solution. F actor solutions from six to

eleven were briefly explored. As the num b er of factors incr ease, the Factor 1 and Factor

5 signatures appear to merge a nd the single source strength fo r tha t prof ile incre a ses to

nearly 10 in that an alys is, indicating the high sim ilarity of the profiles. This m a y be an

indication that these m a y indeed be the sam e source, with just a slight differentiation.

However, two other issues arise from this. Recall that we are characterizing the entire

PM 2. 5 

### data set for the JF K site, not just the sam p le from April 12, 2003. Other solutions

degrade as the num ber of factors increase. For exam ple, in our understanding of the

chem istry of secondary aerosol form ation, th ere should be sim ilar am ounts of ammonium

ion tha t are present in b o th the S-f a c t or a nd the N-factor. However, when the num be r of

factors increase, m o st of the amm oni um ion loads on the S-fact or to the exclusion of the

N-factor. Secondly, the PMF analysis tends to stratify the speciation data in ways that

produce “phantom ” profiles, or tries to strati fy the data too far thus generating too m a ny

profiles, som e of which sim p ly would been part of another pr of ile in solu tions with f e wer

factors selected. Since tim e was lim i t ed to fully analyze the results and ex plore d i fferent

factor solutions, we recommend furt her PMF an alysis of the JFK speciation to further

elucidate the nature of pote ntial sources influencing PM 2. 5 

### values in Kansas City.

0 200 400 600 800 1 000 1 200NH4NO3SO4ECOCAlAtBrCaClCuFePbMgMnNiKSeSiNaStSTiVZn 0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0. 9 1

Figure 19b. Source profile for F a ctor 5.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 340 0. 5

1 1. 5

2 2. 5

3 3. 5

4 4. 56/6/20017/6/20018/6/20019/6/200110/6/200111/6/200112/6/20011/6/20022/6/20023/6/20024/6/20025/6/20026/6/20027/6/20028/6/20029/6/200210/6/200211/6/200212/6/20021/6/20032/6/20033/6/20034/6/20035/6/20036/6/20037/6/2003

Figure 19c. Time series of e s timated Fac t or 1 s o urce str e ngth.

0 1 2 3 4 5 6 76/6/20017/6/20018/6/20019/6/200110/6/200111/6/200112/6/20011/6/20022/6/20023/6/20024/6/20025/6/20026/6/20027/6/20028/6/20029/6/200210/6/200211/6/200212/6/20021/6/20032/6/20033/6/20034/6/20035/6/20036/6/20037/6/2003

Figure 19d. T i me series of e s timated Fac t or 5 s o urce str e ngth.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 35Figure 20. Source pr ofiles i d entified by Ram a da n, et al. (2000) for P M 2.5 speci ati o n data for

Phoe ni x, AZ

.

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 36

## 5.0 Conclusion

The Missouri Departm e nt of Natural Resouces requested that EPA Region VII “flag” 8-

hour ozone monitoring data collected on Apr il 12 and 13, 2003 on the basis of the fact

that em issio n s f r om agricultu ral bu r n ing we re docum e nted to be im pacting eastern

Kansas and virtually all of the State of Missouri. At first gl ance, and in accordance with

existing guidance docum ents related to gran ting exceptional events flags for m onitoring

data, the request did not appear to withstand the test f o r c onsideration as an exceptional

event. It is important to point out, however, that the ex isting EPA guidance for flagging

air quality data is “Guideline on the Identifi cation and Use of Air Quality Data Affected

by Exceptional Events” EPA-450/4-86-007, Ju ly 1986. This guidance docum e nt

provides no specific guidance on data flagging c onsiderations for either 8-hour ozone or

PM 2. 5 

### m onitoring values. The ’86 guidan ce docum ent does specifically address

prescribed burning, but only to the extent th at direct em issions from burning activities

m a y a ffect PM or CO data. Upon furthe r consideration, staff from EPA Region VII

determ ined that a m o re detailed exam inati on of the clim atological conditions and the

am bient air monitoring data m a y elucidate a relationship between biom a ss burning in the

Flint Hills region of Kansas and elevated 8-hour ozone conc e n tra tions m easured in the

Kansas City m e tro.

The key test for determ ination of whether a specific event m a y be considered as

exceptional is the likelihood of recurrence of the cause of that event. Clearly the

likelihood of recurrence of agricultural burning in the Flint Hills of Kansas is very high,

but the likelihood of having the entire burn occu r again within 2 days is very unlikely.

Thus, we do not expect to m easure an 8-hour ozo n e exceedan ce in Kansas City during the

month of April. Analysis of historical m a xim u m 8-hour oz one concentrations m easured

in the m onth of April led to the determ in ation that the value of 0.093 ppm reported on

April 12, 2003 at the L i berty m onitoring site is highly atypical based upon statistical

analysis of historical clim atol ogical trends. If this situat ion would occur again, it would

not lik ely be considered an exception al even t.

Knowing that one of the key factors in fluencing ground level ozone formation is

m e teorology, an analysis of the historical clim atological conditions conducive to ozone

for m ation was perform e d. The analysis conducted by Anderson (2003) concluded that

the probability of occurrence of the synoptic weather pattern observed over the region

during April 12-13, 2003 was approxim a tely 22%. Therefore, we are able to conclude

that there w a s nothing atypical or otherwise exceptiona l about the m e teorological

characteristics of those days. W h ile these m e teorological conditions we re not atypical for

the April tim e fra m e, the occurrence of a 93 ppb 8-hour ozone exceedance is highly

im probable. According to Anderson ( 2003), the probability of an 8-hour exceedance

under this synoptic pattern during any period of the ozone m o nitoring season is 0.3% at

ma x i mu m.

The LPDM analys is clearly illu s t ra te s that the sy noptic pa tte r n in plac e d u ring th e April

12-13 tim ef ram e caused em issions f r om the Flint Hills burn i n g to be trans ported

northward along the Missouri/Kansas border where they were trapped and actually

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February 2004 37

### transported f r om east to west in a retrograd e fashion due to the presence of a blocking

front. The net effect of this m e teorological pattern resulted in trapping fresh and aged

em issions f r om the Flint Hills f i r e s f o r as m u ch as f i ve days o v er eas tern Kansas and

western M i s s ouri. Lik e wise, the inv e rse LPDM analys is con f irm s that the areas of

eastern Kansas and north central Oklahom a were within the source region of influence of

the Clay County, MO ozone m onitors.

Analysis of the am bient air m onitoring da taset was undertaken to determ ine if such

pollutant build-up across the region could be determ ined and whether sufficient

monitoring data existed to dr aw a conclusion about the lik elihood of recurrence of the

cause of the ozone exceedances.

Am bient air monitoring data c l ear ly illus t r a te the build-up of ozone conce n tra tions a c r o ss

the entire S t ate of Missouri and eastern Kans as during the April 10-15 timefram e. In

addition to ozone data, m onitoring data analysis of carbon m o noxide, nitric oxide,

nitrogen dioxide, and P M 2. 5 

### data was undertaken. High correlation between the gaseous

products of biom ass combustion existed across the entire study area. S p ecific analysis of

the Kansas City area monitoring data was undertaken to ascertai n a causal relationship

between the em issions from biom ass bur ning and 8-hour ozon e exceedan ces.

Exceptionally high concentrations of nitr ic oxide (approx 270 ppb hourly m a x) were

m easured at the JFK recreation center in dow ntown Kansas City, Kansas on April 10, 11,

and 12 with corresponding high ozone values m easured at the Liberty monitoring site

which is located approxim a tely twenty m iles downwind. Furtherm ore, the ratio of NO to

NO 2 

### is reversed at Liberty which indicat es photochem ical oxidation of NO in the

atm o sphere during the ozone form ation process.

Of course, biom ass burning is not the only po ssible source of nitric oxide, as power

plants and other com bustion sources can pr oduce significant NO e m issions. Therefore,

analysis of the PM 2. 5 

### chem ical speciation data was undert aken to ascertai n the presence

and source of pollutant smoke that was pres en t in the atm o sphere during the April 12

tim efra m e . Positive m a trix facto r ization analys is of the sulfate, ni trate, ammonium i on,

and carbonate species in c onjunction with m e tals species data in the PM 2. 5 

### datase t f r o m

the JFK m o nitor i ng site indica te th at the m o st likely and influential source on fine

particle concentrations on April 12 was biom ass burning. While other factors m a y have

influenced the speciation data observed on April 12, 2003, we are unable to conclude if

these influences did ind eed exis t or were part of the sam e signature. Other factors such

as m obile source/so il ap pear present on thes e days, but the tim i ng and strength of the

signature is inconsistent with our underst anding of the behavior of m obile source

patterns. It is im portant to note the high de gree of sim ilarity b e tween the s e prof iles an d

therefore there exists the potential for erro r in hum a n judge ment when analyzing these

profiles. We recomm end further, more detailed study of the source apportionm ent

analys is to d e term ine the actua l natu r e of these pr of iles.

Therefore, it is our opinion based upon the av a ila ble f o rensic, m e te orological, and air

quality data, that large sc ale a i r m a ss stagna tion conditions caused a gradual build up of

EPA Region VII/Air Analy s is Group Anal y s is of April 2003 KC Ozone E x ceedances

February 2004 38

### ozone concentrations across all of eastern Kans as and the State of Missouri. Based upon

multiple corroborating analyses (satellite im agery

, inverse LP DM analysis , air quality

analysis, an d source app o rtionm ent), we believe the exceedan ces of April 12 and 13,

2003 to be h i ghly related to the con c urrent b i omass burning in the Flin t Hills reg i on of

Kansas. Lik e ly, the trap ping m echanism created by the retrograde of the stationary front

moving across Missouri in conjunction with the p r esence of an anti-cyclon i c system

situa t ed ove r the sou t h c e ntra l Unite d Stat es cau sed the bu ild up of fresh gaseous

pollutants f r o m the Flint Hills f i r e s to occur in f a r eastern Ka nsas at the J F K site.

Although we conclude that the m e teorological conditions of April 12 and 13 were not

typically conducive to ozone form ation as evidenced by clim a t ologi cal characteristics

(Anderson, 2003), sufficient excess nitric oxide was present in the atm o sphere to react

and add increm entally to the already elevated ozo n e backgrou nd concentrations p r esent at

the Liberty, Watkins Mill, and Rocky Creek m oni toring locations to cause exceedances

of the 8-hour ozone standard to occur only at those sites. Th e coincidence of all of these

factors that contributed sim u ltaneously to 8-hour ozone exceedances at the Liberty,

Watkins Mill, and Rocky Creek m oni toring locations is considered to be truly

exceptional and highly unlikely to recur.



## 6. References

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in the Kansa s City Me tro politan Area . Presenta tio n to Regiona l Scienc e Forum

, United

States Environm ental Protection Agency Region 7, Kansas City, KS. 23 May 2003.

Anderson, Bret A. (2003b): Synoptic Clim atol ogical Analysis of Surface Ozone for the

Kansas City Metropolitan Area (2000-2002). Draft United States Environm ental

Protection A g ency Regio n 7 Technical Report, K a nsas City, KS. 31 December 2003.

Eder, Brian K., Jerry M. Davis, and Peter Bloom field (1993): A Char acterization of the

Spatiotem p oral Variability of Non-Urban Ozone Concentrations Over the Eastern United

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Moody, J.L., Munger, J.W., Goldstein, A.H ., Jacob, D.J. and Wofsy, S.C. (1998):

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History (PA T H).

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Ra m a dan, Ziad, Xin-Hu a Sing, and Philip K. H opke (2000). Identificatio n of Sources of

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Waste Management Association.

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February 2004 39

### Stohl, Andreas (1996): Trajectory statistics – a new m e thod to estab lish so urce-recep to r

relationships of air pollutants a nd its applic ation to the transp ort of particul ate sulfate in

Europe. Atmospheric Environment 30 , 579-587.

Stohl, Andreas (1998): Com putation, accuracy an d applicatio ns of trajectories – a rev i ew

and bibliography. Atmospheric Environment 32 , 947-966.

Stohl, Andreas, and Trickl, Thom as (1999): A textbook example of long-range transport:

Sim u ltaneous observation of ozone m a xi m a of s t ratospheric and North Am erican origin

in the free troposphere over Europe. Journal of G e ophysical Research 104 , 30445-30462.

Stohl, Andreas (2002): A replacem ent for sim p le back trajectory calculations in the

inte rpre tatio n of atm o spheric trace s ubstance m easurem ents. Atmospheric Environment

36 , 4635-4648.

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February 2004 40