Proceedings: US/FRG Workshop on Photochemical Ozone Problem and Its Control; US Experiences and the Situation in Europe


                                                     EPV600/9-89/058
                             PROCEEDINGS             March 1989

                           US/FRG WORKSHOP

                                  ON

             PHOTOCHEMICAL OZONE PROBLEM AND ITS CONTROL.

              US EXPERIENCES AND THE SITUATION IN EUROPE
                            May 4-6, 1988
                            Senats-Hotel
                            Cologne, FRG
                         WORKSHOP CO-CHAIRMEN
B. Dimitriades, US Environmental            D.  Jost,  Unweltbundesampt,  FRG
                Protection Agency
                          STEERING COMMITTEE
                       K. Becker,  FRG,  Chairman
                          K.  Demerjian,  USA
                           H. Jeffries,  USA
                           U. Schurath,  FRG
                              Edited by

                          Basil Dimitriades
       Atmospheric Research and Exposure Assessment Laboratory
                  Research Triangle Park, NC  27711
                                 USA

-------
                                 DISCLAIMER
Although the workshop  described in  this .report has been  funded partially
by the  U.  S. Environmental  Protection Agency  under contracts  to invited
participants, the  report has not been subjected to the Agency's  required
peer and policy review and therefore does not necessarily reflect the views
of the Agency and  no official endorsement should be  inferred.   Mention of
trade names  or  commercial  products  does not   constitute  endorsement  or
recorranendation for use.        .
                          Printed in March 1989

                                  by the

                    US Environmental Protection Agency

                    Research Triangle  Park,  NC  27711

                                   USA

-------
                                 PREFACE



     This Workshop was held within the framework of cooperation under the



IB-German Environmental  Agreanent.   It  contributes  to  high  priority



activities identified by Minister Toepfer and Administrator Thomas during



their December 1987 meeting.

-------

-------
                            TABLE OF CONTENTS






                                                                     Page



Conference Agenda	  vi



Acknowledgment.	  ix



Proceedings Report



     1.0  Introduction	   1



     2.0  Magnitude and Trends of Ozone Problem	   4



     3.0  Emissions	   9



     4.0  Chemical and Meteorological Processes	  14



     5.0  Modeling Technology and Applications	  23



     6.0  Scientific Issues Associated with 03 Control Strategies...  25



     7.0  Conclusions and Recommendations	  27



     8.0  References	  30



List of Participants	  33

-------
                                    WORKSHOP
                THE PHOTOCHEMICAL OZONE PROBLEM AND ITS CONTROL
Senats-Hotel
Unter Goldschmied 9-17
Cologne, West Germany
            May 4-6,  1988
                                  AGENDA
Wednesday, May 4, 1988, 9:00 AM - 6:00 PM

SESSION I:   MAGNITUDE OF OZONE PROBLEM.
             TRENDS                                  Chairman:

             - Ozone and Precursor Emission Trends
               in the US

             - Concentrations of Ozone and Precursors
               in Germany

             - Ozone in Western Europe

             - Background Ozone.  Levels, Trends,
               and Origins

             - Ozone Trends Within Large Metropolitan
               Areas.  The Los Angeles Basin
           D. Jost, FRG

           T. Curran,  USA


           W. Fricke,  FRG


           K.  Nodop,  FRG

           K. Deraerjian,  USA


           T. McGuire, USA
                                   LUNCH

SESSION II:  ON-GOING CONTROL POLICIES

             - Ozone Control in Germany

             - Ozone Control Policy in the U.S.
             - Assessment of Effectiveness of
               Control as an Ozone Control Strategy

             - On the Effectiveness of the U3EPA
               Control Strategy for Ozone.  An
               Opposing Viewpoint
Chairman:  B. Dimitriades,  USA

           E. Weber, FRG

           E. Meyer, USA

           W. Sylte, USA


           H. Walker, USA
                                       VI

-------
 SESSION III;
SESSION IV:
 ESTIMATES OF EMISSION DATA
 FOR VOC AND NOX

 - Problems with Existing Emission
   Inventory Data Bases

                      BREAK

 - Auto Emission Estimates.   Current
   Improvements

 - European Inventory of Ozone  Precursor
   Emissions

 CHEMISTRY OF TROPOSPHERIC
 OZONE  FORMATION

 - Recent Developments in 03 Mechanism
   and  Existing  Issues

 - The  Chemistry of Ozone Formation
   Tested by Atmospheric OH Measurements

 - The  Present Knowledge of Kinetic Data
   Important for Ozone Chemistry
Chairman:
                                                                H. Jeffries, USA


                                                                K. Schere, USA
           F. Black, USA


           C. Veldt, NL


Chairman:  K. Becker, FRG


           H. Jeffries,  USA


           U. Platt, FRG


           A. Kerr,  UK
     7:00 PM  Dinner hosted by Workshop Organizers

Thursday. May 5, 1988, 9:00 AM - 5:00 'PM

SESSION V:    TRANSPORT/DISPERSION OF
              OZONE AND PRECURSORS

              - Transport of Ozone by Airborne
                Measurements

              - Model Prediction of Transport
                and Dispersion
                                       Chairman:  K. Demerjian, USA
                                                  D. Paffrath, FRG
SESSION VI:
- USEPA's Regional Ozone Model

MODELING RESULTS ON OZONE              Chairman-
FORMATION FROM PRECURSORS
UNDER DIFFERENT CONDITIONS

- Effectiveness of Alternative Urban/
  Regional Control Strategies for Ozone

- Assessment of Ozone-Related Controls
  in California Urban Areas
          J. Pankrath/
          I. Jacobsen, FRG

          K. Schere, USA

          H. Jeffries, USA
                                                               E. Meyer/
                                                               J. Tikvart, USA

                                                               T. McGuire, USA
                                      vii

-------
              - Results from Modeling of Ozone Formation        R.  Stern,  FRG
                in Germany and Neighboring Countries

                                   LUNCH

SESSION VII:  VALIDATION OF MODEL                    Chairman:   U.  Schurath,  FRG
              PREDICTIONS.  SENSITIVITY
              TO INPUT DATA/PARAMETERS

              - Sensitivity Analysis of EKMA Input              H.  Jeffries,  USA
                Parameters on VOC Control Require-
                ments

              - Evaluation of USEPA Regional Oxidant            K.  Schere, USA
                Model in the North East US

              - Sensitivity Analysis of Model Predictions       R.  G.  Derwent, UK
                Upon Chemical Input Data

                                   BREAK

              - Evaluation of Urban Airshed Models              S.  T.  Rao, USA
                with Recent Field Measurements in NY

              - Effects of Different Wind Field                 R.  Kessler, USA
                Analyses on Airshed Model Predictions


     5:00 PM  Visit to Bayer Plant and hosted dinner

Friday, May 6, 1988, 9;00 AM - 5:00 PM                ,

SESSION VIII: SO^IARY/CONCLUSIONS                  "  Chairman:   K.  Becker, FRG
                                                     Co-Chairman:   H.  Jeffries,  USA

              - Discussions.  End of Workshop.

                                   LUNCH

              - Steering Committee Meeting           Chairman:   K.  Becker, FRG


Saturday, May 7, 1988. 9:00 AM - As Needed      •          .

              - Steering Committee Meeting           Chairman:   K.  Becker, FRG
                                      Vlll

-------
                             Acknowledgement
     The Workshop was organized at the instigation of Drs. Gary Foley (USA)
and Erich  Weber  (FRG).   The Workshop program  and  agenda  were developed
by Drs.  Dimitriades and  Becker.  Workshop arrangements  were made  under
Dr. Becker's direction.  The Workshop  report was prepared based on meeting
presentations and  on  followup  discussions  by  all  Workshop  participants
under the  guidance of the Workshop Steering Committee.   Drs.  Dimitriades,
Demerjian, Curran, Derwent, Nodop, Fricke, KLey, Liibkert, Schere, Jeffries,
Kerr, Kessler,  Stern,  Meyer, Walker,  Sylte and McGuire  prepared  summary
statements which were  edited by Dr. Dimitriades  into  a  structured report.
The report was  reviewed and finalized by the  Steering  Committee.  Ms.  K.
Curtis and Ms.  C.  Morawa provided secretarial  assistance for  organization
of the Workshop and preparation of the Proceedings  report.  The contribu-
tions of these named individuals and of all other Workshop participants are
acknowledged with gratitude by the Workshop organizers.
                                   IX

-------

-------
               PHOTOCHEMICAL OZONE PROBLEM AND  ITS CONTROL.
                US EXPERIENCES AND THE SITUATION IN EUROPE


1 .0  INTRODUCTION

     The understanding  of  the  significance  of  ozone  occurrence  in the
troposphere can  be  viewed from .three  distinct  points  of  view.   First,
ozone plays  an important role  in controlling the chemical  composition of
the troposphere  as  a result  of being  a major  source  of  hydroxyl   (HO)
radicals.  Second,  ozone  is  a  radiatively active  gas which impacts the
energy budget  of the troposphere so as  to  cause global  warming ("green-
house effect").  And third,  ozone has been found  to cause adverse effects
on human health,  vegetation and materials 1.   Thus,  ozone alone and  with
other pollutants  synergistically irritate  the  respiratory  system  causing
reduction in pulmonary  function  and  increase  susceptibility to infections
and asthma attacks.   Also,  it reduces crop yields and growth and lifetime
of trees,  and  damages rubber, paint,  and other materials^.   And finally,
ozone and  other oxidants  have  been  found to  instigate the  formation of
acid rain and  the  production in  air  of  toxic pollutants  such as formalde-
hyde and other mutagens.

     There has been significant  debate  as  to the quantitative details of
the sources  of ozone in the  relatively clean  free  troposphere, but, in
general, it  is widely accepted that the major sources are the stratosphere
and photochemical reactions of methane, carbon monoxide and nitrogen oxides
(NOx) (Figure 1-1).   In the polluted  tropospheres, however, that is,  within
the 1-2-Rn boundary  layer adjacent to the surface,  ozone and other oxidant
species are being formed mainly from photochemical reactions of non-methane
volatile organics  (NMVOC or  in short VOC with  respect to ozone formation,
including also CO)   and  NOX emissions  associated  with manmade activities
(Figure 1-1).  It is primarily this latter photochemical ozone arising from
polluted atmospheres  that  is  of  interest and  the  subject of this  report.

     The photochemical  ozone  phenomenon  has  been  studied extensively in
the US  and  to  some  extent in Europe,  Japan,  Canada, and  Australia also.
These studies yielded a reasonably good—but not necessarily sufficient—
understanding of the chemistry and meteorology underlying the photochemical
ozone formation process  and  led  to development of  models capable of pre-
dicting photochanical ozone formation in time  and  space.   In the US,  where
the photochemical  ozone problem  is  most  severe,  laws  have been  enacted
since 1970 that  required the  Federal and State Governments  to promulgate
emission control  regulations  sufficiently  stringent  to  reduce  ambient
ozone concentrations down to the national ambient ozone air quality standard
of 0.12 ppm (1-hour concentration not to be exceeded more than 1 day/year).
Progressively more stringent emission and "equipment design" standards were
promulgated during the 1970's  and 1980's, which were intended to bring about
reductions in emission levels that would more than offset the increases due
to growth.  Thus, VOC emissions were estimated to have decreased 19% during
the 1977-86 period and  NOX emissions 8%.  The  improvement associated  with
automobile emissions  was 39%  for VOC and 13%  for  NOX during that  period
and it occurred  despite a 24% increase in vehicle  kilometers  of  travel.

-------
                               1-A
O
Q.

2

 CO
 CO
 "O


 3
 O
 CO
      O3 dry deposition
Sources
                           Stratosphere-

                          ' Troposphere

                            Exchange
                          S02+  O3


                           NMVOC  ?

                          NOx ?
                              Figure 1-1

-------
Despite  such  supposed emission reductions, however,  and contrary to model
predictions,  the photochemical ozone problem in the US is still  severe and
very much  of  concern.   While  peak ozone  concentrations,  generally,  have
been reduced,  there  are still more than 60  "non-attainment" urban areas in
the US,  with  some 75 million of people exposed to ambient ozone  concentra-
tions  that  exceed the  air quality standard  by as much as 0.23 ppm.   The
reasons  for such persistence and pervasiveness of the ozone problem are not
well understood.

     This apparently inexplicable  and disappointingly small success of the
ozone  control  programs  in the IB  raised some questions on the sufficiency
of the current understanding  of the ozone problem.  Critics  have gone as
far as to allege that the  US ozone control policies are grossly misdirected
in being centered around unilateral control of the VOC precursor.  However,
a balanced view of the control program experience  in the US would be  that
progress has  been made but that  more  needs to be done.   Initial control
efforts  emphasized VOC reductions  but in some situations models may be  used
to evaluate  the effectiveness  of  additional NOx  controls particularly  in
terms  of the possible effect on population exposure.  There is an awareness
in the US that most  of the large  stationary  sources are already  controlled
and that future controls  on smaller sources  will be expensive.   For mobile
sources, the  USEPA has proposed onboard equipment  on all new vehicles  to
control  VOC emissions  during refueling.  Other  possibilities  being looked
at include  fuel volatility,  stricter inspection and maintenance require-
ments, and  the possible   use  of  alternative fuels.   Experience to  date
suggests that  future reductions will  be difficult and  there  are definite
concerns about what  an area such as Los Angeles would have to do to attain
the US ozone standard.

     Given the large socioeconoraic penalties incurred by the ozone-related
controls, the  above  uncertainties  and doubts were disturbing and led USEPA
to undertake an effort to  re-examine and revise its ozone control policies.
It is in this spirit of self-assessment that the USEPA agreed to participate
in this Workshop and committed itself to present and discuss the US experi-
ences and to expose its ozone control thinking and policies to the judgment
of the international scientific community.

     On  its part,  the  FRG Government  is  concerned  that  the effects of
photochemical  ozone  on human health and on  the  country's forest resources
have grown  in  severity  to the point  that  serious  consideration must be
given to commencing  a control effort.  The  FRG Government is also  keenly
interested in  assessing  problems   associated  with  the transport  of  ozone-
related  pollutants from or to neighboring  countries.  In the face  of the
questions raised by the US experience, however,  and  of  the costs and poli-
tical complications  associated with  even modest  control measures,  it is
imperative that any control initiatives to be undertaken by the FRG (or the
neighboring countries)  be designed  with  the utmost  care and  confidence.
The accuracy and completeness, therefore, of existing pertinent  scientific
evidence are  the  main  subjects of interest  to Germany  and  the  primary
reason for the German involvement  in this Workshop.

-------
     The two  co-organizer countries agreed  to pursue these  objectives by
convening a group  of experts both from within  and outside the two Govern-
ments .. The  experts  were  selected  among  those  with  internationally or
nationally recognized expertise and so as to achieve a balanced representa-
tion of existing viewpoints and diverse experiences.  A list of all Workshop
participants and  their  affiliations  is  attached  here  as  an  appendix.
Because of the substantial commitments in time and effort required of than,
the non-Government experts were offered monetary compensations.

     The organizers  agreed,  further,  on  a Workshop  format  that was to
dedicate 2  full days  to pre-prepared  presentations and  followup discus-
sions, one-half  day  to  a  plenary discussion,  and the last full  day to
Steering Committee discussions (see attached Workshop Agenda).  The Workshop
Steering Committee,  composed  of  four non-Government  participants,  guided
the Workshop discussion  so  as to  adhere to the Workshop objectives and, at
the end, digested all information presented at the Workshop and reported it
in terms  of relevant  conclusion  statements  and  recommendations included
here.

-------
 2.0  MAGNITUDE AND TRENDS OF OZONE PROBLEM

 2.1  Ozone Problem in Europe

      The general features of  the  ozone distribution throughout Europe have
 slowly emerged  over the  last  15  years  since  ground level  measurements
 commenced.  Elevated hourly ozone  concentrations  over  60  ppb have  been
 observed at some time during almost every year at every site.  The frequency
 of occurrences of higher hourly concentrations falls off so that 120 ppb is
 exceeded only during certain  years and  at  certain  sites.   The  extreme
 hourly ozone  concentrations  reported  for  each  country   cover  the  range
 100-300 ppb.  Meteorological  conditions conducive  to photochemical  ozone
 episodes are those  within high pressure systems  during  summer with  clear
 skies and low windspeed.  The  vertical  mixing is then inhibited and precur-
 sors and oxidants can accumulate.   In urban areas averaged ozone concentra-
 tions are generally lower compared to adjacent  rural (downwind)  areas most
 likely due to chemical  destruction  of ozone  by emitted  NO.   Quantitative
 identification of trends is complicated by the  short  observational record,
 year-to-year variability  in the  weather,   changes   in measurement method
 and calibration techniques  and  changes in  emission patterns.   Sub-micron
 particles can serve as an  indicator  of large-scale  anthropogenic pollution
 as well as PAN.   PAN is,  in addition, an excellent indicator of high photo-
 chemical activity.   Ozone and  PAN show a  similar  behavior both  in  their
 seasonal cycle and  diurnal variation^.

      In the Federal  Republic  of Germany, there were 156  ozone monitoring
 stations operating  during 1987.   Most of them are situated in  urban areas.
 The measurements are based on  chemiluminescenee and  UV absorption  tech-
 niques.   Ozone data up  to 1983 have been  published in a review  report3.
 Table 2-1  shows ozone  concentrations form  1976 to  1986  at some  selected
 sites across the Federal .Republic of Germany.   These measurements  indicate
 the average annual  ozone concentration  to  increase  with altitude and with
 distance from urban areas, presumably due to  dry deposition at the ground
 and the  influence of NO  emission.  Typical  annual averages ranged between
 20 and 80 (ig/nP (10  and 40  ppb).   The records  also show  both a  seasonal
 and diurnal cycle.  The seasonal cycle has a  minimum  in winter and a maximum
 in summer.    In  general,  the  annual  amplitude decreases  with  altitude.
Maximum  ozone concentrations are highest at low altitudes close to certain
 industrialized and urban areas.  They occur  during episodes  in  summer, when
high pressure systems over  Central  or Northern Europe are accompanied by
 easterly flow from  the  continent and  high temperatures.   Vertical ozone
profiles  taken by airplane under these conditions show that ozone concen-
 trations  in excess of those  found in the middle  troposphere are abundant in
 the mixing  layer all over the  warm  part of such  high  pressure systems.
The  spatial extent  of these elevated ozone  concentrations  is  of the order
of a million square  kilometers.  On this  regional  scale  200 jig/m3 (0.10
ppm)  appears  to  be die  upper  limit  for ozone within the  mixing  layer as
shown in  Figure  2-P.   Higher  concentrations  are  due to  local  sources.
The highest ozone concentration ever observed near  the surface in Germany
is 664 pg/nP  or  0.34 ppm (30 min. average)  on  June 23,  1976,  in Mannheim
 (Upper Rhine  Valley)J.    Due  to different  meteorological  conditions  from
year  to  year  the frequencies  of exceeding  certain ozone  concentration

-------
4-A
n i
Q

CJ
•Tit
t
s
rH
cd
^1
0)
-p
,33
PC4
OJ
*Fi

•S

CO
CJ
*j
00
T?
j_>
ft
CD
rH
CD
CO
4J

i
CO
to
8
GO
§
J5
it
crt
B
c
Q/ X
00""
o
c5>s
0
Sc