Kari  Palmer  Clean  Air  Dialogues  WG2  

May  11,  2012  

What  is  Ozone?  

•  A  naturally-­‐occurring  consAtuent  of  the  upper  atmosphere  protecAng  the  earth  from  UV  radiaAon  

•  When  formed  at  ground-­‐level  it  causes  human  health  and  environmental  problems  

Health  &  Environmental  Effects  of  Ozone  

•  High  levels  of  ozone  can  have  an  adverse  impact  on  the  lungs  •  Airway  inflammaAon,  shortness  of  breath,  coughing,  aggravaAon  of  asthma,  emphysema,  bronchiAs  

•  Results  in  increased  medicine  use,  doctor  visits  and  hospital  admissions  

•  ParAcularly  older  adults,  children,  people  who  exercise  outside  

•  Damages  vegetaAon,  trees  and  crops  

Trends  in  Ozone:    Twin  CiAes  Metro,  1999-­‐2011  

0%

20%

40%

60%

80%

100%

120%

Percen

t  of  stand

ard

Standard  

MN  Ozone  ConcentraAons  (2009-­‐2011)  

60   59   59   58  62   61  

63  60   60  

65  63   62  

58  54  

49  

62  

0

10

20

30

40

50

60

70

80

Ozone

 Con

centraAo

n  (ppb

)  

Standard  

2011  Twin  CiAes  Air  Quality  Index  Days  Ozone  

PM2.5  

Ozone  ConcentraAons  Across  the  U.S.,  2010  

Ground-­‐Level  Ozone  FormaAon  in  MN  

•  A  chemical  reacAon  between  nitrogen  oxides  (NO  and  NO2),  oxygen,  and  volaAle  organic  compounds  (VOCs)  

•  Sunlight  fuels  the  reacAon  -­‐  at  night  ozone  levels  decrease  

•  Hot  days  above  85˚F  

•  Winds  can  transport  ozone  and  precursors  

Ozone  

Ozone  Chemistry  •  OH  radical  is  central  to  

ozone  and  secondary  PM  chemistry  

•  OH  iniAates  reacAons  of  VOCs  (and  CO)  that  produce  radicals  

•  Radicals  interact  with  NOx  (NO  and  NO2)  in  sunlight  to  form  ozone  

 •  Ozone  requires  both  

NOx  and  VOC  precursors  

Ozone  FormaAon  

Ozone  cycle  disrupted  by  VOCS  

VOC  +  OH  =  RO2  +  H2O  RO2  +  NO  =  NO2  +  RO    

Normal  ozone  cycle  NO2  +  sunlight  =  NO  +  O  O  +  O2  =  O3  NO  +  O3  =  NO2  +  O2  

June  6,  2011  Ozone  Exceedance  

June  6,  2011  Ozone  Event  Time  Lapse  

Hourly  Ozone  ConcentraAons  Across  Minnesota  June  5-­‐June  7  

Locally  Influenced  Ozone  Event  6/25/2009-­‐6/27/2009  

2008  Emissions  of  Ozone  Precursors  VOCs  

•  VegetaAon-­‐55%  •  Miscellaneous-­‐17%  •  Off-­‐highway-­‐8%  

•  Snowmobiles,  boats,  ATVs,  etc.  

•  Highway  vehicles-­‐8%  •  Gasoline  vehicles  

•  Solvent  Use-­‐7%  

EPA  NaAonal  Emissions  Inventory,  2008  version  2  

Natural  vegetaAon  

55%  

Miscellaneous  17%  

Off-­‐highway  equipment  

8%  

Highway  vehicles  8%  

Solvent  use  7%  

Petroleum  storage  and  tranport  

2%  

Other  fuel  combusAon  

2%   Other  1%  

2008  Emissions  of  Ozone  Precursors  Nitrogen  Oxides  

Highway  vehicles  39%  

Off-­‐highway  equipment  

23%  

Fuel  combusAon  

from  electrical  uAliAes  15%  

Metals  processing  

6%  VegetaAon  

6%  

Fuel  combusion  industrial  

5%  

Fuel  combusion  

other  3%  

Other  3%  •  Highway  vehicles-­‐39%  

•  Gasoline  vehicles  •  Off-­‐highway-­‐23%  

•  Railroads,  agricultural,  construcAon  and  recreaAonal  equipment  

•  Electric  uAlity  fuel  combusAon-­‐15%  

EPA  NaAonal  Emissions  Inventory,  2008  version  2  

July  14,  2005  

Area  of  ozone  formaAon  that  is  VOC-­‐limited  shrinks  through  the  day  

10  am   12  pm   4  pm  

• Slide  #19.    Very  Important!    If  you  Atle  this  slide  “What  emissions  decreases  maoer”?  Include  the  wrioen  answer,  “We  don’t  know”.    And  then  say,  the  Agency  uses  photochemical  models  to  simulate  the  complex  processes  in  the  formaAon  of  ozone  and  parAculate  maoer.    And  as  discussed  earlier,  these  processes  are  intertwined.    Largely  we  have  focused  our  efforts  on  Regional  haze,  and  now  PM2.5,  however,  we  did  use  photochemical  models  to  look  at  ozone  to  help  inform  Clean  Air  Minnesota  back  in  2003,  and  in  2010  evaluated  the  processes  of  ozone  formaAon  for  a  few  episodes  in  2005.    In  this  slide  (and  #20)  you  can  see  spaAally  throughout  one  day  how  ozone  formaAon  is  limited  by  the  amount  of  available  VOC  in  the  urban  area  and  how  that  shrinks  throughout  the  day.    The  booom  row  shows  how  ozone  formaAon  is  sensiAve  to  the  amount  of  available  NOx.    This  does  not  provide  any  definiAve  answers  on  what  to  reduce  but  illustrates  the  process  of  ozone  formaAon  in  Minnesota.        NOTE:    I  don’t  believe  the  bullet  statements  are  correct.

July  14,  2005  

Area  of  ozone  formaAon  that  is  VOC-­‐limited  shrinks  through  the  day  10  am   12  pm   4  pm  

What  Emissions  Decreases  Maoer?  

•  We  aren’t  sure  

•  Photochemical  modeling  can  help  

MN  Point  Source  NOX  Emission  Trends  

0

25,000

50,000

75,000

100,000

125,000

150,000

2006 2007 2008 2009 2010

Tons

Other Pulp & paper Refineries Mining Electric utilities Manufacturing

Take  Away  Messages  •  Ozone  causes  serious  health  and  environmental  damage  

•  ConcentraAons  are  currently  below  standards  and  have  been  decreasing.  

•  Ozone  chemistry  is  complex  •  Non-­‐linear  reacAons  of  NOx  and  VOCs  

•  Main  sources  are  fuel  combusAon  •  On  and  off-­‐highway  equipment,    

•  Electric  uAliAes  •  Natural  sources  are  important  

•  NOx  and  VOC  reducAons  may  be  important  

Thanks  to  

•  Cassie  McMahon  

•  Margaret  McCourtney  

•  Catherine  Neuschler