Title: The Role of Ozone Transport in the Washington DC Area
1The Role of Ozone Transport in the Washington DC
Area
- Tad Aburn and Jeff Stehr, MDE and UMCP
- Transportation Planning Board
- February 18, 2004
2Topics Covered
- Transport 101- Where does Marylands poor air
quality come from - Background on Marylands air quality
- The role of transported pollution
- Transport 201 The three types of transport
- Short-range transport
- Westerly transport
- Low level night time jets
3Marylands Air Quality
- Ozone levels in Maryland are very high
- Fine particulate levels are high
- Air pollution contributes significantly to Bay
pollution - Regional haze and air toxics are also significant
air pollution problems in Maryland
4Ozone Days Above the 1-hour Standard
of Days
Source MARAMA 2002 Data
5Fine ParticulatePercent of Monitors Above the
Annual Standard
Percent Monitors
Source MARAMA 2001 Data
6Nitrogen Deposition to the Chesapeake Bay
7A Quick Primer on How Ground Level Ozone is
Formed
8Are Our Emissions Higher Than Other Areas?
Source U.S. EPA - 1999 figures
9Are Our Emissions Higher Than Other States?
tons per year
Source U.S. EPA - 1999 data
10So Where Does It Come From?
- Air pollution floating in from other states
(called transport) is a significant contributor
to our air pollution problems - Maryland the meteorologically challenged state
- MDE/UMCP Aircraft that measure incoming
pollution - Models that predict state by state contributions
11Classic Ozone Weather in the Mid-Atlantic
Maryland sees its worst air pollution during the
summer when a Bermuda High sets up over the
Carolinas
H
12Power Plant Emissions
- Very large power plant emissions concentrated
along the Ohio River valley - Air aloft circulates clockwise around the high
H
13How Much Comes From Out of State?
- MDE works in partnership with the University of
Maryland College Park to measure and analyze
pollution being transported into Maryland - On our worst days we measure ozone at 110 parts
per billion (ppb) floating into the state from
the West - The 1-hour standard is 125 ppb
14Who is Contributing to Marylands Ozone Problem?
- From EPAs modeling to support the 22 state
regional NOx reduction program called the NOx
SIP Call
15Are Local or Regional Reductions Better?
- In Maryland, our technical analyses show that on
our worst days - Local reductions are not very good at reducing
local ozone. - In other areas, like Atlanta, local reductions
seem to be much more effective - On days where our ozone is more home grown
local reductions are more important - Not our worst days, but we often see high ozone
16Transport 201
- The different types of transport
- The elevated ozone reservoir
- Short range transport
- Westerly transport
- Low level night time jets
17Is It Just Power Plants or are There Other Types
of Transport?
- Marylands location places us at the air
pollution crossroads when if comes to transport. - Air pollution floats to us from the west and the
south. - Sometimes the air pollution we transport to the
north actually re-circulates back to us. - Power plants, cars and area sources are all
involved in the transport process
18Three Types of Transport That Affect Maryland
- Short range
- VA to MD to PA, etc.
- Long range (synoptic scale)
- 100s of miles
- Generally from W or NW
- Low Level Night-time Jets
- 100s of miles
- SW to NE along the Atlantic
- All types of transport collect in an elevated
reservoir of ozone
19The Elevated Ozone Reservoir
Early Morning Ozone Western Maryland
- Every bad ozone day, before any new ozone has
been formed, a large reservoir of ozone sits
above Maryland waiting to mix down. - Ozone levels in the reservoir can routinely reach
80 to 100 ppb
Ozone 2000 feet above the surface is very high
Surface ozone is very low
20What Creates the Reservoir?
- At night the earth cools and a nocturnal
inversion is created several hundred meters
above the surface - Ozone, created earlier in the day is trapped
above the inversion and moved to the north by
night-time jets. - Ozone below the inversion drops to very low
levels.
21Ground Level Ozone at Night
This hourly ozone graph for a summer day near
Frederick, Maryland shows ozone concentrations
reaching a minimum in the early morning hours.
22Regional Scale Ozone
In this case from July, 1999, the high elevation
monitor at Methodist Hill in southern PA is above
the nocturnal inversion. By late morning, mixing
has brought all monitors to the common regional
level.
23Where Does the Reservoir Come From?
- The elevated ozone reservoir above Maryland is a
complex mix of pollution that originated in the
west (primarily power plants) and the south
(cars, area sources and stationary sources)
24Short Range Transport
- Central VA to DC
- DC to Baltimore
- Baltimore to PA
- Ground level winds from the southwest to the
northeast - Emissions from cars, area sources and stationary
sources float to the northeast and add to high
ozone levels downwind
25Westerly Transport
- On Marylands worst ozone days westerly
transport plays a significant role in creating
high ozone.
26Classic Ozone Weather in the Mid-Atlantic
Maryland sees its worst air pollution during the
summer when a Bermuda High sets up over the
Carolinas
H
27Power Plant Emissions
- Very large power plant emissions concentrated
along the Ohio River valley - Air aloft circulates clockwise around the high
H
28Westerly Transport What Does the Data Tell us
About Its Origin?
DOES NOT CORRELATE WELL WITH CO NOT CARS
HIGH OZONE ALOFT
CORRELATES WELL WITH SO2 PROBABLY POWER PLANTS
CORRELATES WITH HIGH AGED NOX ITS OLD
29The Low Level Jet
- Night time transport that moves air from NC to
MD, MD to NJ, etc. - The Jet is funneled northward by the Appalachians
on the west and the Atlantic on the east - Wind speeds up to 40 miles per hour can move
pollution hundreds of miles overnight.
Low Level Jet
30Low Level Jet Recorded Above Fort Meade Maryland
WHAT DOES THIS GRAPH TELL US? WIND SPEED AND
DIRECTION ABOVE FT MEADE MD
35 MPH FOR 6 HOURS IS ABOUT 200 MILES
AUGUST 10 WINDS FROM THE SOUTHWEST AT ABOUT 25
to 30 MPH 1000 FEET ABOVE THE SURFACE
AUGUST 11 WINDS FROM THE SOUTHWEST AT ABOUT 30
to 40 MPH 1000 FEET ABOVE THE SURFACE
AUGUST 12 WINDS FROM THE SOUTHWEST AT ABOUT 30
to 40 MPH 1000 FEET ABOVE THE SURFACE
AUGUST 10 10 PM TO 8AM . . .
AUGUST 12 10 PM TO 9AM am . . .
AUGUST 11 10 PM TO 8AM. . . .
LLJ
LLJ
LLJ
NOCTURNAL INVERSION UP TO ABOUT 1000 FEET .
31Model Depiction of the Low Level Jet High Wind
Speeds In Red
900 PM
1100 PM
0100 AM
0300 AM
0500 AM
0700 AM
32How Much Ozone May be in the Low Level Jet?
- Still analyzing this issue
- Theory and recent work by Penn State around
Philadelphia (using laser technology called
LIDAR) indicates that the low level jet can
routinely carry 80 to 90 ppb ozone.
33Take Home Messages
- The Washington areas air quality is significantly
affected by transport from upwind areas to the
west and the south - On the worst ozone days well over half of the
measured ozone in Washington originates in upwind
states - Sources that transport pollution to Washington
include power plants, cars and area sources.
34Policy Implications
- Current suite of NOx controls is good but more
will be needed - 2003/2004 NOx SIP Call
- 2007 Tier 2 vehicle and heavy duty diesel
standards - Congressional debate over multi- pollutant
power plant legislation (Clear Skies Act, etc.)
will be critical - Low level jet issue raises some interesting new
questions - Should the level playing field for mobile and
area source controls be stretched to the south?
35Key Transportation Issues
- Are the mobile source reductions in the
Washington area needed? - Yes, on some days local mobile emissions drive
our high ozone - New, tougher standards for ozone and fine
particulate begin in 2004 and will require even
more controls
36Key Transportation Issues(continued)
- Should areas to the south and west of the
Washington area be subject to the same level of
mobile source controls now require in DC? - Yes, the playing field for mobile source controls
should be leveled from Atlanta to Boston - Marylands new low level jet research supports
this
37Key Transportation Issues(continued)
- Shouldnt other sources (like power plants) be
regulated better before local mobile sources are
further controlled? - Yes and no.
- MDE is pushing very hard for tougher controls on
upwind power plants and areas sources. - Local reductions still help!!!
- Conformity is required in the Clean Air Act
- With or without reductions in upwind areas