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The Basic Science of Air Pollution Transport. Brian J. Hug Division Chief, Air Quality Planning and Policy Division. Maryland’s Air Quality. Ozone levels in Maryland are very high Fine particulate levels are high Air pollution contributes significantly to Bay pollution

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The basic science of air pollution transport

The Basic Science of Air Pollution Transport

Brian J. Hug

Division Chief, Air Quality Planning and Policy Division


Maryland s air quality
Maryland’s 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



A primer on transport
A Primer on Transport

  • Transport 101- Where does Maryland’s poor air quality come from

    • Background on Maryland’s air quality

    • The role of “transported” pollution

  • Transport 201 – The three types of transport

    • Short-range transport

    • Westerly transport

    • Low level night time jets




Are emissions higher in maryland
Are Emissions Higher in Maryland?

States

Source: U.S. EPA - 1999 data

tons per year


So where does it come from
So 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


Classic ozone weather in the mid atlantic
Classic 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


Power plant emissions
Power Plant Emissions

  • Very large power plant emissions concentrated along the Ohio River valley

  • Air aloft circulates clockwise around the high

H


How much comes from out of state
How 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 8-hour standard is 85 ppb


Who is contributing to maryland s ozone problem
Who is Contributing to Maryland’s Ozone Problem?

  • From EPA’s modeling to support the 22 state regional NOx reduction program called the “NOx SIP Call”


Are local or regional reductions better
Are Local or Regional Reductions Better?

  • In Maryland, our technical analyses show that on our worstdays

    • 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


Transport 201
Transport 201

  • The different types of transport

  • The elevated ozone reservoir

  • Short range transport

  • Westerly transport

  • Low level night time jets


Is it just power plants or are there other types of transport
Is It Just Power Plants or are There Other Types of Transport?

  • Maryland’s 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


Three types of transport that affect maryland
Three Types of Transport That Affect Maryland Transport?

  • 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


The elevated ozone reservoir
The Elevated Ozone Reservoir Transport?

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


What creates the reservoir
What Creates the Reservoir? Transport?

  • 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.


Ground level ozone at night
Ground Level Ozone at Night Transport?

This hourly ozone graph for a summer day near Frederick, Maryland shows ozone concentrations reaching a minimum in the early morning hours.


Regional scale ozone
Regional Scale Ozone Transport?

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.


Where does the reservoir come from
Where Does the Reservoir Come From? Transport?

  • 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)


Short range transport
Short Range Transport 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


Westerly transport
Westerly Transport Transport?

  • On Maryland’s worst ozone days “westerly transport” plays a significant role in creating high ozone.


Classic ozone weather in the mid atlantic1
Classic Ozone Weather in the Mid-Atlantic Transport?

Maryland sees its’ worst air pollution during the summer when a “Bermuda High” sets up over the Carolinas

H


Power plant emissions1
Power Plant Emissions Transport?

  • Very large power plant emissions concentrated along the Ohio River valley

  • Air aloft circulates clockwise around the high

H


Westerly transport what does the data tell us about its origin
Westerly 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”

* IT’S OLD *


The basic science of air pollution transport

The Low Level Jet Origin?

  • 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


The basic science of air pollution transport

Low Level Jet Recorded Above Fort Meade Maryland Origin?

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

.


The basic science of air pollution transport

Model Depiction of the Low Level Jet Origin?

High Wind Speeds In Red

9:00 PM

11:00 PM

01:00 AM

03:00 AM

05:00 AM

07:00 AM


How much ozone may be in the low level jet
How Much Ozone May be in the Low Level Jet? Origin?

  • 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.


Take home messages
Take Home Messages Origin?

  • Maryland’s 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 Maryland originates in upwind states

  • Sources that transport pollution to Maryland include power plants, cars and area sources.


Thanks brian hug division chief planning and policy division 410 537 4125 bhug@mde state md us
Thanks….. Origin?Brian HugDivision Chief, Planning and Policy Division410-537-4125bhug@mde.state.md.us