the impact of global change on air quality · photo image area measures 2” h x 6.93” w and can...

Darrell Winner, Ph.D. U.S. EPA; ORD/NCER/ASD [email protected]

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July 15, 2009

http://www.epa.gov/ncer/science/globalclimate

The Impact of Global Change on Air Quality

Office of Research and Development National Center for Environmental Research

Outline

• Potential impact of climate change on:

–Ozone

–Particulate matter

–Toxics

–Pollen


Acknowledgements

• Doug Grano, OAR/OAQPS

• Anne Grambsch ORD/NCEA

• Chris Weaver ORD/NCEA

• John Dawson, AAAS fellow ORD/NCER

• Ken Mitchell, EPA Region 4

• Daniel Jacob, Harvard

• X.Z. Liang, Illinois State Water Survey


Climate Change Science

• The Intergovernmental Panel on Climate Change (IPCC)

– Established in 1988 by the World Meteorological Organization and the United Nations Environment Program to assess the risk of human-induced climate change.

• The latest IPCC report is Climate Change 2007 (http://www.ipcc.ch/)

– Based on over 2500 scientific expert reviewers and 450 lead authors from over 130 countries.

– Evidence for warming of the climate system is unequivocal.

– The role of greenhouse gases is well understood and their increases are well identified.

– The net effect of human activities is now quantified and known to cause a warming at the Earth’s surface.


Human Contribution to Climate Change

• Global atmospheric

concentrations of greenhouse gases

increased markedly as a result of human activities

• In 2005, the concentration

of CO2 exceeded by far the natural range over the last

650,000 years

10,000 5,000 0

Time (before 2005)

IPCC 9-07


Between 1970 and 2005, GHG Emissions Increased 70%

IPCC 5-07


IPCC 9-07


Ranges of predicted surface warming

IPCC 9-07


Climate Change 2080-2099 vs. 1980-1999

(Ensemble of 20 GCMs from IPCC 4th assessment report)

Jacob and Winner, 2009


Changes in earth’s energy balance

• Radiative forcing

– Measure of the cooling or warming (radiative) effect due to a change (forcing) in the climate system

• For example, an increase in the concentration of carbon dioxide has a warming effect

• The following chart indicates

– The relative importance of Greenhouse Gases

– Forcing from various factors over the last 250 years

– The uncertainties associated with these estimates

Greenhouse radiative forcing of climate between 1750 and 2005 [IPCC, 2007]

Referenced to forcing agent Referenced to emission

Ozone radiative forcing: 0.35 W m-2

compare to 1.6 W m-2 for CO2

…but NOx emissions have net cooling effect, due to offsetting effectson methane and nitrate

The best strategy to decrease ozone radiative forcing is to decrease methane emissions – also decreases ozone background D. Jacob, Harvard


Impact of climate change on air quality - Ozone


Empirical evidence suggesting climate change could affect AQ

• O3 episodes (mostly summer) are generally

what we care about

• Right combination of meteorological

conditions – e.g., high temperature, clear

skies, stagnant air – with the right blend of

precursor pollutants, e.g., NOx, VOCs

• Global climate change has the potential to

affect both regional meteorology and regional emissions

• Likely to see different degrees of change in

different regions

Example: Probability of max

daily 8-hour O3 exceeding 84

ppb as a function of max daily T

Lin et al. [2001]


Air Quality Assessment Framework

Air Quality Modeling (NERL, Harvard, Georgia Tech, Carnegie Mellon, Illinois, Berkeley, WSU,

Harvard, Columbia, Johns Hopkins)

Regional Change

Scenarios

Regional Emissions

Regional Meteorology

Regional Boundary Conditions

Global Change Scenarios (tech change, population growth, economic activity levels…)

Global Meteorology

Global Emissions

Global Air Quality

Regional Air Quality

Global Chemistry Modeling (Harvard,

Carnegie Mellon, Illinois)

Technology Assessments with MARKAL (NRMRL)

Biogenics modeling (NERL, Forest Service, UC-

Boulder, UNC, UT-Austin, UNH)

Emissions Modeling (NRMRL, OAR, Illinois)

Intercontinental Air Pollution (OAR)

Climate Downscaling

(PNNL, Illinois, WSU, Columbia, Harvard,

Carnegie Mellon)

Climate Effects of Aerosols

(OAR)

Socio-economic scenarios (NCEA)

Regional development (Georgia Tech, UC-

Davis, RFF, UT-Austin, UW-Seattle, Illinois,

Johns Hopkins, Columbia)

Consequences of Global Change for Air Quality

• EPA STAR grants exploring the effect of

Climate, land use, technology, and demographic change on

Ozone, particulate matter, and precursor emissions • Modeling future impact of global changes on US air quality (6 grants, $5.4 million

FY 02)

• Future anthropogenic air pollution emissions (2 grants, $1.5 million FY 03)

• Future biogenic air pollution emissions (4 grants, $2.8 million FY 03)

• Regional development, population trend, and technology change impacts on

future air pollution emissions (8 grants, $4.9 million FY 04/05)

• Fire, climate, and air quality (3 grants, $2.2 million FY 06)

• Consequences of Global Change for Air Quality (10 grants, $9.0 million FY 07/08)

• Prequel - Consequences of interactions between human activities and a changing

climate (3 relevant grants, $4.2 million FY 00)

• http://www.epa.gov/ncer/science/globalclimate


Disproportionately large climate-induced changes for high-O3 extremes

Mean MDA8 O3

95th Percentile MDA8 O3

Shift in Typical Duration of > 84 ppb O3 Episodes

Shift in the O3 Distribution

Wu et al. [2008]

Hogrefe et al. [2004]

Nolte et al. [2008]

Daniel J. Jacob (P.I.) and Loretta J. Mickley, HarvardJohn H. Seinfeld, CaltechDavid Rind, NASA/GISS

Joshua Fu, U. TennesseeDavid G. Streets, ANL

Daewon Byun, U. Houston

an EPA-STAR project (R830959 and R833370)

2000-2050change inclimate

2000-2050change inpollutantemissions

2000-2050 change in U.S. air quality

GISS GCM 31950-2050 transient climate

simulation

GEOS-Chem CTMglobal O3-PM-Hg

simulation

MM5 mesoscaledynamics simulation

CMAQO3-PM-Hgsimulation

boundaryconditions

met. input

met. input

boundaryconditions

2050 vs. 2000 climate

IPCC scenariosand derived emissions

greenhousegases

ozone and PM precursorsmercury

Global United States

2000 emissions

% change,2000-2050

2000 emissions

% change, 2000-2050

NOx, Tg N y-1

Anthropogenic Lightning Soils (natural)

344.96.1

+71%+18%+8%

6.00.140.35

-39%+21%+11%

NMVOCs, Tg C y-1

Anthropogenic Biogenic

46610

+150%+23%

9.340

-52%+23%

CO, Tg y-1 1020 +25% 87 -47%

Methane, ppbv 1750 2400 (+37%)

2000 emissions: GEOS-Chem, including NEI 99 for United States2000-2050 % change, anthropogenic: SRES A1B scenario2000-2050 % change, natural: GISS/GEOS-Chem

Wu et al. [2008]results from EPA STAR grant R830959, Harvard

(2050 emissions & 2000 climate) (2050 emissions & climate)

1999-2001 ozone, ppb (2000 emissions w/ 2050 climate)

Wu et al. [2008]results from EPA STAR grant R830959, Harvard


2000 climate with NOx emissionsreduced by 40%

2050 climate- 50% NOx

2050 climate- 60% NOx

Climate Change Penalty

Wu et al. [2008]

Harvard study

suggests that climate change in the

Northeast U.S. would necessitate a 50% NOx

reduction to achieve

the same O3 goals as a 40% reduction today


• Leibensperger et al. (2008), ACP

– Decreasing trend in mid-latitude cyclone frequency in US (1980-2006)

• Significant for NCEP/NCAR reanalysis (-0.15 yr-1) & NOAA maps

• Not significant for NCEP/DOE reanalysis

“We find that if mid-latitude cyclone frequency had not declined, the northeastern

US would have been largely compliant with the ozone air quality standard by 2001”


Observed average number of summer days in the

Northeast U.S. with 8-hour O3 > 84 ppb

Interannual Variability …

Nolte et al. [2008]

From EPA NERL study,

simulated increases in

O3 in 2050 are of same

order as present-day

year-to-year variability

in some regions.


Extension of O3 Season?

Nolte et al. [2008]

EPA NERL Simulation Results: Change in MDA8 O3

from present to 2050s for September-October


Modeling Future Changes in the Mid-Latitude Storm Tracks

2045-2052

1995-2002

Mickley et al. [2004]

MDA8 O3

change

by 2050s

Harvard Carnegie Mellon


Key: Is isoprene nitrate

a terminal or temporary

sink for NOx in model

chemistry … ?

MDA8 O3

change

by 2050s

Harvard Carnegie Mellon

Modeling Isoprene Nitrate Chemistry


Impact of climate change on air quality – Particulate matter


• Warming climate affects particulate matter

– More water vapor plus changing weather patterns

• Increasing rainout events (decreasing PM in some regions)

• Increasing drought (increasing PM in some regions)

– Increase in number and length of stagnation events

– Changing biogenic emissions

– Changing some particles to the gaseous state

– Drought-related increases in dust emissions.

– Longer wildfire seasons and larger fires.

• The net impact is unclear.

Major predicted climate effects on PM


Carnegie Mellon modeling setup

• Models

– GISS II’ GCM/CTM

– MM5

– PMCAMx

• 5 present and 5 2050s climate (IPCC A2)

• Present-day PM/precursor emissions

GCM/CTM

(GISS II’)

Regional

met model

(MM5)

Regional

CTM

(PMCAMx)

Meteorology

Meteorology

Chemical

boundary

conditions

Climate / emissions

scenario

Regional-

scale air

quality


July PM2.5 Future – Present,

A2 climate change, present day emissions

• Mix of species/met effects: Largely sulfate

• Stagnation

• Mixing height

• Precipitation?

• Temperature?

PM2.5 (μg m-3)

Land-cell average = +2.2 μg m-3

Dawson et al. (2009)


Important processes not well-represented

• Organics?

• Wildfires?

• Feedback effects?

• Global transport?

Insights into the effect of climate change on air quality

Ozone PM (aerosol)

Stagnation

Temperature

Mixing depth

Precipitation

Cloud cover

Humidity

Effect of climate change

=

=?

?=?

? (relative)

Jacob and Winner, AE 2009


Impact of climate change on air quality - Toxics

Courtesy of Sustaining the Environment and Resources for Canadians


Climate Impacts on Toxics-General

• Mitigation measures in response to climate change

may alter air toxic emissions from a variety of

sources

– Reformulation of vehicle fuels

• E85 will increase two major carcinogens, acetaldehyde and formaldehyde while slightly reducing another, butadiene, and reducing a fourth, benzene. (E85 subject of STAR grant)

– Less fossil fuel combustion as other fuels are developed

– More geothermal production, waste incineration, and woodstove use?

• Higher temperatures indicate greater evaporative emissions

– Mobile sources evaporative emissions, including benzene

– Stationary sources evaporative emissions, including solvents


Example….Climate Impacts on Mercury

• Mercury chemistry and emission rates are affected by temperature

– Increased rates of re-emission of mercury from land and ocean are associated with increased temperatures.

– Temperature increases in the North Atlantic are projected to increase rates of mercury methylation in fish and marine mammals, thus increasing human exposure via consumption.

• Mercury in biomass (plants and litter) and soil carbon pools are

affected by climate change and in turn can affect mercury uptake,

sequestration and emission.

– Plant growth may be initially enhanced by increased CO2 levels.

– Increases in wildfires may release more biomass/soil mercury to the atmosphere.

[IPCC 2007 WGII Adaptation]

[Obrist STAR grant]

[Jacob STAR grant]


Mercury-Climate Change Research

• Several EPA grants are underway to explore Hg chemistry and transport as

a function of climate and emissions changes through the use of both

models and observational datasets

• Climate change can potentially impact a number of atmospheric processes

that help determine the fate of Hg

– heterogeneous oxidation of gas-phase Hg

– dry deposition of elemental

– reactive gas-phase and particulate Hg

– Hg chemistry in the presence of fog, clouds, and photochemical smog.

• Focus on present and future Hg distribution for the U.S. as a whole, as well

as for particular regions (e.g., Great Lakes, Florida)

• Work aimed at improving Hg chemistry in linked climate and air quality

modeling systems by incorporating additional reactions and refining

existing representations


Impact of climate change on air quality - Pollen


Climate impacts on pollen

• Warming and climate extremes are likely

to increase respiratory illness, including

exposure to pollen (IPCC 2007)

• Climate change has caused an earlier

onset of the spring pollen season in the

Northern Hemisphere.

– It is unclear whether the allergenic content of these pollen types has changed (pollen content remaining the

same or increasing would imply increased exposure)

• A doubling of the atmospheric CO2

concentration stimulated ragweed-pollen

production by over 50%.


Using air quality results in health impact studies

• Combine air quality results with tools used to calculate health impacts of air pollution (e.g. Benmap)

• Pat Kinney (Columbia) and his team have led the way (you will hear from him this afternoon)

• Brand new results from Ted Russell (Georgia Tech) and his group: Potential Impact of Climate Change on Air Pollution-Related Human Health Effects (2009) E. Tagaris, K.-J. Liao, A. J. DeLucia, L. Deck, P. Amar, A. G. Russell, Environmental Science & Technology 43 (13), 4979-4988

– Results suggest that climate change driven air quality-related health effects will be adversely affected in more than 2/3 of the continental U.S.

– Changes in health effects induced by PM2.5 dominate compared to those caused by ozone.

– PM2.5-induced premature mortality is about 15 times higher than that due to ozone. Nationally the analysis suggests approximately 4000 additional annual premature deaths due to climate change impacts on PM2.5 vs 300 due to climate change-induced ozone changes.

– High uncertainty

• Expect more studies soon…

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