European air pollution trends 1980-2010 Leonor Tarras ón EMEP/MSC-W

European air pollution trends 1980-2010

Leonor TarrasónEMEP/MSC-W

Workshop on Review and Assessment of European Air Pollution Policies

25-27 October 2004, Gothenburg, Sweden

EMEP Assessment Part I : European Perspective

EMEP Assessment Part II: National Assessment

20 national contributions, CCC, MSC-E, MSC-W, IVL

Gun Löblad

Main questions addressed by the EMEP Assessment Report

Meteorologisk Institutt met.no

• What is the result of emission reductions for air quality ?

• What are the reasons behind the trends and are the trends in line with current understanding?

• What is the present status of environmental air quality and what is the need for further actions?

SULPHUR TRENDS


Sulphur emissions 1980-2000

0

5000

10000

15000

20000

25000

30000

35000

40000

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

1110987654321

Countries SO2

CE = Czech Rep., Hungary, Poland and Slovak Rep.

-73%

CW = Austria, Switzerland and Germany

-89%

E = Estonia, Latvia, Lithuania and Russia (European part)*

-73%

N = Denmark Finland Iceland, Norway and Sweden

-87%

NW = Belgium, Luxemburg, the Netherlands, Ireland and United Kingdom

-76%

S = France, Greece, Italy, Portugal and Spain

-62%

SE = Albania, Armenia, Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, Georgia, Kazakhstan, Republic of Moldova, Romania, Slovenia, The FYROM Macedonia, Turkey, Ukraine and Yugoslavia

-40%

TOTAL EUROPE (excluding ships )

-67%The decrease is not achieved in one single sector, and is generally larger after 1990

0

20

40

60

80

100

120

140

1978

-01-

01

1979

-01-

01

1980

-01-

01

1981

-01-

01

1982

-01-

01

1983

-01-

01

1984

-01-

01

1985

-01-

01

1986

-01-

01

1987

-01-

01

1988

-01-

01

1989

-01-

01

1990

-01-

01

1991

-01-

01

1992

-01-

01

1993

-01-

01

1994

-01-

01

1995

-01-

01

1996

-01-

01

1997

-01-

01

1998

-01-

01

1999

-01-

01

Daily means measured at SE02

1978-2000

Episodes with high SO2 have decreased both in frequency and magnitude

DK 03 / SO2

0

2

4

6

8

10

12

14

Jan Feb Mar Apr Mai Jun Jul Aug Sep Oct Nov Dec

1979-1981

1999-2001

GB 04 / SO2

0

2

4

6

8

10

12

Jan Feb Mar Apr Mai Jun Jul Aug Sep Oct Nov Dec

1982-1984

1999-2001

Episodes occurred during winter. The decrease in SO2 concentrations has been larger in winter than in summer, most likely due to a larger emission decrease in the cold season. However, weather may also have contributed to the change.

GB04 DK03

The seasonal variation of SO2 has changed

FR05SO2 and SO4 trends

0

2

4

6

8

10

1977 1983 1989 1995 2001

ug

S/m

3

SO2 airSO4 air

Sulphate in air has also decreased, … but not as much as the sulphur emissions and SO2 in air

FR05

IT04

How to explain this?

IT04SO2 and SO4 trends

0

2

4

6

8

1977 1983 1989 1995 2001

ug

S/m

3

SO2 airSO4 air

FI04SO2 and SO4 trends

0

2

4

6

8

1977 1983 1989 1995 2001

ug

S/m

3

SO2 airSO4 air

FI04

Meteorologisk Institutt met.noEMEP/MSC-W

Meteorologisk Institutt met.noEMEP/MSC-W

Sulphate formation is determined by availability of oxidants (OH,H2O2,O3)

No oxidant limitation

With oxidant limitation:

Ammonia plays also a role in explaining sulphur trends

SO2/(SO4 air+SO4 prec)


y = -0.91Ln(x) + 0.44

R2 = 0.30

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2

NH4/(2SO4+NO3)

Rat

io o

f the

con

cent

ratio

n ch

ange

of S

O2/

(SO

4 ae

r+S

O4

rain

)

Netherl. SO2/(SO4+SO4)

Vavih SO2/(SO4+SO4)

Deuselbach, GE

GB 2

DK 3

NH4/(SO4+NO3)

Logaritmisch (NH4/(SO4+NO3))

0

0.5

1

1.5

2

2.5

3

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000

Year

Rat

io o

f the

con

cent

ratio

n ch

ange

rel

ativ

e to

198

0 as

SO

2/(S

O4

aer+

SO

4 ra

in)

Netherlands

Vavih

Bredk

Deuselbach, GE

GB 2

IT 4

Increases the pH inside clouds (added effect to SO2 concentration decrease) which affects the oxidation rate from SO2 to SO4.

Decreasing sulphur emissions have also resulted in decreased sulphate in precipitation

Annual mean values in precipitationPL02

0

1

2

3

1985 1987 1989 1991 1993 1995 1997 1999 2001

XS

O4-

S m

g/l

Annual mean values in precipitationAT02

0

1

2

3

1987 1989 1991 1993 1995 1997 1999 2001

XS

O4-

S m

g/l

Annual mean values in precipitationLV10

0

1

2

3

1985 1987 1989 1991 1993 1995 1997 1999 2001

XS

O4-

S m

g/l

PL02

AT02

The decrease in sulphate in precipitation is similar to that of particulate sulphate in air

LV10

The reduced sulphate in precipitation has further resulted in:

Generally, increasing pH in precipitation

Decreased deposition

Decreased dry and wet deposition to forests

as measured in a Swedish throughfall monitoring network

0

5

10

15

20

25

1985 1990 1995 2000 2005

BlekingeBlekingeV. GötalandV. GötalandNorthNorth

Annual mean values in precipitationCZ01

3.5

4

4.5

5

5.5

1977 1983 1989 1995 2001

pH

CZ01

SULPHUR


• Overall decrease of emissions by nearly 70%, largest in Central European countries.

• Sulphur dioxide concentrations have decreased accordingly. In addition, the frequency and magnitude of episodes has decreased and the seasonal variations have changed.

• Sulphate concentrations in air and precipitation have not decreased at the same rate as the emissions.

• This is because SO4 is a secondary pollutant controlled by chemical precursor & oxidant availability, pH dependences (…NH3!)

NITROGEN TRENDS


Nitrogen emissions 1980-2000

Countries NOx NH3

CE = Czech Rep., Hungary, Poland and Slovak Rep.

-42% -46%

CW = Austria, Switzerland and Germany

-49% -23%

E = Estonia, Latvia, Lithuania and Russia (European part)*

+21% -48%

N = Denmark Finland Iceland, Norway and Sweden

-21% -10%

NW = Belgium, Luxemburg, the Netherlands, Ireland and United Kingdom

-36% -13%

S = France, Greece, Italy, Portugal and Spain

-4% +1%

SE = Albania, Armenia, Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, Georgia, Kazakhstan, Republic of Moldova, Romania, Slovenia, The FYROM Macedonia, Turkey, Ukraine and Yugoslavia

-26% -12%

TOTAL EUROPE (excluding ships )

-24% -20%0

1000

2000

3000

4000

5000

6000

7000

1975 1980 1985 1990 1995 2000 2005

S

CE

SE

E

N

CE

CW

NW

E

Regional differences in N emission changes are more pronounced than for sulphur emissions.

The decrease is lower than for sulphur, but is of the same magnitude for oxidised (NOx) and reduced (NH3) nitrogen

Comparison of ammonia and Nox emissions

0

1

2

3

4

5

6

7

8

9

10

1975 1980 1985 1990 1995 2000 2005

NH3-NNOx-NNOx-N (expert´s estimate )NOx-N (exp est. incl.ships)

Million tons/year

0

5000

10000

15000

20000

25000

30000

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Sector 11Sector 10Sector 9Sector 8Sector 7Sector 6Sector 5Sector 4Sector 3Sector 2Sector 1

Sector allocation of emissions

0

1000

2000

3000

4000

5000

6000

7000

8000

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

sector 11sector 10sector 9sector 8sector 7sector 6sector 5sector 4sector 3sector 2sector 1

NOx emissions 1000 tons NO2/year

NH3 emissions 1000 tons/year

NOx reductions mainly due to changes in combustion sectors (40%) and transport (25%)

Decreased NH3 is due to activity changes and control measures in agricultural sector

DK05

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

1977 1982 1987 1992 1997 2002

[ug

N/m

3]

Total-NO3

Total-NH4

GB02

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1977 1982 1987 1992 1997 2002

[ug

N/m

3]

NO3-totalNH4-total

As for sulphur, the most oxidised nitrogen oxide compound show a slightly lower decrease due to the decreased sulphur emissions leaving more of the oxidants in the atmosphere

Total nitrates and ammonium at DK03 and GB02

Trends are similar for total nitrate and total ammonium at most of the sites available, even if the local emissions reductions are different

CH02

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1977 1982 1987 1992 1997 2002

[mg

N/l]

NH4-precip

NO3-precip

FI04

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

1977 1982 1987 1992 1997 2002

[Mg

N/l]

NH4-precipNO3-precip

Total nitrates and ammonium in precipitation at CH02 and FI04

Example: trends in Nordic countries


Increases in total N deposition may be due to influence not only from local but also from more distant contributions. In addition, the changes may be due to changes in the rates of chemical interactions between pollutants p.e.NH4+NH3/SO4, due to a changing atmospheric composition

NITROGEN - I


• Overall decrease of emissions by 20-30%, similar for NOx and NH3 emissions.

• As for sulphur, the most oxidized nitrogen compound (NO3) shows a less pronounced trend. This is probably due to the fact that reduced sulphur emissions leave a potential for further oxidation in the atmosphere.

• Trends of ammonium in air and precipitation are more similar to trends nitrate in air and precipitation, that what national emission trends would suggest. The explanation is not straigthforward.

•Less monitoring sites with long-term data, need for further studies to analyse the nitrogen trends also in relation to the ratios between NH3+NH4/SO4

NITROGEN -II


Some interesting differences:

• Over land areas, reduced nitrogen depositions and air concentrations generally dominate over oxidized nitrogen (since 1995)

• Over sea areas, oxidized nitrogen is the dominant form of nitrogen

…. This brings the attention to ship traffic emissions

Comparison of oxidized and reduced nitrogen trends

1980-2010


EMEP Land areas Sea areas

Influence of ship emissions in 2010to PM2.5 air concentrations (CLE-15%)


μg/m3 reduction % reduction

Influence of ship emissions in 2010to SOMO35 (CLE – 15%)


ppb days reduction % reduction

Concentrations in air (S,N)


The contribution to PM10 mass from SO4 and NO3 dominates over NH4 contribution


SO 4 / PM10 (%)

0

5

10

15

20

25

30

35

40

45

50

Winter

Spring

Summer

Fall

Natural Rural Near-City Urban

NO 3 / PM10 (%)

0

5

10

15

20

25

30

35

40

Winter

Spring

Summer

Fall

Natural

Rural Near-City Urban

In addition to SIA, there is a primary and organic component


O C / PM10 (%)

0

2

4

6

8

10

12

14

16

18

Winter

Spring

Summer

Fall


DU /PM10 (%)

0

5

10

15

20

25

30

Winter

Spring

Summer

Fall


EC / PM10 (%)

0

1

2

3

4

5

6

7

8

9

Winter

Spring

Summer

Fall


OZONE TRENDS


Maps produced by M

Coyle

Example from UK

Mean AOT40 calculated for for the five years 1994-1998.

Crops Forests

CL=3000 ppbh CL=10000 ppbh

Surface ozone

Threshold conc of O3 are exceeded over large parts of Europe

Peak ozone vs. exceedance to critical levels


A reduction in peak ozone values during the 1990s is reported from several regions in Europe, while there is no clear trend in the exceedances of the critical level (expressed as AOT40).

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

ppb.

h

Zillertaler Alpen (1805 m)

Gerlitzen (1895 m)

St. Koloman (1020 m)

Vorhegg (1020 m)

Illmitz (117 m)

Pillersdorf (315 m)

Critical Level

AOT40 values for forests in Austria (April – September, daylight hours)

Trend evaluation for O3

Long-term trends for O3 are difficult to assess:

- O3 is formed in the air via photochemical reactions between NOx and VOCs, closely linked to the weather situation and its variations between years.

0

10

20

30

40

50

60

Jan-9

8

Feb

-98

Ma

r-98

Ap

r-98

May-9

8

Jun-9

8

Jul-98

Aug

-98

Se

p-98

Oct-9

8

Nov-98

Dec-98

O3

, p

pb

Global

Asian

N American

European

Stratospheric

Orgins of Model Ozone at Mace Head, Ireland- The hemispheric background of O3 - determined by emissions and processes outside Europe - is a considerable source.

Model calculation by R Derwent

Stations in the north and west show increasing hemispheric background concentrations , which partly counterbalance the reduced peak values.

15

20

25

30

35

40

45

50

55O

ZO

NE

CO

NC

(P

PB

)

O3 Baseline monthly means 12-month moving averageLinear (12-month moving average)

The risk for high ozone conc remains. Climate effects may increase the conditions for “ozone summers”

Data from Mace Head

Health exposure to ozone: SOMO35


2000

SOMO35 is high and will continue to be high …

2010

Ozone


• The reduction in peak ozone values is in line with model predictions based on the decreased precursor emissions in Europe and is a very likely result of emission abatement. Intermediate ozone more difficult to reduce.

• Stations in the North and West report increasing hemispheric background concentrations of 0.3-0.5 ppbv year-1.

• The declining trend of the peak values is to some extent counterbalanced by the gradual rise in background ozone and may also be counteracted by climatic change giving higher risks of hot and ozone-rich summers.

• Further policies to reduce the emission of all ozone precursors including the cross-continental, hemispherical perspective will be necessary to reduce the harmful effects from ozone on the environment, crops and human health.

Conclusions I


• Considerable reductions of air emissions since 1980 have resulted in improved air quality in Europe

• Despite this considerable reduction, pollution levels are still high and exceedances of critical loads and levels still represent a significant risk for ecosystems and health.

Conclusions II:


• Improved understanding of the inter-relations between atmospheric air pollutants – PM,O3 policies need to consider links to other greenhouse gases and climate policies

•In particular, more focus should be given to NH3 control

• smallest level of reduction so far,

• reduced nitrogen generally dominates over land areas

• controls the formation and deposition of SIA

•Sources outside Europe are becoming increasingly important (international ship traffic, aircraft emissions, intercontinental sources ) – Link to hemispheric scale and global change

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European air pollution trends 1980-2010 Leonor Tarras ón EMEP/MSC-W

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