Satellite based versus traditional air pollution monitoring: Requirements, limitations, and chances Dominik Brunner, Christoph Hueglin, Christoph Zellweger,

Materials Science &Technology

Satellite based versus traditional air pollution monitoring: Requirements,

limitations, and chances

Dominik Brunner, Christoph Hueglin, Christoph Zellweger, and Brigitte Buchmann

Empa, Swiss Federal Laboratories for Materials Testing and Research Laboratory for Air Pollution and Environmental Technology

8600 Dübendorf, Switzerland

2Materials Science&Technology

50km N

Basel

BernChaumont

Davos

DübendorfHärkingen

Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich Traditional air pollution monitoring

Network concepts, regulations Design and applications of Swiss National Air

Pollution Monitoring Network NABEL

Satellites for air pollution monitoring? Sufficient spatial resolution? Sufficiently accurate?

How limiting is restriction to clear sky overpasses? Analysis of hourly NABEL observations for clear

and all skies Comparison of frequency distributions, diurnal cycles,

and interannual variability under clear and all skies

Conclusions

Outline

Outline

Traditionalmonitoring

Air pollutionmonitoringusingsatellites?

Limitationsof clear-skyoverpasses

Conclusions


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich Monitoring networks

Purpose: Representative measurement of concentrations of all major

(regulated) air pollutants relevant for human health, agriculture, ecosystems, and material degradation

Characterize existing and identify new potential threats Monitor current pollution levels and long-term trends Support for decision makers (warnings, control of success of

air quality policy (short and long-term reduction measures)

Requirements Should cover full range of pollution levels from street level

(human health) to remote locations (ecosystems) Should represent the different regions of a country or region,

e.g. north and south of the Alps, different altitude levels Use reference measurement techniques, traceable to

reference standards High accuracy across network needed for reliable trend

estimates and intercomparability Reliable and simple continuous operation Near real-time data availability

Traditional air pollution monitoring

Outline




Conclusions


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Urban, near street Rural < 1000 m amslUrban, in park Rural > 1000 m amslMotorway Prealpine, forestAgglomeration Alpine

Swiss Air Pollution Monitoring Network (NABEL)

Air Pollution/Environmental Technology

50kmN

Basel

Bern

Chaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

PayerneRigi

Sion

Tänikon

Zürich

Outline




Conclusions


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

NABEL Measurement Programme Air Pollution & Climate Change

GAW

Pollutants with limit value in the Swiss ordinance

PM (PM10, PM2.5, PM1) mass, EC/OC, size distribution

Greenhouse gases (CH4, N2O, halocarbons, SF6), VOCs

Nitrogen Compouds (NH3, NH4

+, N2O, HNO3)

Meteo (p, T, RH, radiation, wind)

Traffic parameter

Auxiliary Parameters:

EMEP / EU

Outline




Conclusions


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich Application: Characterization of air pollution

based on NABEL sites

B

B

C

D

HLL

M

P

R

ST

Z

J

0 10 20 30 40 50 60

010

2030

40

NO2 (ug/m3)

PM

10 (

ug/m

3)

urban, kerbsideurban, in parkat motorwaysuburbanrural < 1000 m aslrural > 1000 m aslhigh-altitude

B

B

C

D

HLL

M

P

R

ST

Z

J

0 20 40 60 80 100

010

2030

40O3 (ppb)

PM

10 (

ug/m

3)

urban, kerbsideurban, in parkat motorwaysuburbanrural < 1000 m aslrural > 1000 m aslhigh-altitude

NABEL: annual mean values 2004


Materials Science&Technology

50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Application: Monitoring of long-term trends, e.g. PM10 (annual means)

Limit value

annual limit valuesSwitzerland 20 EU 2005 40WHO, EU 2010 20

Outline




Conclusions



50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

1990 1995 2000 2005

0.5

1.0

1.5

2.0

Year

Ye

arl

y N

Ox

mix

ing

ra

tios

rela

tive

to 1

99

8 (

Sta

tion

s) /

rela

tive

NO

x e

mis

sio

ns

(Co

un

trie

s)

BERHAELAULUGSIOZUEJFJJFJ NOy

ATCHDEFRIT

Application: Independent control for emission reportingCountry-by-country emissions reported to EMEP versus time evolution of observed concentrations

Emissionsper country

Annual meanconcentrationsat urban stationsand Jungfraujoch

Outline




Conclusions


Nitrogen oxides (NOx)All values normalized to 1997


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Air pollution monitoring from satellites?

PhD D. Schaub

GOME(launch 1995)

320 40 km2

SCIAMACHY(launch 2002)

60 40 km2

Sufficient spatial resolution?

Schaub, D. et al., Atmos. Chem. Phys. 5, 23-37, 2005 Schaub, D. et al., Atmos. Chem. Phys. 6, 3211-3229, 2006 Schaub, D. et al., Atmos. Chem. Phys. 7(23): 5971-5987, 2007

PhD Y. Zhou

OMI(launch 2004)

up to 24 13 km2

Jan 2006 – July 2007 mean

Outline




Conclusions

Dispersion modelGrid size

400 400 m2


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Ground-based columns using averaging kernel informationGround-based columns using averaging kernel information(see Schaub et al., 2006)(see Schaub et al., 2006)

OMI NO2 VTCs vs. ground-based NO2 VTCs

All data points:r = 0.82

Precision of better than 1 x 1015 molec cm-3

highly desired

Outline




Conclusions

Air pollution monitoring from satellites?Sufficiently accurate?


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Limitations of clear-sky observations1. Frequency distributions of hourly means

Bern, urban kerbside

Payerne, rural

Zurich, urban background

Significant undersampling of polluted situations if restricted to clear-sky observations at urban background and rural sites

An

nu

al m

ea

n li

mit mean values

95% percentiles

Outline




Conclusions


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Limitations of clear-sky observations2. Annual average diurnal cycles

- Evening traffic peak is missed during most time of the year ifrestricted to daytime observations

- Surface level NO2 is increasedin the morning and decreasedin the evening on clear-sky days

daytime onlydaytime clear sky only

All observations

Outline




Conclusions

11 hrs

13 hrs


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Limitations of clear-sky observations3. Interannual variability of annual means

- Annual mean values are significantly reduced if restrictedto OMI clear sky overpasses

- But: interannual variabilityreasonably well captured

All observations

OMI clear sky overpasses only

Daytime clear sky only

Annual mean limit

Outline




Conclusions


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich

Limitations of clear-sky observations3. Interannual variability

- About 70% of variance in annual means captured with clear sky sampling

- Reduced to 60% if restricted to OMI overpasses- Still 50-60% of variability in extremes captured

Correlations between annual means/percentiles of subsamples and full annual means

Annual means 95% percentilesOutline




Conclusions

All stationsurbanrural


50km N

Basel

BernChaumont

Davos


Jungfraujoch

Lägeren

Lausanne

Lugano

Magadino

Payerne Rigi

Sion

TänikonZürich Air quality monitoring requires high spatial resolution

(exposures, critical loads)

Reliable long-term trends important for policy control-> continuity in satellite missions required-> large resolution and design changes from instrument to instrument causes some problems

Comparison with in-situ observations quite satisfactory precision of better than 1 x 1015 molec/cm3 NO2 highly desired

Clear-sky observations is a significant limitation for extremes(in Switzerland) but less so for interannual and long-term variations.

Good boundary layer scheme mandatory for a-priori NO2 profiles

Spatially resolved reliable long-term trends is probably themost exciting (air quality) product from satellites so far

Models add a lot to the value of satellite missions

Conclusions for TROPOMI mission

Outline




Conclusions

Documents

Satellite based versus traditional air pollution monitoring: Requirements, limitations, and chances Dominik Brunner, Christoph Hueglin, Christoph Zellweger,