STUDY OF PM CORRECTION FACTORS IN THE UKDr Janet DixonDepartment for Environment, Food and Rural Affairs, UK

Content

• Background to the UK equivalence study• UK equivalence study• Criteria used• Results + problems• Equivalence Guidance• Policy issues

Current UK PM10 network

Previous equivalence work in the UK

• May 99 to Oct 02, • Published May 04 (www.airquality.co.uk)• 6 sites• Single PM10 Kleinfiltergerat (KfG) and TEOM at each site• Data evaluated using the then draft Guidance• Expanded uncertainty of full data set = 30.5% - FAIL

UK Equivalence study

• Began Mar 04, published June 06 (www.airquality.co.uk)• Costs:

• Equipment - £280,000 (400,000 Euros)• Study - £240,000 (345,000 Euros)

• 9 organisations involved• Equipment on national network• Other equipment offered by suppliers/ manufacturers

•

Bristol

East Kilbride

Birmingham

Teddington

Site type winter summer

Teddington Suburban 14/11/04 to 21/03/05

22/03/05 to 25/07/05

Birmingham Urban Background

28/11/04 to 22/03/05

23/03/05 to 22/07/05

East Kilbride

Suburban 13/10/05 to 12/01/06

01/08/05 to 12/10/05

Bristol Roadside 13/10/05 to 12/01/06

10/08/05 to 12/10/05

Equipment on the study

• PM10 – Kleinfiltergerat (ref sampler)• PM10 Partisol 2025;• PM10 TEOM;• PM10 TEOM retrofitted with a Filter Dynamics

Measurement System (FDMS);• PM10 OPSIS SM200, (SM200 Beta and

SM200 Mass); • PM10 Met-One Beta Attenuation Monitor

(BAM);• PM10 Met-One BAM retrofitted with a heater

(Smart BAM);• PM2.5 – Kleinfiltergerat (ref sampler)

• PM2.5 TEOM retrofitted with an FDMS .

Practical Problems encountered

• KfG –samplers stopping at high temp and %RH• Partisol – minor problems• TEOM – minor problems• FDMS – sensitive to temp of station – 18-22oC• SM200 – filter identification; initial filter thickness• BAM – leak flow test failures• Smart BAM – major problems with initial set-up – excluded

from statistical analysis

Summary of deviations from CEN standards and Equivalence Guidance

• EN12341 – teflon coated glass fibre filters used• EN14907 – no commercially available monitors• Equivalence Guidance

• outliers due to human error rather than instrument error• slopes of all datasets were all greater or all less than 1,

and/or the intercepts of all datasets were all greater or all less than zero

• failure on WCM for the <50 % LV dataset alone• Logic steps to determine whether an instrument meets the

criteria for equivalence

Data examples: TEOM(3,1.03,1.3) and FDMS TEOM

Expanded uncertainty:• Annual LV = 32.68% Annual LV = 15.37%• Daily LV = 40.38% Daily LV = 14.68%

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80

PM10 KFG / μg m-3

TE

OM

(3,1

.03,1

.3)

/ μ

g m

-3

Birmingham Winter

Birmingham Summer

Teddington Winter

Teddington Summer

Bristol Winter

Bristol Summer

East Kilbride Winter

East Kilbride Summer

< 25 μg m-3 Line

> 25 μg m-3 Line

< 20 μg m-3 Line

> 20 μg m-3 Line

All Data Line

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80

PM10 KFG / μg m-3

PM

10 F

DM

S / μ

g m

-3

Birmingham Winter

Birmingham Summer

Teddington Winter

Teddington Summer

Bristol Winter

Bristol Summer

East Kilbride Winter

East Kilbride Summer

< 25 μg m-3 Line

> 25 μg m-3 Line

< 20 μg m-3 Line

> 20 μg m-3 Line

All Data Line

Data examples: PM2.5 FDMS TEOM

-10

0

10

20

30

40

50

60

70

-10 0 10 20 30 40 50 60 70

PM2.5 Leckel / μg m-3

PM

2.5 F

DM

S /

μg

m-3

Birmingham Winter

Birmingham Summer

Teddington Winter

Teddington Summer

Bristol Winter

Bristol Summer

East Kilbride Winter

East Kilbride Summer

< 12.5 μg m-3 Line

> 12.5 μg m-3 Line

All Data Line

Expanded uncertainty:• Annual concentration cap

= 24.45%• Daily LV = not applicable

Results of the UK StudyCandidate Instrument

Equivalence Criteria Met? Correction Required

Partisol 2025 Meets criteria No correction required

TEOM Does not meet criteria Correction does not aid the adherence of equivalence criteria

PM10 FDMS Meets criteria No correction required

PM2.5 FDMS Meets criteria No correction required

SM200 by Beta Meets criteria No correction required

SM200 by Mass Meets criteria after application of slope and intercept correction factors

BAM† Meets criteria after application of a slope correction factor

ambient conditions:

819.0

286.1200200

MassSMMassSM Corrected

273.1Ambient

CorrectedAmbient

BAMBAM

Policy Implications

• TEOM – UK currently applies the ‘consistent’ relationship allowed in the Directive

• TEOM x 1.3 is overly conservative at some sites• Although non-equivalent – broad conclusions from TEOM

will be same as those from equivalent instruments• elevated levels of PM in some places; and• particles pose a large public health risk across the UK

• Checking of UK national modelling will be affected

• UK has begun a transitional period of making the network equivalent – initially using FDMS units retrofitted to existing TEOMs

• UK local authorities can continue to use TEOMs to fulfil their obligations under the Local Air Quality Management regime

• Implications on any epidemiology studies currently underway

Policy Implications

Comparison of FDMSbase vs TEOM

• 3 measurements from FDMS: non-volatile (base); volatile and total

• relationship between the FDMSbase and TEOM measurements with and without the USEPA and UK correction factors:

• TEOM(0,1,1) = (PM10 FDMSbase+ 2.061)/1.360• TEOM(3,1.03,1.3) = PM10 FDMSbase+ 5.826

Summary

• Study report published 13 June 06• In the UK:

• TEOM fails equivalence tests• Partisol 2025 Sequential Sampler; TEOM retrofitted

with FDMS (for PM10 and PM2.5); and the OPSIS SM200 (by Beta) pass without correction

• OPSIS SM200 (by Mass) and Met One BAM pass with correction

• Have determined relationship between FDMSbase and TEOM for future comparisons

• UK has commenced upgrading National Network initially using FDMS units retrofitted to existing TEOMs