IssueIssue and and ConcernsConcerns in Diffusive in Diffusive SamplingSampling FactorsFactorsInfluencingInfluencing performanceperformance

ImprovingImproving Diffusive Diffusive SamplingSampling Rate Rate Through a Through a RadialRadial DesignDesign

Danilo CotticaDanilo CotticaEnvironmentalEnvironmental ResearchResearch CenterCenter

PaduaPadua –– ItalyItaly

AIHceAIHce –– PhiladelphiaPhiladelphia –– junejune 20072007

““Salvatore MaugeriSalvatore Maugeri”” FoundationFoundationWork and Work and RehabilitationRehabilitation

InstituteInstitute of Care and of Care and ScientificScientific ResearchResearch

Established in 1965 as “Clinica del Lavoro”(Presidential Decreee n. 991 dated 15-6-1965) on theinitiative of prof. Salvatore Maugeri

Main aims:protection of occupational healthrehabilitative medicine

TheoreticalTheoretical background of passive background of passive samplingsampling

The The FickFick’’s s diffusiondiffusion lawlaw::

dm/dm/dtdt = = adsorbedadsorbed mass m mass m duringduring time ttime t

D = D = diffusiondiffusion coefficientcoefficient

dCdC/dl = /dl = concentrationconcentration gradientgradient

dm dCD S dldt= ⋅ ⋅

The The axialaxial diffusiondiffusion comparedcompared withwithradialradial diffusiondiffusion

Axial diffusive samplersAxial diffusive samplers

D = diffusion coefficient

S/l = geometrical ratio (diff. surface/diff. path)

Q (uptake rate) = D S/l

In In axialaxial diffusive diffusive samplerssamplers::

Q

m SD Ct l

= ⋅ ⋅

RadialRadialdiffusive samplerdiffusive sampler

D = diffusion coefficienth = cylinder heightRd = diffusive cylindrical surface radiusRa = adsorbing surface radiusQ (uptake rate) = D 2πh/(Ln rd/ra)

In In radialradial diffusive diffusive samplersampler::

2

ln d

a

m hD Crtr

π ⋅= ⋅ ⋅

Qm

Q tC =

⋅

Diffusive Diffusive samplingsampling raterateradialradial vsvs axialaxial

Diffusive Diffusive samplingsampling rate rate forfor benzene benzene on on actact. . charcoalcharcoal//chemicalchemical desorptiondesorption (25 (25 °°CC))radialradial 80 ml/80 ml/minminAxialAxial typetype 77--8 ml/8 ml/minmin

Diffusive Diffusive samplingsampling rate rate forfor formaldehydeformaldehydebyby 2,42,4--DNPH DNPH chemisorptionchemisorption (25 (25 °°CC))radialradial 99 ml/99 ml/minminAxialAxial typetype 25 ml/25 ml/minmin

Measuringthe diffusive samplingrate

InIn--fieldfield validationvalidation of of chemicalchemical//thermalthermaldesorptiondesorption BTEX BTEX samplerssamplers

12 monitoring campaigns aug. 03-aug. 04Exposure in a traffic site2-d, 7-d, 10-d, 14-d exposuresReplicates: 3 per sampler type (chemical/thermal) and per exposure durationBenzene concentration range 2.9 – 8.2 µg/m3 (7-d average)Toluene 13.4 – 28.5 µg/m3

Xylenes 15.4 – 34.2 µg/m3

Four different diffusive bodies (membranes)

WhiteWhite (standard) (standard) forfor VOC/VOC/actact. . charcoalcharcoal and and othersothers

BlueBlue (standard + (standard + colourcolour) ) forforlightlight--sensitive sensitive samplingssamplings(NO2, (NO2, ozoneozone, , aldehydesaldehydes))

YellowYellow (high (high thicknessthickness) ) forfor TD TD –– VOCsVOCs samplingsampling ((toto avoidavoidretrodiffusionretrodiffusion))

SiliconeSilicone treatedtreated forforanaestethicsanaestethics

Many different radial diffusive samplers:

Aldehydes (chemisorption on 2,4-DNPH)VOCs/BTEX for CS2 chemical desorption(activated charcoal) suited for workplaceVOCs/BTEX for thermal desorption(graphitised carbon) suited for ambient airNO2/SO2/HF (chemisorption on TEA)O3 (chemisorption on 4,4’-DPE)

Many different radial diffusive samplers (2):

H2S (chemisorption on zinc acetate)Ammonia (chemisorption on phosphoric acid)HCl (adsorption on silica gel)Anaesthetic gases (N2O and halogenatedadsorbed on act. charcoal/mol. sieves)Phenols (adsorption on Tenax TA)

General standard for diffusive sampling

EN 13528:2002 (parts 1,2,3): ambient air quality –Diffusive samplers for the determination of concentrations of gases and vapoursEN 838:1995: workplace atmospheres – Diffusive samplers for the determination of gases and vapours –requirements and test methods (radial sampler)ISO/FDIS 16200-2 workplace air quality – Sampling and analysis of volatile organic compounds by solvent desorption/gas chromatography – Part 2: Diffusive sampling method (radial sampler)EN 14412:2004: indoor air quality - Diffusive samplers for the determination of concentrations of gases and vapours – Guide for selection, use and maintenance

Specific standard for diffusive sampling

EN 14662-4:2005: ambient air quality – Standard method for the measurement of benzene concentration – Part 4: Diffusive sampling followed by thermal desorption and gas chromatographyEN 14662-5:2005: ambient air quality - Standard method for measurement of benzene concentrations - Part 5: Diffusive sampling followed by solvent desorption and gas chromatography (radial sampler)ISO/FDIS 16000-4:2004: indoor air – Part 4:Determination of formaldehyde - Diffusive sampling method

Annual book of ASTM Standards, 2004: D6196-3 Practice for Selection of Sorbents, Sampling, and Thermal DesorptionAnalysis Procedures for Volatile Organic Compounds in Air

Studies & Projects Using Radial SamplersStudies & Projects Using Radial Samplers

Validation Studies by ERLAP for Ambient Air Monitoring– EUR 19594 EN

Validation of Radiello Diffusive Sampler for Monitoring O3 in Ambient Air– EUR 20860 EN

Laboratory and Field Inter-comparisons of NO2 diffusive samplers– EUR 21754 EN

Laboratory and Field Inter-comparisons of O3 diffusive samplers

EU Projects (LIFE) on Air Monitoring– MACBETH project

Monitoring of Atmospheric Concentrations of Benzene in European Towns and Homes, LIFE 96 ENV/IT/070

– RESOLUTION project Development of a high spatial resolution atmospheric monitoring model to verify the actual emissions reduction of ozone precursors foreseen by Auto-Oil program, LIFE99ENV/IT/081

– ARTEMIDE Project High temporal resolution monitoring of VOC’s by diffusive sampler, LIFE 00 ENV/IT/000005

ApplicationsApplications

1

23

4

56

79

Industrial hygieneAmbient air quality

Indoor air quality

Emissions impact

ApplicationsApplicationsIndustrial hygiene

personal exposurearea monitoring (mapping)

Ambient air qualityhigh-spatial-resolution monitoring and fixednetwork optimisationlong term monitoring (check of annual mean vs. LV)citizens’ exposure

Indoor air qualityindividual exposure checkpollution characterisation (health concerns)

Emissions impactlandfills & waste treatment plantsindustrial facilities (chemical, painting, plastics, ...)

IndustrialIndustrial hygienehygiene

with diffusive samplinghomogeneous exposuregroups (EN 689) are more easily studied, taking a lotof samples with limitedresources

Logprobability Plot andLeast-Squares Best-Fit Line

1%2%5%10%16%25%50%75%84%90%95%98%99%

0,0001 0,001 0,01 0,1 1 10

Concentration

WorkplaceWorkplace –– personal personal samplingsamplingpetrolpetrol refineryrefinery plantplant

benzene

y = 0,8437x - 0,6437R2 = 0,9132

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35

radiello

pum

ped

sam

pler

s

WorkplaceWorkplace –– personal personal samplingsamplingpetrolpetrol refineryrefinery plantplant

MTBE

y = 0,7137x + 0,0648R2 = 0,8043

0

20

40

60

80

100

120

140

160

0 50 100 150 200

radiello

pum

ped

sam

pler

s

12 hour sampling 24 hour sampling

PEOPLE

PERSONAL EXPOSURE ENVIRONMENT

NON SMOKERS INDOOR POLLUTION URBAN OUTDOOR

TRAVELERS SEDENTARY DOMESTIC LOCATIONS

SPECIFIC LOCATIONS

SMOKERS

PERSONAL CAR

PUBLIC TRANSPORT

WALKING BIKING

Schools Public Offices Shops Restaurants/ bars

Support from citizens Support from local authorities

Background sites Hot spots Peri-urban sites

European Commission

European Commission

smoking43%

indoor environments

20%

travelling37%

smoking43%

automotive transport23%

outdoor+walk+bike14%

passive smoking10%

other4%

workplace6%

PEOPLE in BRUSSELSFactors affecting the personal exposure

European Commission

Benzene distribution in Brussels on 22nd October 2002Concentrations in µg/m3

IsoconcentrationsIsoconcentrationsmapsmaps

RESOLUTIONRESOLUTIONMonitoringbenzene in ROMA

Calculation of diffusive sampling rate for thermaldesorptionsamplersaccording to the model of Pennequin-Cardinal et al. Atmos. Environ. 39(2005) 2535-2544

Comparing diffusive and pumped method

benzene - august 2004

00.5

11.5

22.5

33.5

4

diff.Chem.

diff.Therm.

pumped diff.Chem.

diff.Therm.

pumped

7-days 14-days

µg/m3

meanmin.max.

LocatingLocating pollutionpollutionsourcessources

Ammonia emission from a waste treatment plant

RadialRadial diffusive diffusive samplingsampling forforassessingassessing ambientambient air air qualityquality

VIS0.3-3,000 µg/m3

7-14 dH2S

VIS0.1-2,000 µg/m3

7-14 dNH3

RH<70%TEA-IC2-1,000 µg/m37-dNO2

& NO2TEA-IC3-1,300 µg/m37-dSO2

RemarksAnalyticalmethod

Measuringrange

Exposuretime

Subst.

RadialRadial diffusive diffusive samplingsampling forfor assessingassessingambientambient air air qualityquality

coolDPE-VIS2-400 µg/m37-dO3

TDCgraph./GC0.01-20 µg/m37-14 dotherVOCs

CD or TDGC0.1-50·103µg/m37-14 dBTEX

EN14662Cact./GC0.1-25·103µg/m37-14 dbenzene

RemarksAnalyticalmethod

Measuring rangeExposuretime.

Substance

RadialRadial diffusive diffusive samplingsampling forforassessingassessing ambientambient air air qualityquality

IC0.5-1,500 µg/m3

7-dcarboxyacids

coolHPLC0.1-1,200 µg/m3

7-d aldehydes

TDTenax/GC0.05-10 µg/m37-dphenols

RemarksAnalyticalmethod

Measuring rangeExposuretime

Substance

RadialRadial diffusive diffusive samplingsampling forforassessingassessing indoor air indoor air qualityquality

coolDPE-VIS2-400 µg/m37-dO3

VIS0.2-2,000 µg/m3

7-dNH3

RH<70%TEA-IC2-1,000 µg/m37-dNO2

& NO2TEA-IC3-1,300 µg/m37-dSO2

RemarksAnalyticalmethod

Measuringrange

Exposuretime

Subst.

RadialRadial diffusive diffusive samplingsampling forforassessingassessing indoor air indoor air qualityquality

TEA-IC130-1,600 µg/m37-dAcetic/formicacids

TDCgraph./GC0.02-40 µg/m37-dVOCs

coolHPLC0.1-400 µg/m37-dFormaldehydeand other ald.s

Cact./GC0.1-50·103

µg/m3

7-dBenzene

RemarksAnalyticalmethod

Measuringrange

Exposuretime

Substance

radialradial sequentialsequential samplingsampling

RADIAL SEQUENTIAL SAMPLERRADIAL SEQUENTIAL SAMPLER

ReplacingReplacing pumpspumps withwith radialradial samplersampler: : whywhy??

High sensitivityno batteryno flow-meterno weight on worker’s trousersno long-trained personnelno noiseno explosion risklow investment costcomparable consumable costsno glass end to break in laboratoryeasy-to-use methods

GoodGood work work withwithradialradial diffusive diffusive samplersampler !!

www.radiello.comwww.radiello.com