Source apportionment of the carbonaceous aerosol –

Quantitative estimates based on 14C- and organic tracer analysis

1. Norwegian Institute for Air Research 2. Norwegian Meteorological Institute3. Technical University of Vienna4. Lund University

Bordeaux 23 - 25 April 2008

KE Yttri1, D Simpson2, H. Puxbaum3, K Stenström4, T Svendby1

SORGA- Main objectives

• Quantify the contribution of biogenic and anthropogenic carbonaceous matter to PM in the Nordic urban and rural environment Biogenic/anthropogenic fraction in urban and rural areas Separate the biogenic and the anthropogenic fraction into primary

and secondary carbonaceous matter Size-distribution (PM1 and PM10) of biogenic and anthropogenic

carboanceous matter • Improve current knowledge of what are the concentrations of

VOCs crucial for SOA-formation• Improve the aerosol modules of the following models:

MAPS - EPISODE - EMEP

SORGA- Measurements sites

Oslo (Urban background) Hurdal (Rural Background)

OsloHurdal

Measurement campaigns

Summer period: 19 June - 5 July 2006Winter period: 1 - 8 Mars 2007

SORGA- Aerosol parameters measured

Table 1: Input parameters for source apportionment of the particulate carbonaceous fraction

Yttri et al. in progress

Parameter Size fraction Time resolution Objective

Mass concentration PM1, PM10 12 hours PM concentration

EC, OCp, TCp (QBQ) PM1, PM10 12 hours Carbonaceous PM loading

Levoglucosan PM10 12 hours Wood burning

Sugars and Sugar-alcohols PM1, PM10 12 hours Fungal spores (PBAP)

Cellulose1 PM1, PM10 Grab sample Plant debris (PBAP)

fM (14C-analysis)2 PM1, PM10 Grab sample dayGrab sample night

Separates between modern Carbon and fossil Carbon

1. Cellulose analysis performed at the Technical University of Vienna

2. 14C-analysis performed at the University of Lund

SORGA- Sources of carbonaceous matter

OCbsoa OC from biogenic sec. org. aerosols

OCasoa OC from anthropogenic sec. org. aerosols

OCbb OC from residential wood burning

ECbb EC from residential wood burning

OCff OC from combustion of fossil fuel

ECff EC from combustion of fossil fuel

OCpbs OC from fungal spores

OCpbc OC from plant debris

SORGA- Equations and uncertainty estimates

Confounding factors OCbsoa:

OCnf OCbsoa, OCmeat cooking, condensation of SVOC from biomass(?), PBAP not accounted for by sugars and sugar-alcohols

Equations to calculate carbonaceous subfractionsTable 2: Low, central and high factors used to

estimate the carbonaceous subfractions using LHS

SORGA - Source apportionment of TCp in PM10 Summer

Hurdal (RB) PM10 TCp = 2.9 ± 1.2 µg C

m-3

Oslo (UB) PM10 TCp = 3.7 ± 1.3 µg C m-3

Natural: 72% Anthropogenic: 28%

Natural: 46% Anthropogenic: 54%

SORGA- Source apportionment of TCp in PM1, Summer

Hurdal (RB) PM1 TCp = 1.7 ± 1.1 µg C m-

3

Oslo (UB) PM1 TCp = 2.3 ± 0.8 µg C m-3

Natural: 66% Anthropogenic: 34%

Natural: 36% Anthropogenic: 64%

SORGA- Source apportionment of TCp in PM10 Winter

Hurdal (RB) PM10 TCp = 1.2 ± 0.5 µg C

m-3

Oslo (UB) PM10 TCp = 3.2 ± 1.5 µg C m-3

Natural: 8% Anthropogenic: 92%

Natural: 5% Anthropogenic: 95%

SORGA- Source apportionment of TCp in PM10 Summer Day/night variation

Oslo(UB) PM10 DAY TCp = 3.8 ± 1.2 µg

C m-3

Oslo (UB) PM10 NIGHT TCp = 3.6 ± 1.4

µg C m-3 Natural: 52% Anthropogenic:48%

Natural: 40% Anthropogenic:60%

-3

SORGA- Relative cont. of carb. matter to PM10 (Summer)

Hurdal (RB) PM10

PM10 = 10.4 µg m-3

Oslo (UB) PM10 PM10 = 15.6 µg m-3

Conversion factors: OCbsoa = 1.8; OCpb = 1.6; OCbb = 2.0; ECbb and ECff = 1.1; OCff = 1.3; OCasoa = 1.8

PCM/PM10 = 49% Natural PCM/PM10 = 35%

PCM/PM10 = 38% Natural PCM/PM10 = 19%

SORGA- Relative cont. of carb. matter to PM10 (Winter)

Hurdal (RB) PM10

PM10 = 4.2 µg m-3

Oslo (UB) PM10 PM10 = 9.5 µg m-3

Conversion factors: OCbsoa = 1.8; OCpb = 1.6; OCbb = 2.0; ECbb and ECff = 1.1; OCff = 1.3; OCasoa = 1.8

PCM/PM10 = 45% Natural PCM/PM10 = 3%

PCM/PM10 = 54% Natural PCM/PM10 = 3%

SORGA - Measured vs modelled conc. of OCbsoa (Oslo, summer)

OCp (PM10) 3.2 ± 1.1 µg C m-3

OCbsoa 0.8-1.2 µg C m-3

OCbsoa modeled

0.2 ± 0.3 µg C m-3

OCp (PM1) 1.8 ± 0.7 µg C m-3

SORGA - Measured vs modelled conc. of OCbsoa (Hurdal, winter)

OCp (PM10) 3.0 ± 1.2 µg C m-3

OCbsoa 1.0-1.5 µg C m-3

OCbsoa modeled

0.3 ± 0.3 µg m-3

OCp (PM1) 1.4 ± 1.0 µg C m-3

SORGA- Summary of findings (1)

•The combined effort of 14C, TOA, and organic tracer analysis is a powerful tool to explore various sources of carbonaceous matter

•OCbsoa was the major carbonaceous fraction in summer regardless of site and size fraction

•OCbb was the major carbonaceous fraction in winter regardsless of site and size fraction

•ECff is the major contributor to EC regardless of season and size fraction

Secondary organic aerosols vs primary carbonaceous aerosolsSummer:

Rural background site: SOA > PCA Urban background site: SOA ≤ PCA

Winter:

Rural and urban site: SOA << PCA

SORGA - Summary of findings (2)

Anthropogenic vs natural sources of carbonaceous matter

Urban background site:

Summer: Natural >> Anthropogenic

Winter: Natural << Anthropogenic

Rural background site:

Summer: Natural < Anthropogenic

Winter: Natural << Anthropogenic