Pacific 2001 – Synthesis of Pacific 2001 – Synthesis of Findings and Policy Findings and Policy

Implications Implications

Roxanne VingarzanRoxanne Vingarzan

Pacific and Yukon RegionPacific and Yukon Region

Pacific 2001 StudyPacific 2001 Study Previous large scale studies in the FV addressed ozone and

visibility issues but a knowledge gap remained concerning fine PM

Policy Relevant Questions Policy Relevant Questions 11 policy-relevant questions were identified in order to provide 11 policy-relevant questions were identified in order to provide

guidance with policy setting and air quality management in the guidance with policy setting and air quality management in the regionregion

Subject areas:Subject areas: Aerosol Distribution & Transport Aerosol Distribution & Transport Particle Chemistry & Spatial PatternsParticle Chemistry & Spatial Patterns Particle Formation and GrowthParticle Formation and Growth Particle Events - causes Particle Events - causes Sources Sources Addressing fine PMAddressing fine PM

ContributionsContributions

Synthesis is based on a review of 20 papersSynthesis is based on a review of 20 papers 14 papers published in first special issue of AE 14 papers published in first special issue of AE 6 papers submitted for the second special issue 6 papers submitted for the second special issue

Contribution of a large number of authorsContribution of a large number of authors AQRB, Downsview AQRB, Downsview EC, PYREC, PYR 9 Canadian universities9 Canadian universities 3 US universities3 US universities 1 UK universities1 UK universities

Aerosol Distribution Aerosol Distribution

NightNightConcentrated aerosols in the Concentrated aerosols in the tributary valleystributary valleys

AfternoonAfternoonConcentrated aerosols in the Concentrated aerosols in the eastern part of the LFVeastern part of the LFV

WISE EFFECTWISE EFFECT

WISE

•Wake Induced Stagnation Effect

•Build-up of pollutants over the Gulf & San Juan islands area

High PM levels over the Strait of Georgia afternoon of August 26

Upslope flow of aerosol during the nightUpslope flow of aerosol during the night

• Polluted layers were occasionally, Polluted layers were occasionally, entrained into clean air masses at the entrained into clean air masses at the surface by the PBL.surface by the PBL.

PBL Studies PBL as found to be suppressed in height and occur several hours earlier during sea breeze conditions.

Above ground aerosol layers at Harrison Lk.Above ground aerosol layers at Harrison Lk.

Transport Mechanisms Transport Mechanisms

From Strawbridge and Snyder, 2004 From Strawbridge and Snyder, 2004

Particle Chemistry - InorganicsParticle Chemistry - Inorganics

From Pryor et al. 2004

Nitrate Chemistry Nitrate Chemistry

DaytimeFine mode dominated by ammonium sulphateCoarse mode dominated by NaNO3 Cl- ion depletion from reaction of HNO3 with sea salt particles

NighttimeFine mode nitrate production from NO3-N2O5-HNO3 pathwayFine mode ammonium nitrate occurred almostalways during the night.

Sumas Sumas

From , McLaren et al. 2004

The Ammonium Ion & Fine PM The Ammonium Ion & Fine PM Sulpha te /Nitra te /Am m onium M ole Ra tios for Pa rticle s in the S ize Ra nge 133-168 nm

La ngle y Sum a s0

1

2

3

4

5

6

mo

le ratios

Sulpha te Nitra te Am m onium

•Ammonium ion excess •What is the excess ammonium bound to?

Particle Chemistry - OrganicsParticle Chemistry - Organics Organic carbon was found to comprise approximately half of the Organic carbon was found to comprise approximately half of the

particle composition particle composition

A broad suite of organic substances were detected, including A broad suite of organic substances were detected, including alkanes, aromatics and various oxidized hydrocarbons including alkanes, aromatics and various oxidized hydrocarbons including fatty acids fatty acids

Both anthropogenic and biogenic hydrocarbons were found to be Both anthropogenic and biogenic hydrocarbons were found to be photochemically reactive and contribute to SOA and ozone photochemically reactive and contribute to SOA and ozone formationformation

Isoprenes and monoterpenes were the dominant biogenic Isoprenes and monoterpenes were the dominant biogenic hydrocarbons detected - their presence at all sites indicated the hydrocarbons detected - their presence at all sites indicated the broad influence of biogenic organics throughout the FV broad influence of biogenic organics throughout the FV

Particle EventsParticle Events

Sulphate growth eventsSulphate growth events were associated with photochemical production from advected SO2 from were associated with photochemical production from advected SO2 from industrial sources in north-west Washington state. industrial sources in north-west Washington state. • Fine particle nitrate eventsFine particle nitrate events were associated with advection of HNO3 from the urban core into the were associated with advection of HNO3 from the urban core into the eastern FV reacting with local sources of ammonia. eastern FV reacting with local sources of ammonia. • Organic particle growth eventsOrganic particle growth events were associated with stagnant conditions and advection of air over were associated with stagnant conditions and advection of air over urban Vancouver.urban Vancouver.

Sources - HighlightsSources - Highlights Primary sulphate in the FV is consistent with gasoline, diesel Primary sulphate in the FV is consistent with gasoline, diesel

& gas combustion. & gas combustion.

Approximately 30% of the sulphate in PM2.5 aerosols Approximately 30% of the sulphate in PM2.5 aerosols estimated to be derived from the oxidation of DMS. estimated to be derived from the oxidation of DMS.

Organic aerosols were found to have significant contributions Organic aerosols were found to have significant contributions from terrestrial (plant material) sources during the summer from terrestrial (plant material) sources during the summer months and from fossil fuel sources during the spring months. months and from fossil fuel sources during the spring months.

Hydrocarbon species indicated contributions of light and Hydrocarbon species indicated contributions of light and heavy-duty (diesel) traffic, meat cooking & biogenic sources. heavy-duty (diesel) traffic, meat cooking & biogenic sources.

Biomass burning generally had a small but measurable impact Biomass burning generally had a small but measurable impact on the composition of ambient aerosols in the FV.on the composition of ambient aerosols in the FV.

Spatial PatternsSpatial PatternsSlocan

emission controlled regime PM dominated by organics, both anthropogenic and biogenicmobile sector emissions - gasoline and diesel combustion and fugitive emissions of petroleum fuels. Biogenic organics important

Langley

formation controlled regime PM dominated by inorganicsSulphate levels highest due to the influence of advected SO2 from oil refineries in north-west Washington state. Elevated ammonia and biomass burning markers reflected the influence of agricultural sources.

Sumas

Mixed emission/formation regime dominated by urban, agricultural and biogenic sources. Fine mode nitrate importantThe chemistry was most variable

Golden Ears

PM dominated by biogenic organics chemistry impacted by anthropogenic sources due to upslope flow biogenically derived SOAs were transported into the FV by downslope flow.

Policy Implications – Addressing Policy Implications – Addressing Fine PM in the FVFine PM in the FV

Hypotheses for emission scenario modelling Hypotheses for emission scenario modelling

Ammonia EmissionsAmmonia Emissions Ammonia was found not to be a limiting species Ammonia was found not to be a limiting species Limited ammonia reductions are not expected to offer a significant Limited ammonia reductions are not expected to offer a significant

improvement in reducing fine PM levels but large reductions may be more improvement in reducing fine PM levels but large reductions may be more effective effective

Reductions may result in secondary negative secondary effects, such as Reductions may result in secondary negative secondary effects, such as changes to the acidity of ambient aerosols and of atmospheric deposition changes to the acidity of ambient aerosols and of atmospheric deposition

SOx EmissonsSOx Emissons Sulphate was a limiting species Sulphate was a limiting species SOx reductions may aid in partially reducing fine PM, SOx reductions may aid in partially reducing fine PM,

however only if accompanied by NOx reductions (NH4NO3)however only if accompanied by NOx reductions (NH4NO3) Contributions from biogenic sulphate during spring/summer may limit Contributions from biogenic sulphate during spring/summer may limit

successsuccess

Policy Implications - continuedPolicy Implications - continuedNOx EmissionsNOx Emissions Nitrate was a limiting substance Nitrate was a limiting substance NOx reductions are expected to reduce NH4NO3 production in NOx reductions are expected to reduce NH4NO3 production in

the eastern FV (esp. in wet season). the eastern FV (esp. in wet season). Reductions in NOx in the absence of VOC reductions may result Reductions in NOx in the absence of VOC reductions may result

in an increase in SOAs in urban areas (increase in oxidants)in an increase in SOAs in urban areas (increase in oxidants)

VOC EmissionsVOC Emissions VOC reductions may provide some benefits to air quality VOC reductions may provide some benefits to air quality Benefits would be limited by the biogenic contribution to fine Benefits would be limited by the biogenic contribution to fine

PM. PM. Targeting VOC reductions in the absence of NOx reductions Targeting VOC reductions in the absence of NOx reductions

may result in an increase nitric acid in NOx rich areas. may result in an increase nitric acid in NOx rich areas.

Concurrent Emission ReductionsConcurrent Emission Reductions in ammonia, SOx, NOx and VOC in ammonia, SOx, NOx and VOC emissions may be required to reduce fine PMemissions may be required to reduce fine PM

PAC2001 Policy Relevant Findings SummaryPAC2001 Policy Relevant Findings Summary Identified mechanisms of aerosol transport: seabreeze-landbreeze flows, Identified mechanisms of aerosol transport: seabreeze-landbreeze flows,

upslope-downslope flows and north-south valley flowsupslope-downslope flows and north-south valley flows

Identified areas of enhanced aerosol concentrations: eastern FV, north-south Identified areas of enhanced aerosol concentrations: eastern FV, north-south tributary valleys & the WISE zonetributary valleys & the WISE zone

Confirmed the importance of organic carbon and biogenic organics in fine Confirmed the importance of organic carbon and biogenic organics in fine PM PM

Characterized the chemistry of coarse & fine mode PMCharacterized the chemistry of coarse & fine mode PM

Identified both anthropogenic and biogenic sources contributing to secondary Identified both anthropogenic and biogenic sources contributing to secondary organic aerosol formationorganic aerosol formation

Identified geographical patterns in emission regimes, PM composition and Identified geographical patterns in emission regimes, PM composition and aerosol processingaerosol processing

Provided hypotheses for testing out emission scenarios aimed at reducing fine Provided hypotheses for testing out emission scenarios aimed at reducing fine PMPM