Natividad Urquizo, W. Pugsley, D. Spitzer* & M. RobinsonCity of Ottawa*A-MAPS Environmental

Mapping Small Scale Air Mapping Small Scale Air Pollution Distribution Pollution Distribution using Satellite using Satellite Observations in a Large Observations in a Large Canadian CityCanadian City

Mapping Small Scale Air Mapping Small Scale Air Pollution Distribution Pollution Distribution using Satellite using Satellite Observations in a Large Observations in a Large Canadian CityCanadian City

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Project LocationProject Location

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Using satellite data map pollution concentrations for 5,600 km2 area.

Identify “hot spots” spatially at 1-km2 resolution hour by hour for the following air contaminants:

Nitrogen oxides (NO, NO2, NOx) Carbon monoxide Ground level ozone PM2.5

ObjectivesObjectives

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Data sourcesData sources Ground level air quality monitors

NAPS permanent stations (3) One Quebec station (PM2.5 & O3) Mobile labs for 8 locations

Aura satellite data (13 x 24 km resolution) Air and ground transportation data Meteorological data Land use data Data processing by A-MAPS Environmental

Inc.

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Ground Level Monitoring LocationsGround Level Monitoring Locations

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Total Mapping AreaTotal Mapping Area

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Data IntegrationData Integration Time of satellite overpass:

Determine grid point value at the centre of each satellite pixel

Used Kriging to interpolate with 1-km2

Smooth ground data with 3-hour running average

Calculate field ratio of ground level measurement to satellite

Calibrate pixel with spatial average of field ratio

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Data Integration … continueData Integration … continue Calculate hourly concentrations from

interpolation in time using closest ground station

Modify values using traffic emissions and the Green function, advection and diffusion equations

Finally calibrate 1-km values from measured concentration at nearest emission source

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Confirm previous findingsConfirm previous findings

Pollutants below hourly Canada Wide Standards 95% of the time

Pollution is locally produced and result of trans-boundary pollution

Smog events not restricted to summer days (December 13-14th)

Major roads exhibit more pollution at peak hour

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High Pollution NodesHigh Pollution Nodes

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Transportation Impact on NO2 ExceedancesTransportation Impact on NO2 Exceedances

NO2 > 50ppb 2007-12-10 - 2007-12-12

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New Findings: NO2 west-east gradientNew Findings: NO2 west-east gradient

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O3: West-East GradientO3: West-East Gradient

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PM2.5: west-east gradientPM2.5: west-east gradient

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More new findingsMore new findings

Origin of worst episodes: From the east (Montreal, Sept 14th) From the south (Ohio Valley, Sep 21st

& 25th) Locally produced (Dec 13th)

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September 14th 2007 Episode Montreal InfluenceSeptember 14th 2007 Episode Montreal Influence

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Confidence levelConfidence level

Pollutant STD (Map) STD (MOE)

CO (ppm) 0.1 - 0.18 0.11 – 0.14

NO (ppb) 5 - 9 8.5 – 8.74

NO2 (ppb) 5 - 10 10.65 – 11.5

NOx (ppb) 12 - 18 17 – 17.5

O3 (ppb) 11 - 14 13 – 13.78

PM2.5 (ug/m3) 6 5.84 – 6.75

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Single pixel comparisonSingle pixel comparison

Orleans site measurements using mobile lab and results of modelling shows good cross-validation

Pollutant

STD

CO 0.007 (ppm)

NO 2.4 (ppb)

NO23.0 (ppb)

NOx4.4 (ppb)

O33.8 (ppb)

PM2.53.3 (ug/m3)

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Downtown NOx concentrationsDowntown NOx concentrations

Peak hour pollution lasts 4 hours or less

Three-hour running average smoothes traffic effect

City Hall 2008-05-08

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Relative Exposure Concentration of PM and Influence of traffic Krzyzanowski et al (2005) http://tinyurl.com/258hql

Relative Exposure Concentration of PM and Influence of traffic Krzyzanowski et al (2005) http://tinyurl.com/258hql

Shows 24 hour traffic generated exposure for PM2.5

Light pink: regional background, light blue: urban ambient and peaks in traffic

Exposure while commuting represents half of exposure to PM from traffic

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Major Origin-Destination Flows – Morning Trips 2005Ref:http://tinyurl.com/6vlrcf

Major Origin-Destination Flows – Morning Trips 2005Ref:http://tinyurl.com/6vlrcf

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NO2 hourly un-smooth mapsNO2 hourly un-smooth maps

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NO2 October 4th, 2007 at 2 h

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NO2 October 4th, 2007 at 3 h

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NO2 October 4th, 2007 at 4 h

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NO2 October 4th, 2007 at 5 h

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NO2 October 4th, 2007 at 6 h

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NO2 October 4th, 2007 at 7 h

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NO2 October 4th, 2007 at 8 h

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NO2 October 4th, 2007 at 9 h

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NO2 October 4th, 2007 at 10 h

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NO2 October 4th, 2007 at 11 h

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NO2 October 4th, 2007 at 12 h

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NO2 October 4th, 2007 at 13 h

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NO2 October 4th, 2007 at 14 h

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NO2 October 4th, 2007 at 15 h

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NO2 October 4th, 2007 at 16 h

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NO2 October 4th, 2007 at 17 h

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NO2 October 4th, 2007 at 18 h

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NO2 October 4th, 2007 at 19 h

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NO2 October 4th, 2007 at 20 h

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NO2 October 4th, 2007 at 21 h

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NO2 October 4th, 2007 at 22 h

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NO2 October 4th, 2007 at 23 h

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NO2 October 5th, 2007 at 0 h

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Public Health Policy ChallengesPublic Health Policy Challenges

Answers required: What sort of spatial accuracy and temporal

frequency for air pollutant concentrations is needed to comply with public health requirements?

What response or action is needed at urban “hotspots” for short duration high intensity events or for extended events?

What threshold for each pollutant should be established as a trigger for corrective action?

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Technical Breach Areas – City of Yorkhttp://www.york.gov.uk/environment/airquality/Tech_breach.pdf

Technical Breach Areas – City of Yorkhttp://www.york.gov.uk/environment/airquality/Tech_breach.pdf

Sample of roads with pollution above standard

Ottawa/Gatineau exhibit similar “hot spots” during peak hours

Future AQ modelling at neighbourhood level

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AcknowledgementsAcknowledgements This mapping project was possible with funding from:

GeoConnections (Natural Resource Canada) The Ottawa International Airport The City of Ottawa

In kind contributions from: Transport Canada Environment Canada Ontario Ministry of the Environment (MOE) Ministère du Développement durable, de l'Environnement et des

Parcs (of the province of Quebec) and Health Canada

A-MAPS Environmental was contracted for this project

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Contact information:Contact information:

Natividad Urquizo 613-580-2424 x 27914Natividad.Urquizo@ottawa.ca