This document discusses the linkages between air quality and climate change. It notes that climate change presents serious global risks and requires an urgent response. Several key greenhouse gases that affect climate change are also air pollutants. Changes in climate can impact air quality through changes in emissions, transport, chemistry and deposition. Climate change may increase extreme air pollution events like heat waves and stagnant winter days. The effects of some air pollutants on climate change are complex, as they can both warm and cool the climate depending on chemical interactions. Solutions to improve air quality and reduce greenhouse gases must consider these complex interactions.

1. Air Quality and Climate Change
Mark Chapman
Air Quality & Acoustics Technical Coordinator

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“The scientific evidence is now overwhelming: climate change
presents very serious global risks, and it demands an urgent
global response.”
Stern Review, 2006

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Local Air Quality
UK Air Quality Strategy
• Benzene
• 1,3-butadiene
• Carbon monoxide
• Lead
• Nitrogen dioxide
• Ozone
• Particulate Matter (PM10)
• Sulphur dioxide
• Polycyclic Aromatic
Hydrocarbons (PAHs)
UK Air Quality Regulations
• Benzene
• 1,3-butadiene
• Carbon monoxide
• Lead
• Nitrogen dioxide
• Nitrogen oxides
• Particulate Matter (PM10)
• Sulphur dioxide

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Climate Change
What is understood by the term ‘Climate Change’?
1. Impact on the Planet
2. Weather
3. Impact on People
4. Uncertainty
5. Things or Events
6. Causes
7. Global Warming
8. Fear
9. Time Context
10.Other
Public Perception of Climate Change
(2006 Risk Communication Study - UWE) 56 Participants in Bristol
Top 10 ‘Themes’
• Climate Change is an ‘Environmental’ Issue 
• Climate Change is an ‘Society’ Issue 

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The Simplified Greenhouse Effect Explanation

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The ‘Enhanced’ Greenhouse Effect

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Air Quality & Climate Change
Linkages
Climate Change
Main Greenhouse Gases
• Carbon dioxide (CO2)
• Methane (CH4)
• Nitrous oxide (N2O)
• Hydrofluorocarbons (HFCs)
• Perfluorocarbons (PFCs)
• Sulphur hexafluoride (SF6)
• Chlorofluorocarbons (CFCs)
• Hydrochlorofluorocarbons (HCFCs)
Air Quality
Major Indirect Greenhouse Gases
• Carbon Monoxide (CO)
• Nitrogen oxides (NOx)
• Volatile Organic Compounds (VOCs)
e.g. ammonium
Aerosols
• Sulphur dioxide (SO2)  Secondary
Sulphate Particles
• Particulate Matter (PM10) / Nitrate
• Organic Carbon
• Black Carbon (Soot)

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The Effects of Climate Change on Air Quality
Climate Change is not just about changes in temperature:
• Humidity (Specific)
• Clouds and Precipitation
• Winds
• Others…
How might this affect Air Quality?
• Emissions – Temperature dependence
• Transport – Winds
• Chemistry – Temperature and humidity
• Deposition – Precipitation

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The Effects of Climate Change on Air Quality
Climate Change will increase the probability of local air pollution
events
• Number and strength of summer highs
(The ozone episode of 2003 will be a ‘normal’ occurrence)
• Number and duration of calm winter days
(The ‘Great’ London Smog)
• Mean concentrations are likely to remain unchanged
• Higher chance of extreme concentrations
• Likelihood of increased associated mortality rates

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The Effects of Air Quality on Climate Change
VERY COMPLICATED – VERY LOW SCIENTIFIC UNDERSTANDING
A few examples:
Nitrogen Oxides (NO + NO2) – Fossil Fuel Combustion and Natural Sources
• Reacts to produce ozone  WARMING
• Reacts to produce nitrate aerosol  COOLING
• Reacts to increase methane removal  COOLING
• Overall NET COOLING
Volatile Organic Compounds (VOCs) – Industry and Natural (Major Source)
• Reacts to produce ozone  WARMING
• Reacts to decrease methane removal  WARMING
• Reacts to form organic carbon aerosol  COOLING
• Overall NET ??? – Species Dependent : Some have better ozone production efficiency/others don’t form
aerosols
Sulphur Dioxide (SO2) – Coal-Fired Power Stations, Shipping and Natural
• Reacts to produce sulphate aerosol  COOLING

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Climate (or Radiative) Forcing:
Change in the average net radiation at the top of the
troposphere

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Solutions?
• Energy Conservation and Efficiency Improvements
• Abatement Measures - (Flue-gas desulphurisation, catalytic
converters, particle filters, NOx traps
– Improve air quality, but mostly INCREASE CO2 through
decreased efficiency (getting better – but very costly)
– Removing aerosol precursors can warm climate even further
– Removing black carbon particles cools climate
– Catalytic converters can generate N2O and greater primary
NO2
• Fuel Switching (e.g. Petrol to Diesel)
– Less CO2, but more black carbon (GWP 680)
– Bad for AQ; but NET effect on Climate ???

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Summary
What can we provide for our Clients to help bridge the Air Quality
Climate Change Gap?
• Traffic Emission Optimisation Recommendation
– Speed
– HGV
– Driving Patterns
• Quantification and Relative Comparison of CO2e
• Abatement Specification and Design Advice

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Further Details
Mark Chapman
Air Quality & Acoustics Technical Coordinator
Planning & Consultation (1401)
West Hall
Tel: 01932 337 590
Mobile: 07976 344 311
mark.chapman@mouchelparkman.com