Air pollutants in the troposphere Basics: Chemical fate of pollutants in the troposphere Basics: Chemical fate of pollutants in the troposphere Photochemical smog and ‘classical smog’ Photochemical smog and ‘classical smog’ The Gothenburg protocol The Gothenburg protocol Norwegian emissions Norwegian emissions Air Quality Guidelines and exceedances in Norway Air Quality Guidelines and exceedances in Norway Heavy metals Heavy metals POPs POPs

2 O3O3 NO NO 2 O2O2 O( 3 P) NO h M O 2 HNO 3 NO 2 sink: OH, M Wet deposition Dry deposition h h  310 nm O* O2O2 M H2OH2O OH. (hydroxyl radical) CO CO 2 H.H. O2O2 HO 2. (hydroperoxyl radical) NO NO 2 O2O2 HO 2. H 2 O 2 (hydrogen peroxide) h Tropospheric chemistry in a nutshell The ‘detergent’ of the atmosphere

3 O3O3 NO NO 2 O2O2 O( 3 P) NO h O 2, M HNO 3 NO 2 sink: OH, M Wet deposition Dry deposition h h  310 nm O* O2O2 M H2OH2O OH. (hydroxyl radical) CH4 H2OH2O CH 3. O2O2 CH 3 O 2. (methylperoxyl radical) NO NO 2 O2O2 HO 2. H 2 O 2 (hydrogen peroxide) h Oxidation of methane and other hydrocarbons

CH 3 O 2. (methylperoxyl radical) NO 2 CH 3 O. NO CH 3 O. O2O2 HCHO (formaldehyde) HO 2 Further degradation and oxidation of formaldehyde via photolysis or reaction with OH or HO 2 to CO and finally to CO 2

Photochemical smog Los Angeles Smog Where there is much traffic and sunshine Main reagents: – NOx, VOC, O 3, CO Oxidative Huston, Texas

Fluctuations in concentrations of photochemical smog during the day Sunlight + VOC + NOx = O 3 The dominant oxidant is O 3. The figure is a generalisation based on various studies. O3O3 Sunlight and PAN

Why is the oxidant concentration in photochemical smog (mainly ozone) increasing during mid-day? When exposed to sunlight, NO 2 can cause formation of ozone: First atomic oxygen is formed Atomic oxygen can react with O 2 to form ozone Since mainly NO is emitted, we need a reaction that gives NO 2. However, oxidation by O 3 would reverse the reaction, i.e. decrease O 3 Reactions with free peroxyl radicals may instead oxidise NO to NO 2 RO 2 radicals may have been formed through reactions involving hydrocarbons, e.g.: A chain reaction involving CO, OH and HO 2 may also produce NO 2 (net reaction): NO 2 + hν (λ< 400 nm)  NO + O O + O 2 + M  O 3 + M* NO 2 + O 2  O 3 + NO O 3 + NO  NO 2 + O 2 (O 3 is often low within cities) NO + HO 2  NO 2 + HO NO + RO 2  NO 2 + RO OH + CH 4  CH 3 + H 2 O CH 3 + O 2 + M  CH 3 O 2 + M* CO + NO + O 2  CO 2 + NO 2

Both NO x and VOC emissions must be reduced O 3 concentration isolines NO x conc. VOC conc. 100 ppb 160 ppb 140 ppb 120 ppb The non-linearity between NOx and VOC At high NOx levels: NO is titrating O 3 → O 3 may increase if only NOx is reduced.

Classic smog London smog Where there is much burning of fossil fuels Main constituents: – Particles (incl soot), CO, S-compounds

Comparison of Los Angeles and London smog CharacteristicLos Angeles (Photochemical smog) London (Classic smog) Air temperature 24 to 32  C-1 to 4  C Relative humidity< 70%85% (+fog) Visibility< 0.8 to 1.6 km< 30 m Months of most frequent occurrence August – SeptemberDecember – January Time of max. occurrenceMid-dayEarly morning Major fuelsOilCoal and oil products Principle componentsO 3, NOx, CO, VOCParticles (incl. soot), CO, S- compounds Chemical conditionOxidativeReductive, acidic Principal health effectsLung function, cough, shortness of breath O 3 ) Temporary eye irritation (PAN Peroxyacetylnitrate) Bronchial irritation, coughing (particles/SO 2 ) Effects on materialsRubber cracked (O 3 )Corrosion of many materials (iron, zinc, sandstone) Effects on plantsOzone damage many plantsSO 2, particles and acid fog damage many plants

Priorities given to local, regional and global pollution problems Regional LRTAP Geneva 1979 SO 2 NOxVOCMulti Gothenburg 1999 Climate Change IPCCRioKyoto 1997 Kyoto approved by China 2002 Marrakesh Local S-limits for residual oil Limits for point sources Catalytic cars Focus on NO 2 and PM LRTAP: Long-range transboundary pollution IPCC: Intergovernmental Panel on Climate Change

The Gothenburg protocol (1999) The Gothenburg protocol (1999) A sophisticated environmental agreement  Addresses three different air pollution problems: - Acidification - Eutrophication - Ground-level ozone  Four different gases/groups of gases: - Sulphur dioxide (SO 2 ) - Nitrogen oxides (NO x ) - Ammonia (NH 3 ) - Volatile organic compounds (NMVOCs)  Based on scientific studies through an integrated assessment of critical loads, deposition patterns and abatement costs

Norwegian emissions and targets in the Gothenburg Protocol

Trends in Norway

Norwegian NOx emissions

Norwegian SO 2 emissions Commitment reached

Historical development of sulphur dioxide emissions in Europe (Source: Vestreng et al., 2007)

European sulphur emissions CountriesSO 2 CE = Czech Rep., Hungary, Poland and Slovak Rep. -73% CW = Austria, Switzerland and Germany -89% E = Estonia, Latvia, Lithuania and Russia (European part)* -73% N = Denmark Finland Iceland, Norway and Sweden -87% NW = Belgium, Luxemburg, the Netherlands, Ireland and United Kingdom -76% S = France, Greece, Italy, Portugal and Spain -62% SE = Albania, Armenia, Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, Georgia, Kazakhstan, Republic of Moldova, Romania, Slovenia, The FYROM Macedonia, Turkey, Ukraine and Yugoslavia -40% TOTAL EUROPE (excluding ships ) -67%  The decrease is generally larger after 1990  Greater from sources that emit S that is deposited in sensitive regions 1000 tones/yr

Norwegian NH 3 emissions

European nitrogen emissions CountriesNOxNH3 CE = Czech Rep., Hungary, Poland and Slovak Rep. -42%-46% CW = Austria, Switzerland and Germany -49%-23% E = Estonia, Latvia, Lithuania and Russia (European part)* +21%-48% N = Denmark Finland Iceland, Norway and Sweden -21%-10% NW = Belgium, Luxemburg, the Netherlands, Ireland and United Kingdom -36%-13% S = France, Greece, Italy, Portugal and Spain -4%+1% SE = Albania, Armenia, Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, Georgia, Kazakhstan, Republic of Moldova, Romania, Slovenia, The FYROM Macedonia, Turkey, Ukraine and Yugoslavia -26%-12% TOTAL EUROPE (excluding ships ) -24%-20% Regional differences in N emission changes are more pronounced than for sulphur emissions tones/yr

Norwegian emissions of non-Methane Volatile Organic Compounds

Norwegian emissions of particles (PM 10 ) Particles less than 10 μm are along with CO and NOx of largest importance for air quality in cities Burning of biomass and metallurgic industry the most important sources

PM is a mixture of components

Classical air pollutants are generally reduced in Europe Figure from Monks et al 2009

(GHG emissions in Norway)

Norwegian emissions of environmental toxins Large reductions due to – Improved flue cleaning technology Esp. waste incineration – Shutdown of chemical and metallurgic industry – Pb reduction due to unleaded petrol

Trends of cadmium emissions and depositions in Europe for

Air quality guidelines for some pollutants (mg/m 3 ) Concentration of air pollutant below which adverse effects to human health are acceptable. Compound Averag- ing time WHONorway CO8 h h3025- NO 2 1 yr months h h NO1h O3O3 8 h t SO 2 1 yra months h Particles, PM h 1 yr HEALTHVEGETATION a. WHO argue that if the 24 hour limit is satisfied, the annual average will be satisfactory. Guideline for 10 min: 0.5 mg/m 3

PM is the most important local air pollutant in Norwegian cities

Concentrations in Oslo (down town) air. Guidelines NOx PM 10

Developed vs developing countries Monks et al 2009

China top SO 2 emitter today

Average annual PM 10 concentrations (particular matter with diameter less than 10 μm) in selected Asian cities in 2003 WHO guideline

Air pollution – not only local and regional problem anymore Increasing evidence that many air pollutants are transported on a hemispheric or global scale. Observations and model predictions show the potential for intercontinental transport of – ozone and its precursors – fine particles – acidifying substances – mercury – persistent organic pollutants

Ozone (surface level) – damage to crops Exposure-response functions for yield loss

Persistent Organic Pollutants (POPs)  The grasshopper effect”: POPs evaporate and deposit several times (distillation)  Concentrations in cold polar areas may therefore become serious.

POPs (Europe) Trends of PCDD and PCDF C, Cl, O, H 2,3,7,8-tetrachlorodibenzodioxin DIOXINS and FURANS PCDD: Polychlorinated dibenzo-p-dioxins PCDF: Polychlorinated dibenzofurans emissions concentrations in air and soil