Ecophysiological Responses of Plants to Air Pollution


In industrialised and heavily populated regions of the world, air pollution has an important influence on vegetation, affecting the production, abundance and distribution of plants. The principal primary pollutants are reactive compounds of sulphur, nitrogen and hydrocarbons emitted during the combustion of fossil fuels in industry, transport and from intensive farming. Increasing in importance is the secondary pollutant ozone. The direct effect of pollutants on plants is strongly influenced by the extent of their uptake into the plant tissues. Pollution also affects soils through increasing soil acidity and altering the balance of soil nutrients affecting roots and plant nutrition. Air pollution affects plants interactions with pests and pathogens and the sensitivity of vegetation to cold and drought stress. Understanding the ecophysiological responses and mechanisms by which air pollutants affect plants helps policymakers to set guidelines for air pollution to protect vegetation, crops and ecosystems.

Key Concepts:

  • Fossil fuel combustion and intensive agriculture are the main sources of air pollutants, which may be transported over long distances to affect plant life on a global scale.

  • In developed nations, sulphur dioxide, smoke and acid rain were the main acute air pollution concerns in the past, but now ozone and reactive nitrogen may pose the greatest threats.

  • Pollutants are deposited to plants as dry deposition of gases and particles and wet deposition in rain and cloudwater.

  • Stomata and cuticle on plant's surfaces provide an important control on uptake by vascular plants.

  • Bryophytes and lichens are vulnerable to air pollution as they lack a protective cuticle.

  • Acid rain, ozone, SO2 and other pollutants can directly injure the physiology of above ground plant tissues such as leaf gas exchange, carbon transport or flowering.

  • Soils are affected by increased acidity and nitrogen deposition which have long term effects on plant nutrient uptake, root system health and species competition.

  • Biodiversity and structure of plant communities appears to be damaged by long term nitrogen deposition.

  • Air pollution increases plant attack from pests and pathogens and increases vulnerability to cold and drought stress.

  • More understanding is needed of damage mechanisms to inform air quality guidelines to protect plants and their ecosystems.

Keywords: air pollutants; wet and dry deposition; acidification; nitrogen; ozone; plant uptake; plant physiology; ecology

Figure 1.

Reduced crown density, a symptom of forest decline, in trees of the Harz mountains in northern Germany. The extent of thinning of the needles in the crown is widely used in forest tree health surveys.

Figure 2.

The resistance analogy used to describe the processes of deposition of air pollutants to vegetation. Symbols: ra=aerodynamic resistance; rb=boundary layer resistance; and rc=canopy resistance. The canopy resistance is made up of resistances offered by the stomata, the leaf surface (cuticle), the surface water and the soil.

Figure 3.

Gas exchange in cotyledon leaves of cabbage measured one day after an experimental acid rain treatment (a 30 min spray of acidic water of pH 3.0 compared with a control spray of pH 5.6). The rate of photosynthesis was not affected by the acid spray treatment. In contrast, as the light was lowered, the stomatal resistance increased markedly in the control plants but showed much less change in the acid‐treated leaves. This showed that the normal closing of stomata in the dark had not occurred in the acid‐treated leaves.

Figure 4.

Proposed mechanism for type I forest decline in Norway spruce trees, as seen in parts of central Europe in the 1980s (after Roberts et al., ). The yellowing of needles is ultimately explained by magnesium deficiency, which results mainly from reduced uptake by the roots and leaching of this nutrient from the soil.

Figure 5.

Relationship between total plant species richness and (above) modelled Nitrogen deposition at 22 heather moorlands sites in northern Britain 2006, and (below) the percentage Nitrogen content of the surface litter layer at each site (Caporn et al., ).



Ågren GI and Andersson FO (2012) Terrestrial Ecosystem Ecology. Cambridge, UK: Cambridge University Press.

APIS (2012) UK Air Pollution Information System. Centre for Ecology and Hydrology, UK Natural Environment Research Council. (accessed 4th May 2012).

Ashmore   (2002) Air quality guidelines and their role in pollution control policy. In: Bell JNB and Treshow M (eds) Air Pollution and Plant Life, pp. 417–430. Chichester, UK: John Wiley.

Bell JNB and Treshow M (2002) Air Pollution and Plant Life. Chichester, UK: John Wiley.

Black VJ, Black CR, Roberts JA and Stewart CA (2000) Impacts of ozone on the reproductive development of plants. New Phytologist 147: 421–447.

Bleasdale JKA (1952) Atmospheric pollution and plant growth. Nature 169: 376–377.

Bobbink R, Hicks K, Galloway J et al. (2010) Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis. Ecological Applications 20(1): 30–59.

Caporn SJM, Dise NB, Emmett BA et al. (2010) Analysis of experimental results in combination with spatial surveys to identify the most sensitive indicators for both N deposition and N enrichment. In: UKREATE (2010) Terrestrial Umbrella: Effects of Eutrophication and Acidification on Terrestrial Ecosystems. CEH Contract Report NEC03425. Defra Contract No. AQ0802, pp. 17–22.

Caporn SJM, Mansfield TA and Hand DW (1992) Low temperature‐enhanced inhibition of photosynthesis by oxides of nitrogen in lettuce (Lactuca sativa L.). New Phytologist 118: 309–313.

Cawley LE (2000) Pollutant Nitrogen and Drought Tolerance in Heathland Plants. PhD thesis, Manchester Metropolitan University.

Crittenden P and Read DJ (1978) The effects of air pollution on plant growth with special reference to sulphur dioxide. I. Introduction and chamber conditions. New Phytologist 80: 33–48.

Davison AW and Barnes JD (2002) Air pollutant‐abiotic stress interactions. In: Bell JNB and Treshow M (eds) Air Pollution and Plant Life, pp. 359–378. Chichester, UK: John Wiley.

Dise NB, Ashmore MR, Belyazid S et al. (2011) Nitrogen as a threat to European terrestrial biodiversity (chapter 20). In: Sutton MA, Howard C, Erisman J‐W et al. (eds) The European Nitrogen Assessment, pp. 463–494. Cambridge, UK: Cambridge University Press.

Dohmen GP, McNeill S and And Bell JNB (1984) Air pollution increases Aphis fabae pest potential. Nature 307: 52–53.

Emberson LD, Ashmore MR, Cambridge HM, Simpson D and Tuovinen J‐P (2000) Modelling stomatal ozone flux across Europe. Environmental Pollution 109: 403–413.

Fangmeier A, Bender J, Weigel H‐J and Jager H‐J (2002) Effects of pollutant mixtures. In: Bell JNB and Treshow M (eds) Air Pollution and Plant Life, pp. 251–272. Chichester, UK: John Wiley.

Ferguson P, Lee JA and Bell JNB (1978) Effects of sulphur pollution on the growth of Sphagnum species. Environmental Pollution 16: 151–162.

Fluckiger W, Braun S and Hiltbrunner E (2002) Effects of air pollutants on biotic stress. In: Bell JNB and Treshow M (eds) Air Pollution and Plant Life, pp. 379–406. Chichester, UK: John Wiley.

Fowler D (2002) Pollutant deposition and uptake by vegetation. In: Bell JNB and Treshow M (eds) Air Pollution and Plant Life, pp. 43–68. Chichester, UK: John Wiley.

Fowler D, Cape JN, Leith ID et al. (1988) The influence of altitude on rainfall composition at Great Dun Fell. Atmospheric Environment 22: 1355–1362.

Galloway JN (1996) Anthropogenic mobilisation of sulphur and nitrogen: immediate and delayed consequences. Annual Review of Energy and the Environment 21: 261–292.

Granath G, Strengbom J and Rydin H (2012) Direct physiological effects of nitrogen on Sphagnum: a greenhouse experiment. Functional Ecology 26: 353–364.

Hawksworth DL and Rose F (1970) Qualitative scale for estimating sulphur dioxide air pollution in England and Wales using epiphytic lichens. Nature 227: 145–148.

Hetherington AM and Woodward IF (2003) The role of stomata in sensing and driving environmental change. Nature 424: 901–908.

Honour SL, Bell JNB, Ashenden TW, Cape JN and Power SA (2009) Responses of herbaceous plants to urban air pollution: effects on growth, phenology and leaf surface characteristics. Environmental Pollution 157: 1279–1286.

Houghton J (2009) Global Warming. The Complete Briefing. Cambridge: Cambridge University Press.

Lee JA (1998) Unintentional experiments with terrestrial ecosystems: ecological effects of sulphur and nitrogen pollutants. Journal of Ecology 86: 1–12.

Mansfield TA (1999) SO2 pollution: a bygone problem or a continuing hazard? In: Press MC, Scholes JD and Barker MG (eds) Physiological Plant Ecology, pp. 219–240. Oxford: Blackwell Science.

Maskell LC, Smart SM, Bullock JM, Thompson K and Stevens CJ (2010) Nitrogen deposition causes widespread loss of species richness in British habitats. Global Change Biology 16: 671–679.

McDonald AG, Bealey WJ, Fowler D et al. (2007) Quantifying the effect of urban tree planting on concentrations and depositions of PM10 in two UK conurbations. Atmospheric Environment 41: 8455–8467.

Mills G and Harmens H (2011) Ozone pollution: a hidden threat to food security. Report prepared by the ICP Vegetation. Centre for Ecology and Hydrology, UK Natural Environment Research Council.‐ICPVegetationreport 2011‐published.pdf (accessed 4th May 2012).

Mills G, Hayes F, Simpson D et al. (2011) Evidence of widespread effects of ozone on crops and (semi‐)natural vegetation in Europe (1990–2006) in relation to AOT40‐ and flux‐based risk maps. Global Change Biology 17: 592–613.

Nash TH (2008) Lichen Biology. Cambridge: Cambridge University Press.

Nordin A, Strengbom J and Ericson L (2006) Responses to ammonium and nitrate additions by boreal plants and their natural enemies. Environmental Pollution 141: 167–174.

Nussbaum S and Fuhrer J (2000) Difference in ozone uptake in grassland species between open‐top chambers and ambient air. Environmental Pollution 109: 463–471.

Percy KE, Manninen S, Häberle K‐H et al. (2009) Effect of 3 years’ free‐air exposure to elevated ozone on mature Norway spruce (Picea abies (L.) Karst.) needle epicuticular wax physicochemical characteristics. Environmental Pollution 157: 1657–1665.

Phoenix GK, Emmett BA, Britton AJ et al. (2012) Impacts of atmospheric nitrogen deposition: responses of multiple plant and soil parameters across contrasting ecosystems in long‐term field experiments. Global Change Biology 18: 1197–1215.

Pilkington MG, Caporn SJM, Carroll JA et al. (2005) Effects of increased deposition of atmospheric nitrogen on an upland moor: Leaching of N species and soil solution chemistry. Environmental Pollution 135: 29–40.

Roberts TM, Skeffington RA and Blank LW (1989) Causes of type 1 spruce decline in Europe. Forestry 62: 179–222.

Rockström J, Steffen W, Noone K et al. (2009) A safe operating space for humanity. Nature 461: 472–475.

RoTAP (2012) Review of Transboundary Air Pollution: Acidification, Eutrophication, Ground Level Ozone and Heavy Metals in the UK. Contract Report to the Department for Environment, Food and Rural Affairs. Centre for Ecology & Hydrology.

Smith RA (1872) Air and Rain: The Beginnings of a Chemical Climatology. London: Longmans.

Stevens CJ, Dise NB, Mountford JO and Gowing DG (2004) Impact of nitrogen deposition on the species richness of grasslands. Science 303: 1876–1879.

Stevens CJ, Dupre C, Dorland E et al. (2010) Nitrogen deposition threatens species richness of grasslands across Europe. Environmental Pollution 158: 2940–2945.

Sutton MA, Howard C, Erisman J‐W et al. (eds) (2011) The European Nitrogen Assessment. Cambridge, UK: Cambridge University Press.

Tiwary A and Colls J (2010) Air Pollution Measurement, Modelling and Mitigation. Abingdon, UK: Routledge.

Vitousek PM, Mooney HA, Lubchenco J and Mellilo J (1997) Human domination of the earth's ecosystems. Science 277: 494–499.

Wilkinson S and Davies WJ (2010) Drought, ozone, ABA and ethylene: new insights from cell to plant to community. Plant Cell and Environment 33: 510–525.

Wilkinson S, Mills G, Illidge R and Davies WJ (2012) How is Ozone pollution reducing our food supply? Journal of Experimental Botany 63: 527–536.

Wilson DB (2003) Effect of Nitrogen Enrichment on the Ecology and Nutrient Cycling of a Lowland Heath. PhD. thesis, Manchester Metropolitan University.

Further Reading

Ashmore MR (1997) Plants and pollution. In: Crawley MJ (ed.) Plant Ecology, pp. 568–581. Oxford: Blackwell Science.

Brimblecombe P (1987) The Big Smoke. London: Routledge.

Larcher W (1995) Physiological Plant Ecology. Berlin: Springer‐Verlag.

Lovett GM, Tear TH, Evers DC, Findlay SEG and Jack B (2009) Effects of air pollution on ecosystems and biological diversity in the Eastern United States. Annals of the New York Academy of Sciences 1162: 99–135.

NEGTAP (2001) Transboundary Air Pollution: Acidification, Eutrophication and Ground‐level Ozone in the UK. (Prepared by the UK National Expert Group on Transboundary Air Pollution). (accessed 4th May 2012).

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Caporn, Simon JM(Feb 2013) Ecophysiological Responses of Plants to Air Pollution. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0003206.pub2]