Food crops worth millions lost due to ozone

University of York calculates huge economic impact of ozone

Increased ozone concentrations at ground level may be causing millions of pounds of damage to UK food crops, according to a University of York researcher. Building on a previous study on ozone concentrations in the environment, which estimated that in 1990 alone the UK lost £130million in crops due to ozone taken up by plants, Dr Lisa Emberson of the Stockholm Environment Institute has been developing new methods to calculate the amount of ozone that agricultural crops absorb.

Her figures incorporate factors such as species-specific and environmental conditions (e.g. growing season, drought and humidity) that, in combination with ozone concentrations, determine plant susceptibility. Applying this new method for the UK, the loss of production in two staple crops, wheat and potato, translates into economic losses of approximately £70million and £14million respectively. The scale of damage varies by region according to ozone levels, climate, and crop distribution.

The figures only take into account the effect on the quantity or yield of the crop, and do not include other ozone damage such as leaf injury or poor grain quality. Work is now underway to assess the threat to maize, tomato, sunflower and sugar beet – economically important crops which are sensitive to ozone. Ozone is a naturally occurring atmospheric gas. High up in the earth’s atmosphere, it plays a crucial role in filtering out harmful ultraviolet radiation that would otherwise damage life on earth. However, at ground level, it damages human health, vegetation and materials and is also a potent greenhouse gas.

Before industrialisation, annual mean ozone concentrations were between 10 to 15 parts per billion (ppb). Concentrations have now risen to around 30 ppb, and hot sunny days in the UK lead to concentrations that can exceed 100 ppb. Dr Emberson said: “Research into the effects of ozone on UK crops is remarkably limited given the economic implications of the problem. Most research has focused on visible injuries or reductions in yield rather than nutritional content.” Dr Emberson says ozone is a significant global problem. Concentrations have been increasing in many parts of the world, particularly in Asia where crop losses may hit the poor the hardest. “It’s crucial to agricultural management to understand the combined stresses of ozone pollution and climate, especially given the projected increase in background ozone concentrations and changes in climate likely to occur in coming decades,” she added.

Dr Emberson is co-editor of the recently-published ‘Air Pollution Impacts on Crops and Forests’ which has collated key studies in which the Asian region was identified as facing the most serious risks to agricultural productivity both now and in the future.

The Stockholm Environment Institute at York has established an Air Pollution Crop Effect Network, and a workshop in Bangkok organised by Dr Emberson brought together 30 delegates from 15 different countries to initiate a co-ordinated effort to assess air pollution impacts across the south Asian region. Further details of this project can be found at http://www.york.ac.uk/inst/sei/rapidc2/impactscrops.html