Food production hit by increasing ozone levels

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Food production hit by increasing ozone levels

 

08/10/2004 - Dr Lisa Emberson of the University of York tells Anthony

Fletcher why high ozone concentrations could cost food producers

millions in damaged crops.

 

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 £130

million in crops due to ozone taken up by plants, Dr Lisa Emberson of

the Stockholm Environment Institute at York 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, such as growing season, drought and

humidity, which, in combination with ozone concentrations, determine

crop 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 £70 million and £14 million 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.

 

" The increase in ozone levels is due to human activity, " Emberson told

FoodProductionDaily.com. " It is a secondary pollutant. It is formed

when nitrogen oxides react with volatile organic compounds (VOCs) that

are emitted into the atmosphere through fossil fuel burning and

various industrial processes. "

 

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.

 

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. But

at ground level, it damages human health, vegetation and materials and

is also a potent greenhouse gas.

 

" We've tried to accurately evaluate the economic threat. Food

producers are probably not aware that ozone is a regional pollutant,

which makes it difficult assess, " said Emberson.

 

" We've tried to assess the absorbed dose of ozone and calculate the

exact cost this has on crop yield. "

 

Emberson, who is co-editor of the recently published `Air Pollution

Impacts on Crops and Forests,' does believe that progress, at least in

Europe, is slowly being made to reduce VOC emissions that contribute

to excess levels of ozone. But she is concerned that while peak

concentrations seem to have been reduced, background concentrations,

especially in Asia, appear to be on the increase.

 

" Rather than being exposed to short sharp bursts, crops are

increasingly subject to more long term exposure to high ground levels

of ozone, " she said. " This could potentially be very serious. "

 

Emberson says that it is vital that food producers fully 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.

 

Work is now underway to assess the threat to maize, tomato, sunflower

and sugar beet – economically important crops that are sensitive to ozone.

 

The Stockholm Environment Institute at York (SEI–Y) is one of the

constituent centres of the Stockholm Environment Institute, an

independent, international research organisation committed to the

implementation of practices supportive of global sustainable development.

 

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