Future air quality may put plants at risk

Although the research findings focus on the impact in the US, they raise wider concerns for global air quality.

"Ozone affects photosynthesis, causing pigmentation on leaves, stunting growth and reducing yield," said Maria Val Martin from University of Sheffield's faculty of engineering, and lead researcher.

The team combined data on climate change, land use and emissions to create a picture of air quality across the US in 2050.

If greenhouse gas emissions peak in 2040, then by 2050 surface ozone will remain below levels set to safeguard human health, despite increases in ozone caused by higher temperatures and changes in agriculture and forestation, showed research.

If emissions continue to rise until 2100, then some areas of the US will see surface ozone above the safe levels set for human health, warned the study.

By looking at the cumulative impact of ozone over three months in the summer - a growing season - the team found that under both scenarios, the surface ozone levels would be high enough to cause damage to plants.

It is because during summer, there were higher emissions from vehicular transport and industry of nitrogen oxides, which react with sunlight to create ozone.

The research showed that we may need more stringent controls of certain emissions - such as nitrogen oxides or methane - that contribute to ozone levels, explained Maria.

"Protecting natural ecosystems - and our enjoyment of them - will require us to consider and manage the impacts of emissions and climate change on future air quality," concluded professor Colette Heald from Massachusetts Institute of Technology.

The findings appeared in Atmospheric Chemistry and Physics Discussions.