There are up to 70% fewer pollinator visits in areas with high air pollution

Common air pollutants may be reducing the pollinating abilities of insects by preventing them from sniffing out crops and wildflowers, new research has shown. 

Scientists from the Universities of Reading and Birmingham found that there were up to 70% fewer pollinators, up to 90% fewer flower visits, and an overall pollination reduction of us to 31%  when common ground-level air pollutants, including diesel exhaust and ozone, were present. 

The study, published in the journal Environmental Pollution, is the first to observe a negative impact of air pollution on pollination. 

Dr. Robbie Girling, Associate Professor in Agroecology at the University of Reading, who led the project, said: ‘We knew from our previous lab studies that diesel exhaust can have negative effects on insect pollinators, but the impacts we found in the field were much more dramatic than we had expected.’

The study used a purpose-built fumigation facility to regulate levels of nitrogen oxides (NOx) – present in diesel exhaust fumes – and ozone in an open field environment. They then observed the effects these pollutants had on the pollination of black mustard plants by free-flying, locally-occurring pollinating insects over the course of two summer field seasons.

They used pollution concentrations well below maximum average levels – equating to 40-50% of the limits currently defined by US law as safe for the environment

Observations revealed there were 62-70% fewer pollinator visits to the plants located in polluted air.

This reduction was seen in seven pollinator groups, particularly bees, moths, hoverflies, and butterflies. There were also 83-90% fewer flower visits by these insects, and ultimately a 14-31% reduction in pollination, based on seed yield and other factors.

These findings could have wide-ranging implications because insect pollination delivers hundreds of billions of pounds worth of economic value every year. It supports around 8% of the total value of agricultural food production worldwide, and 70% of all crop species, including apples, strawberries, and cocoa, rely on it.

Dr Christian Pfrang, Reader in Atmospheric Science at the University of Birmingham and a co-author on the study, said: ‘This truly cross-disciplinary work demonstrated very clearly how atmospheric pollutants negatively impact on pollination with direct consequences for food production as well as the resilience of our natural environment.’