Bees and other beneficial bugs are disproportionately harmed by air pollution compared to crop-destroying pests, according to a new study. Researchers from the University of Reading analysed data from 120 scientific papers to understand how 40 types of insects in 19 countries respond to air pollutants like ozone, nitrogen oxides, sulfur dioxide and particulate matter. The study published in the journal Nature Communications found that pollinators — including bees and some moths and butterflies — experienced a 39% decline in foraging efficiency after being exposed to elevated air pollution levels. In contrast, plant-eating aphids and other pests were not significantly impacted.

The researchers suggest that beneficial insects — such as bees and wasps — are more affected by air pollution due to their reliance on scent-based communication. Many beneficial insects use airborne chemical signals to locate flowers, find mates, or hunt their prey. 

Air pollutants can chemically alter these scent trails or interfere with insects’ ability to detect them, essentially disrupting their sensory landscape. In contrast, many pests rely less on long-distance scent cues and more on direct contact or visual cues, making them less vulnerable to air pollution’s effects on airborne chemical signals.

The study focused on how air pollution impacts various insect behaviour and biological aspects, including feeding, growth, survival, reproduction, and ability to locate food sources. Of all these factors, insects’ ability to find food was most severely impaired by air pollution, declining by about one-third on average.

Among air pollutants, ozone emerged as particularly harmful to beneficial insects, reducing their ability to thrive and carry out their roles in the ecosystem by 35%. Ozone pollution has the most detrimental impacts and even low ozone levels below current air quality standards can cause significant damage. Nitrogen oxides also substantially impaired beneficial insects.

“Changes in invertebrate performance are not dependent on air pollutant concentrations, indicating that even low levels of pollution are damaging. Predicted increases in tropospheric ozone could result in unintended consequences to global invertebrate populations and their valuable ecological services,” the researchers write.  “While our results provide clear conclusions as to the impacts of individual pollutants applied in experimental settings, there are currently few studies into the effects of co-occurring air pollutants and how these pollutants interact at the different mixing ratios that could result from current and future emissions scenarios.”