WELLINGTON, Sept. 17 (Xinhua) -- A New Zealand study has found that El Nino years are associated with longer and more intense grass pollen seasons, heightening risks for hay fever and asthma sufferers.
Researchers looked at data from three grass pollen seasons in New Zealand's largest city Auckland, each one corresponding to a La Nina, El Nino, or neutral phase, and found that El Nino summers produce higher pollen levels, while wetter La Nina conditions suppress pollen release.
The research, published in the Switzerland-based journal Aerobiology this week, said the pollen season during the La Nina phase was shorter and less intense than the other two phases, which the team thinks is due to increased summer rains from La Nina conditions suppressing more grass pollen.
"Despite much speculation about how pollen allergies, especially hay fever and asthma, are affected by the El Nino Southern Oscillation cycle, until now we have lacked the data to know for sure," said Professor Rewi Newnham at New Zealand's Victoria University of Wellington.
The authors caution that the findings are based on a limited dataset and highlight the need for more robust pollen monitoring across New Zealand, as El Nino conditions are forecast to become more frequent with global warming, raising concerns for public health. ■
