Half the population could suffer from hay fever within 20 years,experts warn..
专家们警告说,世界上一半的人口将在20年内患上花粉症。
Some 15 million Britons are currently afflicted, but with more people moving to cities, the number of sufferers will double to 32million by 2030.
英国有约1500万人目前已染上这种病症,而且随着越来越多的人口向城市迁移,这一数字将在2030年前成倍增长,达到3200万。