郑州市夏季中长波紫外线强度及防紫外线伞对紫外线的遮蔽作用

Intensities both Ultraviolet A and B in Summer of Zhengzhou and the Shielding Effect of Ultraviolet-proof Umbrella

目的研究郑州市2011年7月16日-8月31日紫外线强度变化规律,评估防紫外线伞对紫外线的遮蔽作用。方法从2011年7月16日-8月31日白天每隔两小时的7个时间点分别测量防紫外线伞下和直接日光下的长波紫外线(UVA)和中波紫外线(UVB)强度,并使用重复测量数据的方差分析对比伞下和日光下紫外线强度的统计学差异。结果郑州市从2011年7月16日-8月31日每日6:00,8:00,10:00,12:00,14:00,16:00和18:00点正上方的UVA平均强度分别为(51.09±39.24)μw/cm2,(669.72±253.69)μw/cm2,(1553.06±669.31)μw/cm2,(2116.20±1007.23)μw/cm2,(1883.79±904.29)μw/cm2,(1000.69±480.39)μw/cm2,(276.22±124.89)μw/cm2;UVB平均强度分别为(1.03±1.47)μw/cm2,(47.31±17.46)μw/cm2,(128.51±49.87)μw/cm2,(180.74±75.55)μw/cm2,(154.85±67.73)μw/cm2,(77.83±34.32)μw/cm2,(14.59±7.34)μw/cm2。防紫外线伞下的紫外线强度明显低于日光下,差异有统计学意义(P<0.05)。结论郑州市2011年7月16日-8月31日UVA和UVB强度均从早晨至中午逐渐增强,然后减弱;早晨和傍晚UVA和UVB强度变化较小,中午前后波动较大。防紫外线伞可以有效阻挡紫外线辐射。

Objective To study the changing pattern of ultraviolet intensity from July 16 to August 31,2011 in Zhengzhou and to evaluate the effect of an ultraviolet-proof umbrella in shielding against ultraviolet ray.Methods Ultraviolet A（UVA） and Ultraviolet B（UVB） intensity were measured seven times a day at two hours’ interval in daytime from July 16 to August 31,2011 in Zhengzhou,both under sunlight and under an ultraviolet-proof umbrella.The data obtained in the two conditions were compared statistically with repeated measures analysis of variance.Results From July 16 to August 31,2011,the mean intensities of UVA at 6：00,8：00,10：00,12：00,14：00,16：00 and 18：00 were（51.09±39.24）μw/cm2,（669.72±253.69）μw/cm2,（1 553.06±669.31）μw/cm2,（2 116.20±1007.23）μw/cm2,（1 883.79±904.29）μw/cm2,（1 000.69±480.39）μw/cm2 and（276.22±124.89）μw/cm2,respectively;and the intensities of UVB at the same time points were（1.03±1.47）μw/cm2,（47.31±17.46）μw/cm2,（128.51±49.87）μw/cm2,（180.74±75.55）μw/cm2,（154.85±67.73）μw/cm2,（77.83±34.32）μw/cm2 and（14.59±7.34）μw/cm2,respectively.Both UVA and UVB intensities under the ultraviolet-proof umbrella were statistically significantly weaker than those under sunlight（all P〈0.05）.Conclusion From July 16 to August 31,2011,both of the intensities of UVA and UVB elevate gradually from morning and reach their peaks at noon before going down;and they only change mildly in the morning and evening,while they fluctuate greatly around noon.UV-proof umbrella may shield against ultraviolet radiation effectively.