阅读理解
5G, the fifth generation of wireless, promises lightning-fast download speeds and could lay foundation for high-tech advancements like self-driving cars. But like many new technologies, it's causing concern about potential health issues.
The first generation of wireless introduced mobile phones, and 2G brought texting. 3G laid the groundwork for smart-phones, and 4G allowed video streaming and more. 5G is expected to download data 20 times faster than its predessor(前任)，and some experts argue it could be much faster.
Too much of a good thing?
It's not just about streaming data faster, it's about streaming more of it. On a 5G network, a user can download a movie instantly, and data will flow between connected objects without delay. The amount of data people use on mobile devices has gone up 40 times since 2010 and is only expected to increase. 5G networks are wireless companies attempts to satisfy that demand.
Uncertain effects
The untested nature of 5G, and the extensiveness of its infrastructure(基础设施)has some worried that the increased exposure could have serious health effects. Wireless safety advocates(倡议人士)have called for more studies on the effects of the exposure, and one group is trying to stop the installment of 5G networks in Chicago's neighborhoods.
The federal government has safety rules that wireless companies must obey that limit human exposure to radio waves, including frequencies uses with 5G.
Wireless industry association CTIA says typical exposure to 5G infrastructure is comparable to Bluetooth devices and baby monitors, and there is no scientific evidence of negative health effects.
Still, assurances from government agencies and industry operators are not enough for Chicago resident Judy Blake. Additional studies on 5G's health impacts likely wouldn'tsootheher either. She said, "People can't choose whether or not to be exposed to this radiation."
"I don't need another test. The only test that's going to happen now is people's lives," said Blake, 67.
Only time will tell?
Though little is known about the long-term health impact of the millimeter waves that 5G operates on, some research has shown short-term exposure could be problematic, said Joel Moskowitz, a public health expert at the University of California at Berkeley.
The eyes and sweat glands(腺体)are among several body parts studies have shown could be at risk. Moskowitz said. Insects and plant life could also be affected, he added.
The millimeter waves used in SG are absorbed by the upper layers of skin, potentially causing the temperature of the skin to rise, said Suresh Borkar, senior lecturer in the Department of Electrical and Computer Engineering at the Illinois Institute of Technology. The effects of extended rises in skin temperature "become a big unknown," he said.
This isn't the first time people will come into contact with millimeter waves: They're also used in airport body scanners, said Lav Varshney, assistant professor of electrical and computer engineering at the University of Illinois at Urbana-Champaign. Still, it's the first time the high- frequency waves will he used on such a scale, and concerns surrounding new technologies are common throughout history.
"When cars first started replacing horse-drawn carriages, people were afraid of what the health impacts of traveling at high speeds would be," Varshney said. "There has always been occurrence of this fear."
