China’s “zero-Covid” policy relies heavily on mobile phone apps that display a health code in one of three “traffic light” colors: red, yellow, or green. Users install the apps via WeChat or Alipay, ...

Smoke from Canadian wildfires has impacted the air quality throughout United States, including in the northern High Plains, Midwest, Great Lakes, southern Mid-Atlantic and into the Northeast. This has ...

The science behind colors is fascinating, and it is the unique way they interact with our eyes and the environment that decides how to best apply them. Take, for example, the traffic lights, or danger ...