The comments indicate that it takes 26mS to get an accurate reading. The delay allows that time to elapse.
To get rid of the delay statement, you'll need to turn the sensor on, and then return. Create a new function to read the sensor. Use millis() to read the time that the sensor was turned on. Use millis() in each pass through loop, and call the function to get the results when 26 or more milliseconds has elapsed.