At the beginning of this year, she started hearing an eerie hum that got louder at night. Virginia has had explosive growth in data centers since the early 2000s, when Loudoun County started allowing data centers to be built. Loudoun County residents say the noise started this past winter and gets louder at night when it's cooler. In Loudoun County, residents said they could hear the data center even with their windows closed. Unlike previous data centers, the new ones use so-called free air cooling , designed to leverage lower temperatures to use less electricity than most data centers.

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Persons: Stephanie Brookes, Brookes, Les Blomberg, he's, Mike Turner, Ted Lewis, Turner, Eric Lee, Jeff Mach, Mach, Katy Hancock, Hancock, Chris Crosby, Blomberg, it's, Lewis, Arline Bronzaft, Wire Blomberg Organizations: Business, Compass, Pollution, The Washington Post, county's, Supervisors, Loudoun County's, Public, Lehman College Locations: Loudoun County , Virginia, Virginia, Loudoun County, Leesburg, New York, Ashburn, Loudoun, Loudoun County's