The seventh air monitor in North Texas' Barnett Shale went on line this week in the Everman area in south Tarrant County to provide "information about local air quality 24 hours a day, 365 days a year," the Texas Commission on Environmental Quality said.

The commission said it's also evaluating Barnett Shale sites for more monitors.

State Sen. Wendy Davis and state Rep. Marc Veasey, both D-Fort Worth, praised the installation of the monitor.

"We support the positive impacts that the Barnett Shale has brought to our local economies, but we must do more to ensure the health and safety of the families living and working very close to the thousands of wells, pipelines, compressors and storage tanks in our communities," Davis said.

Veasey said the public's health "is paramount to any other concern."

A substantial number of producing Barnett natural gas wells and drilling sites are in the general vicinity of the new monitor.

A study commissioned by Fort Worth concluded that emissions from natural gas operations didn't pose "any significant health threats" to residents but recommended ways to reduce emissions at some sites.

The new monitor is an auto gas chromatograph that provides "near real time air quality readings," the commission said. The device tests for 46 volatile organic compounds, including benzene, which may cause cancer.

The commission has beefed up monitoring after being criticized for not doing enough to measure the impact of Barnett operations. More than 15,000 wells are producing in the Barnett, which underlies more than 20 North Texas counties.