The Allegheny County Board of Health yesterday adopted a regulation allowing use of modern smoke monitoring equipment for enforcement of soot emissions limits at industrial facilities.

Continuous opacity monitors, as the devices are called, mandated by the U.S. Environmental Protection Agency since 1997, allow county inspectors to collect emissions data continuously, day and night.

The health department has employed certified "smoke readers" to determine if a facility is emitting too much soot, but such a visual assessment can only be done during daylight hours.

The change brings the county regulations into line with the federal rule.

The Group Against Smog and Pollution, which supported the new regulation, said it enables accurate 24-hour-a-day measurement of soot to ensure compliance.