The state environmental department has said air monitoring showed "no significant risk" to people off site.

The lab specializes in chemical and biological analyses, field sampling services, and air monitoring.

Several past and present employees of the company testified that throughout numerous fumigations in Virginia, safety standards, including the air monitoring, were never followed.

The nationwide surveillance program included air monitoring of more than 100 private properties in the Washington area.

City and state officials said additional air monitoring would be conducted at the site in the coming weeks.

Although air monitoring is expected to continue, officials say they have given up hope of finding a culprit.

Some of it is virtually invisible, such as our syndromic surveillance and air monitoring.

Results from the air monitoring indicate that the concentration of gasoline in the air is not exceeding safety levels.

The race consisted of tasks that ranged from finding and photographing Hong Kong's three air monitoring system to taking photographs with "the blue man".

The air monitoring will continue, but there is no plan to expand the use of the devices, officials said.