News Release

August 22, 2005

HDHHS project provides peek at future of environmental enforcement

A Houston Department of Health and Human Services (HDHHS) project has provided a preview of what enforcement of environmental laws will look like in the future.
The project used a hi-tech sensor mounted on a helicopter to survey seven sections of the Houston ship channel and generate colorful imagery pinpointing possible illegal pollution. The images of the ship channel, a heavy industrial production and storage area where chemical spills or unauthorized emissions are believed to occur, included various zones of the waterway shown in an array of bright, fluorescent colors. Each color indicated the presence of chemical or light petrochemical discharges.

The images—similar to the look of satellite imagery—were produced by a hyperspectral sensor, a device that measures patterns in the reflection of light across a range of wavelengths in the electromagnetic spectrum. All matter reflects light at specific wavelengths so the patterns obtained from the ship channel during the surveying last summer hinted at the identity of the discharges.
Most chemicals detected during the two days of helicopter flights were solvents such as xylene and acetone or enamel paint. Although the project detected many likely petrochemical discharges from barges and chemical plants along the ship channel, definitive identification could not be achieved because today no hyperspectral databases exist for substances most common to the petrochemical industry.

The project, referred to as remote sensing, established the viability of using hyperspectral technology to send ground enforcement crews to collect pollution samples within minutes after the detection of illegal discharges. The ability to instantly send to ground crews precise information on the location of discharges is critical as light petrochemicals evaporate rapidly from the water surface or disperse due to currents, wind and the wave action in the ship channel.
Though the helicopter flew at altitudes between 1,500 and 1,800 feet, the sensor tied pixels from the images to specific coordinates as small as a square yard on the ground and the data along with maps created through GIS, or Geographic Information Systems, were sent immediately to crews waiting nearby on a boat.

“If we obtain discharge samples and then ensure proper chain of custody and laboratory analysis, we end with an efficient enforcement tool,” said Larry York, a senior GIS analyst who developed and managed the project for HDHHS and earlier this year won second place in an international competition sponsored by Research Systems, Inc., a company that developed the hyperspectral software used in the project.

York said that hyperspectral technology could also be used to detect illegal air emissions. Hyperspectral technology can detect chemicals such as benzene and ammonia in gas plumes.

NASA, the United States Geological Survey, large private companies and colleges and universities have used hyperspectral imaging for some time to identify minerals, rocks, clays, dirts and even vegetation density in large tracks of land.
In Houston and Harris County there are 21,595 authorized emission points such as storage tanks and stacks including those in the area’s approximately 300 petrochemical plants.

York said the Environmental Protection Agency is currently researching the use of hyperspectral imaging, but knows of no other city or state health department that has applied it to the enforcement of pollution regulations like HDHHS. He said it is now becoming more feasible for cities or states to purchase hyperspectral sensors due to recent technological advances resulting in the price per unit to drop from nearly $1 million to about $225,000.

The other major expense would be the helicopters needed for surveying, but a solution could involve collaboration with the Houston Police Department, which already owns helicopters similar to the one used for the ship channel surveys. In fact, HPD flew a handful of night missions trying to detect discharges at York’s request even before the hyperspectral imaging project.

If acquiring a hyperspectral sensor ever becomes feasible for HDHHS, York envisions creating a team that he can mentor in remote sensing, mapping and the creation of data for the enforcement of environmental laws.

EPA funds enabled HDHHS to coordinate the project and lease the sensor and helicopter.