E.S.I. Environmental Sensors Inc.

E.S.I. Environmental Sensors Inc.

March 29, 2007 15:44 ET

ESI Announces Successful Alpha Trials on a Revolutionary New Sensor

VICTORIA, BRITISH COLUMBIA--(CCNMatthews - March 29, 2007) - E.S.I. Environmental Sensors Inc. ("ESI") (TSX VENTURE:ESV) is pleased to announce the successful completion of alpha trial testing on its next generation of sensor systems. The sensor design is simple to install and revolutionary within the water management industry. It is capable of providing four measurements; moisture content, temperature, conductivity and "wetting front". This "complete solution" sensor is the first of its kind in the industry to provide growers with this critical information from a single device.

The primary moisture measurement function provides information on average soil moisture, along the length of the sensor and accurately allows the grower to decide when irrigation is required. The wetting front capability detects when the irrigation wetting front reaches the bottom of the sensor and allows the grower to decide when to stop irrigation.

The measurement of bulk in-situ electric conductivity is done using a technique already patented by ESI. Knowing the bulk conductivity allows the moisture sensor to automatically compensate its readings for changes in conductivity. This allows a single sensor to work in soil types ranging from sand to heavy saline clay. The grower will no longer need to have detailed knowledge of their soil characteristics. In addition, this new sensor has an integrated temperature sensor providing the grower with an accurate report of soil temperature. The sensors can be stacked in series to provide the grower with vertical profiling information on volumetric soil moisture, in-situ bulk electric conductivity, soil temperature, and wetting front.

"The stacked wetting front sensors will allow the grower to follow the progress of the irrigation wetting front down through the soil layers. The grower will know for certain that the water has penetrated to the desired depth such as the bottom of the root zone, and that they have not wasted water by allowing the wetting front to penetrate deeper beyond the reach of the plant roots. The grower benefits from water usage optimization and we all benefit from water conservation," said Blair Heffelfinger, CEO.

About ESI

ESI is a leading developer and manufacturer of patented and proprietary systems for industrial and environmental applications where understanding the presence and content of water is important. Major market sectors include: Agriculture, Golf and Turf, Scientific Research and Oil. ESI products have been successfully introduced into over 40 countries to enable customers to optimize their operations by monitoring the presence and movement of water, managing irrigation systems, and monitoring the integrity of landfill covers. Most recently, the FloPoint™ instrument has been introduced to the Oil industry to measure the volumetric presence of water pumped from producing oil wells for characterization and optimization. ESI differentiates itself by translating the best technology and science available into practical, easy to use solutions. Irrigation managers and scientists have adopted ESI's products for their accuracy, ease of use, repeatability, and ability to operate in challenging conditions. ESI is publicly traded on the TSX Venture Exchange under the symbol "ESV". Further information about ESI may be obtained through the Company's website at www.esisensors.com.

On behalf of the Board,

Blair Heffelfinger, President & CEO

E.S.I. Environmental Sensors Inc.

Material Copyright 2006, E.S.I. Environmental Sensors Inc. Reproduction in whole or in part in any form or medium without express written permission of E.S.I. Environmental Sensors Inc. is prohibited.

The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this release.

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