Sampling on the Go

For decades, technologies have been used to test exhaust emissions from cars, trucks and other on-road vehicles under actual operating conditions in the field. Until now, however, this capability has not been readily available for most mobile off-road and non-road sources such as planes, trains and industrial equipment, which have been identified as significant contributors to air-quality and climate-change problems.

In an effort to address emissions from this important portion of the transportation sector, Environment Canada's Environmental Technology Centre (ETC) has created a state-of-the-art, portable, sampling apparatus for testing exhaust emissions from these difficult-to-measure mobile sources. The Dynamic Dilution On/Off-road Exhaust Emissions Sampling System—known as DOES2^TM is typically housed in a box about the size of a forty-inch television and operates with the assistance of a small gas generator.

The DOES2^TM is usually mounted on or in the test vehicle and connected to its exhaust pipe by a probe that takes samples of the raw exhaust during operation. The exhaust is mixed with a controlled volume of ambient air, and proportional samples of the dilute mixture are collected for measurement of both regulated and non-regulated emissions. A portable computer connected to the sampling system records engine data and calculates emission characteristics—all with the same accuracy in the field as would normally be expected in a controlled laboratory setting.

Although the DOES2^TM can be used for conventional on-road vehicles as well as stationary pollution sources, such as generators and turbines, its real value lies in its application to off- and non-road vehicles that cannot be tested in conventional laboratories. Information gathered from such applications will help to promote better understanding and development of pollution-reducing technologies and alternate fuels, and improved strategies for operating and maintaining existing equipment—both by governments from a regulatory/compliance point of view, and by private- sector companies interested in producing related goods and services.

The DOES2^TM has been instrumental in analyzing and demonstrating the performance of retrofitting, upgrading, and fuel-conversion technologies in a number of collaborative projects in Canada, the United States, China and Columbia. In Hong Kong and Columbia, the system has been used to assess the efficiency of alternative fuels in buses. It has also been applied in several projects in the United States to test emissions from underground mining equipment in Cleveland, Ohio, construction equipment in New England, and buses in New York City. In Houston, Texas, one of the ETC's licensees is using the system to conduct tests and demonstrate benefits of their proprietary, alternate-fuel blend—which is a mixture of 20 per cent water—on shipyard equipment.

Environment Canada is continuing to seek proposals from interested private-sector parties to license and commercialize the various applications of the DOES2^TM. The widespread use of this technology will help determine the feasibility and viability of strategies and products that will ultimately contribute to improved air quality in Canada and around the world.

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