Monday, September 14, 2009

Frequently Asked Questions: (3) What is Particulate Emissions Inventory?

This is one of the most important and difficult tasks, although the equation that derives the emissions inventory is quite straight forward; Emissions = Activity * Emission Factors; for the direct emissions.

The activity is in terms of the fuel consumed by various types and the emission factor is defined as the amount of pollutant released upon fuel combustion, which depends on the fuel quality, combustion technology, and pollution control efficiency. The level of uncertainty in the definition and the data available on these emission factors is high, but not an impossible task to better understand the same.

Ideally, any institution concerned about the PM pollution, is expected to have an emissions inventory, but due to inherent challenges in collecting the necessary data, disclosure issues with the industries or handling agencies, or lack of institutional and technical capability to handle the knowledge base, leads to an incomplete or inconsistent emissions inventory.

While a detailed emissions inventory covering all possible sources is desired, it is important that an effort is put in place to start the process of establishing the same, even if it means starting with averages, gross consumption levels, and borrowed factors.

Most often, the non-existence of an emissions inventory is primarily due to the lack of this first step and waiting to develop 100 percent capacity, before a preliminary estimate is made, delays the institutional capacity building aspect.

As much as it is important to establish a baseline, it is also important to acknowledge the uncertainty of the factors in use. If average numbers from similar experiments in a different city or nation are being used, that should be noted and when the local capacity is developed to study more, the factors should be corrected for the local numbers. This is a “learning while building” exercise and only by establishing a baseline with what is available that what is lacking and how to improve is better understood.

See other FAQ's.

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