Indirect Measurements - Input Parameter Protocol

For kitchens with open cooking fires or stoves with no chimneys, the fraction of emissions entering the room is assumed to be 1 (meaning that 100% of emissions enter the room) and therefore not important to measure as an input for the model. For homes where chimney stoves or venting hoods are used, the fraction of emissions entering the room can be important, since all of the emissions do not enter the room. The capture efficiency of these devices can be used to determine what fraction of total emissions from the device is estimated to enter the room (e.g. a capture efficiency of 90% would mean that 10% of the emissions are entering the room).

For chimney stoves where the fugitive emissions (emissions that escape into the room) are measured and known, the fugitive emissions can be used as the input emissions rate and the fraction of emissions entering the room can be set at “1”, just as is the case for open stoves. For cases where a capture efficiency is applied, one can measure this parameter by placing the stove under a dual-hood system, in which one hood covers the entire stove (with the exception of the chimney or exhaust duct), to collect the fugitive emissions (or those that exit through the chimney or exhaust duct), and the second hood is positioned to capture only the emissions that vent from the chimney or exhaust duct.

This arrangement can be challenging as the hood will need to be placed above the chimney on a roof or high inside of a room. An example of this approach can be found in Ruiz and Masera 2018. The authors describe this dual capture system, as well as how the capture efficiency was used in a version of the model (Ruiz and Masera, 2018). The ratio of the fugitive emissions to the total emissions (which includes both the chimney/vent emissions and the fugitive emissions) will provide the capture efficiency.

Ideally, central ambient air sampling in the target communities is conducted to provide a local estimate of the contributions of background concentrations of pollutants to the household. For particulate matter, these measurements should be done with gravimetric equipment at locations that represent the ambient concentrations of the area. Good locations are often the tops of community buildings at the center of town, ensuring that the equipment is not located close to specific sources such as sites where trash is often burned or chimneys that are emitting smoke. If collection of such data is not possible, it may be possible to use literature-based values, if there is relevant information on background concentrations for the target region. Also, there may be pre-existing ambient monitoring stations in the region which can provide background concentration estimates, though care should be taken to ensure that they provide data indicative of the areas where the model is being applied. Specifically, monitoring stations in urban areas are unlikely to provide reasonable background estimates of nearby rural areas given the industrial, transport, and other sources that contribute to air pollution in cities.