Intake fraction is a measurement of pollution and it can be used in the determination of the

environmental health Environmental health is the branch of public health concerned with all aspects of the natural environment, natural and built environment affecting human health. To effectively control factors that may affect health, the requirements for a hea ...

impact of a pollutant source. Intake fraction is the ratio of the mass of a pollutant inhaled or ingested to the mass of the pollutant emitted. Traditionally, scientists and policy makers have used a source-oriented approach to reduce health impacts from pollution. That is, they identified the largest producers of various pollutants and worked to reduce the amount of pollutants emitted.

Exposure assessment Exposure assessment is a branch of environmental science, toxicology, epidemiology, environmental engineering, and occupational hygiene that focuses on the processes that take place at the interface between the environment containing the contam ...

, also referred to as exposure analysis, is a receptor-oriented science, and practitioners in this field focus on the sources of pollutants that result in the largest human exposure. The same principles can be used to assess pollutant impact on non-human organisms, but most exposure analysts focus on humans.

Definition

Intake fraction is the total mass of a pollutant ingested or inhaled by all exposed individuals over a given time, per total mass of the pollutant emitted. The intake fraction can be divided into components that identify the specific pollutant source, route, media, and subpopulation of exposed individuals. For example, policy makers may be interested in the total mass of mercury emitted by one specific coal-burning

electric generator In electricity generation, a generator, also called an ''electric generator'', ''electrical generator'', and ''electromagnetic generator'' is an electromechanical device that converts mechanical energy to electrical energy for use in an externa ...

that is ingested in water by the residents living below the

poverty level The poverty threshold, poverty limit, poverty line, or breadline is the minimum level of income deemed adequate in a particular country. The poverty line is usually calculated by estimating the total cost of one year's worth of necessities for ...

in one specific town. Mathematically, intake fraction can be represented by the mass of pollutant intake divided by the mass of pollutant emitted: Intake Fraction = Mass of Pollutant Intake (summed over all exposed individuals) / Mass of Pollutant Emitted

Determination

Direct measurement of intake fraction would only be reasonably possible in very specific, small scale situations. For example, direct measurement of

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

from a

space heater A space heater is a device used to heat a single, small- to medium-sized area. This type of heater can be contrasted with central heating, which distributes heat to multiple areas. Types Dominant mode of heat transfer All space heaters t ...

in a small house with three occupants could be achieved if each of the occupants used a personal CO monitor. Most situations of interest are too complicated to measure directly and modeling is used to estimate intake fraction. The models take into account the mass of pollutant released from the source, the horizontal and vertical distance between the point of emission and the exposed individuals, atmospheric conditions for outdoor sources, number of exposed individuals, and the time of exposure for these individuals.

Applications

The health impact of a pollutant source can be represented by the product of the total mass of a pollutant emitted, the intake fraction of the pollutant, and the toxicity of the pollutant. In the form of an equation: Health Impact = Total Mass Emitted * Intake Fraction * Toxicity Policy makers can use the intake fraction from various sources of a pollutant to determine which source will yield the largest return on the investment to reduce the pollutant. For example, an

oil drilling An oil well is a drillhole boring (earth), boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produ ...

facility may emit far greater mass of pollutants than a refueling station. However, if the oil drilling is located on a platform 10 miles offshore and the refueling station is in an urban area, then very few people will be exposed to the emitted pollutants. A relatively small reduction in emissions from the refueling station may yield a larger reduction in health impact than a large reduction at the

oil platform An oil platform (also called an oil rig, offshore platform, oil production platform, etc.) is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms w ...

. Policy makers may also be interested in comparing the intake fraction among various groups within the population to assess

environmental justice Environmental justice is a social movement that addresses injustice that occurs when poor or marginalized communities are harmed by hazardous waste, resource extraction, and other land uses from which they do not benefit. The movement has gene ...

. For example, it may be of interest to determine the intake fraction of

low-income Poverty is a state or condition in which an individual lacks the financial resources and essentials for a basic standard of living. Poverty can have diverse

residents of a town versus high-income residents of the town.{{cn, date=April 2024

References

* Exposure Analysis by Wayne Ott, Anne Steinemann, and Lance Wallace,

Taylor & Francis Taylor & Francis Group is an international company originating in the United Kingdom that publishes books and academic journals. Its parts include Taylor & Francis, CRC Press, Routledge, F1000 (publisher), F1000 Research and Dovepress. It i ...

. * Intake fraction distributions for indoor VOC sources in five European cities. Ilacqua V, Hänninen O, Kuenzli N, Jantunen MF. Indoor Air. 2007 Oct;17(5):372-83.

External links

* https://web.archive.org/web/20091015231024/http://eetd.lbl.gov/ie/

US Department of Energy US or Us most often refers to: * Us (pronoun), ''Us'' (pronoun), the objective case of the English first-person plural pronoun ''we'' * US, an abbreviation for the United States US, U.S., Us, us, or u.s. may also refer to: Arts and entertainme ...

, Environmental Energy Technologies Division, Indoor Environment Department. * http://en.opasnet.org/w/Main_Page. National Institute for Health and Welfare, Finland Environmental health