aerosol: (adj. aerosolized) A tiny solid or liquid particle suspended in air or as a gas. Aerosols can be natural, such as fog or gas from volcanic eruptions, or artificial, such as smoke from burning fossil fuels.
asthma: A disease affecting the body’s airways, which are the tubes through which animals breathe. Asthma obstructs these airways through swelling, the production of too much mucus or a tightening of the tubes. As a result, the body can expand to breathe in air, but loses the ability to exhale appropriately. The most common cause of asthma is an allergy. Asthma is a leading cause of hospitalization and the top chronic disease responsible for kids missing school.
average: (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.
colleague: Someone who works with another; a co-worker or team member.
diesel fuel: Heavier and oilier than gasoline, this is another type of fuel made from crude oil. It’s used to power many engines — not only in cars and trucks but also to power some industrial motors — that don’t rely on spark plugs to ignite the fuel.
economist: Someone who works in the field of economics: how a society’s resources relate to the things it produces or achieves. Often this is measured in the goods people make, the money they earn or the costs they encounter (such as pollution or sickness). Economists might calculate this for something as small as a village or as large as a nation — even for workers living across the globe.
epidemiologist: Like health detectives, these researchers look to link a particular illness to what might have caused it and/or allowed it to spread.
fossil fuel: Any fuel — such as coal, petroleum (crude oil) or natural gas — that has developed within the Earth over millions of years from the decayed remains of bacteria, plants or animals.
global warming: The gradual increase in the overall temperature of Earth’s atmosphere due to the greenhouse effect. This effect is caused by increased levels of carbon dioxide, chlorofluorocarbons and other gases in the air, many of them released by human activity.
link: A connection between two people or things.
natural gas: A mix of gases that developed underground over millions of years (often in association with crude oil). Most natural gas starts out as 50 to 90 percent methane, along with small amounts of heavier hydrocarbons, such as propane and butane.
nitrogen oxides: Pollutants made up of nitrogen and oxygen that form when fossil fuels are burned. The scientific symbol for these chemicals is NOx (pronounced “knocks”). The principle ones are nitric oxide (NO) and nitrous oxide (NO 2 ).
pneumonia: A lung disease in which infection by a virus or bacterium causes inflammation and tissue damage. Sometimes the lungs fill with fluid or mucus. Symptoms include fever, chills, cough and trouble breathing.
policy: A plan, stated guidelines or agreed-upon rules of action to apply in certain specific circumstances. For instance, a school could have a policy on when to permit snow days or how many excused absences it would allow a student in a given year.
random: Something that occurs haphazardly or without reason, based on no intention or purpose. Or an adjective that describes some thing that found itself selected for no particular reason, or even chaotically.
renewable energy: Energy from a source that is not depleted by use, such as hydropower (water), wind power or solar power.
sustainability: (adj: sustainable) To use resources in a way that they will continue to be available in the future.
threshold: A lower limit; or the lowest level at which something occurs.