Chapter 1- The Air We Breathe

Catalyst

A chemical substance that particles in chemical reaction and influences its rate without itself undergoing permanent change

mixture

A physical combination of two or more pure substances present in variable amounts

matter and mass

In a chemical reaction, matter and mass are conserved

Parts per Million (PPM)

One ppm is a unit of concentration 10,000 times smaller than 1%

Violate

Readily passes into the vapor phase; that is, evaporated easily

scientific notation

a system of writing numbers as the product of a number and 10 raised to the appropriate power

organic compound

always contains carbon, almost always contains hydrogen, and may contain elements such as oxygen and nitrogen

carcinogenic

capable of causing cancer

Coalescents

chemicals added to soften the latex particles in paint so that these particles spread to form a continuous film of uniform thickness

metals

elements that are shiny and conduct electricity and heat well

nonmetals

elements that do not conduct heat or electricity well and have no one characteristic appearance

metalloids

elements that lie between metals and nonmetals on the periodic table and do not fail cleanly into either category

Aerosols

liquid and solid particles that remain suspended in the air rather that settling out

parts per billionth (ppb)

one part out of one billion, or 1000 times less concentrated than one part per million

chemical symbols

one- or two-letter abbreviations for the elements

periodic table an

orderly arrangement of all the element based on similarities in their properties

groups

organize elements according to important properties that they have in common and are numbered from left to right

percent

parts per hundred

Nanotechnology

refers to the creation of materials at the atomic and molecular (nanmoeters) scale: 1 nanometer (nm) = 1x10^-9m

chemical equation

representation of a chemical reaction using chemical formulas

exposure

the amount of substance encountered

troposphere

the lower region of the atmosphere in which we live that lies directly above the surface of the Earth

PMv10

Includes particles with an average diameter of 10um (micrometers 10^-6) or less, a length on the order of 0.0004 inches

hydrocarbons

compounds made up only of the elements hydrogen and carbon

ambient air

the air surrounding us, usually meaning the outside air

combustion

the chemical process of burnung; that is, the rapid combination of fuel with oxygen to release energy in the frm of heat and light

Respiration

the food we eat are metabolized to produce carbon dioxide and water

shifting baselines

the idea that what people expect as 'normal' on our planet has changed over time, especially with regard to ecosystems

toxicity

the intrinsic health hazard of a substance

Risk assessment

the process of evaluating scientific data and making predictions in an organized manner about the probability of an outcome.

atoms

the smallest unit of an element that can exist as a stable, independent entity

molecule

two or more atoms held together by chemical bonds in a certain spatial arrangement

megacities

urban areas with 10 million people or more

tragedy of the commons

when a resource is common to all and used by many, but no one is particularly responsible for it. As a result, the resource may be destroyed by overuse to the detriment of all who use it.

green chemistry

'benign by design.' It calls for designing chemical products and processes that reduce or eliminate the use or generation of hazardous substances

secondary pollution

It is produced from chemical reactions involving one or more other pollutant

sustainability

The ability to keep in existence or maintain. A sustainable ecosystem is one that can be maintained. "Meeting the need of the present without compromising the ability of future generations to meet their needs"

PMv2.5

The subset of PMv10 and includes particles with an average diameter of less than 2.5 um (micrometers 10^-6)

significant figure

a digit that is included (or excluded) to correctly represent the accuracy with which an experimental quantity is known

microgram

a millionth of a gram (g) or 10^-6 g

diatomic

a molecule consisting of two atoms

chemical reaction

a process whereby substances described as reactants are transformed into different substances called products

compound

a pure substance made up of two or more different elements in a fixed, characteristic chemical combination

chemical formula

a symbolic way to represent elementary composition of a substance

violate organic compounds (VOCs)

carbon-containing compounds that pass easily into the vapor phase

element

one of the 100 or so pure substances in our world from which compounds are formed

noble gas

one of the inert elements in Group 8A taht undergoes few, if any, chemical reactions

halogens

one of the reactive nonmetals in Group 7A, such as flourine (F), Chlorine (Cl), bromine (Br), or iodine (I)