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Lead (Pb): A soft, heavy, blue-gray metal. It occurs naturally in the earth’s crust, and human activities such as burning fossil fuels, mining, and manufacturing have spread it throughout the environment, including our homes and workplaces. Lead is hazardous to human health. Lead can occur in the air as small particles, often from emissions from lead smelters and other metal-processing plants. Lead exposure can also occur through:
Low birth weight: A baby is considered to be of low birth weight when its weight is less than 5.5 lbs., or 2500 grams, at birth. For Tracking, low birth weight is measured among singleton births only.
Lower Limb Reduction Defects: Lower limb reduction defects occur when a part of or the entire leg (lower limb) of a fetus fails to form completely during pregnancy. The defect is referred to as a “limb reduction” because a limb is reduced from its normal size or is missing.
Lung disease: A broad term that refers to many disorders affecting the lungs. Lung disease includes diseases such as asthma, emphysema, and chronic bronchitis.
Malignant neoplasm: A cancer tumor that is malignant and tends to spread to other parts of the body.
Maximum Contaminant Level (MCL): The MCL is the health based standard defined by the United States Environmental Protection Agency. Arsenic: After 2006 the MCL for arsenic is 10 ug/l. Before 2006 the MCL was 50 ug/l. Disinfection by-products: The MCL for Total trihalomethanes is 80 ug/l and for haloacetic acids is 60 ug/l. Nitrate: The MCL for nitrate is 10 ug/l.
Mean: The average of a list of numbers by calculating the sum of all the members of the list and dividing by the number of items in the list.
Measure: On the Tracking Network, a measure is a summary characteristic or statistic, such as a sum, percentage, or rate. Measures are available for each indicator.
Mercury: A naturally occurring element that is found in air, water and soil. It exists in several forms: elemental or metallic mercury, inorganic mercury compounds, and organic mercury compounds. Elemental or metallic mercury is a shiny, silver-white metal and is liquid at room temperature. It is used in thermometers, fluorescent light bulbs and some electrical switches. When dropped, elemental mercury breaks into smaller droplets which can go through small cracks or become strongly attached to certain materials. At room temperature, exposed elemental mercury can evaporate to become an invisible, odorless toxic vapor. People can be exposed to elemental mercury vapor when products that contain mercury break and expose mercury to the air, particularly in poorly-ventilated spaces. Inorganic mercury compounds take the form of mercury salts and are generally white powder or crystals, with the exception of mercuric sulfide (cinnabar) which is red. Inorganic mercury compounds have been included in products such as fungicides, antiseptics or disinfectants. Some skin lightening and freckle creams, as well as some traditional medicines, can contain mercury compounds. Organic mercury compounds, such as methyl mercury, are formed when mercury combines with carbon. Microscopic organisms convert inorganic mercury into methyl mercury, which is the most common organic mercury compound found in the environment. Methyl mercury accumulates up the food chain.
Metadata: This is simply "data about data". Metadata is the information about a data source, for example, a book contains information, but there is also information about that book such as the author and publisher - this is the metadata.
Metal: A chemical element that usually has a shiny surface, is generally a good conductor of heat and electricity, and can be melted or fused, hammered into thin sheets, or drawn into wires. The metals comprise about two-thirds of all known elements. Unlike nonmetals, metals form positive ions and basic oxides and hydroxides. Upon exposure to moist air, many metals react chemically with the oxygen of the atmosphere to form a metallic oxide, such as rust on exposed iron.
Microgram: A unit of mass equal to one millionth of a gram.
Micron: A unit of length equal to one millionth of a meter.
Microorganisms: Tiny living organisms that can be seen only with the aid of a microscope. Some microorganisms can cause acute health problems when consumed in drinking water. Also known as microbes.
Milligram: A unit of mass equal to one thousandth of a gram.
Morbidity: State of being ill or diseased. Morbidity is the occurrence of a disease or condition that alters health and quality of life.
Mortality: Death. Refers to the number or rate of deaths from a condition or disease.
National Ambient Air Quality Standards (NAAQS): Standards set by the EPA for all criteria pollutants. EPA has established primary standards to protect public health and secondary standards to protect other aspects of public welfare, such as preventing materials damage, preventing crop and vegetation damage, or assuring visibility.
Nitrate: A compound containing nitrogen that can exist in the atmosphere or as a dissolved gas in water and which can have harmful effects on humans and animals. Nitrates in water can cause severe illness in infants and domestic animals. A plant nutrient and inorganic fertilizer, nitrate is found in septic systems, animal feed lots, agricultural fertilizers, manure, industrial waste waters, sanitary landfills, and garbage dumps.
Nitrogen oxide: A criteria air pollutant. Nitrogen oxides (collectively known as NOx) are produced from burning fossil fuels, including gasoline and coal. Nitrogen oxides react with volatile organic compounds to form smog. Nitrogen oxides are also major components of acid rain. They may be harmful to the lungs and aggravate asthmatic symptoms.
Nonattainment area: A geographic area of the United States in which the level of a criteria air pollutant persistently exceeds the level allowed by the National Ambient Air Quality Standards (NAAQS). An area may have acceptable levels of one criteria air pollutant but unacceptable levels of one or more other criteria air pollutants; thus, an area can be both attainment and nonattainment at the same time. It has been estimated that 60% of Americans live in nonattainment areas.
Non-Rural: The NH Rural Health and Primary Care Program defines rurality for Public Health Region (PHR) using population and population density measures. PHRs with a population of more than 100,000 and with a population density of more than 150 people per square mile are considered non-rural. PHRs that do not meet these criteria are categorized as rural. Note: Public Health Region by Rural/Non-Rural identifies a PHR entirely as either rural or non-rural, and does not identify/exclude rural areas within the PHR.
Obesity: Obesity in adults is defined as body Mass Index > 30. Body Mass index (BMI) is calculated using a person’s weight and height.
Outcome: The possible or likely result of an activity or process.
Overlay: Placing a layer of information on top of another layer to see how they are related.
Ozone (O3): A criteria air pollutant. Ozone is a variety of the oxygen molecule that consists of three atoms of oxygen instead of the more common two atoms. It occurs in nature, for example, when lightning strikes. Ozone is also formed by a chemical reaction of nitrogen oxides and volatile organic compounds together with sunlight and warm temperatures. In the upper atmosphere, high concentrations of ozone act to shield the Earth from harmful ultraviolet radiation from the sun. Holes in the ozone layer allow excess radiation to reach the Earth's surface, which increases the risk of skin cancer in humans. At ground-level, ozone is often referred to as smog. Breathing too much ozone can damage lung tissue and aggravate respiratory problems like asthma and emphysema. High ozone levels are also harmful to plants, crops, and trees, as well as to materials like rubber and paints. Ozone is a widespread and serious urban air pollution problem.