Air Pollution

any alteration of the physical, chemical and biological properties of the atmospheric air

any matter found in the atmosphere other than oxygen, nitrogen, water vapor, carbon dioxide, and the inert gases in their natural or normal concentrations, that is detrimental to health or the environment,

general amount of pollution present in a broad area and refers to atmospheric average purity

air around us

released directly from the source into the air in a harmful form

converted to a hazardous form after they enter the air or are formed by chemical reactions as components of the air mix and interact

those that do not go through a smoke stack

Six Conventional or Criteria Pollutants

most widespread pollutants (7)

Natural sources of sulfur in the atmosphere include evaporation of sea spray, erosion of sulfate-containing dust from arid soils, fumes from volcanoes and hot springs, and biogenic emissions of hydrogen sulfide (H2S) and organic sulfurcontaining compounds

Highly reactive gases formed when nitrogen in fuel or in air is heated (during combustion) to temperatures above 650°C in the presence of oxygen.

Colorless, odorless, nonirritating, but highly toxic gas

is a product of photochemical reactions (reactions initiated by sunlight) between other pollutants, such as NOx or volatile organic compounds. A general term for products of these reactions is photochemical oxidants

Most abundantly produced metal air pollutant

Includes solid particles or liquid droplets suspended in a gaseous medium

particles those found in smoke and haze, and produced by fires, power plants, or vehicle exhaust, are among the most dangerous particulates because they can be drawn into the lungs , where they damage respiratory tissues

Coarse inhalable particles are larger than 2.5 micrometers but less than 10 micrometers in diameter

4 OTHER POLLUTANTS

Many toxic metals are released into the air by burning coal and oil, mining, smelting of metal ores, or manufacturing. Lead, mercury, cadmium, nickel, arsenic (highly toxic metalloid), and others are released in the form of metal fumes or suspended particulates by fuel combustion, ore smelting, and disposal of wastes

Some 370 billion tons of ________ are emitted each year from respiration (oxidation of organic compounds by plant and animal cells). These releases are usually balanced by an equal uptake by photosynthesis in green plants.

The EPA is charged with regulating six greenhouse gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. These are gases whose emissions have grown dramatically in recent decades

A special category of toxins monitored by the U.S. EPA because they are particularly dangerous.

These chemicals include carcinogens, neurotoxins, mutagens, teratogens, endocrine system disrupters, and other highly toxic compounds

Any undesirable change in the physical characteristics or chemistry of the atmosphere, such as noise, odors, and light pollution