Air Polution

Air Pollution

any alteration of the physical, chemical and biological properties of the atmospheric air, or any discharge thereto of any liquid, gaseous or solid substances that will or is likely to create or to render the air resources of the country harmful, detrimental, or injurious to public health, safety or welfare or which will adversely affect their utilization for domestic, commercial, industrial, agricultural, recreational, or other legitimate purposes (RA 8749, 1999).

Air Pollutant

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, which includes but not limited to smoke, dust, soot, cinders, fly ash, solid particles of any kind, gases, fumes, chemical mists, steam and radio-active substances.

Ambient air quality

the general amount of pollution present in a broad area; and refers to the atmosphere's average purity as distinguished from discharge measurements taken at the source of pollution

Ambient Air

The air around us

Primary Pollutants

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

Secondary Pollutants

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

Fugitive Emissions

those that do not go through a smoke stack.

Sulfur Dioxide

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 sulfur-containing compounds.

Nitrogen Oxides (NOx)

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.

Carbon Monoxide (CO)

Colorless, odorless, nonirritating, but highly toxic gas.

Ozone (O3) and Photochemical Oxidants

Ground level O3 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.

Lead

Most abundantly produced metal air pollutant.

Particulate Matter

Includes solid particles or liquid droplets suspended in a gaseous medium.

Mercury (Hg)

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. Among these, lead and mercury are the most abundantly produced toxic metals.

Carbon Dioxide

Some 370 billion tons of CO2 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.

Halogens

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.

Hazardous Air Pollutants (HAPs)

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

Aesthetic Degradation

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

Indoor Air

The EPA has found that concentrations of toxic air pollutants are often higher indoors than outdoors.

Temperature Inversions

Can greatly concentrate air pollutants.

Stratospheric Ozone

In 1985 the British Antarctic Atmospheric Survey announced a startling and disturbing discovery: Stratospheric ozone concentrations over the South Pole were dropping precipitously during September and October every year as the sun reappeared at the end of the long polar winter.

Bronchitis

a persistent inflammation of bronchi and bronchioles (large and small airways in the lung) that causes mucus buildup, a painful cough, and involuntary muscle spasms that constrict airways.

Emphysema

severe bronchitis, an irreversible chronic obstructive lung disease in which airways become permanently constricted and alveoli are damaged or even destroyed.

Acid Precipitation

The deposition of wet acidic solutions or dry acidic particles from the air.

Air Pollution Control Facilities (APCF)

General term for structure or installation controlling the quality of emissions of air pollution source equipment (APSE).

Particulate Removal

Involves filtering air emissions. Filters trap particulates in a mesh of cotton cloth, spun glass fibers, or asbestos-cellulose.

Sulfur Removal

Important because sulfur oxides are among the most damaging of all air pollutants in terms of human health and ecosystem viability.

Six Conventional or Criteria Pollutants

These six conventional or criteria pollutants were addressed first because they contributed the largest volume of air quality degradation and also are considered the most serious threats to human health and welfare

Other Pollutants

Mercury, Carbon dioxide, Halogens, Hazardous air pollutants(HAPs)

Nitrogen Oxides (NOx) Control

Can be reduced in both internal combustion engines and industrial boilers by as much as 50 percent by carefully controlling the flow of air and fuel. Staged burners, for example, control burning temperatures and oxygen flow to prevent formation of NOx. The catalytic converter on your car uses platinum-palladium and rhodium catalysts to remove up to 90% of NOx, hydrocarbons and carbon monoxide at the same time.

Hydrocarbon Controls

Mainly involve complete combustion or controlling evaporation. Hydrocarbons and VOCs are produced by incomplete combustion of fuels or by solvent evaporation from chemical factories, paints, dry cleaning, plastic manufacturing, printing, and other industrial processed. Closed systems that prevent escape of fugitive gases can reduce many of these emissions. In automobiles, for instance, positive crankcase ventilation (PCV) systems collect oil that escapes from around the pistons and unburned fuel and channels them back to the engine for combustion. Controls on fugitive losses from industrial valves, pipes, and storage tanks can have a significant impact on air quality. Afterburners are often the best method for destroying VOCs in industrial exhaust stacks.