Air Hygiene

Atmosphere

• The atmosphere is the gaseous envelope that surrounds the earth and constitutes the transition between its surface and the vacuum of space.

• The atmosphere is composed primarily of nitrogen (N2) and oxygen (O2) and is made up of many layers of air, each one identified by their thermal characteristics or temperature changes, chemical composition, movement and density. Life on earth is supported by this atmosphere, solar energy, and our planet's magnetic fields.

 Constituent of air  Approximate percentage by volume  Significance

 Nitrogen  78.1%  Dilutes the air, moderates respiration and combustion; essential for plants to produce proteins

 Oxygen  20.9%  Essential for respiration and combustion

 Carbon dioxide  0.03 - 0.04%  Essential in the production of carbohydrates by photosynthesis

 Water vapor  Variable  Determines the climatic conditions, such as humidity, rain, snow, dew, mist, etc

 Noble gases  0.94% Helium used in balloons; Neon used on electronic 

advertisement signs; Radon used in radiotherapy for treatment of cancer

 Dust particles  Variable  Serve as nuclei for the condensation of water vapor

Constituents of Air and their Significance

 Constituent of air  How removed form air  How added to air

 Nitrogen Lightning, leguminous plants, dissolving in natural water and industries

 Decomposition of nitrogenous organic compounds by bacteria

 Oxygen

 Respiration by living organisms, combustion, dissolving in natural water, industries and rusting

 By the process of photosynthesis in plants of both land and sea

 Carbon dioxide

 Photosynthesis, dissolving in natural water, setting of lime or cement mortar, drying process of white washing, formation of shells of shell fish

 Respiration of living organisms, combustion of fuels, fermentation, decay of carbonaceous organic matter, decomposition of lime stones, shells, etc. from making quick lime

Constituents of Air and their Significance

Definition of air pollution

Air pollution occurs when the air contains gases, dust, fumes or odour in harmful amounts.

That is, amounts which could be harmful to the health or comfort of humans and animals or which could cause damage to plants and materials.

Classification of air pollutants

Ambient air

Is the air to which the general public has access, i.e. any unconfined portion of the atmosphere.

The two basic physical forms of air pollutants

Particulate matter Gases

small solid liquid particles

dust, smoke, sand, pollen, mist, and fly ash

Carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NO2), and volatile organic compounds (VOCs).

The substances that cause air pollution are called pollutants.Pollutants

Air pollutants

Criteria pollutants Hazardous air pollutants

(HAPs)

The Environmental Protection Agency (EPA)

Common and detrimental to human welfare

Six pollutants as criteria pollutants carbon monoxide (CO), sulfur oxides (SOx), nitrogen oxides (NOx), ozone (O3), lead (Pb), and particulate matter (PM)

Refers to chemicals that cause serious health and environmental hazardsare those pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects.

examples include carbon monoxide from car exhausts and sulfur dioxide from the combustion of coal.

Further pollution can arise if primary pollutants in the atmosphere undergo chemical reactions. The resulting compounds are called secondary pollutants. Photochemical smog is an example of this.ozone created from organic vapors given off at a gasoline station. The organic vapors react with sunlight in the atmosphere to produce the ozone, the primary component of smog

Pollutants that are pumped into our atmosphere and directly pollute the air are called primary pollutants

Air pollutants primary

pollutantsSecondary pollutants

Sources of air pollution

A source of air pollution is any activity that causes pollutants to be emitted into the air. -

1- Biogenic sources

Natural sources of air pollution. For example, volcanoes have spewed particulate matter and gases into our atmosphere for millions of years. Lightening strikes have caused forest fires, with their resulting contribution of gases and particles, for as long as storms and forests have existed. Organic matter in swamps decay and wind storms whip up dust. Trees and other vegetation contribute large amounts of pollen and spores to our atmosphere.

Less problematic

human-generated pollutants

2- Anthropogenic sources.

Mobile sources Stationary sources

include most forms of transportation such as automobiles, trucks, and airplanes.

consist of non-moving sources such as power plants and industrial facilities.

A point source An area source

a source at a fixed point, such as a smokestack or storage tank, that emits air pollutants.

a series of small sources that together can affect air quality in a region.

more problematic

Sources of air pollution

Types and sources of air pollutants

Stationary sources

Stationary sources

CAFOs Concentrated Animal feeding

operations

Are agricultural enterprises where animals are kept and raised in confined situations. CAFOs congregate animals, feed, manure and urine, dead animals, and production operations on a small land area.

Animal house factory

What is the difference between animal house and any factory?????????

Figure 1. Fate and Transport of Air EmissionsAssociated with Animal Feeding Operations

Source: The University of Iowa and The University of Iowa Study Group, Iowa Concentrated Animal Feeding

Operations Air Quality Study, Final Report, 2002, p. 87.

• Ammonia is a colorless gas with a pungent odor that is noticeable at concentrations above 50 ppm.

• It is poisonous if inhaled in great quantities and is irritating to the eyes, nose, and throat in lesser amounts.

• It is highly soluble in water, with one volume of water absorbing 1.148 volumes of ammonia The danger associated with ammonia is that it is explosive when mixed with air in certain

• proportions, approximately one volume of ammonia to two volumes of air, and is much more so when

• mixed with oxygen.

Ammonia

Character of ammonia

the fertilizer manufacture industry coke manufacture fossil fuel combustion livestock management refrigeration methods.

INDUSTRIES EMITTING AMMONIA

Include:-

Ammonia from livestock

Ammonia is produced as a by-product of the microbial decomposition of the organic nitrogen compounds in manure.Nitrogen occurs as both unabsorbed nutrients in manure and as either urea (mammals) or uric acid (poultry) in urine.

Urea and uric acid will hydrolyze rapidly to form ammonia and will be emitted soon after excretion. The formation of ammonia will continue with the microbial breakdown of manure under both aerobic and anaerobic conditions.

Because ammonia is highly soluble in water, ammonia will accumulate in manures handled as liquids and semi-solids or slurries, but will volatize rapidly with drying from manures handled as solids.

Therefore, the potential for ammonia volatilization exists wherever manure is present, and ammonia will be emitted from confinement buildings, open lots, stockpiles, anaerobic lagoons, and land application from both wet and dry handling system

Most of the ammonia emitted is generated from livestock waste management and fertilizer production, comprising about 90% of total ammonia emissions.

The volatilization of ammonia from any AFO operation depends on:-

- Total ammonia concentration, - Temperature - pH - Storage time.

the primary impact of aerial ammonia is as an irritant of the eye and respiratory membranes; and as a chronic stressor that can affect the course of infectious disease as well as directly influence the growth of healthy young animals

Ammonia - Livestock Health Effects

At both 100 and 150 ppm aerial ammonia, rate of gain was reduced by 30% andtracheal epithelium and nasal turbinate showed lesions consistent with a tissue irritant

It has recently been recommended that the maximum long-term ammonia exposure limit for swine should be less than 20 ppm.

In pigs

Ammonia concentrations within cattle facilities varied greatly from 80 to 2001 mg/h per animal depending on:1- Type of housing (concrete floors vs slatted flooring, ventilated vs closed)2- Bedding 3- Age of animals4- Environmental conditions 5- Waste storage system employed6- Frequency of cleaning 7- Ration

Cattle

The most significant air pollutant in cattle barns as its irritating effect on the respiratory epithelium appears to directly reduce the number of ciliated cells and thus decrease the efficiency of mucociliary transport

At concentrations less than 100 ppm and in a poorly ventilated facility, ammonia appears to affect pulmonary function in cattle.

Five mechanisms protect the lungs from invasion of foreign materials: cellular and humoral immunity, mucociliary transport, macrophage function, cough reflex, and nasopharyngeal filtration. Of these defensive mechanisms, mucociliary transport and alveolar macrophage functions are most severely affected by ammonia and possibly hydrogen sulfide

poultry

Ammonia is considered the most harmful gas in broiler chicken housing

Ambient ammonia levels of 50 ppm for prolonged periods irritate respiratory airways and predispose chickens to respiratory infections with the added risk of secondary infections and development of lesions of keratoconjunctivitis of the eye is associated with ambient ammonia levels of 60 ppm

A reduced rate of bacterial clearance from the lungs was measured in turkeys exposed to 40 ppm aerial ammonia.Excessive mucous production, matted cilia, and deterioration of normal mucociliary apparatus was found in turkeys exposed to ammonia concentrations as low as 10 ppm for 7weeks .

The human health effects of inhalation of ammonia

Ammonia has a strong, sharp, characteristic odor that many people find objectionable.The odor is generally detectable at concentrations greater than 50 ppm, so harmful exposures are likely to be detected early enough for the exposed person to take evasive action.

Ammonia emissions decrease the nutrient value of manure and represent a significant loss of fertilizer value. The emissions have a

negative effect on the environment such as soil acidification and eutrophication of surface water (water is nutrient-rich, supporting

plant life that kills animal life by depriving it of oxygen).

Ammonia that is lost to the atmosphere combines with nitric acid to form aerosol nitrate, which contributes significantly to total particulate

matter. These particles have serious effects on human health and cause air quality impairment.

Ammonia poses a threat to both animals and agricultural workers in livestock facilities. It is a significant respiratory hazard for workers

who experience continuous, long-term exposure to the gas at concentrations greater than 25 parts per million (ppm). In addition to respiratory effects, ammonia can cause skin and eye irritation and

displace oxygen in the bloodstream. Long-term exposure to ammonia can cause pneumonia

Why Control Ammonia Emissions?

Several approaches have been suggested and evaluated for reducing ammonia emissions from excreted animal manure; reductionof nitrogen excretion through dietary manipulation, reduction of volatile ammonia in the manure to stop ammonia loss, andsegregation of urine from feces to reduce or stop contact of urease and urine. When urine-feces segregation is not an option,urease inhibitors can be used to reduce or eliminate the hydrolysis of urea into ammonia. Methods for reducing volatile ammoniain manure include the reduction of pH, which shifts the equilibrium balance in favor of ammonium over ammonia, use of otherchemical additives that bind ammonium-N, and use of biological nitrification-denitrification to convert ammonium into other Nspeciessuch as nitrite, nitrate, or gaseous nitrogen. Other methods for mitigating ammonia emissions target emitting surfaces, andinclude capturing (using physical covers) and treating captured air to remove ammonia (using biofilters or biocovers, andscrubbers), and direct manure injection or incorporation into the soil. Manure collection facility designs and appropriate facilitymanagement are also essential for abating ammonia emissions.