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AIR PURIFICATION

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INTRODUCTION:Ensuring air quality is a daunting task, particularly in rapidly developing areas, where growing manufacturing and mining output, rising urban populations and the construction of numerous new power plants and waste incinerators take a toll. 405/03/23

INTRODUCTION(cont)The occurrence of airborne infectious agents, such as severe acute respiratory syndrome (SARS) provide a fresh warning that these pandemic threats continue to flourish.

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INTRODUCTION(cont)Filtration technologies, which eliminate the airborne spread of infectious agents, are an area of significant interest for public safety. 605/03/23

INTRODUCTION(cont)They are frequently being implemented in homes, businesses, communities and transportation systems to reduce the health risks associated with naturally occurring, as well as man-made chemical pollutants that originate with a range of consumer products.

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Objectives:At the end of this course the students should be able to:-

1.Define air purification.2.Mention five major agents,

which are responsible for air purification.

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Objectives(cont)3.Explain how five major

agents can purify air.4.Describe air purification in

sterile product manufacturing room under the following sub-heading:-

Laminar air flow Radiation

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Definition:

Air purification is a process of cleansing the air from impurities and microorganisms.

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Agents purifying the Air

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:

Rain:

As it falls, washes air free from many of the suspended impurities. It carries airborne particulates to the ground. It also removes much of the chemical impurities that may be present, including gases such as oxides of sulphur, oxides of Nitrogen, etc which dissolve in water.

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2.WindTends to produce uniformity of composition, and diffuse of air produce a similar results.

Dilutes and sweeps away the impurities and get replaced by pure air

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3.Plants

Plants, as has already been explained, remove co2 from the air during the day

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4. Oxygen and Ozone:Ozone (O3,), or trioxide, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope (O2).

4. Oxygen and Ozone(cont) Ozone in the lower atmosphere is an

air pollutant with harmful effects on the respiratory systems of animals and will burn sensitive plants; however, the ozone layer in the upper atmosphere is beneficial, preventing potentially damaging electromagnetic radiation from reaching the Earth's surface.Ozone is present in low concentrations throughout the Earth's atmosphere

4. Oxygen and Ozone(cont)Ozone is a powerful oxidizing agent, far stronger than O2. It is also unstable at high concentrations, decaying to ordinary diatomic oxygen

Oxygen and Ozone:

Ozone oxidizes airborne pollutants, then reverts to oxygen, leaving behind cleansed and refreshened air.

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Ultraviolet light

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IntroductionUltraviolet (UV) light is a range of light invisible to human eyes. While it cannot be seen, UV light is useful to humans in a wide range of areas. Astronomers measure UV light to study stars and planets. Medical doctors use UV light to identify and treat ailments.

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Introduction(cont)Geologists use UV light to identify gems. Ephemera collectors use UV to identify fake collectibles. Police detectives use UV in criminal investigations. Civil engineers use UV to purify water and air.

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What is ultraviolet light?Ultraviolet, or UV for short, is a form of light that is invisible to humans. UV makes up a small section on the entire spectrum of light. As shown below, the entire light spectrum also includes infrared light, X-rays, gamma rays and the visible light we see.

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What is ultraviolet light?(cont)

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What is ultraviolet light?(cont)Light is commonly categorized by its wavelength. The light to the left on the above spectrum has the longest wavelength, while the light on the right side has the shortest. Ultraviolet light is just to the left of the color violet in the visual light spectrum.

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What is ultraviolet light?(cont)

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What is ultraviolet light?(contUltraviolet literally translates to beyond violet, with ultra being Latin for beyond or past. Infrared, just on the other side of the visible light, means beyond or past red, with infra meaning the same as ultra.

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What is ultraviolet light?(cont)Humans can only see visible light and its colors violet to red. Human can't see any of the other type of light. The visible colors have different wavelengths from each other.

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The different categories of UVlight, including black light 

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The different categories of UVlight, including black light(cont)Ultraviolet light itself is commonly divided into categories. As with all light, the sections are defined by the wavelength.

The most common categories you will see are UVA (also known as long wave UV and black light), UVB (mid-wave UV) and UVC ( shortwave UV and germicidal light).

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The different categories of UVlight, including black light(cont)Common names:

UVA = long wave UV = black lightUVB = mid wave UVUVC = short wave UV = germicidal light

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Measuring and representing ultraviolet light: wavelengths.

Light is represented and measured in different ways. The most common way is to represent it is as waves. Length of the wave is measured from crest to crest, though you can also measure it bottom to bottom.

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Measuring and representing ultraviolet light: wavelengths(cont)

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Measuring and representing ultraviolet light: wavelengths(cont)Wavelength is commonly measured in nanometers (abbreviated as nm). A nanometer is one billionth of a meter, or one millionth of a millimeter. One will occasionally find light represented in Angstroms (A), which is one tenth (1/10th) of a nanometer

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Measuring and representing ultraviolet light: wavelengths(cont)An easy conversion.1 nanometer = 10 Angstroms1 Angstrom = 0.1 nanometer

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Measuring and representing ultraviolet light: wavelengths(cont)The following are the wavelengths in

nanometers for UVA, UVB and UVC:UVA (long wave, black light)

= 320 to 400 nmUVB (mid-wave)= 280-315nmUVC (shortwave, germicidal) = 200-280 nm

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5.Ultraviolet light (cont)There are 3 different types of UV light

UVA (315-400nm) is commonly known as "black light". This is fairly safe UV light. UVB (280-315nm) is dangerous with overdose and will cause the skin to burn and blister. UVC (100-280nm) is very dangerous and is mostly blocked from the sun by the earth's atmosphere . 3605/03/23

5.Ultraviolet light (cont)Germicidal lamps are designed to emit UVC radiation because of its ability to kill bacteria. In humans, UVC is absorbed in the outer dead layers of the epidermis

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Agents purifying the Air:Accidental overexposure to UVC can cause corneal burns, commonly termed welders' flash, and snow blindness, a severe sunburn to the face.

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Agents purifying the Air:UVB is typically the most destructive form of UV radiation because it has enough energy to cause photochemical damage to cellular DNA, yet not enough to be completely absorbed by the atmosphere.

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5.Ultraviolet light (cont)UVB is needed by humans for

synthesis of vitamin D; however, harmful effects can include erythema (sunburn), cataracts, and development of skin cancer.

Individuals working outdoors are at the greatest risk of UVB effects. Most solar UVB is blocked by ozone in the atmosphere, and there is concern that reductions in atmospheric ozone could increase the prevalence of skin cancer.4005/03/23

5.Ultraviolet light (cont)UVA is the most commonly encountered

type of UV light. UVA exposure has an initial pigment-darkening effect (tanning) followed by erythema if the exposure is excessive. Atmospheric ozone absorbs very little of this part of the UV spectrum. UVA is needed by humans for synthesis of vitamin D; however, overexposure to UVA has been associated with toughening of the skin, suppression of the immune system, and cataract formation. UVA light is often called black light. Most phototherapy and tanning booths use UVA lamps.

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5.Ultraviolet light (cont). The cleansing mechanism of UV is a

photochemical process. The contaminants that pollute the indoor environment are almost entirely based upon organic or carbon-based compounds. These compounds broken down when exposed to high-intensity UV at 240 to 280 nm. Short-wave ultraviolet light can destroy DNA in living microorganisms and break down organic material found in indoor air. UVC's effectiveness is directly related to intensity and exposure time.

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5.Ultraviolet light (cont) The particular wavelength of light

used is absorbed by DNA. The light causes mutations in the DNA.

Since the DNA encodes what proteins organisms make, organisms damaged by UV light are unable to continue to make the proteins which keep them alive and allow them to reproduce. 4305/03/23

5.Ultraviolet light (cont)Bacteria and fungi are single-celled

organisms, so they have nothing but a thin cell membrane separating them from the ultraviolet, and the waves pass easily through.

Viruses are even more vulnerable, since they don't have cell membranes. The ultraviolet light will not necessarily kill the bugs outright, but it will weaken them and render them unable to cause harm or survive for long.

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5.Ultraviolet light (cont)Limits of UV LightUltraviolet light is only able to harm bugs that it contacts. Even a small crack can hide spores in its shadow, keeping them safe from the UV. High-intensity ultraviolet lights are also harmful to people, so you can't use UV in your living space.

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Sterilization by radiation:Ionizing radiations include gamma and x-rays. In a sufficient dose, these radiations are lethal to all cells, including bacterial spores, which are generally more resistant than vegetative cells. 4605/03/23

Sterilization by radiation(cont)

Bacterial species differ in their sensitivity to ionizing radiations and the degree of resistance varies during the growth cycle..

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Sterilization by radiation(cont)

It is used for the commercial sterilization of large amounts of pre-packed single use items such as plastic syringe and catheters

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Sterilization by radiation(cont)gamma raysgamma rays have electromagnetic radiation of wavelengths shorter than X-rays,. Gamma rays used in nuclear medicine have higher energy than diagnostic X-rays and greater penetration; higher doses are used in radiotherapy..4905/03/23

Sterilization by radiation(cont)The powerful nature of gamma rays has made them useful in the sterilization of medical equipment by killing bacteria. They are also used to kill bacteria and insects in foodstuffs, particularly meat, marshmallows, pies, eggs, and vegetables, to maintain freshness.

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Sterilization by radiation(cont)The gamma radiation can reach inside even the most complex shapes and it doesn't expose delicate equipment to high temperatures.  There's also no need to rinse off chemicals afterwards.

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Sterilization by radiation(cont)Due to their tissue penetrating property, gamma rays/X-rays have a wide variety of medical uses such as in CT Scans and radiation therapy (see X-ray). However, as a form of ionizing radiation they have the ability to effect molecular changes, giving them the potential to cause cancer when DNA is affected

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Air purification in a sterile product manufacturing room

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Air purification in a sterile product manufacturing room(cont)The aseptic technique is achieved when the source of contamination is well known in mind, which includes air or atmosphere, hands, clothing, hair, fingers, nails and lastly benches and equipment.

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Air purification in a sterile product manufacturing room(cont)The term aseptic will be used to indicate a controlled process OR condition in which the level of microbial contamination is reduced to the designed that microorganisms can be excluded from the product during processing.

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Air purification in a sterile product manufacturing room:Sterilization (or sterilization,) is a term

referring to any process that eliminates (removes) or kills all forms of life, including transmissible agents (such as fungi, bacteria, viruses, spore forms, etc.) present on a surface, contained in a fluid, in medication, or in a compound such as biological culture media. Sterilization can be achieved by applying the proper combinations of heat, chemicals, irradiation, high pressure, and filtration. 5605/03/23

Laminar air flow car binate OR chamber

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DefinitionA system of circulating filtered air in parallel-flowing planes in hospitals or other health care facilities. The system reduces the risk of airborne contamination and exposure to chemical pollutants in surgical theaters, food preparation areas, hospital pharmacies, and laboratories.

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Laminar air flow car binate:

A laminar air flow cabinet or laminar flow closet or tissue culture hood is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples, or any particle sensitive device. Air is drawn through a HEPA filter and blown in a very smooth, laminar flow towards the user..

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Laminar air flow car binate(cont)

The cabinet is usually made of stainless steel with no gaps or joints where spores might collect.Such hoods exist in both horizontal and vertical configurations, and there are many different types of cabinets with a variety of airflow patterns and acceptable uses.

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Laminar air flow car binate(cont)

Lamina air flow cabinets may have a UV-C germicidal lamp to sterilize the shell and contents when not in use. (It is important to switch this light off during use, as it will quickly give any exposed skin sunburn and may cause cataracts.) 6105/03/23

Laminar air flow car binate(cont)

The most important  part of a laminar flow hood  is a high efficiency bacteria-retentive filter.    Room air is taken into the unit and passed through a pre-filter to remove gross contaminants (lint, dust etc). 6205/03/23

Laminar air flow car binate(cont)

The air is then compressed and channeled up behind and through the HEPA filter (High Efficiency Particulate Air filter) in a laminar flow fashion--that is the purified air flows out over the entire work surface in parallel lines at a uniform velocity. The HEPA filter removes nearly all of the bacteria from the air.

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Laminar air flow car binate(cont)

Why control room air? The environmental control of air is of concern because room air may be highly contaminated. Example: Sneezing produces 100,000 - 200,000 aerosol droplets which can then attach to dust particles. These contaminated particles may be present in the air for weeks.

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Laminar airflow chamber

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Laminar airflow chamber

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Laminar airflow chamber

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Ahsanteni sanaBwana awabariki

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