embodiments will now be described in detail with respect to an apparatus and method for assessing skilled professional qualities reflecting the inventors &# 39 ; present preferred embodiments and the best means for practicing the invention . those skilled in the art will recognize that the embodiments described herein are subject to modification and alteration without departing from the teaching herein . therefore , the present discussion should not be considered limiting but an exemplification of the features of the invention . in the illustrated embodiment in fig1 - 2 , an air filtration and purification unit 1 is shown . the air filtration and purification unit 1 has a shroud or housing 100 , a pre - filter 101 , a box fan assembly 102 , and a post - filter 103 . the pre - filter and post filters 101 , 103 sandwich the fan assembly 102 , and are held in place by clips , clamps , or crimping 111 . in the illustrated embodiment , filters 101 , 103 are identical . the shroud 100 surrounds the pre - filter 101 , the fan assembly 102 , and the post - filter 103 on at least three sides and further includes lips 107 on all three sides which act as stops so the filter does not fall out of place . at least one side may be open to allow for easy replacement of filters 101 , 103 . the shroud 100 may be made from metals such as stainless steel , galvanized steel , aluminum , plastics , such as polycarbonate , or any appropriate materials known in the art , whether now known or later developed . on the exterior of the shroud 100 , located on top of the unit is a fan speed selection switch 104 which may have high , medium , low , and off positions . also on top of the shroud 100 is a handle 112 for easy movement and portability of the air purification and filtration system . it is understood that the thickness of the filters will alter the dimensions of the shroud 100 and does not limit the invention , i . e . 20 × 20 × 2 inch filters , 20 × 20 × 4 inch filters . it is understood that an x - pattern grid filter holder may also be used herein with the invention . fig3 shows a cross - sectional view of an air filtration and purification unit 1 . air will flow in direction a . the filters 101 , 103 may be made from fibrous material , paper , or other known or yet to be known materials in the art . the filters 101 , 103 are pleated with individual pleats 110 . these pleats 110 are folded such that they create a 45 degree isosceles triangular pattern in a uniform pattern . a standard efficient filter is made from a merv rated material as is known in the art , and then is folded a pre - set number of times ( creating pleats ) for a given standard dimension , thereby having a set surface area and length of material used that is known in the art that will create a merv rated filter . the pleated design of the filters 101 , 103 have less pleats 110 than a standard efficient filter and therein use less surface area , but still are efficient to be rated to a minimum efficiency reporting value ( merv ) rating of 11 or better , which goes against the logic that the more pleats ( or surface area ) the better the filtration of the created filter . fig4 shows the flow of air 200 through the air filtration and purification unit 1 . the air flows through the pre - filter 101 , then through the fan assembly 102 , and thereafter through the post filter 103 . by placing the pleats 110 at angles with respect to one another , the air flow 200 splits to create a venturi effect at this first constriction . the fan assembly 102 controls the speed of the air flow 200 , and at slower fan blade speeds , the filters 101 , 103 can clean without harming the filters 101 , 103 . the filters 101 , 103 are placed at opposite ends of the fan assembly 102 . the split air flow 200 has the added advantage of reducing the noise of the air flow 200 through the filtration and purification system . in the addition , the filters 101 , 103 may by pleated in a variety of ways and will be further discussed below , and the number of pleats may be varied to slow the air flow 200 . by using the post filter 103 after the air passes through the fan 102 , the air is defused and again goes through a venturi effect as it passes through the post filter 103 , which cleans as much as 40 % more than using the pre - filter 101 only . as a result , the filters 101 , 103 last much longer and clean better . current air handling and heating , ventilation , and air conditioning ( hvac ) systems are designed for high air speed and air volume ( i . e between 2 . 5 m / s to 30 m / s dependent upon the size of the system ). the use of the pre - filter 101 and the post - filter 103 in such hvac systems would create too much drag or resistance to the air flow , and such systems would not operate correctly . accordingly , the fan assembly 102 should be selected so that it has a lower , slower air speed and volume ( e . g ., 0 . 2 m / s to 0 . 666 m / s ), which allows the system to clean the air more thoroughly and more efficiently , and preserves and prolongs the life of the filters 101 , 103 . slower air speed / volume fans are also generally less expensive and quieter , so their use in this application may well impart an economic advantage to this air filtration and purification system , as well as a quieter , more pleasant environment . moreover , slower speed fans 102 are typically smaller and weigh less than high speed , high volume fans , making the portable air filtration and purification system easier to move and position . indeed , testing has shown that use of the fan 102 to cause the air to slow down and circulate within the unit 1 allows for more particulates in the air to be captured , such that the air 200 ultimately exiting the post - filter 103 is substantially cleaner as compared to the air exiting prior art filtration systems . it is foreseen that the filters 101 , 103 may be replaced with standard high efficiency pleated filters with a merv rating of 8 or better as known in the art and this would be within the scope of the invention . it is also foreseen that they may be any combination of the filters disclosed herein and standard high efficiency pleated filters may be used . in the illustrated embodiment in fig5 - 7 , an air filtration and purification unit 2 is shown . the air filtration and purification unit 2 has a shroud or housing 300 , a pre - filter 301 , a box fan assembly 302 , and a post - filter 303 . the air filtration and purification unit 2 is substantially similar to the air filtration and purification unit 1 , with the exception of the filters 301 , 303 utilized in the embodiment . the pre - filter and post filters 301 , 303 sandwich the fan assembly 302 . the pre - filter 301 may be made from fibrous material , paper , or other known or yet to be known materials in the art . the pre - filter 301 may be dimensioned to be 20 × 30 × 2 inches or a standard filter size known in the art . the pre - filter 301 has five individual pleats 320 , 322 , 323 , 325 , 327 ( fig7 ) with the pleats facing towards the fan in the direction of the air a . the outer pleats 320 , 327 are angled from a top 329 to a bottom 330 of the shroud 300 at an angle c with respect to the horizontal between 50 and 60 degrees , preferably at 55 degrees and then folded back at an angle d with respect to the horizontal between 55 and 65 degrees , preferably at 59 . 7 degrees . the inner pleats 322 , 325 adjacent the outer pleats 320 , 327 are angled from the outer pleats 320 , 327 at an angle e with respect to the horizontal between 35 to 45 degrees , preferably at 40 . 6 degrees and then folded back at an angle f with respect to the horizontal between 45 and 55 degrees , preferably at 48 . 8 degrees . the center pleat 323 is angled from the inner pleats 322 , 325 at an angle g with respect to the horizontal between 25 and 30 degrees , preferably at 28 . 6 degrees . the non - uniform folding pleated design of the pre - filter 301 and post - filter 303 in unison outperform current known in the art standard uniform pleating designs having multitudes of pleats in the same dimension . the pleated design of the pre - filter 301 filters uses less material ( in comparison to a same dimensioned standard pleated filter ) due to the nature of the curves and also filters in the 0 . 3 μm range to be rated to a merv rating of 11 or better . the pre filter 301 is better rated than currently known in the art standard pleated using material with a merv rating of 13 - 15 that have more uniform horizontal pleats or folds ( not shown ) and use a greater surface area having the same dimensions , i . e . 20 × 20 × 2 inches . it is foreseen that the pre - filter 301 may be utilized to test different filtrations efficiencies by observing the filtration efficiency of a single pleat design at the above noted angle ranges through the air filtration and purification unit 2 . this efficiency can then be compared to a standard pleated filter having the same dimensional size . it is foreseen that the pre - filter 301 may be oriented on either side of the fan or utilized as both the pre - filter 301 and the post - filter 303 . the post - filter 303 , likewise may be made from fibrous material , paper , or other known or yet to be known materials in the art . the post - filter 303 may be dimensioned to be 20 × 20 × 2 inches or any standard filter size known in the art . the post - filter 303 has several individual pleats 310 pointed in the direction of the airflow a , and each pleat 310 is angled downwardly with respect to a horizontal , at an angle a between 25 to 35 degrees ( fig7 ) preferably at 29 . 7 degrees and then folded over itself at an angle b between 10 to 20 degrees with respect to the horizontal , preferably at 14 . 2 degrees . the pleated design of the post - filter 303 filters uses less material and therefore less surface area ( in comparison to a same dimensioned standard pleated filter ) due to the natural of the downward curves and also filters in the 0 . 3 μm range to be rated to a merv rating of 11 or better . the post filter 303 is better rated than currently known in the art standard pleated filters using materials with a merv rating of 13 - 15 that have more uniform horizontal pleats ( not shown ) and use a greater surface area . the non - uniform angular design may not be made using standard pleating machinery . the post - filter 303 may be oriented on either side of the fan or utilized as both the pre - filter 301 and the post - filter 303 . fig8 shows a cross - sectional view of another embodiment of an air filtration and purification unit 3 . the filters 401 , 403 may be made from fibrous material , paper , or other known or yet to be known materials in the art . the filters 401 , 403 may be dimensioned to be 20 × 20 × 2 inches or a standard filter size known in the art . the pre - filter 401 and the post filter 403 are identical in the illustrated embodiment . the filters 401 , 403 have several individual pleats 410 oriented in the direction of air a , and each pleat 410 is angled downwardly with respect to a horizontal h , at an angle h between 55 to 65 degrees , preferably at 60 degrees and then folded over itself at an angle j between 50 to 55 degrees with respect to the horizontal h , preferably at 52 degrees . from there the material is wrapped about rod or conduit 420 that is held in place by a bearing ( not shown ). the pleated design of the filters 401 , 403 were tested at several downwardly sloping angles that approached 90 degrees or vertical ( which will not allow any air through ), and these angles h , j were determined to filter out the most microbial particles at the 0 . 3 μm range , thereby making a merv 15 though utilizing material with merv rating of 11 . one result of such a test given by assuredbio is given below . the standard filter with a merv rating of 11 , there were 16 , 493 spores / m 3 detected inside and 14 , 841 spores / m 3 detected outside , whereas with the non - uniform angled downward pleat design filters 401 , 403 , 13 spores spores / m 3 were detected inside and 164 spores / m 3 were detected outside . the results being a magnitude difference between the two filters tested , each being the same dimension and using the same merv 11 rated material . the filters 401 , 403 use less material ( in comparison to a same dimensioned standard pleated filter ) due to the natural of the downward curves and also filter in the 0 . 3 μm range . in a 20 × 20 × 2 inch filter size , 92 inches of material is used for a conventional known in the art pleated filter and in the filters 401 , 403 at those dimensions , 82 inches of material is utilized . the filter 401 , 403 is better rated than currently known in the art standard pleated designs made of the same material that have more uniform horizontal pleats ( not shown ) and use a greater surface area . it is foreseen that the air filtration and purification system 3 may be utilize any versions of filters previously discussed or a standard conventional filter . the portable air filtration and purification system disclosed herein may be used in areas where it is most needed or desired . it thoroughly cleans the air in the area in which it is placed , is easy to move , economical , is quiet , and prolongs the life of the filters . it may also be used with or in addition to current hvac systems wherein each filter may be placed at beginning and ends of ventilation systems . it is also understood that the filters discussed herein may be utilized outside the air filtration and purification unit , in the realms of automotive engines , includes cars , boats , aircraft , as well as ventilation systems and human made environments ( satellites , space shuttles , etc .). thus , the present inventions have been described in detail with the understanding that the present detailed description is subject to modification and alterations without departing from the teaching herein . therefore , the present invention should not be limited to the precise details presented herein but should encompass the subject matter of the claims and their equivalents , which follow .