My Aim is to put a air filter for normal mask or respirator to kill COVID-19 Using UVC LED

UVC is effectively used in germicidal irradiation and in market low cost UV-C tubes from Philips are already prevalent

So here i wish to do a calculation for my understanding , how can we reduce the size of UV filters from bulky[4] to a standard BV Filter size[3]

Lets move to Calculations, taken from chapter of air stream disinfection of UVGI Handbook

Step 1 : Exposure time = Volume / Airflow

For simplicity let me consider a cuboid of L = 5cm, B = 5cm and H = 15cm, Volume = 375 cm3

Air flow is the flow of Air from Human Lung, Most Bacterial or viral filters with a maximum tidal volume to 100L/min [5] considering this airflow multiplied by 1000 gives me the airflow in cubic cm per second as 1666.66 cm3/s

From this Exposure time is 0.225 seconds

Step 2 : Calculation of Irradiance

RR = 1- exp(- k * Im * Et)

RR is removal rate, k is rate constant, Im is irradiance , Et is exposure time

I took k = 0.03433 from [2] and RR as 0.9, as k given in reference is for D90

From this Irradiance comes to 29.8 mW/cm2

I agree that the k given in [2] is for surfaces, in air it may be very less ! ?

Kindly comment on this approach of taking air sterilizers as small as possible

Step 3 : Selection of UVC LED

A Study from laser components [6] says at 0.1mts they can deliver 11mW/cm2 using a 5x5 LED Array which will be bulkly any how, but need to calculate the same for single LEDS placed in four planes of the BV filter

i am not sure about irradiance by LED alone from laser components , so will update soon.

References:

1. UVGI Handbook Kowalski (The Guru of UVGI)

2. Technical Report 2020 COVID-19 Coronavirus Ultraviolet Susceptibility

3. https://github.com/jcl5m1/ventilator/wiki/Bacterial-Viral-Filter-for-CPAP-Machines

4. https://patents.google.com/patent/US20150297858A1/en?assignee=Medi-Immune&oq=Medi-Immune

5. https://www.medtronic.com/content/dam/covidien/library/us/en/product/ventilator-filters/dar-sales-sheet.pdf

6.