Page 72 - Annual Report_21-22

Bio-aerosol design of chamber experiment for the evaluation of facemask filtration efficiency

During the COVID-19 pandemic period, chamber then N95 (both with or without valves) or KN95 masks are
experiment designed and conducted to evaluate the recommended. Surgical masks and heavy knitted cotton
facemask filtration efficiency (Fig.1). From the study if the masks may also be used for this purpose, but with caution
primary objective is to filter particles between 0.5 – 1 µm,

The Times of India, Dt. 06/07/2021

Fig:1 Experimental setup for evaluating the filtration efficiency of commercial facemasks’ materials. The double-sided
tapes were fixed along the annotated dotted lines on the mask with facemasks considered for the study.

Land campaign study to understand the characteristics (chemical, morphological and biological)
of wintertime PM2.5

Gravimetric measurement of mean PM varied between sites, respectively. Chemical characterization and Positive
2.5
101 - 142 µg/m at different locations, in Bhubaneswar Matrix Factorization (PMF) indicated the four most
3
city, was approximately 65 - 135 % higher than the 24 h probable sources of PM with major contributions from
2.5
average NAAQ (National Ambient Air Quality) standards. vehicular emissions (32%), followed by industrial (26%),
Spectrometric measurements of PM and PM depicted combustion (coal, oil, and biomass burning at 22%), and
2.5
1.0
a typical diurnal pattern with distinct morning/evening crustal sources (20%). Minor contributions from fertilizer
peaks, confirming similar source contribution and a higher industries, brick kilns, natural dust, and sea salt are also
accumulation mode particle over the traffic location. For evinced from the PMF analysis. Single particle analysis
example, 85.7, 79.1, 80.6, and 84.8% of PM contributed with an electron microscope revealed four different types
1.0
to PM at reference, residential, industrial, and traffic of particles (i.e., soot or carbonaceous particles,
2.5
70 ANNUAL REPORT 2021-22