Environment technology

ⅰ. Rapid monitoring of infectious bioaerosols

Airborne infectious viruses (Coronavirus and influenza viruses) entering the electrostatic air sampler are charged by the air ions and collected on the continuously flowing liquid (aerosol-to-hydrosol (ATH) sampling).
The ATH-collected viruses were simultaneously delivered to a fluidicchannel for hydrosol-to-hydrosol (HTH) enrichment.
The injected viruses adsorbed onto the concanavalin A (ConA) coated magnetic particles (CMPs) installed on the inner wall of the channel for enrichment.
After the enrichment, fresh liquid wasinjected into the channel to flush out the enriched viruses for analysis

ⅱ. Rapid monitoring of infectious bioaerosols

Bioaerosols were charged by the air ions and sampled in a flowing liquid containing both a cell lysis buffer and adenosine triphosphate (ATP) bioluminescence reagents.
While the liquid was delivered to the bioluminescence detector, sampled bioaerosols were dissolved by the cell lysis buffer and ATP was extracted
The ATP was reacted with the ATP bioluminescence reagents, causing light to be emitted.
When the concentration of bacteria in the aerosols was varied, theATP bioluminescence signal in relative light units (RLUs) closely tracked the concentration in particles per unit air volume (#/cm3), as measured by an aerodynamic particle sizer (APS).
In the field test with indoor bioaerosols, it was found that the variation of the bioluminescence signal closely followed the variation in CFU concentration and 1 RLU corresponded to 1.66 CFU/m3 of indoor bioaerosols.

PN₁ (Particle Number less than 1µm) sensor was designed and fabricated for real-time measurement of indoor air quality.
The sensor comprised a particle-classification unit(virtual impactor), a particle-charging unit (corona charger), and a particle-detection unit (aerosol electrometer).

For measurement of number based size distribution of PM(Particulate Matter) 5, an electrical cascade impactor (ECI) is designed and fabricated.
The ECI is composed of particle charging part (corona charger), particle classification part (cascade impactor), and particle sensing part (Electrometer).
The 11-stage electrical cascade impactor was applied to measure the size distribution of PM2.5 in real-time.

Dielectric barrier discharge (DBD): non-thermal plasma discharge generated by high AC voltage applied between two electrodes with dielectric barrier.
DBD has higher energy density than corona discharge.
DBD is widely used in various gas purification processes (VOC removal, NOx/SOx removal, PM removal, O₃ generation)

Water solubility of gas is an important factor for high scrubbing efficiency.
NOx consists of NO (not soluble to water) and NO₂ (soluble to water).
In general, 95% of NOx is emitted as NO.
→ Portion of NO₂ should be increased for NOx scrubbing.
DBD ozonizing methodwas proposed to increase portion of NO₂. (NO + O₃→ NO₂ + O₂)
With this process, simultaneous removal of NOx and SO₂ is possible in wet scrubber.

DBD reactor can be used as electrostatic precipitator.
At the low frequency (60Hz) AC power operation, DBD plasma can collect particles by particle charging and electrostatic force.
Collected particles can be removed from electrode by applying high frequency AC power to Dielectric barrier discharge.
At high frequency, collected particles are decomposed to gas species (CO₂, CxHy, ...) by highly energetic ions and electrons in the plasma.