Cool but dangerous: How climate change is increasing the risk of airborne infections

Abstract

Cool but dangerous: How climate change is increasing the risk of airborne infectionsLess obvious but more certain and immediate than future droughts and floods, the escalating use of air conditioning (AC) globally is directly resulting in conditions favoring increased person-to-person transmission of airborne infections such as tuberculosis (TB), influenza (flu), and measles. Unlike the gradual environmental effects of increased CO 2 emissions, the impact of AC on airborne infection is nearly instantaneous. This is because for efficient AC use, windows and doors must be closed, immediately eliminating the natural ventilation upon which much of the world depend for diluting and disinfecting room air. Moreover, the most common, highly efficient AC models are ductless or split units, that is, they quietly cool and F I G U R E 2 An example of a Germicidal UV fixture above the window used together with low-velocity ceiling fan for mixing upper and lower room air Low-velocity ceiling fan Upper room GUV fixture

UV-LED disinfection of Coronavirus: Wavelength effect

“…Incident irradiance (fluence) was measured for each well separately using Ocean Optics USB4000 spectroradiometer with fiber core diameter of 600 μm (QP600-2-VIS-NIR), the small footprint of the fiber optic end allowing accurate measurements. To this end, a printout of the 24-well plate was placed under the UV LED system and the spectroradiometer optic fiber end was placed on the geometric center of the measured well on the printout, perpendicular to the surface and facing the UV LEDs [ 2 ]. Height was adjusted to confirm that the fiber end was in the same distance from the UV LED as was the plate bottom in the irradiation experiments.…”

“…SARS-CoV-2, the causal agent of COVID-19, is not only contagious through respiratory droplets, but can also spread through nasal, oral and eye mucus-contaminated surfaces [ 1 ]. Moreover, it has recently been suggested that SARS-CoV-2 could be airborne [ 2 ], although clear evidence for such transmission has not yet been presented. Furthermore, SARS-CoV-2's ability to survive in aerosols for at least 3 h and up to 72 h on plastic surfaces was recently demonstrated [ 3 ], suggesting long-term infection risk from such.…”

Air Disinfection for Airborne Infection Control with a Focus on COVID‐19: Why Germicidal UV is Essential†

“…The most common and growing type of air conditioning, ductless or split systems, provide no outside air ventilation. The result of closing windows and turning on ductless air conditioning is a steep rise in rebreathed air fraction (RAF)—that fraction of a breath recently exhaled by others—a good correlate of risk of airborne infection (19). RAF is reasonably well estimated by ambient CO 2 levels (20).…”

“…RAF is reasonably well estimated by ambient CO 2 levels (20). A recent demonstration showed a doubling of RAF and risk of infection within an hour of closing a window and turning on the split system AC (19).…”

Mechanism of transient photothermal inactivation of bacteria using a wavelength-tunable nanosecond pulsed laser

“…The recent pandemic of SARS-CoV-2, the causal agent of COVID-19, is not only contagious through respiratory droplets but can also spread through nasal, oral and eye mucus-contaminated surfaces 1 . Moreover, it has recently been suggested that SARS-CoV-2 could be airborne 2 , although clear evidence for such transmission has not yet been presented. Furthermore, SARS-CoV-2's ability to survive in aerosols for at least 3 h and up to 72 h on plastic surfaces was recently demonstrated 3 , suggesting long-term infection risks.…”