tetano
Editor, Senior Moderator
Environ Sci Technol
. 2024 Oct 11.
doi: 10.1021/acs.est.4c04734. Online ahead of print. Salt Supersaturation as an Accelerator of Influenza A Virus Inactivation in 1 μL Droplets
Aline Schaub[SUP] 1 [/SUP], Beiping Luo[SUP] 2 [/SUP], Shannon C David[SUP] 1 [/SUP], Irina Glas[SUP] 3 [/SUP], Liviana K Klein[SUP] 2 [/SUP], Laura Costa[SUP] 1 4 [/SUP], Céline Terrettaz[SUP] 1 4 [/SUP], Nir Bluvshtein[SUP] 2 [/SUP], Ghislain Motos[SUP] 4 [/SUP], Kalliopi Violaki[SUP] 4 [/SUP], Marie O Pohl[SUP] 3 [/SUP], Walter Hugentobler[SUP] 4 [/SUP], Athanasios Nenes[SUP] 4 5 [/SUP], Silke Stertz[SUP] 3 [/SUP], Ulrich K Krieger[SUP] 2 [/SUP], Thomas Peter[SUP] 2 [/SUP], Tamar Kohn[SUP] 1 [/SUP]
Affiliations
Influenza A virus (IAV) spreads through exhaled aerosol particles and larger droplets. Estimating the stability of IAV is challenging and depends on factors such as the respiratory matrix and drying kinetics. Here, we combine kinetic experiments on millimeter-sized saline droplets with a biophysical aerosol model to quantify the impact of NaCl on IAV stability. We show that IAV inactivation is determined by NaCl concentration, which increases during water evaporation and then decreases again when efflorescence occurs. When drying in air with relative humidity RH = 30%, inactivation follows an inverted sigmoidal curve, with inactivation occurring most rapidly when the NaCl concentration exceeds 20 mol/(kg H[SUB]2[/SUB]O) immediately prior to efflorescence. Efflorescence reduces the NaCl molality to saturated conditions, resulting in a significantly reduced inactivation rate. We demonstrate that the inactivation rate k depends exponentially on NaCl molality, and after the solution reaches equilibrium, the inactivation proceeds at a first-order rate. Introducing sucrose, an organic cosolute, attenuates IAV inactivation via two mechanisms: first by decreasing the NaCl molality during the drying phase and second by a protective effect against the NaCl-induced inactivation. For both pure saline and sucrose-containing droplets, our biophysical model ResAM accurately simulates the inactivation when NaCl molality is used as the only inactivating factor. This study highlights the role of NaCl molality in IAV inactivation and provides a mechanistic basis for the observed inactivation rates.
Keywords: airborne transmission; expiratory droplet; influenza A virus; respiratory organics; salinity.
. 2024 Oct 11.
doi: 10.1021/acs.est.4c04734. Online ahead of print. Salt Supersaturation as an Accelerator of Influenza A Virus Inactivation in 1 μL Droplets
Aline Schaub[SUP] 1 [/SUP], Beiping Luo[SUP] 2 [/SUP], Shannon C David[SUP] 1 [/SUP], Irina Glas[SUP] 3 [/SUP], Liviana K Klein[SUP] 2 [/SUP], Laura Costa[SUP] 1 4 [/SUP], Céline Terrettaz[SUP] 1 4 [/SUP], Nir Bluvshtein[SUP] 2 [/SUP], Ghislain Motos[SUP] 4 [/SUP], Kalliopi Violaki[SUP] 4 [/SUP], Marie O Pohl[SUP] 3 [/SUP], Walter Hugentobler[SUP] 4 [/SUP], Athanasios Nenes[SUP] 4 5 [/SUP], Silke Stertz[SUP] 3 [/SUP], Ulrich K Krieger[SUP] 2 [/SUP], Thomas Peter[SUP] 2 [/SUP], Tamar Kohn[SUP] 1 [/SUP]
Affiliations
- PMID: 39392017
- DOI: 10.1021/acs.est.4c04734
Influenza A virus (IAV) spreads through exhaled aerosol particles and larger droplets. Estimating the stability of IAV is challenging and depends on factors such as the respiratory matrix and drying kinetics. Here, we combine kinetic experiments on millimeter-sized saline droplets with a biophysical aerosol model to quantify the impact of NaCl on IAV stability. We show that IAV inactivation is determined by NaCl concentration, which increases during water evaporation and then decreases again when efflorescence occurs. When drying in air with relative humidity RH = 30%, inactivation follows an inverted sigmoidal curve, with inactivation occurring most rapidly when the NaCl concentration exceeds 20 mol/(kg H[SUB]2[/SUB]O) immediately prior to efflorescence. Efflorescence reduces the NaCl molality to saturated conditions, resulting in a significantly reduced inactivation rate. We demonstrate that the inactivation rate k depends exponentially on NaCl molality, and after the solution reaches equilibrium, the inactivation proceeds at a first-order rate. Introducing sucrose, an organic cosolute, attenuates IAV inactivation via two mechanisms: first by decreasing the NaCl molality during the drying phase and second by a protective effect against the NaCl-induced inactivation. For both pure saline and sucrose-containing droplets, our biophysical model ResAM accurately simulates the inactivation when NaCl molality is used as the only inactivating factor. This study highlights the role of NaCl molality in IAV inactivation and provides a mechanistic basis for the observed inactivation rates.
Keywords: airborne transmission; expiratory droplet; influenza A virus; respiratory organics; salinity.