Synergistic Effect of Ambient Ozone, Relative Humidity, and Temperature on Epidemic Patterns of Influenza: A Hypothesis and Its Verification
5 affiliations
- 1Virus Research Center, Clinical Research Division, Sendai Medical Center National Hospital Organization Sendai Japan
- 2Mediair Japan Inc. Yokohama Japan
- 3Department of Clinical Microbiology University Hospitals of Leicester NHS Trust Leicester UK
- 4Respiratory Sciences University of Leicester Leicester UK
- 5Niterra Co. Ltd. Aichi Japan
Abstract
The mechanisms underlying seasonal patterns in influenza epidemics have long been an enigma. Our laboratory study revealed that ambient ozone significantly inactivates airborne influenza viruses synergistically with higher relative humidity and temperature. This led us to hypothesize that natural seasonal fluctuations in these ambient factors enhance or mitigate the influenza‐transmission risk by altering the efficiency of airborne virus inactivation, thereby contributing to the continuation or subsiding of influenza epidemics. To test the hypothesis, we examined datasets covering 5 years of annual environmental ozone concentrations, relative humidity, and temperature, and reported influenza case numbers in two cities in Japan, Sendai and Naha, which exhibit typical temperate and subtropical climate patterns, respectively; based on the findings of our previous study and actual ambient environmental data, we estimated the influenza airborne‐transmission risk in these cities and compared it with observed epidemics. In both cities, the persistence of winter epidemics was strongly associated with low ozone concentration (< 35 ppb), and their subsiding in spring was associated with increases in ozone (≧ 35 ppb) and relative humidity (≧ 50%), even at lower temperature (< 20°C). The summer outbreak in Naha was not suppressed solely under high temperatures (25°C–30°C) and relative humidity (≧ 70%), but was associated with a subsequent increase in ozone (≧ 35 ppb). A similar phenomenon was recognized during the 2009 influenza pandemic. These results were consistent with our hypothesis: influenza epidemic patterns corresponded with the influenza transmission risk estimated from the synergistic inactivation patterns of airborne viruses by ambient ozone, relative humidity, and temperature.
Related
- Impact of low temperature on the efficacy of chlorous acid water and sodium hypochlorite solution for inactivating avian influenza virus on material surfaces
- Corrections to: Color as a gate to verification: Super-additive costs in oculomotor disengagement.
- Reproductive Biology, Pollination Optimization, and Hybrid Verification of Acacia mangium × A. auriculiformis
- Potential mechanisms of Bifidobacterium-mediated synergistic antibiotic eradication of drug-resistant Helicobacter pylori
- Enhancing physiological performance and antioxidant defense in Mexican lime (Citrus aurantifolia) under water-deficit: synergistic effects of PGPB and KNO₃ application
BibTeX
@article{nishimura2026synergistic,
title = {{Synergistic Effect of Ambient Ozone, Relative Humidity, and Temperature on Epidemic Patterns of Influenza: A Hypothesis and Its Verification}},
author = {Hidekazu Nishimura and Soichiro Sakata and Julian W. Tang and Suguru Ohmiya and Masanori Katsumi and Takahiro Yokoyama},
journal = {Microbiology and Immunology},
year = {2026},
month = sep,
doi = {10.1111/1348-0421.70089},
url = {https://doi.org/10.1111/1348-0421.70089},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Synergistic Effect of Ambient Ozone, Relative Humidity, and Temperature on Epidemic Patterns of Influenza: A Hypothesis and Its Verification
AU - Hidekazu Nishimura
AU - Soichiro Sakata
AU - Julian W. Tang
AU - Suguru Ohmiya
AU - Masanori Katsumi
AU - Takahiro Yokoyama
PY - 2026
DA - 2026/09/16
JO - Microbiology and Immunology
DO - 10.1111/1348-0421.70089
UR - https://doi.org/10.1111/1348-0421.70089
AB - The mechanisms underlying seasonal patterns in influenza epidemics have long been an enigma. Our laboratory study revealed that ambient ozone significantly inactivates airborne influenza viruses synergistically with higher relative humidity and temperature. This led us to hypothesize that natural seasonal fluctuations in these ambient factors enhance or mitigate the influenza‐transmission risk by altering the efficiency of airborne virus inactivation, thereby contributing to the continuation or subsiding of influenza epidemics. To test the hypothesis, we examined datasets covering 5 years of annual environmental ozone concentrations, relative humidity, and temperature, and reported influenza case numbers in two cities in Japan, Sendai and Naha, which exhibit typical temperate and subtropical climate patterns, respectively; based on the findings of our previous study and actual ambient environmental data, we estimated the influenza airborne‐transmission risk in these cities and compared it with observed epidemics. In both cities, the persistence of winter epidemics was strongly associated with low ozone concentration (< 35 ppb), and their subsiding in spring was associated with increases in ozone (≧ 35 ppb) and relative humidity (≧ 50%), even at lower temperature (< 20°C). The summer outbreak in Naha was not suppressed solely under high temperatures (25°C–30°C) and relative humidity (≧ 70%), but was associated with a subsequent increase in ozone (≧ 35 ppb). A similar phenomenon was recognized during the 2009 influenza pandemic. These results were consistent with our hypothesis: influenza epidemic patterns corresponded with the influenza transmission risk estimated from the synergistic inactivation patterns of airborne viruses by ambient ozone, relative humidity, and temperature.
SN - 0385-5600
SN - 1348-0421
ER -