Mumps incidence linked to weather and air pollution in Chongqing study

The relationships were nonlinear and delayed, and only the combination of mean temperature and carbon monoxide showed a statistically significant synergistic interaction. Researchers combined geodetectors, distributed lag nonlinear models and bivariate response models to assess the independent and interactive relationships between these factors and reported cases in Chongqing, a mountainous city in Southwest China with a dense population. Temperature was associated with an initial increase and subsequent decrease in incidence risk as temperature rose.

Relative humidity had an approximately U-shaped association with incidence. The pollutant exposure–response curves also differed from one another: sulfur dioxide and nitrogen dioxide had S-shaped relationships, while carbon monoxide showed a continuously rising association with incidence. All five environmental factors had statistically significant lagged effects within particular lag windows, indicating that their modeled relationships with reported cases were not confined to the same day.

Seven meteorology–pollutant pairs were evaluated for interaction. Only the mean-temperature–carbon-monoxide combination showed statistically significant synergy. Its relative excess risk due to interaction was 0.237, with a 95% confidence interval of 0.032 to 0.477, while its attributable proportion due to interaction was 0.232, with a 95% confidence interval of 0.039 to 0.39.

The other five tested pairs did not have statistically significant interactions. These model estimates indicate a joint association beyond the additive combination of the two factors in the analyzed data; they do not establish that temperature or carbon monoxide caused mumps infections or that either factor directly increased an individual’s risk.

Subject of Research: Environmental associations with reported mumps incidence in Chongqing, 2015–2024

Article Title: Interactive effects of meteorological factors and air pollutants on mumps incidence in Southwest China, 2015–2024

Article References: Yang, C., Yang, L., Wang, N., Yang, S., Tang, X., & Qi, L. (2026). Interactive effects of meteorological factors and air pollutants on mumps incidence in Southwest China, 2015–2024. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14314-2

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14314-2

Keywords: mumps, Chongqing, air pollution, carbon monoxide, temperature, relative humidity, infectious disease, environmental epidemiology, time-series analysis, Interactive, effects, meteorological