A recent study indicates that climate-related weather events, particularly fuel fires in the western U.S., may be pushing residents indoors more often, potentially facilitating the spread of infections. The research, published Wednesday, highlights how the deterioration of air quality due to wildfires has led to increased indoor activity, creating optimal conditions for viruses like Covid-19 and influenza to thrive, according to PLOS climate.
Julia Plano, a public health researcher at Georgetown University and lead author of the study, remarked on how the findings reveal a notable rise in indoor activities linked to wildfires, which in turn can facilitate the spread of respiratory illnesses.
By analyzing air quality data from heavily affected counties in Oregon and Washington between July and November 2020, researchers noted a significant number of wildfires burning in September alone.
They modeled indoor and outdoor activity patterns using anonymized data from a mobile phone tracking service, which monitored visits to over 4.6 million locations nationwide.
Counties in Oregon and Washington experienced increases in indoor activity—averaging 10.8% and 14.3%, respectively—while Portland and Seattle saw spikes of 11% and 16% during the 2020 wildfire season.
To determine how these changes in behavior during wildfires affected the flow of respiratory illnesses, researchers combined activity data with models of disease transmission.
The results indicated that higher levels of indoor activity significantly influenced the spread of diseases, particularly those with shorter infection cycles. For illnesses like Covid-19 and influenza, which have incubation periods of under a week, there was a “significant increase in relative peak incidence,” the study found.
Conversely, diseases with longer incubation periods, such as pertussis, which can take up to 25 days to manifest, did not show the same correlations.
The researchers also explored the possible effects of mask usage in indoor settings as a means to mitigate risks. They discovered that even a slight increase of 10% in mask compliance could significantly lessen the peak incidence tied to increased indoor activity during wildfire events.
However, they cautioned that to achieve substantial reductions in exposure risks, mask adherence would need to be considerably higher.
The team expressed hope that their findings could lay the groundwork for further research into the indirect effects of environmental issues on public health.
Finally, they underscored the critical need to address the secondary consequences of climate change on health, emphasizing that public health strategies must adapt as our environment continues to evolve under climate change pressures.
