A new study says that long-term to exposure wildfire smoke can increase your risk of dementia when compared with other sources of air pollution. The study was presented at the Alzheimer’s Association International Conference in Philadelphia. The research was conducted by researchers from the universities of Washington and Pennsylvania.

For the study, researchers analysed the health records of 1.2 million older adults in Southern California between 2009 and 2019. The researchers measured the impact of PM2.5 - air pollution particles that are 2.5 microns or smaller in diameter from wildfire smoke as well as other sources, such as motor vehicles and factories.

The researchers found a link between PM2.5 from wildfires and dementia diagnosis. A report in CNN states that the odds of someone exposed to wildfire smoke being diagnosed with dementia rose 21% for every increase of 1 microgram of PM2.5 concentration per cubic meter of air over a three-year average. In comparison, for other sources of PM2.5 pollution, the odds of a dementia diagnosis went up 3% for every increase of 3 micrograms per cubic meter of air over a three-year average.

The study also highlights that the link between wildfire smoke and dementia diagnoses is the highest among people from racially and ethnically minoritized groups and in high-poverty areas.

Alzheimer’s Association chief science officer Maria Carrillo said that it’s not clear why there would be a difference. But with wildfires increasing, this needs more study. That’s especially considering that the risk of Alzheimer’s, the most common form of dementia, is higher for lower-income populations who may have a harder time avoiding unhealthy air, she said.

Health warnings urge staying indoors when air quality is poor but “there are a lot of people who don’t have the option to stay home or they work outside,” she noted.

Two other studies say that exposure to fine particulate matter (PM2.5) air pollution increases the risk of hospitalisation for severe heart and lung disorders. The studies which were published in the journal BMJ suggest that there’s no safe threshold for heart and lung health. The Global Burden of Disease study says that exposure to PM2.5 accounts for an estimated 7.6 per cent of total global mortality and 4.2 per cent of global disability-adjusted life years (a measure of years lived in good health).