Researchers at the University of California, Los Angeles (UCLA) say more than 52,000 Californians died from inhaling wildfire smoke from 2008 to 2018.

A new report by the university published June 7 in the journal Science Advances says the deaths caused by people inhaling the fine particles of unhealthy air—that is, particulate matter less than 2.5 micrometers in diameter—also cost the state economy up to $456 billion.

A changing climate, forest mismanagement, and expanded residential spaces were causing wildfires in the state to worsen, according to Rachel Connolly, lead study author and staff researcher in the Environmental Health Sciences Department.

The study’s authors say it is the first of its kind to explore how chronic, long-term smoke exposure affects Californians.

The number of deaths—from 52,500 to 55,700—topped previous estimates because prior measurements didn’t consider long-term smoke exposure leading to disease formation, according to the researcher. Such diseases include atherosclerosis, asthma, lung function decrements, and diabetes, the study said.

For example, one study found that the 2018 California wildfires caused or contributed to 3,600 deaths, but the new UCLA research is putting wildfire deaths at about 5,000 a year.

“A growing body of research suggests that particulate matter from wildfire smoke is more harmful to human health than particulate matter from other pollution sources,” Ms. Connolly said.

Ms. Connolly, project director for air quality and environmental equity research with the Luskin Center for Innovation at the UCLA’s Luskin School of Public Affairs, suggested investing in forest management and climate mitigation to generate “significant health benefits.”

However, Ms. Connolly did not detail what forest management would involve, and she didn’t return requests for more information.

The study researched Californians from 2008 to 2018. Ms. Connolly said she suspects more significant health burdens to develop since 2018, when the state experienced record-setting fire years.

Researchers used an air quality modeling system to estimate wildland fire particulate matter and applied death data from California ZIP codes to quantify how many people probably died of wildfire smoke over the 11-year period, according to the report.