MADISON, WISCONSIN – New data from digital inhalers confirms that exposure to the air pollutant ozone is strongly linked to increased use of inhaled medications for asthma symptoms, according to a new study from CommonSpirit Health; Propeller Health; UC Berkeley; and UC San Francisco, published in Environment International.

Asthma is one of the most common chronic respiratory diseases in the United States, resulting in more than $82 billion a year in healthcare costs. In the Sacramento and San Joaquin Valleys of California, people have unusually high levels of asthma-related emergency department visits and hospitalizations. This prompted CommonSpirit to study environmental factors that could be worsening asthma symptoms for its patients.

CommonSpirit partnered with Propeller Health, UC Berkeley and UC San Francisco to come up with a solution. Researchers gave connected inhalers to 287 patients in the two areas to manage and track the onset of asthma symptoms.

They were able to capture the date, time and location of medication use and determine whether that use was associated with increased levels of ozone in the air. The air pollutant ozone is formed when pollution from cars, power plants and refineries reacts to sunlight. When ozone reaches unhealthy levels, it can cause wheezing, shortness of breath and other adverse symptoms, particularly in people with pre-existing respiratory illnesses such as asthma or chronic obstructive pulmonary disease.

The U.S. Environmental Protection Agency has set the level of safe ozone in the air at 70 parts per billion. This study found that when ozone concentrations in the air increased by just 17 ppb, children used their rescue inhalers 11.3% more often, and adults used them 8.4% more often, even when average ozone levels in the air in this study (26 ppb) were more than 60% lower than the EPA’s recommended level.

“The data we are now able to collect and analyze on environmental conditions helps us more closely engage with our patients so we can help keep them healthier and improve their quality of life,” said Dr. Rajan Merchant, co-author of the study and a practicing physician and asthma expert at the Dignity Health Medical Foundation in Woodland and Davis, which is part of CommonSpirit Health. “Incorporating digital health tools into medical treatment allows us to extend care beyond the clinic and deepen our understanding of how patients are impacted by the environment on a daily basis.”

“There’s been strong evidence that air pollution leads to more emergency department visits, hospitalizations and mortality for asthma patients, but it’s been very difficult to measure its effect on daily symptoms,” said Meredith Barrett, PhD, study co-author and head of Population Health Research at Propeller Health. “By using sensors to passively collect data on the time and place of symptoms, we can draw a clearer line between pollution and poor health.”

Previous studies on the effects of ozone exposure have been limited for several reasons. First, researchers have had to use people’s residential addresses to determine where they may have been exposed to ozone, rather than being able to evaluate their exposure throughout the day. Some past studies have also relied on patients to self-report their symptoms, which can be burdensome for patients and result in incomplete data.

With connected inhalers, researchers can pinpoint the exact time and location of a patient’s medication use and cross-reference that information with data on ozone levels where they are, without requiring patients to perform tedious record-keeping.