California is one of the largest producers of oil and gas in the U.S. More than 7% of Californian residents live within 1 mile of an active oil and gas well, and by 2021, one in ten children had ever been diagnosed with asthma. Research from other states have found that oil and gas development is associated with higher asthma cases. However, no studies have yet looked at this issue in California.

In this study, we examined data on children’s asthma visits to emergency rooms across California from 2013 to 2022. We compared this health data to the density of new oil and gas sites across zip codes, taking factors such as time and location into account.

We found that areas with the highest density of new oil and gas sites had higher rates of asthma emergency visits compared to areas with no oil and gas density. However, there was no evidence of an association in areas with lower density levels of new oil and gas activity. Our future work intends to expand upon these results by incorporating other factors such as wildfire smoke and regional patterns into our model.