Short-term associations between ambient air pollution and emergency department visits for Parkinson disease, multiple sclerosis, migraine, and seizure in California, 2005-2018.

Background: Previous studies have linked ambient air pollution to worsening neurological conditions, but research in the United States is limited. This study aims to investigate short-term associations between emergency department (ED) visits for four disorders affecting the nervous system (Parkinson disease, multiple sclerosis, migraine, and seizure) and three major air pollutants: fine particulate matter (PM Methods: Daily estimated exposure concentrations at 12 km were aggregated to the ZIP-code level and linked to 6 million ED visits in California (2005-2018). Using a time-stratified case-crossover design with conditional quasi-Poisson regression, we evaluated lag-specific associations and stratified analysis by patient characteristics. Risk ratios (RRs) are reported per interquartile range increase in exposure. Results: For Parkinson disease, CO showed the strongest short-term association at lag 0 (RR = 1.007, 95% confidence interval [CI]: 1.003, 1.011). No associations were found for multiple sclerosis. For migraines, same-day PM Conclusion: Same-day high ambient air pollution levels were associated with increased ED visits for migraine, Parkinson disease, and seizures. These findings support the growing evidence that short-term air pollution exposure may adversely impact patients with neurological conditions.