Studying the Impact of Air Pollution on Google Search Trends for Asthma

Author(s): Aiyer P, Surani SR, Mominkhawaja A, Sheta A.

Background: This study aimed to examine the relationship between air pollutant levels— nitrogen dioxide (NO₂), particulate matter (PM2.5), and air quality index (AQI)—and public interest in asthma-related information, tracked through Google search activity. Design and Methods: Using an ecological study design, we examined air quality data alongside weekly Google Trends data for keywords related to asthma (“cough” and “inhaler”) in Los Angeles County for 2023. Correlation analysis, timelagged correlations, and Mann-Whitney U tests assessed relationships between air pollutant levels and public search interest. Results: Average values for NO₂, PM2.5, and AQI were 22.6 ± 6.6 ppb, 12.1 ± 3.4 μg/m³, and 52.3 ± 15.2, respectively. A moderate positive correlation was found between NO₂ levels and search interest in asthma-related terms, especially at a 0-week lag (r = 0.60, p < 0.05). PM2.5 and AQI levels showed no significant correlations with search behavior. The Mann-Whitney U test showed that high-NO₂ periods corresponded with significantly increased search interest (test statistic = 566.5, p = 0.00013). Conclusion: Our findings suggest a link between NO₂ levels and increased public concern for asthma, reflected in Google search trends. The lack of similar correlations with PM2.5 and AQI underscores NO₂ ’s role in asthma-related search activity. This study highlights Google Trends as being valuable for real-time health monitoring and timely public health interventions. Future research could explore public health information-seeking behaviors via digital platforms in response to a wider range of pollutants in diverse populations.