Evaluating the U.S. Air Quality Index as a risk communication tool: Comparing associations of index values with respiratory morbidity among adults in California

Abstract

Background The Air Quality Index (AQI) in the United States is widely used to communicate daily air quality information to the public. While use of the AQI has led to reported changes in individual behaviors, such behavior modifications will only mitigate adverse health effects if AQI values are indicative of public health risks. Few studies have assessed the capability of the AQI to accurately predict respiratory morbidity risks. Methods and findings In three major regions of California, Poisson generalized linear models were used to assess seasonal associations between 1,373,165 respiratory emergency department visits and short-term exposure to multiple metrics between 2012–2014, including: daily concentrations of NO2, O3, and PM2.5; the daily reported AQI; and a newly constructed health-based air quality index. AQI values were positively associated (average risk ratio = 1.03, 95% CI 1.02–1.04) during the cooler months of the year (November-February) in all three regions when the AQI was very highly correlated with PM2.5 (R2 ≥ 0.89). During the warm season (March-October) in the San Joaquin Valley region, neither AQI values nor the individual underlying air pollutants were associated with respiratory morbidity. Additionally, AQI values were not positively associated with respiratory morbidity in the Southern California region during the warm season, despite strong associations of the individual underlying air pollutants with respiratory morbidity; in contrast, health-based index values were observed to be significantly associated with respiratory morbidity as part of an applied policy analysis in this region, with a combined risk ratio of 1.02 (95% CI: 1.01–1.03). Conclusions In regions where individual air pollutants are associated with respiratory morbidity, and during seasons with relatively simple air mixtures, the AQI can effectively serve as a risk communication tool for respiratory health risks. However, the predictive ability of the AQI and any other index is contingent upon the monitored values being representative of actual population exposures. Other approaches, such as health-based indices, may be needed in order to effectively communicate health risks of air pollution in regions and seasons with more complex air mixtures.

Parental knowledge and usage of air quality in childhood asthma management

“…As the AQI represents the highest individual pollutant and does not consider the effects of multiple pollutants, the health impacts associated with AQI could differ regionally and by varying pollutant concentrations. For example, a recent study in California found the AQI was associated with all cause adult respiratory emergency department visits when and where the AQI strongly correlated with fine particulate matter ( 29 ). Given the well-established link between outdoor air pollution and asthma exacerbations in children, it remains prudent to recommend usage of the AQI and speculatively, it is likely to be most beneficial when used as a tool to learn personal susceptibilities.…”

Air pollution and hospital admissions for critical illness in emergency department: a tertiary-center research in Changsha, China, 2016–2020

“…Accumulating evidences concluded that respiratory diseases were more associated with increased levels of air pollutants (Fuller et al 2020, Szyszkowicz andde Angelis 2021). In America, the association between 1,373,165 respiratory ED visits and short-term exposure to air pollutants between 2012 and 2014 were retrospectively analyzed and concluded that air quality index (AQI) values were significantly positive associated with respiratory diseases (RR = 1.03, 95% CI 1.02-1.04) and PM 2.5 was very highly linked with AQI (R 2 = 0.89) (Cromar et al 2020). One study illuminated that positive associations of ambient PM 2.5 with respiratory disease ED visits were presented, with an increase of 4% per 6.1 μg/m 3 increase in PM 2.5 (Tapia et al 2020).…”

Associations of weather and air pollution with objective physical activity and sedentary time before and after bariatric surgery: a secondary analysis of a prospective cohort study

“…Specifically, MVPA levels decreased after ~70 AQI score. Although this value is considered acceptable for the general population, it is considered a risk for some people who are unusually sensitive to air pollution 28 . People with obesity may be more sensitive to air pollutants during MVPA than individuals without obesity given the inflammatory and mechanical (i.e., excess fat deposited on the chest wall and abdominal cavity) effects of obesity decreasing respiratory function and exercise tolerance 39,40 .…”