Air Quality Perceptions, Awareness, and Associated Behaviors Among U.S. Adults With and Without Heart Disease.

Introduction: Exposure to ambient air pollution can worsen cardiovascular disease and increase the risk of stroke, myocardial infarction, and cardiovascular disease mortality. Strategies to reduce air pollution exposure can therefore help prevent cardiovascular morbidity and mortality. This study was conducted to assess the awareness among U.S. adults of the effect of air pollution on cardiovascular health and actions individuals can take to reduce their air pollution exposure. Methods: In May-July 2022, 4,156 adults responded to the summer wave of the 2022 ConsumerStyles survey and self-reported their heart disease status and perceptions, awareness, and behaviors about ambient air pollution and health. In 2023, the data were analyzed to generate weighted population estimates representative of noninstitutionalized U.S. adults. Associations between heart disease and responses about perceptions, awareness, and behaviors were estimated using binomial and multinomial regression methods for weighted data. Results: Overall, 90% of the weighted population estimate of U.S. adults reported that air pollution can impact a person's health, and 44% reported that air pollution can cause or worsen heart disease. Percentages of adults reporting that air pollution can impact a person's health (prevalence ratio=1.09; 95% CI=1.06, 1.12) and that air pollution can cause or worsen heart disease (prevalence ratio=1.28; 95% CI=1.08, 1.51) were higher among adults with than without heart disease. Conclusions: Less than half of U.S. adults are aware that air pollution affects heart disease. Improvements in awareness of the effect of air pollution on cardiovascular health and strategies to reduce exposure could help protect individuals with heart disease.

Electric vehicles and health: A scoping review.

BACKGROUND: The health impacts of the rapid transition to the use of electric vehicles are largely unexplored. We completed a scoping review to assess the state of the evidence on use of battery electric and hybrid electric vehicles and health. METHODS: We conducted a literature search of MEDLINE, Embase, Global Health, CINAHL, Scopus, and Environmental Science Collection databases for articles published January 1990 to January 2024. We included articles if they presented observed or modeled data on the association between battery electric or hybrid electric cars, trucks, or buses and health-related outcomes. We abstracted data and summarized results. RESULTS: Out of 897 reviewed articles, 52 met our inclusion criteria. The majority of included articles examined transitions to the use of electric vehicles (n = 49, 94%), with fewer studies examining hybrid electric vehicles (n = 11, 21%) or plug-in hybrid electric vehicles (n = 8, 15%). The most common outcomes examined were premature death (n = 41, 79%) and monetized health outcomes such as medical expenditures (n = 33, 63%). We identified only one observational study on the impact of electric vehicles on health; all other studies reported modeled data. Almost every study (n = 51, 98%) reported some evidence of a positive health impact of transitioning to electric or hybrid electric vehicles, although magnitudes of association varied. There was a paucity of information on the environmental justice implications of vehicle transitions. CONCLUSIONS: The results of the current literature on electric vehicles and health suggest an overall positive health impact of transitioning to electric vehicles. Additional observational studies would help expand our understanding of the real-world health effects of electric vehicles. Future research focused on the environmental justice implications of vehicle fleet transitions could provide additional information about the extent to which the health benefits occur equitably across populations.

Medicaid Expansion and Health Care Use Among Adults With Asthma and Low Incomes: The Adult Asthma Call-Back Survey.

OBJECTIVES: Asthma disproportionately affects Black people and people with low incomes, but Medicaid expansion (hereinafter, expansion) data on these populations are limited. We investigated health care use among adults with asthma, before and after expansion, and examined whether asthma-related health care use after expansion varied by demographic characteristics. METHODS: We analyzed data from the 2011-2013 and 2015-2019 Behavioral Risk Factor Surveillance System Adult Asthma Call-Back Survey on participants aged 18-64 years with current asthma and low incomes in 23 US states. We assessed 5 asthma-related outcomes, including medical visits (routine and emergency) and medication use, for expansion and nonexpansion groups. We used t tests to compare weighted percentages and 95% CIs, then performed adjusted difference-in-differences analyses. Secondary analyses stratified data by race, ethnicity, and sex. RESULTS: Primary analyses (N = 10 796) found no significant associations between expansion and any outcome. Analyses stratified by race and ethnicity found no significant changes (eg, asthma controller medication use among non-Hispanic Black participants in the expansion group was 24.1% [95% CI, 14.4%-37.5%] in 2011-2013 and 35.5% [95% CI, 27.0%-45.1%] in 2015-2019; P = .13). Use of asthma controller medication increased significantly among non-Hispanic Other participants in the nonexpansion group (2011-2013: 16.0% [95% CI, 9.5%-25.5%]; 2015-2019: 40.2% [95% CI, 25.5%-56.8%]; P = .01). Asthma-related hospitalizations decreased significantly among women in the expansion group: 2011-2013 (7.8%; 95% CI, 5.3%-11.3%) and 2015-2019 (3.5%; 95% CI, 2.5%-4.9%) (P = .009). CONCLUSIONS: Investigating factors other than health insurance (eg, social determinants of health) that influence the use of asthma-related health care could advance knowledge of potential strategies to advance health equity for adults with asthma and lower incomes.

Ambient Air Quality and Fatal Asthma Exacerbations among Children in North Carolina.

BACKGROUND: Little is known about the role of air quality in fatal asthma exacerbations among children. METHODS: We collected information about 80 deaths that occurred in North Carolina from 2001 through 2016, among children aged 5-17 years, with asthma identified as the primary cause of death. We linked information about each death with county-level estimates of particulate matter ≤2.5 µm (PM2.5) and ozone (O3). Using the linked data, we conducted a case-crossover analysis of associations between PM2.5 and O3 lagged by 3-5 days with the odds of fatal asthma exacerbations. RESULTS: In the highest tertile of PM2.5 lag(3-5), the odds of a fatal exacerbation of asthma were more than twice the odds in the lowest tertile (odds ratio = 2.2; 95% confidence interval = 1.1, 4.6). CONCLUSION: These findings from North Carolina provide evidence to support the hypothesis that ambient air pollution increases the risk of fatal exacerbations of asthma among children.

Asthma-Associated Emergency Department Visits During the Canadian Wildfire Smoke Episodes - United States, April- August 2023.

During April 30-August 4, 2023, smoke originating from wildfires in Canada affected most of the contiguous United States. CDC used National Syndromic Surveillance Program data to assess numbers and percentages of asthma-associated emergency department (ED) visits on days with wildfire smoke, compared with days without wildfire smoke. Wildfire smoke days were defined as days when concentrations of particulate matter (particles generally ≤2.5 µm in aerodynamic diameter) (PM2.5) triggered an Air Quality Index ≥101, corresponding to the air quality categorization, "Unhealthy for Sensitive Groups." Changes in asthma-associated ED visits were assessed across U.S. Department of Health and Human Services regions and by age. Overall, asthma-associated ED visits were 17% higher than expected during the 19 days with wildfire smoke that occurred during the study period; larger increases were observed in regions that experienced higher numbers of continuous wildfire smoke days and among persons aged 5-17 and 18-64 years. These results can help guide emergency response planning and public health communication strategies, especially in U.S. regions where wildfire smoke exposure was previously uncommon.

The Impact of Climate Change on Asthma and Allergic-Immunologic Disease.

PURPOSE OF REVIEW: This review discusses climate change-related impacts on asthma and allergic-immunologic disease, relevant US public health efforts, and healthcare professional resources. RECENT FINDINGS: Climate change can impact people with asthma and allergic-immunologic disease through various pathways, including increased exposure to asthma triggers (e.g., aeroallergens, ground-level ozone). Climate change-related disasters (e.g., wildfires, floods) disrupting healthcare access can complicate management of any allergic-immunologic disease. Climate change disproportionately affects some communities, which can exacerbate disparities in climate-sensitive diseases like asthma. Public health efforts include implementing a national strategic framework to help communities track, prevent, and respond to climate change-related health threats. Healthcare professionals can use resources or tools to help patients with asthma and allergic-immunologic disease prevent climate change-related health impacts. Climate change can affect people with asthma and allergic-immunologic disease and exacerbate health disparities. Resources and tools are available to help prevent climate change-related health impacts at the community and individual level.

Social Vulnerability in US Communities Affected by Wildfire Smoke, 2011 to 2021.

Objectives. To describe demographic and social characteristics of US communities exposed to wildfire smoke. Methods. Using satellite-collected data on wildfire smoke with the locations of population centers in the coterminous United States, we identified communities potentially exposed to light-, medium-, and heavy-density smoke plumes for each day from 2011 to 2021. We linked days of exposure to smoke in each category of smoke plume density with 2010 US Census data and community characteristics from the Centers for Disease Control and Prevention's Social Vulnerability Index to describe the co-occurrence of smoke exposure and social disadvantage. Results. During the 2011-to-2021 study period, increases in the number of days of heavy smoke were observed in communities representing 87.3% of the US population, with notably large increases in communities characterized by racial or ethnic minority status, limited English proficiency, lower educational attainment, and crowded housing conditions. Conclusions. From 2011 to 2021, wildfire smoke exposures in the United States increased. As smoke exposure becomes more frequent and intense, interventions that address communities with social disadvantages might maximize their public health impact. (Am J Public Health. 2023;113(7):759-767. https://doi.org/10.2105/AJPH.2023.307286).

Large-scale agricultural burning and cardiorespiratory emergency department visits in the U.S. state of Kansas.

BACKGROUND: Prescribed agricultural burning is a common land management practice, but little is known about the health effects from the resulting smoke exposure. OBJECTIVE: To examine the association between smoke from prescribed burning and cardiorespiratory outcomes in the U.S. state of Kansas. METHODS: We analyzed a zip code-level, daily time series of primary cardiorespiratory emergency department (ED) visits for February-May (months when prescribed burning is common in Kansas) in the years 2009-2011 (n = 109,220). Given limited monitoring data, we formulated a measure of smoke exposure using non-traditional datasets, including fire radiative power and locational attributes from remote sensing data sources. We then assigned a population-weighted potential smoke impact factor (PSIF) to each zip code, based on fire intensity, smoke transport, and fire proximity. We used Poisson generalized linear models to estimate the association between PSIF on the same day and in the past 3 days and asthma, respiratory including asthma, and cardiovascular ED visits. RESULTS: During the study period, prescribed burning took place on approximately 8 million acres in Kansas. Same-day PSIF was associated with a 7% increase in the rate of asthma ED visits when adjusting for month, year, zip code, meteorology, day of week, holidays, and correlation within zip codes (rate ratio [RR]: 1.07; 95% confidence interval [CI]: 1.01, 1.13). Same-day PSIF was not associated with a combined outcome of respiratory ED visits (RR [95% CI]: 0.99 [0.97, 1.02]), or cardiovascular ED visits (RR [95% CI]: 1.01 [0.98, 1.04]). There was no consistent association between PSIF during the past 3 days and any of the outcomes. SIGNIFICANCE: These results suggest an association between smoke exposure and asthma ED visits on the same day. Elucidating these associations will help guide public health programs that address population-level exposure to smoke from prescribed burning.

Changes in asthma emergency department visits in the United States during the COVID-19 pandemic.

OBJECTIVE: A better understanding of the impacts of the Coronavirus disease 2019 (COVID-19) pandemic on emergency department (ED) visits for asthma is needed to improve asthma control. METHODS: Using data from the National Syndromic Surveillance Program (NSSP), we assessed changes in average weekly asthma ED visits in the United States in 3 surveillance periods: 1) March 15, 2020-January 2, 2021; 2) January 3, 2021-January 1, 2022; and 3) January 2-March 5, 2022, relative to pre-pandemic comparison periods between December 30, 2018 and December 28, 2019. For each surveillance period, we assessed changes in asthma ED visits by age group and sex. RESULTS: For the surveillance period beginning March 15, 2020, average weekly asthma ED visits declined 31% relative to what was observed during the comparison period - that is, from 45,276 visits/week in 2019 to 31,374 visits/week in 2020. Declines of over 19% and 26% were observed for 2021 and 2022, respectively, relative to the comparison periods. In all surveillance periods, the largest declines occurred among children, especially those ages 0-4 (74%) and 5-11 (66%) years. CONCLUSIONS: The COVID-19 pandemic impacted asthma ED visits in the United States. The impact was greater among children than adults, as ED visits among children were notably lower during all three pandemic surveillance periods than during the corresponding pre-pandemic periods. Additional information about the roles of behaviors of patients with asthma and changes in asthma care might improve our understanding of the reasons underlying these observed changes.

Public health applications of historical smoke forecasts: An evaluation of archived BlueSky data for the coterminous United States, 2015-2018.

Background: Wildfires are increasing in magnitude, frequency, and severity. Populations in the wildland-urban interface and in downwind communities are at increased risk of exposure to elevated concentrations of fine particulate matter (PM2.5) and other harmful components of wildfire smoke. We conducted this analysis to evaluate the use of modeled predictions of wildfire smoke to create county-level measures of smoke exposure for public health research and surveillance. Methods: We evaluated four years (2015-2018) of grid-based North American Mesoscale (NAM)-derived PM2.5 forecasts from the U.S. Forest Service BlueSky modeling framework with monitoring data from the Environmental Protection Agency Air Quality System (AQS), the Interagency Monitoring of Protected Visual Environments (IMPROVE), the Western Regional Climate Center (WRCC), and the Interagency Real Time Smoke Monitoring (AIRSIS) programs. To assess relationships between model-derived estimates and monitor-based observations, we assessed Spearman's correlations by spatial (i.e., county, level of urbanization, states in the western United States impacted by major wildfires, and climate regions) and temporal (i.e., month and wildfire activity periods) characteristics. We then generated county-level smoke estimates and examined spatial and temporal patterns in total and person-days of smoke exposure. Results: Across all counties in the coterminous United States and for all days, the correlation between county-level model- and monitor-derived PM2.5 estimates was 0.14 (p < 0.001). Correlations were stronger using data from temporary monitors and for areas and days impacted by high wildfire smoke, especially in the western United States. Correlations between county-level model- and monitor-derived estimates in non-metropolitan counties, and at higher concentrations ranged from 0.25 to 0.54 (p < 0.001). Conclusions: In general, public health practitioners and health researchers need to consider the pros and cons associated with modeled data products for conducting health analyses. Our results support the use of model-derived smoke estimates to identify communities impacted by heavy smoke events, especially during emergency response and for communities located near wildfire episodes.

Wildfire smoke and symptoms affecting mental health among adults in the U.S. state of Oregon.

The physical and mental health impacts of wildfires are wide-ranging. We assessed associations between exposure to wildfire smoke and self-reported symptoms affecting mental health among adults living in Oregon. We linked by interview date and county of residence survey responses from 5807 adults who responded to the 2018 Behavioral Risk Factor Surveillance System's depression and anxiety module with smoke plume density, a proxy for wildfires and wildfire smoke exposure. Associations between weeks in the past year with medium and heavy smoke plume densities and symptoms affecting mental health during the two weeks before the interview date were estimated using predicted marginal probabilities from logistic regression models. In the year before completing the interview, 100% of respondents experienced ≥2 weeks of medium or heavy smoke, with an average exposure duration of 32 days. Nearly 10% reported being unable to stop or control their worrying more than half the time over the past two weeks. Medium or heavy smoke for 6 or more weeks in the past year, compared to ≤4 weeks in the past year, was associated with a 30% higher prevalence of being unable to stop or control worrying more than half the time during the past two weeks (prevalence ratio: 1.30, 95% confidence interval: 1.03, 1.65). Among adults in Oregon, selected symptoms affecting mental health were associated with extended durations of medium and heavy smoke. These findings highlight the burden of such symptoms among adults living in communities affected by wildfires and wildfire smoke.

Decline in Lung Function From Mid-to Late-Life With Central Arterial Stiffness: The Atherosclerosis Risk in Communities Study.

We investigated the association of lung function at mid-life, later in life, and its 20-year decline, with arterial stiffness later in life. We examined 5720 Atherosclerosis Risk in Communities Study participants who attended Visits 1 (1987-1989) and 5 (2011-2013). Lung function measures were forced expiratory volume in one second (FEV1) and forced vital capacity (FVC), obtained at Visits 1, 2 (1990-1992), and 5. Central artery stiffness (carotid-femoral pulse wave velocity [cfPWV]) was measured at Visit 5. We evaluated associations of lung function with later-life central artery stiffness and cfPWV >75th percentile by multivariable linear and logistic regressions. Lung function at Visit 1 (FEV1 ß: -26, 95% Confidence Interval [CI]: -48, -5; FVC ß: -14, 95% CI: -32, 5) and Visit 5 (FEV1 ß: -22, 95% CI: -46, 2; FVC ß: -18, 95% CI: -38, 2) were inversely associated with cfPWV at Visit 5, and with odds of high cfPWV in fully adjusted models. Twenty-year decline in lung function was not associated with continuous or dichotomous measures of arterial stiffness (FEV1 ß: 11, 95% CI: -46, 68; FVC ß: -4, 95% CI: -52, 43). Lung function at mid-life and late-life was inversely associated with arterial stiffness in later life.

Communication channels for receiving air quality alerts among adults in the United States.

Exposure to air pollution is associated with respiratory and cardiovascular effects, particularly among people with underlying respiratory and heart disease. It is therefore important for individuals with respiratory and heart disease to be aware of air quality. However, information about the most effective communication channels for disseminating air quality alerts is limited. We assessed communication channels used for receiving air quality alerts among U.S. adults using data from the summer 2020 wave of ConsumerStyles, a nationally representative survey of U.S. adults (n = 4053). We calculated weighted percentages of respondents who received air quality alerts from six communication channels and stratified by demographic and health characteristics. We calculated weighted prevalence ratios (PRs) adjusted for sex, age, race/ethnicity, and education to assess if communication channel use varied by presence of respiratory or heart disease. Sixty-four percent of U.S. adults had heard or read about air quality alerts. Television was the most commonly reported communication channel for receiving alerts (57.5%), followed by app on mobile phone or device (30.2%) and internet or social media (26.4%). Communication channels differed most prominently by age. The proportion of adults receiving alerts from specific communication channels did not notably vary by presence of heart disease. Adults with respiratory disease more often reported receiving alerts from their doctor's office than adults without respiratory disease (PR: 3.10, 95% confidence interval: 1.49, 6.45). These findings can be used by public health officials to increase awareness of poor air quality days and improve the reach of alerts to target populations.

Air Quality Awareness and Behaviors of U.S. Adolescents With and Without Asthma.

INTRODUCTION: Among U.S. adolescents, the knowledge that air pollution can impact health is relatively high and varies by the demographics of the respondents and the places they live, but the influence of asthma status is unknown. This study assesses the role of asthma in U.S. adolescents' awareness, perceptions, and behaviors related to air pollution. METHODS: In 2020, data were analyzed from 817 adolescents aged 12-17 years who responded to the 2020 Porter Novelli Public Services YouthStyles survey, a nationally representative survey of U.S. adolescents. Respondents self-reported having or having had asthma in the past year and their awareness, perceptions, and behaviors related to air pollution. For each aspect of air quality awareness, perception, and behavior, weighted percentages of responses were calculated by asthma status. RESULTS: Overall, an estimated 11.5% of U.S. adolescents self-reported asthma. Awareness that air pollution can impact health, awareness that respondents can limit their air pollution exposure, and having heard or read about air quality alerts were similar among adolescents with and without asthma, with some differences reported in where they heard or read about air quality alerts. Those with asthma reported discussing with a health professional about ways to limit exposure more frequently than those without asthma. CONCLUSIONS: Despite the well-known risk of asthma exacerbations from air pollution exposure, air quality awareness was similar among adolescents with and without asthma. These findings reveal the areas in which air quality awareness and behaviors to reduce exposure can be improved among adolescents with and without asthma.

Outdoor Air Quality Awareness, Perceptions, and Behaviors Among U.S. Children Aged 12-17 Years, 2015-2018.

PURPOSE: This study aimed to assess U.S. adolescents' perceptions and knowledge about air quality and their behaviors aimed to reduce air pollution exposure and whether they vary by demographic characteristics. METHODS: We analyzed data from the Porter Novelli Public Services YouthStyles survey, a nationally representative survey of U.S. adolescents aged 12-17 years. In survey years 2015-2018, a total of 3,547 adolescents self-reported awareness, perceptions, and behaviors related to air pollution. We calculated weighted percentages of respondents reporting each aspect of air quality awareness, perception, and behaviors overall and by categories of age, gender, parental education, metropolitan status, region, and survey year. RESULTS: Overall, an estimated 81% of U.S. adolescents thought outdoor air pollution could impact health, 52% thought there were things they could do to limit their or their family's exposure, 19% were aware of air quality alerts, 46% of those who thought or were informed air quality was bad did something differently, and 19% always or usually avoided busy roads to reduce air pollution exposure; differences were reported by some demographic variables. CONCLUSIONS: Among U.S. adolescents, awareness that air pollution could impact health was relatively high. However, gaps were found in the awareness of the potential impacts and other aspects of awareness and perceptions related to air pollution and the engagement in behaviors to reduce exposure, some of which varied by demographic characteristics. These results can be used to inform interventions that increase awareness and behaviors to reduce air pollution exposures among U.S. adolescents.

Daycare attendance and asthma control, Asthma Call-back Survey 2012-2014.

OBJECTIVE: To examine the association between daycare attendance and asthma control among children aged 0 to 4 years with asthma. METHODS: We analyzed 2012-2014 data from the Behavioral Risk Factor Surveillance System Asthma Call-back Survey on 388 children with asthma aged 0 to 4 years with information on daycare attendance in the past 12 months. We calculated weighted prevalence ratios to assess the association between daycare attendance and asthma control (categorized based on day-time and nighttime asthma symptoms, activity limitation, and short-acting beta agonist use). Adjusted models controlled for parent or guardian education, household income, race, sex, cost barriers to asthma care, long-term control medication use, and the number of other children in the child's household. RESULTS: In this sample of children with asthma, representative of 520,400 children in 26 U.S. states, 34% attended daycare in the past 12 months. Only 32% of children who attended daycare in the past 12 months reported having an asthma action plan on file at the daycare they most recently attended. Presence of the asthma triggers of pets, mold, and smoking in a child's daycare were reported to be uncommon. Prevalence of uncontrolled asthma was 44% in children who attended daycare in the past 12 months and 68% in children who did not. The adjusted prevalence ratio between daycare attendance and uncontrolled asthma was 0.96 (95% confidence interval 0.73, 1.25). CONCLUSIONS: When adjusting for covariates, we observed no evidence of an association between daycare attendance in early life and uncontrolled asthma.

Medicaid expansion, health insurance coverage, and cost barriers to care among low-income adults with asthma: the Adult Asthma Call-Back Survey.

OBJECTIVE: To examine Medicaid expansion (ME) effects on health insurance coverage (HIC) and cost barriers to medical care among people with asthma. METHOD: We analyzed 2012-2013 and 2015-2016 data from low-income adults with current asthma aged 18-64 years in the Behavioral Risk Factor Surveillance System Asthma Call-Back Survey (state-level telephone survey). We calculated weighted percentages and 95% confidence intervals from ME and non-ME jurisdictions (according to 2014 ME status). Outcomes were HIC and cost barriers to buying asthma medication (MED), seeing a health care provider for asthma (HCP), or any asthma care (AAC). Using SUDAAN, we performed survey-weighted difference-in-differences analyses, adjusting for demographics. Subgroup analyses were stratified by demographics. RESULTS: Our study population included 6445 participants from 25 states plus Puerto Rico. In 2015-2016 compared to 2012-2013, HIC was more common in ME jurisdictions (P < 0.001) but unchanged in non-ME jurisdictions. Adjusted difference-in-differences analyses showed ME was associated with a statistically significant 13.36 percentage-point increase in HIC (standard error = 0.053). Cost barriers to MED, HCP, and AAC did not change significantly for either group in descriptive and difference-in-differences analyses. In subgroup analyses, we noted variation in outcomes by demographics and 2014 ME status. CONCLUSIONS: We found ME significantly affected HIC among low-income adults with asthma, but not cost barriers to asthma-related health care. Strategies to reduce cost barriers to asthma care could further improve health care access among low-income adults with asthma in ME jurisdictions.

Air Quality Index and air quality awareness among adults in the United States.

BACKGROUND: Information about local air quality is reported across the United States using air quality alerts such as the Environmental Protection Agency's Air Quality Index. However, the role of such alerts in raising awareness of air quality is unknown. We conducted this study to evaluate associations between days with Air Quality Index ≥101, corresponding to a categorization of air quality as unhealthy for sensitive groups, unhealthy, very unhealthy, or hazardous, and air quality awareness among adults in the United States. METHODS: Data from 12,396 respondents to the 2016-2018 ConsumerStyles surveys were linked by geographic location and survey year to daily Air Quality Index data. We evaluated associations between the number of days in the past year with Air Quality Index ≥101 and responses to survey questions about awareness of air quality alerts, perception of air quality, and changes in behavior to reduce air pollution exposure using logistic regression. RESULTS: Awareness of air quality alerts (prevalence ratio [PR] = 1.23; 95% confidence interval [CI] = 1.15, 1.31), thinking/being informed air quality was bad (PR = 2.02; 95% CI = 1.81, 2.24), and changing behavior (PR = 2.27; 95% CI = 1.94, 2.67) were higher among respondents living in counties with ≥15 days with Air Quality Index ≥101 than those in counties with zero days in the past year with Air Quality Index ≥101. Each aspect of air quality awareness was higher among adults with than without asthma, but no differences were observed by heart disease status. Across quintiles of the number of days with Air Quality Index ≥101, air quality awareness increased among those with and without selected respiratory and cardiovascular diseases. CONCLUSIONS: Among U.S. adults, air quality awareness increases with increasing days with alerts of unhealthy air. These findings improve our understanding of the extent to which air quality alerts prompt people to take actions to protect their health amidst poor air quality.