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 risk of wildfire smoke exposure is increasing because of climate change, land management practice, and growth of wildland-urban interface areas, particularly in locations that have not historically experienced wildfire smoke (7). Syndromic surveillance data identified excess asthma-associated ED visits related to wildfire smoke and serve as some of the earliest available detection indicators. Community preparedness and appropriate and prompt response are crucial to reduce wildfire smoke exposure and morbidity. Recommended actions include assessing a possible health care utilization surge related to wildfire smoke exposure. Clinicians can consider counseling patients on protective measures (e.g., awareness of current and predicted air quality levels, staying indoors, using air filtration, and using properly fitted N95 respirators when outdoors), especially among persons with asthma, chronic obstructive pulmonary disease, cardiovascular disease, or children, older adults, and pregnant persons (8). Additional guidance to protect from wildfire smoke can be found online (9) and by using AirNow’s Fire and Smoke Map, the AirNow app, or by listening to the Emergency Alert System and the National Oceanic and Atmospheric Administration’s Weather Radio to monitor wildfire smoke levels. The findings from this report provide actionable information to identify and engage in wildfire smoke preparedness and risk communications to meet the needs of populations at highest risk for wildfire smoke–related adverse health effects.
(Should you prepare in advance to counter this threat in your home or wait until your breathing is impaired or death? This summer of smoke must be considered an SOS from Mother Nature: a moment where we stop, re-evaluate our practices and plan how we will keep her – and each other – safer and healthier. A disaster is something that overwhelms local systems, so to prevent that, everyone from decision makers to community members must make themselves familiar with the smoke, temperature and precipitation projections for their area, and have a plan to help through floods, forest fires and heat-related emergencies. Unfortunately, doing nothing is often the pathway taken as it has zero cost and will not disrupt existing comforts and conveniences. It is as if saving small amounts of money has priority over suffering and death. Prepare to survive.)