How the Growing Impact of Wildfires May Affect Pediatric Respiratory Outcomes

Wildfires in the United States are growing in size. Since 2000, an average 7.0 million acres have burned each year, which is nearly double the average 3.3 million acres that had burned annually in the 1990s.1

There is evidence that exposure to wildfire smoke leads to an increase in cardiopulmonary-related health care utilization among adults, but authors of a new study2 wanted to analyze the impact that wildfire smoke has had on health care utilization among children. 

By reviewing data from San Diego, California’s Rady Children’s Hospital Emergency Department (ED) and Urgent Care (UC) clinics, the researchers determined that the Santa Ana Wind–driven Lilac Fire was associated with 16 more pediatric respiratory visits per day to the ED during the time the wildfire burned, from December 7 to December 16, 2017. Similar results were seen in the UC.

The respiratory visits were defined as children having had a chief concern of difficulty breathing, respiratory distress, wheezing, asthma, or cough. Pulmonology Consultant asked the study’s co-author, Sydney Leibel, MD, MPH, from Rady Children's Hospital, about the role daily particulate matter less than 2.5 micrometers (PM2.5) played in the increase of these visits as well as what clinicians can do to prepare patients for wildfires and other climate change–related events.

Consultant360: What prompted you to conduct this study?

Sydney Leibel: We decided to do this study because there has been an increase in devastating fires—both in size and length of season—here in California over the last few years, and we wanted to look at the impact of wildfire on pediatric respiratory outcomes. The two largest fires in state history have occurred within the last 3 years and, due to climate change, we believe we will see a further increase in both size and frequency of wildfires in the future. As the population of California grows, the health effects of wildfire will be felt by a larger population. Young children are a particularly vulnerable population we are concerned will be disproportionately affected. 

C360: What are the short-term and long-term effects children may experience from both acute and extended PM2.5 exposure? And how can your findings on the far reach of PM2.5 exposure influence understanding of the potential health impact of future wildfires?

SL: There is significant evidence in the literature that demonstrates harmful health effects associated with acute and chronic exposure to PM2.5 in children. From a pulmonary standpoint, PM2.5 can be inhaled deep in the respiratory tract and cause lung injury, potentially through oxidative stress. With smaller airways and higher ventilation rates, children have been estimated to have more than one-third greater the deposition rate of PM2.5 compared with adults.3 In children with asthma, acute PM2.5 exposure can lead to asthma exacerbations and increased ED visits and hospitalizations. There is also evidence that there are long-term effects, including a reduction in lung function. Our findings—and findings from other studies—demonstrate that PM2.5 can be carried long distances by wind, affecting populations that may not be directly exposed to the source of PM2.5. While increased health care utilization was most evident among children who lived at the boundary of the wildfire, children that live 30 miles downwind of the fire also had increased ED respiratory visits. This evidence suggests that wildfires have health impacts in children far beyond those living near the source of a wildfire. 

C360: What was the association between children’s age and respiratory visits? How should this impact the way clinicians manage their pediatric patients of various ages? 

SL: In general, all pediatric age groups demonstrated an increase in ED and urgent care clinic visits in our study. However, children that were aged 6 to 12 years had the highest relative increase in utilization, and newborns to children aged 6 years had the highest absolute increase in utilization. We suspect that there is increased vulnerability—particularly in younger children—and that clinicians should exercise extra caution when seeing these patients during wildfires to help prevent hospital and urgent care visits.  

C360: As wildfires are expected to grow in number and power, what are some preparedness and adaptation efforts clinicians can take to help protect their pediatric patients?

SL: Firstly, clinicians should inform families to follow emergency alerts if they are in the path of a wildfire and ordered to evacuate. Clinicians should become familiar with the Environmental Protection Agency's Air Quality Index (AQI), which takes into account PM2.5. On days when the air quality is poor because of pollution or wildfires, clinicians may advise children to limit outdoor activity or stay indoors entirely. For pediatric patients with asthma, clinicians will want to make sure that families have albuterol and their controller medication if indicated. They will also want to make sure families know how to use their asthma action plan and what steps to take if symptoms such as cough, wheeze, or shortness of breath progress despite home treatment. 

C360: Wildfires are just one way that climate change can impact patient health. What responsibility do you think clinicians have in keeping abreast of the latest information regarding climate change’s impact on health and using that information to inform and treat patients?

SL: The increase in wildfires in California is only one small part of climate change that has had significant health effects. In California, modelling shows an increase in fires is due in part to a changing precipitation regimen that leads to drought and flood cycles. Flooding can immediately displace families and also cause damage to homes and increase mold exposure after the floods have receded, as was seen with Hurricane Katrina. An increase in heat waves is also attributable to climate change and can precipitate asthma exacerbations and other health issues. As these and other climate change–related events increase in the future, they will impact larger populations of patients, and clinicians will need to be prepared to manage these patients. By staying informed on these health impacts, clinicians will be better able to help patients take preventive steps and manage acute health issues related to climate change in the future.


  1. Wildfire Statistics [In Focus Report]. Washington, D.C.:Congressional Research Service; October 3, 2019. Accessed January 15, 2020.
  2. Leibel S, Nguyen M, Brick W, et al. Increase in pediatric respiratory visits associated with Santa Ana Wind-driven wildfire smoke and PM2.5 levels in San Diego County [published online December 20, 2019].
  3. Bennett WD, Zeman KL. Effect of body size on breathing pattern and fine-particle deposition in children. J Appl Physiol. 2004;97(3):821-826. doi:10.1152/japplphysiol.01403.2003.