As Los Angeles County battles the most destructive wildfires in its history, a new study suggests U.S. policies should prioritize equity and education regarding steps people can take to protect themselves from harmful smoke pollutants. of forest fires.
People who have limited access to air conditioning may be at higher risk of seeking emergency care for health problems after exposure to wildfire smoke, according to a new study led by the Boston University School of Public Health. (BUSPH).
Published online ahead of publication in the magazine. Environmental Research: HealthThe study found that exposure to fine particulate matter (PM2.5) from California wildfire smoke is associated with higher rates of emergency department visits for all causes, non-accidental causes, and respiratory illnesses. This risk varied by age and race, but was especially high for people who lived in areas with less availability of air conditioning.
The findings come at a critical time, as Southern California firefighters continue to battle multiple wildfires that have been burning in and around Los Angeles County since Tuesday, Jan. 7, including the Palisades Fire, which is likely the largest and most destructive wildfire in county history. Health experts urge residents who are not under evacuation orders and can safely remain in their homes to turn on air conditioners and/or air purifiers if they have access to these devices.
Despite this guidance, and the growing threat of more frequent and intense wildfires due to worsening climate change, very little research has examined how the health effects of exposure to wildfire smoke may differ by access. of people to air conditioning. Understanding this relationship can inform policies and interventions that mitigate barriers to air conditioners and protect vulnerable populations from the consequences of inhaling PM2.5 and other harmful pollutants from this smoke, which can permeate the air by hundreds or thousands. kilometers away.
“Depending on the type of system and filter used, air conditioning can modify the impact of smoke exposure on human health,” says study leader and corresponding author Dr. Jennifer Stowell, a climate and health research scientist at BUSPH, noting that the analysis only addressed the likelihood of access to air conditioning, rather than types of air conditioning or their actual use. “Studies like these will become increasingly relevant as exposure to wildfires increases. California is perhaps the best example of this in the US, with larger fires and longer fire seasons. An upcoming An important step will be to identify ways to better characterize access to air conditioning.”
For the study, Dr. Stowell and his colleagues at BUSPH, Boston University College of Arts and Sciences (CAS), and the Health Effects Institute used a nationwide dataset of health care claims to evaluate more than 50,000 emergency department visits during the 2012 to 2019 California wildfire seasons, which occurred from May to November each year. They quantified the adverse health effects of PM2.5 exposure among all study participants, as well as subgroups of participants.
Consistent with previous research, wildfire smoke exposure was most strongly associated with emergency department visits for respiratory problems, but not with cardiovascular disease-related complications. These visits were generally higher among children under 10 years of age, adults between 20 and 74 years of age, and among black populations, although they were also high among white, Hispanic, and Asian/Pacific Islander populations.
People living in areas with lower availability of air conditioning had a 22 percent higher risk of visiting the emergency department for respiratory conditions associated with exposure to wildfire smoke. It is essential to better understand the use of air conditioning as a pollutant filtering tool and the barriers that certain populations face in accessing these cooling systems, as wildfires are expected to occur more regularly in the wildland-urban interface (WUI). ), areas where human activity is in close contact with dry fuel sources. This is exactly what is happening now in Los Angeles County, says Dr. Stowell, as fires destroy thousands of homes and businesses near the vegetation.
“WUI fires are particularly concerning because of the burning of man-made structures and the additional toxic chemicals and particles that can be found in their smoke plume,” says Dr. Stowell. “The current fires in Los Angeles are out-of-season fires driven by strong Santa Ana winds coming from the mountains. As climate change continues, temperature differences between land and sea will grow and potentially increase increasingly at late season or off-season wind events.”
So how can residential air conditioners help dissipate PM2.5 from homes? The filters in these cooling systems can remove particles, although certain filters are more effective at filtering out particles than others. “HEPA filters can remove most particles larger than 0.3 µm, but are significantly more expensive than fiberglass air filters, which only remove larger particles and can allow large amounts of fine particles to penetrate inside,” says Dr. Stowell. “Generic pleated air filters are also quite efficient at filtering out most particles.”
Air conditioning systems with a minimum efficiency reporting value (MERV) of seven or higher are believed to be the most efficient at removing particles from outside air, but they are also more expensive.
The study’s findings indicate the need for stronger policy measures that can reduce the health risks associated with exposure to wildfire smoke.
“Many homeowners don’t understand the differences between MERV ratings and how they could affect their health,” says Dr. Stowell. “Policymakers should consider providing better information to the public, such as the types and classifications of filters that work best, especially for those residing in smoke-prone regions.”
Since marginalized populations appear to be disproportionately affected by the health effects of wildfire smoke exposure, economic assistance should also be considered, he says, particularly for low-income populations residing in smoke-prone regions. smoke. “Given the current fires in California, state and local governments should step up their responses to these events and develop plans and policies to reduce exposure before fires occur,” says Dr. Stowell.
The lead author of the study is Dr. Gregory Wellenius, professor of environmental health and director of the Center for Climate and Health at BUSPH. The study was co-authored by Dr. Ian Sue Wing, professor of Earth and Environment at CAS; Dr. Yasmin Romitti, scientist at the Health Effects Institute, and Dr. Patrick Kinney, Beverly Brown Professor of Urban Health at BUSPH.