Our Correspondent
New Delhi, July 11:
Climate changes related to temperature, humidity, and drought are associated with increased frequency, duration, and severity of wildfires in many countries, says the Journal of the American Medical Association (JAMA).
In its study “Wildfires and Human Health” released on Wednesday, the JAMA says exposure to poor air quality from wildfires is associated with adverse cardiopulmonary health, such as asthma, chronic obstructive pulmonary disease (COPD), myocardial infarction, arrhythmias, heart failure.
It is also associated with low birth weight, dementia, stroke, and infectious diseases. “Reactive oxygen species, localized and systemic inflammation, endothelial damage, nervous system dysfunction, and epigenetic modifications are potential biological explanations for these associations. Individuals affected by wildfires have higher risk for posttraumatic stress disorder, depression, and substance use as a result of population displacement, trauma, and economic stress,” the study reads.
Wildfire smoke can easily spread, causing hazardous air quality in areas with typically low levels of air pollution. This results in adverse health effects for people living far away from the wildfire. In 2023, when wildfire air pollution from Quebec, Canada, spread to New York City, emergency department visits for asthma increased from 181.5 per day to 261 per day.
The health risks of wildfires are distributed inequitably across society. Although most counties in the US have experienced increased days with wildfire smoke exposure (smoke days), census tracts in the highest social vulnerability index tertile experienced the largest increase in the mean number of heavy smoke days.
Vulnerable populations include children, who inhale more air in proportion to their body size than adults, older patients with multiple comorbidities, those living in wildfire-prone areas, unhoused individuals, and those from low socioeconomic backgrounds. Wildland firefighters and others who work outdoors, such as agricultural and construction workers, are at higher risk of adverse smoke-related health outcomes due to occupational exposures.
“Patients with preexisting diseases are at risk for exacerbations due to exposure to air pollution from wildfires. Patients with cardiopulmonary conditions, such as asthma or COPD, should be advised to adjust medication use during wildfire events, such as increasing use of inhaled bronchodilator medications,” the JAMA says.
“Clinicians should counsel all at-risk patients to reduce their smoke exposure by staying indoors with windows closed, improving indoor air quality with portable high-efficiency particulate air (HEPA) cleaners or Minimum Efficiency Reporting Value (MERV) filtration in central ventilation systems, and wearing N95 respirators if going outdoors.”
“These interventions reduce air pollution exposure at the individual level and can meaningfully reduce PM infiltration rates into indoor settings.”
“Clinicians can educate patients about wildfire-associated health risks, air pollution surveillance and exposure reduction strategies, and disaster preparedness resources during clinic visits and hospitalizations.”
Recent major wildfires
Recent major wildfires include those in the US (2017-2023), Australia (2019-2020), Canada (2023), Greece (2023), Russia (2021), the Amazon rainforest (2019), and Bolivia (2010). Each year, approximately 44 million people are exposed to unhealthy air quality due to wildfires worldwide.
Although fire patterns vary year to year, meteorological data on wildfires have demonstrated that worldwide, people experienced 6 more days of high fire danger on average from 2018 to 2022 compared with 2003 to 2007, and this exposure is projected to increase by 9 extra days per person (an 11% increase) by 2050.
Since 1985, land burned by wildfires in the US each year has increased from approximately 1 million hectares (3900 square miles; ~6276 km) to more than 3 million hectares (11 500 square miles; ~18 507 km).
This trend is associated with climate change, geographic seasonal wind patterns, and historic suppression of fires, the practice of extinguishing all fires quickly, leading to an accumulation of unburnt biomass that can fuel future, larger fires.
Human inhabitation of forest lands increases wildfire risk through accidental and intentional fires and places human habitation closer to the wildland-urban interface.
The chemical composition of wildfire air pollution depends on the material burned, the fire temperature, and the duration of burning. Wildfires emit particulate matter (PM) and harmful gases, such as carbon monoxide, volatile organic compounds, and nitrogen oxides.
Ends
