In August 2019, 26,000 individual fires burned through the Amazon rainforests, engulfing the equivalent of the U.S. East Coast in flames.

These tens of thousands of individual fires, in addition to worsening wildfire seasons around the globe, have ignited renewed discussions of the major impact that wildfires have on climate change and to global air quality. According to the 2020 World Air Quality Report, these wildfires in California and the Pacific Northwestoccurred during the hottest year on record (tied with 2016) and are known to have contributed to a rise in average particle pollution levels in theUnited States.

The loss of a vast area of the Amazon rainforests contributes significantly to climate change. The Amazon, home to 10% of the world’s biodiversity and at least 15% of all its fresh water, has long been an enormously important feature of the planet’s ability to capture harmful carbon from the atmosphere and produce a large volume of the earth’s oxygen supply.¹ For this reason, some have labeled the Amazon rainforests the "earth's lungs."

Amazon Rainforest Air Quality Stations

Air quality stations in and around the Amazon measure airborne particle concentrations increased by wildfires.

• Feijo, Acre
• Tarauaca, Acre
• Rio Branco, Acre
• Humaita, Amazonas
• Cacoal, Rondonia
• Ouro Preto do Oeste, Rondonia
• Porto Velho, Rondonia
• Vilhena, Rondonia
• Riberalta, Bolivia
• San Matias, Bolivia
• Santa Cruz de la Sierra, Boliva
• Trinidad, Bolivia
• Puerto Maldonado, Peru
• Abadiania, Goiás
• Edeia, Goiás
• Goiania, Goiás
• Cuiaba, Mato Grosso
• Campo Grande, Mato Grosso do Sul
• Dourados, Mato Grosso do Sul
• Ponta Pora, Mato Grosso do Sul
• Porto Murtinho, Mato Grosso do Sul
• Rio de Janeiro, Rio de Janeiro
• Joinville, Santa Catarina
• Campinas, São Paulo
• Grajaú - Parelheiros, São Paulo
• Regente Feijo, São Paulo
• Ribeirao, São Paulo
• São José do Rio Preto, São Paulo
• Sao Manuel, São Paulo
• Alvorada, Tocantins
• Gurupi, Tocantins
• Curitiba, Paraná
• Foz do Iguacu, Paraná
• Lima, Peru

Wildfire smoke can affect people located far away from these fires. In fact, according to a 2020 study published in Geohealth, nearly 10% of premature deaths in Brazil were associated with PM2.5 from smoke pollution.²

Even when forest fires are burning thousands of miles away, a person can still inhale particulate matter produces by such fires.

Read on to learn why and how to reduce the negative health impacts of wildfire smoke.

How far does wildfire smoke travel?

As with any other wildfire, smoke in South American rainforests travels globally. Wildfire air pollution from the Amazon can travel as far away as Asia on the other side of the world.

And when the smoke produced by the over 87,000 fires recorded in Brazil in 2019 is added into the equation, no one can afford to ignore the air quality impact that sheer volume of smoke can have.³

This impact is due to a combination of the physics of wildfire smoke itself and of wind currents that can carry air pollution across the globe. With the Amazon fires, the smoke rising from vast burning areas covered hundreds of thousands of square miles from the west coasts of South America to Papua New Guinea and Australia, over 11,000 miles away, within mere days.

Here’s how that happens:

• Smoke rises miles into the air due to a mixture of intense heat from flames and conditions in the atmosphere like sunlight, cloud cover, and wind speeds.
• Global wind currents blow smoke for hundreds of miles across the upper atmosphere and spread airborne pollutants for hundreds of miles in every direction. In the case of Amazon fires, the westward-blowing currents along the equator can take the smoke as far west as Australia, China, and Indonesia. Then, the smoke is blown northward by currents near Japan, and then eastward by north Pacific currents that bring that same smoke all the way to the United States, Canada, and Central America.
• Pollutants in the upper atmosphere react with heat from sunlight and lower-lying pollutants in major urban areas. Regions that produce a lot of industrial and traffic pollution are especially vulnerable to the added pollution that smoke can bring to the area – not only are nearby major urban areas like São Paulo in Brazil directly affected by Amazon rainforest fires, but cities as far-flung as Mexico City and as far north as Alaska and eastern Russia were affected mere days after the fires started.

How to defend against wildfire smoke

Wildfire smoke can be long-lasting and harmful to more than just the lungs – even just brief exposure can lead to heart attacks, arrhythmia, and respiratory infections.⁴ PM2.5 can be as much as ten times more harmful to human health than PM2.5 from other sources, according to a 2021 study published in Nature Communications.⁵

According to study findings, respiratory hospitalizations associated with wildfire PM2.5 in Southern California between 1999 and 2012 ranged from 1.3 to up to 10 percent of cases as compared to 0.67 to 1.3 percent of hospitalizations for PM2.5-associated causes that were not during wildfires.

And research shows that wildfire seasons around the world are getting longer. A 2015 study published in Nature Communications found that there was a nearly 19 percent increase in global mean fire weather season lengths between 1979 and 2013.⁶

Here’s what can be done to help protect against wildfire smoke:

• Monitor the local air quality. In the hours or days following a wildfire, use an air quality monitor to see your current air quality and compare it to both historical and forecast data. Using an air quality monitor to view your daily air quality patterns can help you learn to discern any major changes that occur due to fires or increased levels of local pollutants like PM2.5 from traffic or industrial emissions.
• Watch worldwide air quality maps closely.In addition to monitoring your own local air quality, keeping up with world air quality trends can help you prepare for any events that may impact your air quality at home. Visit the IQAir Map page for a live air quality map that also shows how wind currents may carry the smoke beyond its source.
• Avoid going outdoors. Wildfire smoke can linger in your local air for days, weeks, or even months. Try to limit time spent outdoors to only essential activities, such as commuting or buying food and supplies. For individuals who are particularly sensitive to poor air quality, this is an especially important step to take.
• Wear an air pollution protection mask. If you must go outside, a simple dust mask or medical mask won’t do against wildfire smoke – they do nothing to filter out the tiniest and most harmful particles in smoke. Make sure you use a mask that’s at least certified KN95, N95, or FFP2. These masks filter out PM2.5 and quality masks can capture up to 95 percent of airborne particles as small as 0.3 microns, which may be found in dense concentrations in wildfire smoke.They’re designed for long-term use by reducing moisture and CO₂ buildup inside the mask while also applying little pressure to the face and ears.
• Create a clean air safe zone indoors. When wildfire smoke is affecting your local air quality, close all your doors and windows to keep smoke from seeping in. Make sure to close the outdoor air intake on your HVAC system so that polluted outdoor air isn’t pulled into your indoor recirculated air. Use an air purifier for wildfire smoke capable of capturing all types of airborne wildfire pollutants, including PM2.5, carbon dioxide, nitrogen oxides, and thousands of other dangerous compounds.

The takeaway

Extreme events like the 2019 Amazon rainforest wildfires are increasing as temperatures rise around the globe. More intense fires and longer wildfire seasons may be the norm for the foreseeable future. With wildfires comes smoke and particle pollutants that can travel for thousands of miles beyond their source.

But equipped with the right tools, it’s possible to see when those pollutants will be most present and act to minimize wildfire smoke health risks.