Wildland fire sensor, a solution to a problem that knows no borders - Kunak
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Wildland fire sensor, a solution to a problem that has no borders

Wildland fire sensor, a solution to a problem without borders
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  • Wildfire smoke contains substances harmful to our health and ecosystems and it can affect populations dozens of kilometres away.
  • Monitoring stations not only measure wildfire pollution, but also serve as early fire detection systems.
  • The 2017 Wildland Fire Sensor Challenge organised by the US EPA awarded the Kunak stations an Honourable Mention for their performance and reliability.

In September 2020, dozens of fires ravaged large areas of the US. Everyone can still remember the almost apocalyptic scenes of orange skies and tourist attractions emerging through the smoke, such as the Golden Gate Bridge in San Francisco.

But even before California’s shores were affected, wildfire had already left its mark on countries like Australia, Russia and Brazil, and it also had a profound impact on air quality in the areas affected by smoke, which can travel thousands of miles.

Composition of wildfire smoke, a major reason for monitoring

Smoke is a sure sign of fire, but it is also a contributing element to a drastic decrease in air quality. Its negative effects can indeed be felt from tens of miles away, as noted in this article by the BBC. The substances transported by the prevailing winds are responsible for these effects. Although their concentration varies depending on the stage of the fire (1), the main emissions are:

  • Carbon dioxide (CO2), predominant during the flame stage and one of the main greenhouse gas emissions.
  • Carbon monoxide (CO), typical of combustion without flame or ember, known for the health problems caused by its inhalation.
  • Particulate matter (PM10 and PM2.5), whose toxicity may vary depending on the plant species (2). A study published in March 2021 in Nature Communications also shows that PM2.5 from forest fires is more harmful to health than particulate matter from other sources.
  • Volatile organic compounds (VOCs) such as benzene, a carcinogenic substance that can contaminate water resources.
  • Nitrogen oxides (NOx), which often act as precursors in tropospheric ozone (O3) formation, together with VOCs and sunlight. It should be noted that both NOx and VOCs are themselves harmful to health.

Besides its composition, the transformations that this smoke undergoes during its atmospheric transport should also be taken into account. Although this line of research is still under development, studies suggest that its toxicity could increase up to 4 times as the smoke ‘ages’.

Wildland fire sensor, a solution to monitor air quality

There is no doubt that due to the effects of smoke in the environment, there is a need to continuously monitor it in real time. The data provided by this activity are key and make it possible to adopt measures to safeguard the most vulnerable population groups, for example.

The most cost-effective air quality sensors be a clear advantage in this respect. Some of their benefits are a quick deployment capability and a reliability very close to that provided by the reference equipment.

In order to analyse the utility of these solutions, the US Environmental Protection Agency (EPA) organised a challenge in 2017, where two of our Kunak Air A10 stations were introduced. The goal was to measure particulate matter (PM2.5), CO, CO2 and O3.

Wildland Fire Sensor Challenge, a challenge to promote the value of sensor technology

This challenge (3), created with the collaboration of other government agencies, tested the accuracy, precision, linearity and operability of the participating air quality monitoring systems in relation to measurements obtained with reference equipment in two demanding stages.

Stage I was carried out in one of EPA’s research centres, inside a stainless steel chamber. During this stage, the sensor systems had to demonstrate their performance by measuring the target pollutants injected into an air stream without previous calibration. The test was carried out under varying conditions of temperature and relative moisture, thus emulating the distortion usually caused by these factors on air quality readings. To illustrate how demanding the challenge was, the sensors underwent a full day of testing for each temperature and relative moisture setting.

Stage II was carried out at the US Forest Service centre in the Rocky Mountains, where direct gas injection was replaced by various forest fuels that were set on fire in intense 8-day tests.

Results obtained by the Kunak air quality station

The results obtained by our solution merited an Honourable Mention.

Kunak receives US EPA Honorable Mention for the Wildland Fire Sensor Challenge
Miguel Escribano (Business Development Expert) and Javier Fernández (CEO) showing the EPA award.

Our Kunak Air A10 (Solver C) obtained the best results during Stage I for monitoring PM2.5, CO and O3 (CO2 sensors were not included). As regards the deviation caused by temperature and relative moisture, the Kunak Air A10 showed a great performance in relation to thermal variations. With respect to moisture, its performance was more discreet. However, the impact of these factors can be corrected later through algorithms without significantly altering the accuracy of the devices.

During Stage II, our station could not prove its capacity because the solution required a 2G connection to transmit the data to the cloud, a requirement not available at the aforementioned centre.

In short, the Kunak stations showed a rapid response to the changes in the concentration of gases emanating from a wildfire. This enables our solution to be used both as an air quality monitoring device and as an early fire detection system.

The good results obtained during the first stage, in which the sensors were evaluated without previous calibration, also provide for its rapid deployment. This aspect is also reinforced by the reliability of data transmission, which is stored in the cloud and displayed immediately.


The 2017 Wildland Fire Sensor Challenge demonstrated how useful these solutions are in monitoring air quality in the vicinity of wildfire and the excellence of Kunak’s equipment in laboratory tests.

Since this challenge was held, we have continued to innovate and enhance our products and services, realising many of these developments in the new Kunak AIR Pro, launched to the market at the end of 2020.

At Kunak, we have spent years incorporating the best technologies and applying new knowledge to improve every day. Because whether in a wildfire, city or on a scientific expedition, data quality is one of our hallmarks.

Sources consulted:

  • (1) Weise, D., Palarea‐Albaladejo, J., Johnson, T., & Jung, H. (2020). Analyzing wildland fire smoke emissions data using compositional data techniques. Journal Of Geophysical Research: Atmospheres, 125(6). https://doi.org/10.1029/2019jd032128
  • (2) Kim, Y., Warren, S., Krantz, Q., King, C., Jaskot, R., & Preston, W. et al. (2018). Mutagenicity and lung toxicity of smoldering vs. flaming emissions from various biomass fuels: implications for health effects from wildland fires. Environmental Health Perspectives, 126(1), 017011. https://doi.org/10.1289/EHP2200
  • (3) Landis, M., Long, R., Krug, J., Colón, M., Vanderpool, R., Habel, A., & Urbanski, S. (2021). The U.S. EPA wildland fire sensor challenge: Performance and evaluation of solver submitted multi-pollutant sensor systems. Atmospheric Environment, 247, 118165. https://doi.org/10.1016/j.atmosenv.2020.118165

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Wildland fire pollution monitoring in US EPA tests

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