Many parts of the United States have already experienced several days of dangerous air quality during the frequent and intense mountain fire seasons of recent years. At the same time, there are many inexpensive air quality monitors on the market that consumers can use to check the levels of pollutants in their homes and nearby areas. So air quality scientists want to know: are these cheap monitors any good?

The answer is yes.

Their study, recently published in the Journal of Sensors, tested four inexpensive models of air quality monitors in real-life mountain fire pollution events and correlated them with respiratory and cardiovascular problems caused by PM2.5 or PM2.5. We found that the measured particles were less than 2.5 microns. -always higher than the reference monitor used by the regulator. However, the response of each monitor to smoke was relatively consistent, so the measurements could be used to estimate actual PM2.5 levels. Overall, the researchers conclude that the monitors provide practical information.

The experts compared the inexpensive monitors with those used in the regulators of air monitoring stations. The correlation between them proved to be very good. When one went up, the other went up simultaneously and proportionately. This gives great hope that they can be used for real information. It can show someone how their new portable air filter reduces smoke particles. But, in absolute terms, it's clear that these sensors need some tweaking and validation to use these numbers.

The experts tested four inexpensive air quality monitors.

  • IQAir AirVisual Pro
  • The purple air inside.
  • ventilated egg
  • eLichens Indoor Air Quality Professional Station

These devices, which cost hundreds of dollars, have been compared to reference monitors (which cost more than $20,000) used by regulators and researchers. They also tested two monitors used by researchers and industrial hygienists that cost between $5,000 and $10,000. In addition, the researchers compared publicly available data from the PurpleAir PA-II monitor to a nearby monitoring station that was impacted by four hill fires in 2018.

Calibration and adjustment factors

In the past, air quality monitoring was limited to expensive professional monitors that were not accessible to individuals. Manufacturers recommend calibrating equipment for specific sources of pollution, as the optical detection technology used by the sensors reacts differently to different sources of pollution. The size and density of pollution from garden barbecues and car exhaust may be different from that from forest fires, which emit different types of particles compared to urban fires.

Inexpensive monitors use the same light detection technology (based on light scattering to estimate particle concentrations), but use mass-produced light sensors that operate with less precision than specialized equipment. In contrast, the most expensive monitors used by controllers are adjusted based on geometric analysis of particle weights.

Using air quality monitors installed in Berkeley Lab's well-ventilated, single-story laboratory building, researchers collected data from a campfire burning in northern California in the fall of 2018. ... PM2.5 level. It is 1.6 to 2.4 times the value measured by the control reference monitor. However, the relative changes correlate well with regulators and professional monitors.

The primary focus of this study was to evaluate data collected on the Purple Air PA-II monitor, which has been released in the United States and is available to the public via an online map. A study published in the same journal by the U.S. Environmental Protection Agency found that Purple Air monitors responded to smoke from mountain fires with similar results. This EPA website combines data from a regulated air monitoring network with PurpleAir monitors to provide more accurate estimates of local air quality.

Benefits for other indoor pollutants

In another study completed earlier this year, scientists installed six low-cost air quality monitors on the PM2 of 21 common homes - flies, grills, microwave popcorn, vacuum cleaners and candles. Assessments were made by comparing them to standard readings of 5 and PM10. The survey, published in the journal Building and Environment, is an update of the 2018 survey.

They found that for most sources, low-cost monitors can be tracked with a professional monitor within two PM2.5 readings. According to the scientists, consumer monitors can be used to identify activities that release particulate matter from a home. Turning on filters or keeping windows closed can contaminate the outside air, and you will find out if it is effectively reducing indoor exposure if the air is too high. For this reason, they work like professional monitors and seem very reliable.

Experts were impressed and excited by the practicality and performance of these air quality monitors that cost less than $300.

Both studies were supported by the U.S. Department of Energy's Office of Building Technologies and the U.S. Environmental Protection Agency's Indoor Environment Division.

Lawrence Berkeley National Laboratory (LBNL) and its scientists were founded in 1931 with the belief that the team is best at tackling the biggest scientific challenges. You have won 13 Nobel Prizes. Today, Berkeley Lab researchers are developing sustainable energy and environmental solutions, creating useful new materials, pushing the boundaries of computing, and exploring the secrets of life, materials, and space. Scientists around the world are using the Lab's facilities for their own science of discovery. Berkeley Lab is a national multi-project laboratory managed by the University of California Department of Energy's Science Division.

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