experimenting at home with air quality monitors - cheap air purifier

Two years ago, when Thomas Talhelm was a Fulbright scholar in Beijing, he built his own air purifier after growing concerns about Beijing's notorious pollution.
To test his work, he spent about $260 on a portable device that counts tiny particles in the air.
"I have always had my gut feeling that indoor air is cleaner than outdoor air, which is clearly demonstrated in the data," he said . ". Mr.
Talhelm, who used equipment made by a company called Dylos in California, also noticed that cooking could lead to a surge in indoor pollution. Mr.
Talhelm went on to find a company that helped Chinese residents build cheap buildings. it-
Air filter.
Now, scientists and amateurs like him are increasingly trying to use personal devices, including air pollution monitors.
The reason is simple: in any city, there are different levels of pollution in different areas, so the exposure of residents may vary greatly.
New devices are cheaper and more portable than large government monitors, and eventually they can provide information flow to interactive maps to help people understand which streets or communities are particularly contaminated.
But experts warn that the field is still young and changing quickly, so technology is not always reliable and user-friendly. friendly.
"At the moment, air pollution sensors are still expensive and not easy to use, thus limiting the number of people who can use them," said Mark newvin Wesson, a research professor at the Center for Environmental epidemiology studies in Barcelona, Spain, said in an email.
However, he said the technology is being improved and that in a few years devices such as smart watches may contain air pollution sensors.
When the monitor-
It could cost hundreds or thousands of dollars.
Not yet a mass.
The use of market projects, researchers, is surging.
At 2012 and 2013, Dr.
Nieuwenhujsen and other researchers have air pollution monitors for 54 schoolchildren in Barcelona.
These monitors measure black carbon consisting of small coal particles released by diesel engines and other sources.
According to a study published this year in the journal Environmental Science and Technology, children experience the highest level of black carbon on their way to and from work.
The lowest level of pollution is their home.
In Hong Kong, where dense populations are exposed to high levels of car exhaust, Benjamin Bharat researcher at King's College London UK is using portable monitors to study the effects of pollution on people living in skyscrapers.
His team is measuring pollution in the city's streets and canyons.
High-rise streets.
The idea is to understand how traffic pollution is trapped in these passages, and how this may affect people who live high up in buildings with the dispersion of harmful particles.
Interpreting the data can be challenging, which is a central reason in addition to the cost and is why so far few non-scientists have invested in monitoring.
For some machines, "You have to do a lot of research on air quality in order to start to understand what these devices tell you," said Jennifer Gabriel, a researcher at Goldsmith, the University of London tested portable monitors for the European project "citizen feel" used to study environmental monitors.
She took about 15 people for a walk in London in 2013, using air monitoring equipment, and she said, in some cases, "We're really questioning the numbers we get.
"The readings of portable machines are sometimes different from those of large official displays nearby.
She said that the display may be more accurate when the display is stable, rather than moving around.
The display prepared for the use of ordinary citizens begins to arrive.
Last month, Airviz, a company spun off from Carnegie Mellon University in Pennsylvania, launched a fist-sized device designed to sit on a table and measure fine particles in the family, and provide air quality information on electronic display.
"You can see from the horizon, you can see the haze, and when it is bad, you can judge that it is bad," Illah Nourbakhsh said . ", A robotics professor at Carnegie Mellon University, his team developed the device called Speck.
"But in your home there is no cheap way to know how bad it is.
Professor Nourbakhsh's research team purchased tiny dust sensors to scatter light and measure particle content by observing how light reflects.
He said that the sensor is cheap, but usually inaccurate, so researchers must adjust the calibration of each sensor by comparing the data with the established data, expensive machines, and create an algorithm to correct its features.
"We are using machine learning to compensate for a bad sensor," he said . ".
The researchers also added a small fan to ensure a stable air supply.
The display keeps updating the air quality readings, so users can see if the air at home gets worse during cooking or other activities.
Professor Nourbakhsh said the $200 device had sold out by April and the company would add 300 units a month.
He added that the investigation came all the way from Britain, Germany and China.
His team is designing a version that can be used outside.
Users say that so far, small pollution
Monitoring equipment seems to be more successful in measuring how pollution increases or decreases in a day or an hour, and should pay less attention to the exact numbers they give. Mr.
Talhelm, who has tried several monitors in Beijing, is shocked by the number changes every day.
"I don't recommend explaining these numbers literally (e. g.
"Oh, 9 micrograms, so the air is safe! ’)
But the relative change certainly makes sense, "he said in an email.
Researchers say current technology is also often better at measuring tiny particles than in the form of gas such as carbon dioxide.
Gas is usually measured by an electro-chemical sensor in which the gas reacts on the electrode and the current results.
Eventually, the researchers hope that the combination of personal air pollution monitoring equipment and geographic data collected by mobile phones will map new pollution maps for major cities around the world.
In September, Swedish researchers plan to launch a project called "quantitative planet", which will map air pollution measures taken by individuals around the world. Dr.
Nieuwenhujsen is also working on a project called Citi.
This will map air pollution in eight European cities. scale monitors.
But some people are already using these devices to understand their exposure.
A few years ago, the family doctor in Beijing, Richard St. Hill, bought a Dylos particle monitor for about $400 to test how well the air purifier in his home works.
Recent data from the machine shows that although each room has a famous indoor air, the indoor air in my house is still not clean enough
Imported Brands (i. e. expensive)
He wrote in an email: "air purifier.
He did more tests and eventually replaced the new purifier for his home.
"I think the market is
Air pollution monitoring in China and other polluting countries will explode . "Saint Cyr said.
"Hopefully they will continue to be cheaper and more accurate.