Air quality monitor from dj. Carbon Dioxide Measurement
Have you ever thought about how poor air quality in residential and office space affects your well-being? Symptoms can be increased fatigue, drowsiness, dry nose and sore throat, pain in the eyes.
Below, we will try to understand how to be a geek and not only improve the air in the premises so as to improve the quality of life. Will help us in this air quality monitor from the dj.
Why is it important to know the condition of the air in the rooms
Carbon dioxide content
Increased concentration of carbon dioxide in the room can be dangerous to human health. External this is manifested by the appearance of a number of subjective symptoms:
- headache
- feeling of weakness
- dizziness
- irritability
- sleep disturbance
The limit of CO2 concentration is individual for each person, depending on gender, age and state of health, but such limits of comfort are accepted:
- 400–800 ppm - comfortable level
- 800–1200 ppm - manifests drowsiness, fatigue and decreased attention
- from 1200 ppm - may show a loss of performance
Carbon Dioxide in the Atmosphere of the Earth - Wikipedia
Externally, people have hypercapnia characterized by the appearance of a number of subjective symptoms, namely, headache, dizziness, feelings of weakness, irritability, and sleep disorders. Decreased performance accurately correlates with an increase in the percentage of carbon dioxide in ambient air. When this indicator approaches 1%, the motor response time increases, the tracking response accuracy decreases; at 1.5-2%, the mental activity of a person begins to change qualitatively, the functions of differentiation, perception, operative memory and distribution of attention are disturbed. With prolonged work in an atmosphere containing 3% carbon dioxide, significant disorders of thinking, memory, fine motor coordination begin, the number of clerks and activity errors increases sharply, and hearing and vision disorders begin.
Relative humidity
Relative indoor humidity is also important. First of all, mucous membranes that come in contact with open air are affected, they are covered with microcracks and dry up, opening a direct path into the body for harmful bacteria and viruses. With a lack of moisture, the following symptoms can occur:
- feeling of dryness in the nasopharynx
- nasal bleeding (in people prone to this)
- general deterioration of health in patients with bronchial asthma
- "Rez" in the eyes
- frequent colds and illnesses due to dry mucous membranes
With increased humidity, hypertensive patients, atherosclerosis, people with various cardiovascular diseases especially react strongly.
Personally, I have, in the winter periods there is a strong pain in the eyes. Therefore, I bought a humidifier, I advise everyone. Solves the problem.
Air temperature
I think the air temperature is easiest. Without special studies from my own experience, it is clear that it is not comfortable working in extreme heat or cold.
Standards and regulations
For office workers (categories Ia and Ib), according to SanPiN 2.2.4.548-96 , the optimum values ​​are 21–24 ° C in cold and 22–25 ° C in warm periods of the year. Relative humidity of 40-60% in any period of the year.
In domestic documents you can rely on the standard AVOK "Residential and public buildings. Air exchange rates. Thus, in the premises, the upper permissible limit of CO2 concentration: rural area - 970 ppm, small cities - 1047 ppm, large cities - 1149 ppm.
As a recommended reference, the maximum permissible concentration in the outdoor air is proposed: rural areas - 332 ppm (650 mg / m3), small cities - 409 ppm (800 mg / m3), large cities - 511 ppm.
The upper permissible limit of CO2 concentration in residential and public buildings should not exceed 638 ppm in outdoor air.
There is also the European standard EN 13779: 2004. Ventilation for non-residential buildings
With a high room quality category (IDA 1), the level of CO2 should not exceed ambient air of more than 400 ppm.
Overview of the Air Quality Monitor from Dadzhet
Appearance of the device
The device is sold in a good box. On the reverse side we see all the information: brief information about the device, technical characteristics, operating conditions, equipment, etc.
Equipment:
- Monitor carbon dioxide (in fact, it has a built-in relative humidity and temperature meter
- mini usb wire
- Power Adapter 200V \ 5V
- Instruction
The quality level is indicated by LEDs. Everything is intuitive. Green, yellow and red. (<800 ppm; 800 ... 1200 ppm;> 1200 ppm, respectively).
When the concentration of CO2 is exceeded more than 1200 ppm, the device begins to peep softly. On the front surface is the MUTE button. For office, a great feature. Squeaky - air out. But at home it is better to turn off the sound so as not to wake up in a panic at night.
Mute button and LEDs
The display has a white backlight, which does not turn off. It is of medium brightness and can make it difficult for sensitive people to sleep. In this case, do not place the air quality monitor on the bedside table.
This is how the backlight works.
Instrument characteristics
The CO2 measurement method is diffusion infrared dual-beam.
| CO2 measurement characteristic | Value |
|---|---|
| Measuring range | 0 ... 3000ppm |
| Resolution | 1 ppm with 0 ... 1000ppm; 5 ppm at 1001 ... 2000 ppm; 10 ppm with 2001 ... 3000ppm |
| Accuracy | Up to 25 ° C: ± 80 ppm or ± 5% (≤2000 ppm); ± 7% (> 2000 ppm) |
| Response time | About 2 min |
| Warm up time | 2 min at 22 ° C |
| LEDs | Green <800 ppm; Yellow: 800 ... 1200 ppm; Red:> 1200 ppm |
| Temperature measurement characteristic | Value |
|---|---|
| Measuring range | 0 ... 50 ° C |
| Resolution | 0.1 ° C |
| Accuracy | ± 1.5 |
| Response time | 20 ... 30 min |
| Warm up time | 2 min at 22 ° C |
| Moisture measurement characteristic | Value |
|---|---|
| Measuring range | 20 ... 90% |
| Screen resolution | one% |
| Accuracy | ± 5% at 23 ° C |
| Response time | <5 min |
| Working temperature | 0 ... 50 ° C |
| Operating humidity | 0 ... 95% |
Instrument power
The air quality monitor requires 5 V 0.8 A according to the nameplate on the back. The power cord is miniUSB (sorry not micro). Also included is the network adapter into which the wire is inserted. But it is quite possible to get by with the USB connector of the computer, which I did, because I have an included laptop in my workplace 24 Ă— 7.
The capacity of the bank is enough to power the device. I measured consumption: in 475 minutes, 56 mAh was released. That is a current of 7 mA. Yes, so little, I was not mistaken. Moreover, the device consumes energy in pulses about once every 2-5 seconds, and between the meter shows 0.
A standard “can” for 10,000 mAh is enough for 59 days of air quality monitor operation.
I think if the device would remove the permanent backlight and the air quality signaling diodes, then it would be possible to do with 2-3 finger-type batteries instead of the power cord. On the other hand, finding a power outlet is not a problem - but you never have to think about batteries.
Measurements and Tests
Office
The first May weekend lasted from Saturday to Monday inclusive. These three days the office was uninhabited, the windows are tightly closed.
Arriving on Tuesday, I saw 610 ppm, 23.0 ° C, 31%
In the room begins to work 1 person.
After 30 minutes: 715 ppm 24.6 ° C 35%
After another 1 hour: 1050 ppm 25.3 ° C 38%
Findings:
- In a room with the windows closed, the CO2 concentration does not drop to the background level (about 400 ppm) even for 3 days. So the tightness is quite good, there is no place to go to fresh air.
- Although the value of 610 ppm, although not the background, but it is quite acceptable and favorable. However, it ceases to be so after 1.5 hours
Office after night.
We continue the experiments. Leave the window in the micro-ventilation.
Such a hole is enough
Miracles - in the morning the device shows a carbon dioxide level of 405 ppm. Exactly the same level was waiting for us if the office had no windows at all.
In car
Car air quality measurement
It is a pity that the winter has passed and the stove in the car is no longer needed. And I wanted to check the level of relative humidity. Personally, I have - during this period my eyes dry out terribly, it is very unpleasant to drive with a stove. No heating is cold. Therefore, I try to direct the air flow in any direction except myself.
Symptoms of increased carbon dioxide concentration — fatigue and drowsiness — are bad friends of the driver. It was decided to check how things are in my car.
Measure three situations.
- Air conditioner in cooling mode
- Same mode, but with “recirculate” button
- Ajar slits in the windows (windows closed deflectors)
In the air conditioner mode, the air enters the cabin from the outside and is cooled. There are no problems with carbon dioxide concentration, however, the indicators are kept near the upper “green” bar - 710-800 ppm.
The recycling mode is usually used to warm up / cool the interior faster or to avoid the unpleasant smell of a smoking truck. I press a button, and the CO2 concentration rises very quickly to 840-910 ppm and creeps up more slowly. Understandably, for no particular reason you should not go for a long time in this mode.
When the air is fresh: air conditioning or open windows? From the point of view of carbon dioxide, everything is unique here. Windows open a couple of centimeters in front and behind instantly set the concentration of carbon dioxide at 610 ppm. At the same time, I did not arrange a very strong draft - there are deflectors on the windows (these are such visors). But do not forget that when using ventilation, the air passes through filters that trap dust and soot.
As for me - quite enough fresh air in the air conditioner mode.
Impressions
As a person of a technical mentality - I like to know specific values ​​and not be based on subjective feelings. I used to control only the humidity level. Now I can definitely know about the "freshness" of the air.
The air quality monitor from Dadzhet handles all its functions well. Measures, warns. Here are some pros and cons ("Wishlist")
pros
- besides CO2 measures humidity and temperature
- large numbers on the display
- possibility of sound notification if the value is out of the norm (and the ability to disable it)
Minuses
- no synchronization with PC
- the display backlight does not turn off
For blog readers, there is a 10% discount on the purchase of an air quality monitor for 14 days on promo code GT-MKV.
I would be happy to answer your questions in the comments.
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Source: https://habr.com/ru/post/403737/
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