[SOLVED] Environmental outdoor air quality monitoring

[Guest]

Hi all

Please, I need to now where I can find information about environmental outdoor air quality monitoring.

All kind of information will be appreciated, but more important for me are:
- Parameters Monitored;
- Sensores;
- Monitoring Methods and;
- examples from commercial outdoor air quality monitoring devices.


Thanks in advance for your support.

Best Regards,
Pendragon

 

[flatulent]

parameters

The parameters fall into two categories, general weather and specific chemical. Here are the weather ones:

1. Sunlight level measured with a phtocell
2. Temperature (there are many ways to measure this)
3. Wind speed mesured with an anometer (whirling set of three cups) or for low speeds a hot wire which is cooled by the wind. The resistance is measured.
4. Wind direction measured with a flat surface on a pivot
5. Rainfall measured either by the capacitance being changed by the water or by a tilting device where rain is concentrated by a funnel and it fills a cup. When the cup is full it tips over to present another cup to the funnel. These two cups rock back and forth.
6. Relative humidity
7. Barometric pressure

Then the specific chemicals are measured. One example would be sulpher. The problem in measuring specific chemicals is that sensors are usuallysensitive to several chemicals. You will have to select one that is sensitive to chemicals that are not present plus the one you are after.
Another measurement you can do is turbidity. You send a light beam through some of the air (this works for water as well) and measure the transmitted and reflected light. Many parameters can be calculated from these two values. (In lakes the two values are used to calculate the living microscopic plant level.)

 

[Hishamsaleh]

that's completely right...

1-Sunlight level measured :
connect a photo cell directly to voltage meter. u can use a sutable capacitance in between to avoide suden change in sunlight cosed by birds and what ever.

2- Temperature:
**broken link removed**

3- Wind speed mesured:
use tachometer... you need air-tacho

4- Wind direction measured:
connect device 3 to rod... this rod must be connected to a multi cyrcular key selector... you should use at most 8 directions selectance... so it's gona be like colock... the center rod must be free to move... each selector will indicate for a direction... so you will get the main 4 directions + 4 sub ones

5- Rainfall measured:
i have a rainfall detector not measure!!! (unfortionatily)
http://www.aaroncake.net/circuits/raindet.htm

6- Relative humidity:
????

7- Barometric pressure:
someone in the same forum as i remember posted about this,,, search about pressure