I have stopped updating this blog, please head to http://xiwenwendy.wixsite.com/xiwen-lunaticus ! :D

Thursday, 17 April 2014

Tasik Chini Fieldwork - Air Quality

Assoc. Prof. Dr. Ahmad Makmom, our deputy dean of academic and student affairs who taught us Environmental Biology as well this semester.
There are many types of air pollutions that can happen according to the types of pollutants being released into the surrounding air. One of the most obvious air pollutions is the haze which we can even see it apart from smelling the soot. The amount of suspended particles in the air can be measured as parameters to determine air quality by using the gravimetry method, where we measure the weight of the suspended particles present in one litre of air. During this fieldwork we used the Minivol tactical Air Sampler which can take in 5L of air per minute. This is a rather small and portable air sampler compared to the big one which is called high volume sampler which takes in 1700L of air per minute. Air will be sucked through the filter when the pump operates.

The Minivol air sampler before being set up. On the left it is actually the battery, one the right it is the main body of the air sampler with the pump inside and in the front it is the filter.
The inside system of the minivol air sampler where we could decide how long this device operates. Timer can even be set so that a few sampler can start operating at the same time and we can collect accurate data which represents the whole area of research. 
The air is channelled through the impactor (which has to be greased before use) and passed through the filter paper. The suspended particles will land on the filter paper and the filter paper will be weighted so that we can get the mass of the suspended particles. As usual, the filter paper used in collecting suspended particles called glass fibre filter is really expensive just like the Teflon bottle that we use to sample water. So it has to be handled extremely careful by keeping it inside the filter cassette. Once it is dropped or contaminated, it should not be used anymore. Although we cannot see suspended particles using our naked eyes (unless it exists in a huge amount, which is the haze), we have two type of impactors which allow different sizes of suspended particles to pass through. If we do not insert the impactor to the filter, the amount of suspended particles measured will be the total suspended particles in the air. Here are the two types of impactor: 

Impactor PM10 which is used to filter the suspended particles of the size bigger than 10 microns. Micron is actually micrometer.
The very expensive (our faculty can only afford one, this one) impactor PM2.5 that filters what we called fine particles with the size of 2.5 micron. These particles are very dangerous as they can get deeper into our lungs.
This is called renovation! By sliding the filter cassette to the left we can open the case without the risk of dropping the filter paper! This simple design without complicated mechanism is really impressing! (LOL we need creativity)
There are quite a lot of procedures to set up the whole sampler which I cannot memorise. We have to also make sure that there is no leakage etc to so that the precision is the highest for every sampling. Using the battery power, the sampler can continuously filtering air up to 7 days. After getting the data, the data is transferred into computer software to calculate the Air Pollution Index (API) which we will learn some days. Again, this is just another small part of the whole air quality measurement. We have a long way to go.

The completed set up of Minivol Air Sampler. It is not mini at all, right? Hahaha. Quite bulky and heavy.

5 comments:

  1. I Like it .....and Now using ........God mini vol Air Sampler. I am Technician Air Monitoring.....

    ReplyDelete
    Replies
    1. Hi Amaresh, thanks for reading and nice to meet you! =D

      Delete
  2. Hi, Same to you.......and Happy New Year 2015.

    ReplyDelete