Air Quality Control with Active Sampling
A little while ago I wrote about passive sampling for testing your air quality. I examined its strengths, capabilities, and when it should be used. The article touched on Active air sampling, but only enough to compare it to passive sampling. With that in mind you’re probably asking: what can active air sampling do for me? Why does it even need to exist?
What is Active Air Sampling?
Although there are different styles of active air samplers, the one thing they all have in common is the use of a pump to pull air into the sampler through a filter. Though much bulkier when compared to the low profile, electricity-free passive sampler, the active air sampler is much more versatile than the diffusive models and gives you a much clearer picture of the health of your air.
Why would I want an Active sampler?
Passive air sampling is great for determining air quality. Easy to train for, and cheap to use. The samplers are small and seem like the perfect tool. However, passive samplers often lack the adaptability require. They need to be validated by the manufacturer and can only be used under certain ideal circumstances. Diffusive samplers work in a wide variety of circumstances, but there are times they will struggle, and for those situations an active sampler is key.
Active samplers are useful in situations where there isn’t much wind, such as confined spaces, or where there is too much wind for the passive samplers to function. When you need an exact measurement of air flow in an area, as well as the concentration of gases you will need an active sampler. In any situation where you need precise readings of the air quality, a passive sampler won’t work nearly as well.
How does an active air sampler help me determine my air quality?
The most common setup for active air samplers utilizes a battery powered pump. Normally you would wear the pump, attaching it to your belt. You connect the pump to an air filter or glass sorbent tube. You then attach the tube or air filter to your shirt, somewhere in your breathing zone. These pumps must be capable of drawing air through the filter for at least eight hours, even in extreme conditions. You should also calibrate them to the proper flow rate before use.
Who makes Active Sampling equipment?
A few different companies make the pumps, sorbents, and tubing. As with the Passive sampling equipment SKC is one of the leading equipment makers. They are also joined by manufacturers such as Aeroqual and BW Technologies. Due to the complexities and variables involved in active sampling it is best to talk to a trained technician who can walk you through what equipment will work best for your project.
Conclusion
Active Sampling has been around a while and is based on the simple concept of sucking air into a hose and separating the substance you are searching for from everything else. It is a mature technology, and because of that it is very reliable. Although not as affordable or compact as passive samplers, active samplers are much more versatile and are able to do jobs that passive samplers can’t, as well as the jobs they can.
