We currently live in a world where we are able to access a myriad of facts, all a button click away on our phones.
We then enter beautifully manicured websites promising us a utopic world where everything can be monitored and then be directly read to an app on your phone.
The good new is we are getting cost effective monitors that we can carry around with us or use in the home but…. what are they reading.
I have spent most of my life working in air monitoring. In order for a product to give you some information that you can look at and trust you need to have a set of rules to to help define what it is you are looking at.
For example when you buy 5 kg of potatoes in a sealed bag – you either trust your getting five kg or you don’t care you just want spuds. The 5kg comes from the fact that the potatoes have been weighed. We know the weight is correct because at some point in the day, or week a calibration weight of 5kg is placed on the scale where they are packed and the scales are adjusted to be accurate.
This applies to any measurement we take. The thermometer at your doctors, or the speed camera used by the police.
Many indicative monitors don’t have this, though some do
Professional Reference Monitoring equipment would typically cost around £100,00.00. it would use reference monitoring techniques. However it would be used as follows:
- Air Quality Standard https://uk-air.defra.gov.uk/assets/documents/Air_Quality_Objectives_Update.pdf
- Equipment to meet the standard methods of monitoring https://uk-air.defra.gov.uk/networks/monitoring-methods?view=eu-standards
- The Equipment also has to pass a national certification scheme called Mcerts
- Training – organisations have to demonstrate that there workers are competent in being able to take measurements. In some cases the person may need a professional accreditation.
- Finally some organisation who performing testing functions must have UKAS accreditation.
So as you see it is all quite complex. lots of checks.
Moving down below reference equipment is cell technology. It is small and compact. it is what we are seeing out on the street now and in a myriad of pretty boxes for the home. Some of these are accredited and some also have very serious algorithms to correct their functionality. These are professional use tools and cost £3,000 upwards.These are Indicative Monitors. There are also more basic home use indicative monitors
But be careful, many of the Chinese imported products are simply garbage and will respond to anything.
What do most of the Indoor Air Quality Monitors Do well?
- Relative Humidity (%RH)
- Air Presure
- Carbon Dioxide
Areas where they tend to perform poorly
- VOC’s most commercial voc monitors require regular and careful calibration, VOC’s can include anything from Formaldyde , to perfumes & deoudorant
- Nitrogen Dioxide (NO2) – product of combustion
- Fine particulate – respirable dust PM2.5
in test we conduct with a calibrated reference the budget indoor monitor typically showed results 10 x lower PM 2.5 than an accredited calibrated tool. Other items simply did not respond
So there is a reason why tested monitors cost £1,000’s and basic ones a lot lot less. This should change with the emergence of goods British Standards.
In the meantime, rather than look for specific numbers , look for trends. That is significant changes in the air quality