What PM level do you have in your indoor environment?

M. Johnsson*, T. Carlsson, Mann+Hummel Vokes Air, Sweden

High concentrations of particulate matter (PM) have become a big concern around the globe. The high concentration levels of particles have a big impact on our indoor air quality (IAQ) and health. There are many reports stating how hazardous the PM levels are for our health. There was a study in Europe 2013 regarding PM concentrations impact on public health. In this study involving 3 121 944 people, they made the conclusion that an increase of the PM10 concentration with 10 µg/m3 will the lung cancer rate increase with 22 %. The PM2.5 was even more dangerous, with an increase of 10 µg/m3 the lung cancer increase with 36 %. We spend typically 90 % of our time indoors, therefore is this environment very important.

Today we could design the PM levels in our indoor environment in the same way as we design the indoor temperature. To design for a comfortable indoor temperature we use local data for the outdoor temperature. With this data as an input we could design our HVAC system so the temperature will become comfortable year round. In a similar way we could design the PM level indoors. Every city has data about the local PM levels. We could also find data for removal of PM from the HVAC filters, by combining the outdoor PM levels and the filter data we could get a good prediction of the IAQ regarding PM.

However there is one very important parameter that we need to consider when designing PM levels and that is the air bypassing the filter. The air bypassing the supply air filter is caused by:
- Temperature difference over the building envelope (air entering the building envelope via leakages)
- Wind forces (creating overpressure on side of the building and under pressure on the other side)
- The air tightness of the building (define the magnitude of air entering via leakages)
- Leakages in the filter installation
- In some cases surplus air of exhaust air to establish under pressure in the building will contribute to unfiltered air

All these parameters will have an impact on the IAQ due to the fact that the air that is not passing the supply air filter will not be filtered. This paper will show how the IAQ is affected and present a calculation method for the IAQ quality based on filtration efficiency and air leakage. ...

Session: G4 - Air Filtration I
Day: 11 October 2016
Time: 14:45 - 16:00 h