Energy-efficient, comfortable and healthy, these are the core concepts of housing construction today. The importance of healthy indoor air has so far often been an underexposed theme. With an overwhelming attendance of 150 participants, a diverse mix of health specialists, ventilation equipment manufacturers, installers, residents' organizations and builders discussed a wide range of topics.
Presentations on the nuisance of asthma patients due to roasting of muesli, baking bacon pancakes in butter and lung diseases caused by dirty indoor air. About the importance of a effective extraction hood and sufficient extract flows. But also about those cosy candles by the fireplace and the noise from the ventilation box. And yes, the usefulness of opening a window. The Day of the Indoor Air is organized by VLA (the Dutch Association of Suppliers of Ventilation Devices), ISSO (knowledge institute installation technology), TVVL (Technical association for installations in buildings) and stakeholder parties like builders, developers and corporations for very energy-efficient new construction participating in the so called “Spring agreement”.
A presentation of “Longfonds” (the Dutch Lung Foundation helping people with long diseases and promoting a healthy indoor environment) payed attention to the disastrous consequences of smoking, particulate matter in the air in the city and people with asthma. But the Lung-fondation's dream that nobody gets sick lungs through the air that he inhales, also applies to the home. "Because indoors, the air is often dirtier than outside. Not talking about just bad smells, but decent pollution with fine dust. "The indoor air is more important than we think. After all, more than 20 hours a day we are at home or in the office.”
Just an example of normal household cooking activities: roasting muesli in the oven. Measurements with a new PM sensor showed that the concentration of very small particulate matter particles (PM2.5) increased to 100 micrograms per m³. A level immediately noticed by asthma patients. People with respiratory diseases are often “the canary peeps in the mines”. They respond immediately with breathlessness to unhealthy or insufficient air. In the Netherlands 10% of the population suffers from asthma; 32 thousand children in the Netherlands are diagnosed with asthma and of 12 thousand people who die of lung cancer every year, of which 1200 people who have never smoked. Other effects of unhealthy air are cardiovascular diseases and in pregnancy there is a greater chance of preterm birth and lower birth weight. Dirty air leads to 4800 emergency admissions per year and on average to a shortening of the lifespan by 13 months.
The Lung Foundation notes that despite these shocking facts there is little knowledge, awareness and support for measures. "We should all become ambassadors today to change this", Mr.Rutgers of the” Longfonds” continues to his audience. "An alliance of dozens of organizations could be involved in a business network such as 'how healthy is the air in your office?' Because there is indeed an action perspective. "From the bottom up, we started a movement a few years ago to allow a generation of children to grow up in a smoke-free environment; that intention is now included in the coalition agreement of the new cabinet. Something like this can be done with healthy indoor air. "A test with a sensor from Philips in homes should show in mid-December whether households are prepared to intervene if the concentration of CO2 or particulate matter indoors is too high, says Rutgers. "In schools, earlier tests showed that children react well to a traffic light model. They inform the teacher that the meter is in orange or red in the classroom."
Keynote speech Jacqueline Cramer
Although the quality of the indoor air has to do with the outside air, Jacqueline Cramer knows more about the latter, says the former Dutch Environmental Minister (2007–2010). Yet Cramer presents a number of lessons that can be drawn from the increased attention to the quality of the outdoor air. "If there is to be more priority for indoor air, you have to consider that there must be urgency for the problem, there should preferably be a pact with stakeholders and there should be public support for the problem and the solutions," says Cramer. In regards to her experience in the field of outdoor air quality a pact with stakeholders was working. The EU requirements threatened a construction shutdown if the quality of the outside air did not improve significantly, municipal authorities woke up and Ministries put a lot of money at the disposal of research and innovation and they found measures such as speed limits of up to 80 and 100 km/h for cars on the road and the highways near cities.
Even in Cramer's reign it was already difficult to schedule indoor air. "Research showed that poor indoor air in schools led to sleepy and not concentrated pupils, but it was difficult for school boards to take measures, even if they would pay off for themselves within five years,". In short, it takes time and effort to get a process of source-oriented approach, urgency and social support in motion. There is another handicap. "The trend of Danish cosiness is now completely hip. Atmospheric candles, open fire, nice smells, lots of rugs and plaids. "They are all bad for the indoor air quality. But try to oppose it. The citizen can start thinking 'what do you steal away from me'. That can backfire in the residential sector. So, bring your message good and honest.
How to communicate with residents, frivolous videos instead of thick manuals?
Jacqueline Cramer herself lives in a new home, equipped with all modern gadgets. "I have a nice kitchen with a steam oven, mechanical ventilation, heat recovery, underfloor heating and a cooking island with a hood. And my coffee machine is also a whole thing. "But do not expect Cramer to go through all the manuals that are supplied. "All those big books, with all those fine print. It is far from being consumer-friendly. So urgently different, says Cramer. 'Does the cooker hood do something against the dust or not, under which conditions? I use the steam oven instead of baking and roasting on my stovetop. Is that okay? Can you use consumer fine dust meters to point out the new risks in a fair way? Make sure you have better hoods in the foreseeable future. Start thinking from the consumers point of view, provide them with action perspective, give information with frivolous videos instead of thick manuals."
Wrap-up the various sessions where professional and residents exchanged their views
1. Session 'An air-tight home ventilates better'
Residents: Thanks to videos and appealing examples, there is more insight into unintentional air leaks in the home. There are many misunderstandings among residents and professionals about the statement 'a 100% air-tight home ventilates better', but in the end everyone agrees that structural air leaks disturb the ventilation system. That is something different than opening a window for 30 minutes to air the house. That the misunderstanding is persistent is also evident from an interactive survey of this statement after the congress: 'I believe so, but I cannot explain' and 'yes, but it goes against my gut feeling'.
Professionals: Measure the airtightness of the house, not by one way of sampling, but always. Do not calculate based on assumed airtightness properties, but measure.
2. Session 'Cooking air'
Residents: TNO practice research at home and at the lab provides a wealth of tips. (see article Piet Jacobs in this REHVA Journal) Switch on the exhaust hood and ensure a flow rate of 300 m³/h, preferably with discharge directly to the outside. Set the general mechanical ventilation system to the highest capacity and let it run for four hours. Use the rear pits of the cooking appliance and do not bake in butter (given its low burning temperature).
Professionals: Professionals need to better understand how much pollution, particularly by particulate matter, gets produced in the kitchen. Design better range hoods that, for example, turn on automatically when the stovetop is switched on, or vice versa, like an alcohol lock in the car, stoves that do not turn on when the cooker hood is not turned on.
3. Session 'The wonderful world of indoor air'
Residents: Residents learned that 'air must flow'. Ventilators and grids in the facade, residents have to do more with this. Many tips are given, such as 'open a window after the shower, but don’t leave it open.'
Professionals: The performance of ventilation equipment has priority over energy efficiency. Ensure sufficient flow, so arrange good supply and discharge grills.
4. Session 'Indoor air specialist in 60 minutes'
Residents: Ventilation is an eye-opener. One does not know what balanced ventilation is and when you open the facade grilles you also have to open the interior door, for example in the bedroom. After all, exhausted air must be supplied again. Do not put draft stoppers in front of the interior doors.
Professionals: All too often ventilation systems are installed in the wrong places in the home, such as balanced ventilation grilles right next to the head of the bed. This requires problems for the resident. Think integrally and look at the whole house.
5. Session: 'Management and renovation of ventilation'
Residents: The housing corporation has responsibility, but the resident / tenant must also do something for it. Clean grilles and replace filters in time.
Professionals: There is a ventilation door for companies. Five companies are participating. This gives both clients and residents confidence in the cleanliness and capacity of the installations and guarantees for their operation. Communicate clearly with residents.
 This text is based on the report written by René Didde and published in Dutch at