Indoor Allergens - Discussions & Deb... - Asthma Community ...

Asthma Community Forum

21,546 members24,420 posts

Indoor Allergens - Discussions & Debates

5 Replies

This is the forum for discussions and debates on allergen avoidance techniques.

All comments, discussions, debates and observations welcome.

Derek

5 Replies

Control of Relative Humidity (RH)

In reply to the following comment left by Anna on the Dispatches thread:

There is quite a lot of evidence that suggest however that those methods are not effective (looking on specific techniques like barrier covers or special vacuum cleaners). Also where as I have no doubt that keeping your house clean is important I don't believe that it should be treated as an ultimate solution.

Deek’s reply (copied from AUK old boards – original message left by Deek, June 05):

The effect of relative humidity (RH) on asthmatics should not be under estimated.

The recommended ideal conditions for the indoor environment is somewhere between 40% - 70% RH (as a rough guide, 100% RH is wet and 0% RH being uncomfortably bone dry).

It is well recognised by those studying sick building syndrome that when RH falls to the lower end of the recommended levels, the air is dry and this has an irritant effect on the bronchial airways. Asthmatic will almost certainly be affected. This has lead to complaints in some modern (sealed) office buildings fitted with aircon, that the air is too dry.

At the opposite end of the recommended limits, it is recognised that this can create the ideal conditions for dust mites (above 60% RH), dampness, moulds and mildew, etc. The higher the RH, the more likely asthmatics will be affected by dust mites and moulds, etc. In modern office buildings high RH does not happen very often, and if it does it is normally remedied swiftly to minimise damage to the building fabric and finishes.

It is noteworthy, that the internal RH in buildings/houses with openable windows (for free ventilation) will fluctuate in-line with the RH measured externally, this is to be expected. However, it is widely recognised that buildings/houses fitted with double glazing rarely meet the correct ventilation rates and therefore the occupants can experience respiratory problems created by poorly ventilated rooms which can either be very dry (low RH) or very damp (high RH). This is not a design problem, the poor ventilation rates are caused primarily by householders cutting out draughts and keeping windows and vents firmly closed to maximise energy efficiency.

The simplest advice is to ensure that that all rooms are well ventilated and always (where practicable) leave the trickle vents open on the double glazed units. Better still, leave some windows open. But please do not compromised your security in doing so, and never leave windows open when the house is unoccupied.

Some asthmatics may benefit from purchasing a domestic humidifier to place in the bedroom which will ensure that the RH within the room is optimised to suit the individual’s comfort level/respiratory problems. Likewise, if the bedroom is found to be damp, then a dehumidier might be the answer. I believe many are designed for bedroom use and therefore operate with very little noise.

Additional comment from Deek, 10 April 2006:

If the bedroom was thoroughly cleaned (removing say 95% of all dust mites) and then the RH (relative humidity) was controlled in the bedroom 24/7 and set at say 40% RH, then this is below the optimum threshold that dust mites require to survive. This method would afford additional allergen avoidance which should minimise the risk of further/future exposure to dust mites, moulds and spores.

Derek

I would love to get into detailed discussion about this but as I hae just came back home and tomorrow work long day (on respiratory ward, that is going to be fun... not) it will have to wait.

I just had this thought though. Isn't it a bit ironic that while there is some evidence for allergies being coused in first place by the fact that we leave in much clener conditions then be used to the treatment is meant to be living in almost sterile environment.

The Holistic Approach

Hi everyone,

I firmly believe in the holistic approach to an avoidance of indoor allergens.

Although relative humidity does have an important role to play in the control of airways' hyperresponsiveness, so does the use of hard flooring, minimal soft furnishings, including banning all soft toys to...somewhere else, keeping pets out of places like bedrooms, regular damp dusting and vacuuming using hepa filters, to name a few.

But the majority of time for most people is spent in the bedroom!

So that is a very important place to focus upon. (After all you only want to be gasping for the right reasons!)

My own tip for controlling breathing problems in this room is to ensure the bedding is regularly changed. By that I mean changing your pillows every couple of months. They are very cheap to buy now from places like Dunelms etc.If you can afford it the use of silk duvets will make a huge difference. Unlike the polyester hypo allergenic ones, silk duvets allow the body to breathe, so again help with humidity control.The use of a mattress cover has already been discussed and is very important too. Not forgetting of course the damp dusting etc...

Mia

Yes to all of the above and throwing cuddly toys etc in the freezer once a week or even better washing them with all your bedding at 60 degrees helps. I know 60 is completely un environmentally friendly but its just your bedding so i don't think it will do much harm. I watched the dispatches programme the other week on channel 4 and they said to make sure you only wear bed clothes in bed, and to take your duvet off the bed each morning as it exposes the bed to the dry air rather than the duvet keeping it on the humid side which the dustmites love.

I know you get told that you should have floor boards/laminate flooring not carpets, blinds not curtains and leather furniture rather than fabric, but its not always possible especially in rented flats so I steam my carpets a couple of times a month and my curtains at least once a week using the steam feature on the iron and i hoover my furniture once a day with a steam when i do the carpets. It really seems to help.

Bedroom dehumidifier helps prevent dust mites!

I would agree with Drewness that it is not always practical to change floor coverings, curtains, etc. due to various factors like the property being rented or in some cases it may not be possible due to financial reasons. Not everyone can afford to rush out and pay for new laminate flooring/linoleum and special blinds when there is nothing wrong with the bedroom coverings.

On my previous post I stated that by using a dehumidifier it is possible to lower the relative humidity (RH) to around 40% RH which is well below the level that dust mites can survive. If the bedroom carpet and curtains were steam cleaned and then a dehumidifier was introduced, then there should be no reason to implement excessive cleaning procedures. I am NOT saying don’t clean regularly, but I am saying that there is no real benefit in excessive cleaning when a dehumidifier is being used in the bedroom 24/7 because no dust mites will be present in/on the carpets, curtains, furniture, toys and the exposed (upside) of the bed clothes.

The hardest area to control dust mites is the bedding and bed clothes because this is the area (micro environment) where the relative humidity cannot really be controlled. Everyone perspires during slumber and this therefore will create the optimum RH for dust mites to survive and reproduce. So, just as Drewness suggested, take the duvet off the bed each morning as it exposes the bed to the dry air rather than the duvet keeping it on the humid side which the dust mites love. But in addition, remember to expose the sleeping side of the duvet to the air also, and don’t forget the night wear – don’t tuck your pyjamas under your pillow, they must be aired also. Again if a humidifier was used in the bedroom, this would ensure that all exposed dust mites would be killed off due to the low relative humidity in the bedroom. However, due to the risk that the dust mites may burrow into the duvet, it is important that these are washed frequently or special duvet barrier covers and sheets be used to prevent the dust mites from burrowing into the duvet/mattress.

Take care,

Derek

You may also like...

Voice changes after strenuous indoor exercise

Hi all, Oftentimes when I exercise in my house I get changes in my voice after I have finished. Does

Fostair - prescription every 30 days

120/4 does equal 30. However, as is often discussed here, the dosage is affected as the inhaler...

Eosophillic asthma treatment

issues and polyps. Hospital appointment tomorrow to discuss this treatment for myself. Inhalers etc...

adrenal insufficiency

Hi all,has anybody suffered with adrenal insufficiency after reducing their prednisolone.I have been

Problems with alternative inhaler to Seretide

the same , it clearly isn't ,I have changed my technique of inhalation and it makes no difference....