Prevention of Dust

Check into 'smoke-stack' electrostatic particle collectors/screens.

You might try some of this screen...

https://www.amazon.com/PollenTec-Clean-Air-Window-Screen/dp/B00LNBP4WE

...but you'll never get rid of all the dust without some sophisticated filtering strategy = $$$....think clean room....I have built a few, and there are many stages of filtering, and the filter material for the finest particles is expensive and needs to be changed regularly....as do all the filters....because of all the filters the air needs to be driven...So you can mitigate the dust somewhat, but you'll never get rid of it all....even if this screen material works it needs to be rinsed off and cleaned often...A trick I use in painting to control dust is to wet down the floor and walls, this seems to trap a lot of the dust....I had a buddy that used to line the room with plastic, that worked pretty well...basically anything that will pick up a negative static charge will attract dust....

Interesting product. I wonder if the pollen has to get rinsed off. In parts of India they may not last too long before becoming clogged. That is if they actually work as claimed.

Well I guess you could use a vacuum with soft brush attachment...

But spraying it with the hose is much quicker and less labor intensive....

...or maybe something like this....Lint remover thingy...

Maybe something like this. You can buy washable filters to reduce cost in the long run.

That won't work, the fan is not designed to pump air through a restrictive device, the motor will overheat and eventually fail..The motor has to be designed for the load it will pull...and the fan blade needs to be designed for the cfm desired at the pressure that will be produced...

No, unfortunately it will work for awhile and may work quite well if one is lucky in finding just the right cheap fan. If one is not lucky then an overheated fan motor might turn into an electric fire.

Be careful about adding any fan or blower in which the motor is in the airflow path. Any heat dissipated by the motor will be added to the air you are blowing into the living space. In India, that may not be desireable...

A screen acts as a filter; the smaller the openings in the screen, the more restriction of air flow. The openings will also start to get clogged with dust until air flow is completely restricted. The electrostatic approach is the best way to trap dust.

Using electrostatic approach will be effective. From traditional restricting windows, the more smaller the gaps in the restricting window, the smaller will be the dust incoming. But it will also restrict the breeze and that too in India dust intake will be more that will clog the small openings.

Electrostatic precipitator should work, would filter out finest of the particles. I am not very clear about the associated ozone problem

Are You looking for something for the average home? Or is this for commercial apps.

If its for the average home you are never going to get rid of dust since most of the dust is produced by our own bodies in the form of dead cells.

oilcan13

After the wildfires, here in California, we had tremendous amounts of dust, smoke, ash and soot, that covered everything.

We finally settled on using a high end air purifier, for smoke and fine particulates.

The brand we went with was Austin, about $700, good for about 800 sq. ft., but we were able to use our house while others were still evacuated. IT is on little wheels, so you can move it around to the area [s] you will be using the most.

There are many different barands, but we keep ours on 24/7, and filters are changed every 5 years. Just clean the the outside grill every now and then with a vacumn cleaner. Good luck!

The environment in India is not unlike where I live in Arizona.

Any barrier that you use will restrict the flow of wind/dust into your dwelling. Higher wind speeds will increase the flow through your dwelling, but also pick up more dust and bring it along.

We get these every summer.

Do Electrostatic Air Filters Work? The Pros and Cons of Washable ...

Your local shops will know best what will work for you.

The fact of the matter is that in India, a tropical country, a lot of insects such as mosquitoes, flies etc., invade the homes. To protect from them, mosquito nets were invented. These nets cover only the bed, and dust problem is not palpable. but when all the windows are covered with net, air circulation is definitely affected.

If we could air condition the home, at one stroke both the insect and dust are eliminated, but it is definitely not affordable, at the moment. So we need to depend upon natural breeze for cooling, and if at all, there would be fans in some homes, for better circulation of air inside. There should be free ingress and exit of air for the home to be comfortable and hence window nets were devised, which will keep off the insects, restrict, but not totally stop the breeze from coming in, but dust, does make a free entry, as if there is no obstruction. Some one was remarking that it is the body cells that make the dust ! Well, if the quantity of dust were to be made entirely of human body cells, there will be no obese humans at all !

A solution should be affordable, easily installed and reasonably effective. I felt that hanging a thin cotton, synthetic cloth sheet, at a distance from the window net, should prove the most efficacious in the circumstance, as breeze could veer round the cloth, and provide an iota of comfort, and the window net preventing the insects, and the cloth generally shielding the dust particles which try a direct path into the room.

Any better suggestion would be most welcome.

I was the one that made the comment about dead body cells. I did not say all the dust is from dead body cells. I said the majority of dust comes from dead body cells. it is a known fact that that the human body continually sheds dead cells that are replaced by NEW cells. This is why We don't completely disappear while We are still living. Its a different story after one passes on where NEW cells are not created. Check out any clean room all personnel are dressed from head to toe in coveralls this is to keep the dead cells that our body produces from escaping into the room, among other contaminants carried by the human body. I live in an area, Chicago, where We have four distinct seasons. In winter with all windows closed and snow on the ground there is very little dust entering the home from the outside but still there is as much dust in the house as there is in the summer. Even after having heating duct cleaned there is still an accumulation of dust. I have never lived in India and I don't know exactly how much dust You are talking about but if You are looking at a complete elimination of dust I say its not possible.

oilcan13

In Kolkata many years ago many buildings used a thing called ' Khaskhas ' made of coir / jute / special type grass in Windows, soaked with water. It had two effects; first since wet with water dust were deposited on the outer surface; secondly, since breeze was passing through the wet pores, cool air entered the room, giving comfort. You may search such product in India.

Khakhas is good, but it totally prevents light. In drier places, there is good amount of cooling, but in humid coastal areas, it would create more discomfort by increase in humidity of the room too.

In Kolkata many years ago many buildings used a thing called ' Khaskhas ' made of coir/ jute / special type grass in Windows, soaked with water. It had two effects, firstly, due to wet, the dust were deposited on the outer surface and secondly since air passed through the pores it was cool, giving comfort in the room. You may try this product, if available now.

Manindra.

By electrostatic precipitators I meant the filters where parallel plates are charged to about 13kv that charge all particles including fine smoke particles and are then deposited on earth plates. The efficiency is about 90 percent at air velocity of 400fpm. The associated problem is generation of ozone because of high voltage in system. These filters are used for commercial kitchen exhaust. I was wondering if these may be used to filter air in homes

I'd expect they would work but not as the OP asked for instead of using passive airflow (the wind), a fan or blower will be used with these precipitators to assure air moving through the plates. Then there is the requirement for a HV supply. They might as well install an air conditioner.

Yes, these were suggested as a possible solution, with no supporting information, so I put up a site that explained the pros and cons of using them.

As REDFRED said they, and almost any particle air filter requires forcing air through the filter as they are not effective unless air is forced through them. They also do not filter out heavier dust particles.

I suggest that you read the piece I posted or Google other sources.

I would advise colleagues for interest sake to look at the first a/c unit to be installed in a hospital by local companies combining technologies. It is in the Royal Victoria Hospital in Belfast. It was installed in circa 1903. Amazing what could be done with quite basic materials and a bit of space!

https://www.bbc.co.uk/programmes/p047r12j

No doubt quite labour intensive!

You might want to consider a cyclonic system like that used in vacuum cleaners. Use a screen, first, to get rid of the bugs. Then, the cyclonic system with a hepa-filter at the end should remove almost everything. Be careful to not use a system with the motor in the airpath, like a vacuum, or you will be adding heat dissipated by the motor to the incoming air.

If you look up where dust comes from, a lot of it is from clothes and bedding. The rest is pollen and pollution and other stuff floating around.No screen will help you with that. Any particle big enough to be stopped by a screen will just fall to the ground. I just put whole house HEPA filtration (MERV15 filters) in my home, combined with heat recovery ventalators. It is a noticeable difference, the air is almost sweet smelling. It's pollen season and my home is less dusty and my allergies just arn't happening this year. I wish I had done it years ago. I put them on timers so they don't need to run continuously, and ballance the in and out to keep a slight positive pressure on the house.

For keeping positive pressure inside the house, you need to import air from the atmosphere beyond the house. Of course that air could be filtered before letting into the house,

You are speaking of keeping the heat in. I want the breeze to be there, whether cool or hot , without spending on recurring electrical bills. Timers you speak of, are installed for an electrical appliance which we can ill afford.

Right, heat recovery ventalators do just that. They have two pipes to outside and two pipes to inside with a damper on the intake. The inside air exchanges it's heat /cool with the fresh air coming in as it passes through the box. The efficiency is about 90%. That way if it's winter or summer you can get fresh air without wasting all of the energy of heating/cooling it. they are standard equiptment on super air tight new homes in order to bring in fresh air. Mine did not come with filters built in, some do. I built plenum boxes to hold the in/out filters. They actually recomend filtering the inside air being vented before it goes through the heat exchanger so that your dirty inside air doesn't dirty up the heat exchanger!

Did you not read that the OP lives in India?

"super air tight new homes" are not an option there.

I think he is looking for a natural method of filtering incoming air. An almost impossible task.

My bad, I skimmed the question. Money is still an object in this world, India has a range of wealth classes from almost nothing to incredible wealth. If you can't afford powered ventalation, your options are very limited. I suppose that tightly woven fabric coverings with secure sealing to window openings will stop some of the airborn particles. However the ones that realy matter, 1 micron and below, which lodge in the lungs, require energy to filter out. Pleated MERV13-15 filters can be had for less than $50, A salvaged hvac blower could be used to make an inexpensive powered filter (here in USA it would be just an average dumpster dive) but I'm not sure what that means in India, never been there. The Chinese are all wearing respirators, in some cases that might be the best you can do.

A Low Dust, Prairie Dog Ventilator Inspired Taj

The positive pressure mentioned by SolarArts is an extremely important issue. An average negative pressure continually sucks dust in every tiny crevice from the outside and you are doomed. What you want is a laminar flow air concentrator near the highest point in the house to achieve an adequate average positive pressure inside to offset any pressure delta that may intermittently suck outside dust into the house due to turbulence.

The dust outside the house is, on average, worse closer to the ground since the ground is made of dust and since plants generating pollen are rooted in the ground. Thus, the higher your source of ingress air, the better off you are. Also, the ground around your house absorbs most of the sun's energy and re-radiates it as heat and evaporated water forming a hot, humid layer of air near the ground in the daytime which persists well into the evening. Higher air is typically cooler, cleaner, and drier faster than lower air shortly after the sun sets.

To view an ascii art schematic of this structure or to explore design options for your laminar flow concentrator read my own replies to this initial post.

thewildotter

Laminar Flow Concentrator with Reduced Dust

A laminar flow concentrator can be implemented on a vertical stack(hollow cylinder or "chimney") by building a donut shape on the top of the stack. Air flowing over the top of the donut will follow the surface of the donut and dive into the hole slightly raising the pressure in the house. Note that this works regardless of wind azimuth.

Prairie dogs use a kind of doubled version of this trick with great success. They dig holes with two (or more) entrances, one at the top of a hill and one at the bottom of a depression. Both holes have uniform diameters almost to the surface. The hill hole has higher velocity air than the depression hole. Higher velocity air has a lower pressure than lower velocity air. The air flows into the depression hole and out the hill hole due to the pressure delta. They achieve a drying ventilation of their home
this way but it is backwards wrt dust since the intake is very low. Think of the depression entrance as the inner top of a very large donut sunken into the ground. You might observe that the hill entrance is also a kind of donut but since the diameter of the hole is small nearly to the surface the laminar flow action into this hole is overwhelmed by the low pressure being achieved by longer path the air takes to get over the hill. Of course, prairie dogs have dirt homes that they constantly
excavate so they are not conscious of or are resigned to the dust issue.

Now, I know that some will not think stacks topped with toroids(donut shapes) are an attractive home feature and they are probably right. Here is one solution. Use two concentric stacks to support the toroid. On the concentric stacks support the shell
of an ogee that surrounds the toroid. Make the bottom of the ogee a half toroid shape also but larger to surround the inner toroid. Place panels of high flow, passive, permanent electret filters horizontally between the bottom inner edge of the ogee and the outer stack to receive laminar flow air from the lower surface of the ogee. The cleaned air will pass into the ogee, go around the inner toroid and down inside the outer stack. Warm air from high in the house passes up the inner stack and out the
top surface of the ogee. The center of the ogee(the point at the top) is a teardrop shaped shell facing downward into the center stack with a gap between the teardrop and the stack. Struts between stack and teardrop or another innermost, concentric stack or pole support the teardrop shell. The gap between the second stack and the teardrop allows hot air to exit around the teardrop. The outermost two stacks
should share an insulated cylindrical wall to prevent hot outgoing air from warming the cooler incoming air.

Note that the low density warm outgoing air will create a little draw on the inner stack somewhat increasing the flow and significantly higher laminar flow at its exit near the top of the ogee further lowering the inner stack average pressure. If you want, you can place a horizontal flapper valve or one of those passive turbine vents on the top of the center stack hole inside an upper chamber of the ogee to inhibit reverse flow if the air near the ogee might become turbulent. This spinner could optionally be coupled to a squirrel cage passive rotor in the space between outer stacks to encourage continuous smooth flow for the ingress of fresh air down the inside of the outer stack.

Some design effort wrt orifice sizes, stack sizes, and optional turbines is warranted to insure the desired positive average house pressure. An inflatable version of the teardrop, donut, and ogee could be mounted very quickly on top of a rock rubble anchored sonotube multiple stack assembly for mass production of an instant version for cheap, rapid deployment, albeit temporary to test specific location suitability. This balloon assembly could be used in anticipation of a longer lasting ultimate replacement for lower overall lifetime costs and for better high wind survival chances.

Voila, wind driven, filtered, positive house pressure from your own Taj McHall© economical(at least no electric bill) home addition. Architectural, Passive Ventilation and Air Conditioning (APVAC) is a clinical alternative name if Taj McHall© is too silly
for a name.

thewildotter

ASCII Art APVAC

This answer by thewildotter to my question is the nearest best I could expect. Provision of a chimney inside the room, with whatever geometry at the end, would be one of the best solutions ever, since:

1.It would provide a natural draught.

2.It does not need extra energy.

3.It is a one time investment.

In all probability, the dust would tend to go up the chimney, and even if it doesn't totally, it would drop to the bottom, and could be removed periodically.

Temperature at the ground level is always lower, since hot air is lighter. It is only high altitudes, that are colder, due to rarer atmosphere. And the room would be cooler, due to ingress of cooler air.

I had once provided floor level ventilators in a production hall, and conditions there in improved dramatically, rather than providing a number of windows. Near roof level ventilators in any case were there for removal of hotter air.

Thanks to the wildotter.

You could have water trickle down the screen, and then filter it in a continuous loop, adding a bit of chlorine from time to time...you would need a small pump, could be solar powered, and a sump to collect the water, some tubing and a pipe with tiny holes drilled every 2mm or so....this would cool the air and filter the dust...

The screen would wash itself, the water would catch the dust, evaporation would cool the air....Don't know how well this would work in some circumstances, but you could always shut the water off, or just use it to wash the screens....