Air Purifier Reviews | Reviews Air Purifiers

Re: Air Purifier for Wood Stove Smoke

A Reader writes:

Ed,

thank you so much for your detailed reviews and excellent commentaries on air purifiers.

There is no better site out there to gain accurate technical knowledge and insight on air purifiers.

Our family has run into a very difficult situation.

We have been in our home for 25 years and have not had any major air quality problems nor have used any air purifiers.

We just recently had a neighbor move next door who burns “wood” as his source of heat.

We are directly downstream of the smoke coming out of his stack.

At times (mostly especially at night) it can get pretty bad.

If we go outside for just a short while (say to just get the mail) we come in stinking badly of smoke.

We no longer have the freedom to open any windows without the horrible stink of the smoke entering our house.

When we keep all the windows closed we do not notice any significant odor inside the house (thought sometimes a faint odor) but we are experiencing negative health affects in lungs, sinuses and sometimes the eyes.

We went to the township to ask for help to stop the wood stove operation of our neighbor, but were unsuccessful.

We are now looking for alternate ways to help improve our health situation (i.e. sealing around windows and purchasing an air purifier). I have read that the particulate matter of wood smoke is small (PM 2.5) and can enter the house even with windows and doors closed.

So I am thinking that maybe a HEPA, Carbon and Electrostatic combination would be best for us but I am not sure.

Can you please help suggest an air purifier that would be best for our situation?

We would be so grateful for your assistance.

Best Wishes A Reader.

Ed's Reply

Hey Reader;

A Family Tradition

The home hearth has long defined humanity.

Anthropologists consider the control of fire to be a key turning point in the development of modern homo sapiens.

A 2,000 year age of innocence about combustion by products is slowly coming to a close. But economic and political events are driving us to revert to older technologies at an increasing rate.

The smell of wood smoke no longer has the "natural" and "romantic" aura.

When my grandfather was a boy, 90% of American homes burned wood for heating.

By the early 1970's, wood heat was passe, with less than 1% still burning wood.

The "Arab Oil Embargo" in the later 1970's caused a firewood resurgence. Many of my baby boomer friends were participants in the wood stove cottage industry which ensued. Most stoves were amateur engineered by mom-n-pop outfits.

Air quality in rural America took a nose dive.

U.S. EPA regulations took effect in 1992, shutting down most independent builders.

Improved flow engineering, airtight boxes, and catalysts dramatically lowered emissions, and added hundreds of dollars to stove prices.

Today, new wood heaters must be EPA certified.

As a result of the $3K wood stove - a 10x price increase - demand for pre-regulation stoves soared, and demand for new stoves flattened.

But the "temporary recession" of 2009 and rising energy prices have produced a new wood burner boom.

The Census reports that U.S. households heating with wood rose from 1.8 million in 2000 to 2.4 million in 2010, making "wood" the fastest growing heating fuel.

In Europe, where the "austerity" wave has already arrived, the wood burning revival has reached a feverish pace. In Greece, where the possibility of government debt default and currency collapse bring the no-oil-at-any-price debacle ever closer, stove sales are up 100% year-over-year.

There are now an estimated 12 million wood stoves in America, a new "growth industry".

New lower emissions models are marketed as cost effective and eco-friendly, using a "renewable," "carbon-neutral" resource.

Government subsidies for cleaner models propel sales.

This is utter nonsense - despite great strides in technology, wood smoke is still one of the main sources of air pollution in the modern US, and the biofuel fad a hoax which quickly doubled corn prices, just for starters.

Are You ready for the Country?

The smell of wood and garbage burning in stoves and fireplaces is common in my rural Texas neighborhood every winter.

Following every cold front, there are a couple still cold nights with little wind, when smoke accumulates at ground level.

Back in 1981, I bought a lot in a new rural subdivision. It offered 2-5 acre lots - remote, woodsy, and inexpensive. Everybody was homesteading, building our homes from scratch.

Just smell that fresh country air, uh-huh.

One close neighbor ordered a "double barrel stove" kit. He cut up two 55-gallon steel drums and bolted them together with parts supplied in the kit.

This was perhaps the worst polluting and least efficient heater ever devised, a terrible backdrafter which drew combustion air through the home's cracks, needing frequent fuel refills to overcome the incoming cold. Poor sealing created constant leaks into the house.

I also had a wood stove, which I used for three winters, unwisely burning an unlimited supply of free spruce and fir construction scraps. I learned the hard way that burning kiln-dried wood will fill a chimney with gluey creosote in a single season.

Wood Smoke is as Toxic as Cigarette Smoke

PM "2.5" is a convenient catch all used by governments to describe fine particulate. But in reality it is particles below 1 micron that are the worst health threats.

There is no such thing as a "safe level" of very fine particulate.

In wood heaters, woodstoves, and especially fireplaces, incomplete combustion releases far more air pollution than competing heating fuels.

Tobacco smoke and wood smoke are very similar in chemical composition, but wood smoke is a much broader category, with numerous variables determining the emission's content.

Vendors of modern "clean" stoves forget to mention the need for user sophistication and regular maintenance - catalytic combustors can plug up, especially when wood of convenience is used.

Stove smoke contains over 200 Volatile Organic Compounds (VOCs), including carcinogenic Polycyclic Aromatic Hydrocarbons (PAH).

There are other types of burning in my neighborhood.

Manufactured fireplace logs, used in many urban fireplaces as decor, produce toxic fumes, including PCBs(polychlorinated biphenyls).

My rural cabin is in Bastrop County, Texas, where widlfires in the Lost Pines area destroyed 1500 homes in the bone-dry summer of 2011. The fire was 5 miles from my home - and from the hilltop I could see flames 150 feet high and enormous clouds of smoke.

I could see and hear cars and propane tanks exploding and see the blacker smoke where plastic - mobile homes and ect - was burning.

When it finally rained, an 18 month burn ban was lifted, allowing everyone to burn all their saved up garbage. Others are burning brush to make their property fire-proof. This after-the-fire-smoke has a distinct toxic odor that says "cyanide from burnt plastic."

Keep Pollutants Outdoors

Air cleaners alone cannot completely protect your family from wood smoke. By their nature, room air cleaners can only collect pollutants which are already in the room.

Rain will wash fine particulate off sidewalks and porches, but it will track in between storms. I have indoor and outdoor shoes - hard plastic slippers - which I change when exiting.

The particles are so fine that numerous authorities advise sealing leaks with duct tape and plastic sheeting.

After 30 years of experiments, I have found that home-built window filters offer better results than sealing the room - which causes both my wife and me to wake up gasping for breath.

I use a filter with no fan in a window at the head of my bed. I breathe air coming through the filter, using a heavy curtain to control inflow of cold air.

See my page DYI Twin Window Fan Air Filter for details.

For the wood smoke issue, I'd use doubled filters in the MERV 11 and above equivalent range combined with two layers of carbon cloth. These will keep a good percentage of fine particles from entering the room.

Of course, upgrade HVAC with a premium furnace filter, and run the blower full time on cold nights.

Air Purifiers for Wood Smoke

I recommend setting up your bedrooms first, then reclaiming other rooms as experience and finances allow.

Because of the wide range of pollutants involved, air purifiers for seasonal wood smoke need to be premium units. Potassium permanganate added to carbon filter material, to adsorb aldehydes, present in all burning situations, is a good match for wood smoke.

I use an IQAir HealthPro Plus in my bedroom in winter, running less expensive air cleaners during smoke-free times.

I have tried a home-built outdoor air intake for my IQAir, similar to the kit IQAIr sells.

My DYI intake used the side opening of a window unit air conditioner, with a couple layers of polyurethane foam and carbon cloth on the outdoor intake to prefilter incoming air. This worked well on mild nights, but drew lots of cold air into the room when cold outside.

My effort looked very similar to the duct adapter kit sold by Purifresh;

I have NOT tried the Purifresh kit, which includes a heat recovey system to remedy the cold draft, just passing along the concept without endorsement.

IQAir is not a hugely powerful air purifier, just extremely efficient - roughly 200 cfm throughput - so a second machine not connected to an induct arrangement might be needed. I ran other air cleaners, Sharps and Winix, as many as 3 at times, in addition to the ducted IQAir.

Note that I no longer use the duct system since the window filter idea was developed - the window filter is now my first line of defense, with only one air purifier in the bedroom and no ducting.

Depending on the size of your bedroom, for more than 200 square feet a bigger Blueair, maybe a 600-series with the SmokeStop filter option, would be suited.

I would not recommend an electrostatic machine for smoke - they will accumulate an oxidized layer on collection grids and loose efficiency rather quickly.

"Take the Only Tree that's Left..."

Despite the rise of anti-wood-burning groups, and tightening regulation, I expect the demand for wood as fuel to continue accelerating as other fuels supply peaks pass and the economy continues to decline.

What is happening today in Europe ("globalization" "austerity") will come to the US in just a few years.

The popular line is that neighbors of woodburners feel the brunt of wood smoke pollution. While our grievances are real, I think the ignorant wood-burner pays a very high price for his false economy.

Elevated levels of smoke pollutants have been measured in wood burning homes.

Back draft as doors are opened to insert fuel can be substantial, and Carbon Monoxide/VOC levels high. Oxygen depletion from indoor combustion is also a health hazard.

While modern high-tech stoves can address some of the issues, they are no long term solution to the dirty nature of wood heat.

In the neighbor's home, where new owners still use the obsolete barrel stove on winter nights, one man, a non-smoker, died of lung cancer at 70 after running the stove constantly - his doctors assumed he was a smoker after viewing diagnostics.

My long-time next-door neighbor, who did smoke, died of lung cancer at 61, after years of bitter complaints about the stove.

I recently saw a joke about the joys of rural living;

A Texas couple are lying in bed listening to the next door neighbor's dogs. They have been in the backyard barking every night for months.

The wife jumps out of bed and says, "I've had enough of this."

The husband says, "Don't use the .22, my assault rifle is behind the door."

She goes downstairs.

She comes back up to bed; and her husband says, "The dogs are still barking; what did you do?"

The wife says,
"I put their dog in our yard, let's see how THEY like it!"

My best results have come not from threats of legal action, but from gently educating the smoke addict of the dangers to himself and his property.

My neighbors now burn far less than their deceased predecessors, bless their little hearts.

Best wishes,

Ed

Home: Air Purifier Reviews