Last edit: 09/27/15

Air Purifier for the Car

"Indoor" Air Quality

Howard Hughes, the eccentric billionaire, once built a car air purifier in a limo.

Mr. Hughes was reputed to be very paranoid about invisible particles and germs.

The purifier cost more than the limousine, and took up most of the trunk. He couldn't open the windows, but I'm sure he had purified air.

We tend to feel safe inside our vehicle, but the atmosphere in the interiors of cars may be even worse than household indoor air.

With many car air purifiers on the market, we need to know more about the target impurities inside our vehicles.

The majority of automotive air purification devices on the market, mostly small ionizers without filters, are not up to the air purifying challenge.

Lost Highway

I remember when you didn't need a car air purifier, back when there was NO interstate highway system.

In 1955, I saw the last smoky steam locomotive, just before it was retired from service.

Not long after that, interstate highway construction began in earnest.

My mother, who was a staunch believer in "progress," made us walk 4 miles into the country to see the first overpass under construction (we had no car).

For most of my life, a road trip has been an escape from the monotony of daily life. two lane

I rode my first motorcycle, a 1966 Yamaha, west to California on what were then deserted two-lane highways.

The song said "get your kicks on route 66", so I did.

40 years later, driving 18 wheelers, I loved to park overnight in the same towns I rode through back in '66.

But now they are ghost towns of old route 66, their motels and diners broken, inhabited solely by packs of abandoned dogs.

Maybe a mile from the I-40 corridor, the air is pure there, and it's quiet.

Over on the big road, inhabited by packs of smoky tractor trailers, it's a different story.

On the Road, ...Again

"... I'm standing by a river
But the water doesn't flow
It boils with every poison...
You must learn this lesson fast and learn it well
This ain't no upwardly mobile freeway

Oh no, this is the road
I said this is the road
This....is the road to hell"
from Road To Hell, by Chris Rea

A busy interstate corridor has many sources of pollution; gas and diesel exhaust fumes, various particles, pollen, cigarette smoke, and germs.

Air flowing through typical auto interiors is far from pure. traffic

Studies have shown that those living near major highways are more likely to have a cardiovascular event.

Living near a transportation corridor with greater than 20,000 cars a day creates a six-fold increase in the risk of tumor.

Increased rates of lung disease, including asthma, characterize people living within 500 yards of a major roadway. Those driving are in the thickest soup outside a refinery.

Even the highway itself is toxic, consider the frequent repainting of stripes and outgassing of solvents from asphalt.

Latex particles, a growing asthma/allergy concern, are recycled into asphalt. Lead chromate has been used as pigment for yellow lines.

Keep on Truckin'

Diesel trucks: a love-hate relationship if there ever was.

We play with plastic models as kids, and drive wanna be styled pickups as adults.

Like the railroads before them, today’s transports cut a wide path, but not a clean path.

Serious landscape darkeners are soot from diesel fumes and dust from rubber tires.

Black rain, black snow: everything along an interstate corridor has this oily finish, with tiny soot particulates waiting to flurry into the air an auto moves through.

Brake dust, some of which still contains asbestos, accumulates as millions of brake shoes wear over billions of miles traveled. It builds up along the highway.

Mechanics working on brakes and clutches are trained to avoid generating clouds of fibers, but every vehicle on the road raises a huge cloud of roadside dust.

Cars and Purer Air

Clean air standards have made today's landscape look cleaner, and heavy traffic is easier to breathe in than it once was.

But appearances deceive.

Airborne particles can be classified as coarse ( bigger than 2 micron), fine (0.1 to 1 micron), and ultrafine ( 0.02 micron).

Catalytic converters are now standard exhaust cleaning controls on every new gas powered automobile.

Modern catalytic converters break down engine exhaust into fine particles called micron soot.

Fine and ultrafine particles are a minor component by weight, but they are significant by number, which makes them dangerous to health.

Small enough to evade our natural filters and be inhaled deep into the lungs, they can trigger an inflammatory response, causing serious health problems.

Particle pollution is connected with heart attacks, irregular heartbeat, lung disease, and asthma.

Heavy Metals

Heavy Metal in the air is not just loud music.

Like the trucks, the more numerous cars shed copper, lead, zinc, nickel, iron, antimony, and cadmium from wearing parts.

A three-way catalytic converter purifies air in an car's exhaust system, using platinum, palladium, and rhodium as catalysts.

A ceramic biscuit is coated with these metals which speed up the high temperature air purification process. The ceramic catalyst is made from a lightweight, fragile material with a honeycomb structure.

Road debris striking the converter or vibration from broken exhaust pipe supports can cause a catalyst fracture.

When a ceramic catalyst is fractured, the broken pieces can rattle around and grind into powder.

Rhodium, platinum, and palladium content of soils from U.S. roadsides is sometimes dense enough to consider recovery operations.

Mining pollution along the road?

Well, nobody has proposed that, but the point is made, highway roadsides accumulate toxins.

Lead, added to automotive fuels from 1926 to 1984, permeates the soil along any route that carried traffic during those years.

This "legacy lead" may not line recently built interstates, but the older U.S. route running parallel may be loaded.

All pollutants along the highway accumulate and peak just before rains.

A good thunderstorm is an efficient purifier, air is purified and pollutants washed off the right-of-way.

One study found air purity in vehicle interiors was only 24% better than roadside measurements.

That's with windows up.

Heavy stop-and-go traffic means your vehicles' interior is more likely accumulating smog, exhaust, dust, and other impurities.

Smog is Ozone

The nitrogen oxide in diesel exhaust, and volatile organic compounds (VOC), play an important role in the formation of ground-level ozone, otherwise known as smog.

Sunlight is required to produce smog, so ozone levels are highest in the summer.

Since ozone is an even greater part of the air purity problem, I see little purpose for car air purifiers which add ozone while the vehicle is occupied.

Here is a good use for ozone emitting room air purifiers you were thinking of trashing: put the purifier in the auto and plug it in overnight.

Ozone will build up substantially in the interior, oxidizing VOC’s. In the morning, remove the purifier from the car, and ventilate the interior completely before driving.

Carbon monoxide (CO) is a consequence of every combustion process, including cigarette smoking.

CO sticks to vital oxygen carrying hemoglobin in our blood, creating accident causing fatigue.

No car air purifier can filter carbon monoxide, which is concentrated along roads.

Carbon dioxide builds up inside an occupied cabin.

While not directly toxic, it will cause discomfort.

VOC: Unsafe at any Speed

EPA has identified 21 toxic chemicals in highway air.

Some toxic compounds are present in gasoline and are vaporized when gasoline evaporates or passes through the engine unburned.

Benzene, formaldehyde, acetaldehyde, 1,3-butadiene, polycyclic hydrocarbons, and fuel additives such as methyl tertiary butyl ether (MTBE) are present wherever there are autos.

Solvents used in cleaning and repair operations drip onto the pavement.

Leaking antifreeze from radiator hoses is extremely common, as are power steering fluid leaks.

Ions and Ionizers

Ions and their effects on health are discussed under the technology navbar, but the upshot is that rare negative air ions are "good" for particle cleaning and health.

Positive ions and a positive leaning air ion balance are considered "bad."

As air rushes over the exterior metal skin, negative charges are stripped away.

Positive ions build up in interior air, causing stimulation followed by fatigue.

This is why the car air ionizer has become so popular.

Air In Cars

Flow through ventilation is required by law: when the A/C is set to recirculate, all cars still exchange some outside air to maintain adequate oxygen in the vehicle interior.

This admits exhaust fumes and allergens.

Oil leaking on hot engine parts or dripping rubber fuel lines may produce a slight smell of gasoline inside the cab.

Many drivers will not realize this smell is coming from their own ride.

One more phrase has been introduced: "Love that new car smell."

Old automobile smells can be just as bad.

When you appraise a used car ask yourself if the previous owners smoked, used chemical upholstery cleaners, repainted interior metal work, or used solvent containing plastic patching compounds.

Dealers are notorious for using chemicals to makeover a trade in.

Did the doors, window gaskets, or moon-roof ever leak?

Wet carpeting and insulation can make mold very difficult to get rid of.

Some models have incurably wet A/C systems, breeding mold and blowing it in riders faces.

Old heater cores may have tiny anti-freeze leaks, making almost imperceptible smells in the air.

Dust levels in interiors can be far beyond what a small ionizer air purifier can handle.

Ionic air purification is not really air cleaning, it flocks particles into groups too heavy to float in air.

A car has powerful air currents which disturb settled dust. Frequent vacuuming and damp cloth cleaning should accompany installation of an air purifier.

Several manufacturers, mostly from Europe and Asia, have introduced built-in cabin air filters.

Some cleaning products can be toxic in a car's air. Interior air freshener sales continue at a brisk pace.

A vehicle interior is more confined than residential rooms: smoking and side stream smoke are especially unhealthy inside an already toxic car.

Rooms can be painted over, furniture and carpets removed.

Tars and particles from smoking can NEVER BE REMOVED from automobile headliners, upholstery, or AC ducting.

Air Purifiers for the Road

Driving a car can be our single most toxic activity. There are many models of auto air cleaners available. China has thousands of products, which fit the low budget mom and pop electronics explosion there.

Most are small ionizers, and can be plugged into the car's 12v DC cigarette lighter socket.

Few have any ability to actually purify air in cars, with its high impurity levels.

As with indoor air cleaners, better car purifiers have real fans and activated carbon for toxic chemicals.

Some can also double as a travel air purifier, using an optional AC power adapter.

Vehicle Air Purifiers: Reviews

For many car owners, the quickest route to better air in the car is to upgrade their car's cabin air filter with a premium model.

The following page has more on OEM car cabin air filters;

Does Your Car Have an Original Equipment Cabin Air Filter?

I have stopped advising folks whose auto does NOT have an original equipment air filter to buy the hundreds of Chinese ionizers, the choices are stark.

I would get a voltage inverter (12Volt to 120, minimum 1000 watts) and run a room air cleaner in the car.

Site Navigation


End Car Air Purifier, goto Home for air purifier reviews Last edit: 09/27/15

Air Purifier for the Car

"Indoor" Air Quality

Howard Hughes, the eccentric billionaire, once built a car air purifier in a limo.

Mr. Hughes was reputed to be very paranoid about invisible particles and germs.

The purifier cost more than the limousine, and took up most of the trunk. He couldn't open the windows, but I'm sure he had purified air.

We tend to feel safe inside our vehicle, but the atmosphere in the interiors of cars may be even worse than household indoor air.

With many car air purifiers on the market, we need to know more about the target impurities inside our vehicles.

The majority of automotive air purification devices on the market, mostly small ionizers without filters, are not up to the air purifying challenge.

Lost Highway

I remember when you didn't need a car air purifier, back when there was NO interstate highway system.

In 1955, I saw the last smoky steam locomotive, just before it was retired from service.

Not long after that, interstate highway construction began in earnest.

My mother, who was a staunch believer in "progress," made us walk 4 miles into the country to see the first overpass under construction (we had no car).

For most of my life, a road trip has been an escape from the monotony of daily life. two lane

I rode my first motorcycle, a 1966 Yamaha, west to California on what were then deserted two-lane highways.

The song said "get your kicks on route 66", so I did.

40 years later, driving 18 wheelers, I loved to park overnight in the same towns I rode through back in '66.

But now they are ghost towns of old route 66, their motels and diners broken, inhabited solely by packs of abandoned dogs.

Maybe a mile from the I-40 corridor, the air is pure there, and it's quiet.

Over on the big road, inhabited by packs of smoky tractor trailers, it's a different story.

On the Road, ...Again

"... I'm standing by a river
But the water doesn't flow
It boils with every poison...
You must learn this lesson fast and learn it well
This ain't no upwardly mobile freeway

Oh no, this is the road
I said this is the road
This....is the road to hell"
from Road To Hell, by Chris Rea

A busy interstate corridor has many sources of pollution; gas and diesel exhaust fumes, various particles, pollen, cigarette smoke, and germs.

Air flowing through typical auto interiors is far from pure. traffic

Studies have shown that those living near major highways are more likely to have a cardiovascular event.

Living near a transportation corridor with greater than 20,000 cars a day creates a six-fold increase in the risk of tumor.

Increased rates of lung disease, including asthma, characterize people living within 500 yards of a major roadway. Those driving are in the thickest soup outside a refinery.

Even the highway itself is toxic, consider the frequent repainting of stripes and outgassing of solvents from asphalt.

Latex particles, a growing asthma/allergy concern, are recycled into asphalt. Lead chromate has been used as pigment for yellow lines.

Keep on Truckin'

Diesel trucks: a love-hate relationship if there ever was.

We play with plastic models as kids, and drive wanna be styled pickups as adults.

Like the railroads before them, today’s transports cut a wide path, but not a clean path.

Serious landscape darkeners are soot from diesel fumes and dust from rubber tires.

Black rain, black snow: everything along an interstate corridor has this oily finish, with tiny soot particulates waiting to flurry into the air an auto moves through.

Brake dust, some of which still contains asbestos, accumulates as millions of brake shoes wear over billions of miles traveled. It builds up along the highway.

Mechanics working on brakes and clutches are trained to avoid generating clouds of fibers, but every vehicle on the road raises a huge cloud of roadside dust.

Cars and Purer Air

Clean air standards have made today's landscape look cleaner, and heavy traffic is easier to breathe in than it once was.

But appearances deceive.

Airborne particles can be classified as coarse ( bigger than 2 micron), fine (0.1 to 1 micron), and ultrafine ( 0.02 micron).

Catalytic converters are now standard exhaust cleaning controls on every new gas powered automobile.

Modern catalytic converters break down engine exhaust into fine particles called micron soot.

Fine and ultrafine particles are a minor component by weight, but they are significant by number, which makes them dangerous to health.

Small enough to evade our natural filters and be inhaled deep into the lungs, they can trigger an inflammatory response, causing serious health problems.

Particle pollution is connected with heart attacks, irregular heartbeat, lung disease, and asthma.

Heavy Metals

Heavy Metal in the air is not just loud music.

Like the trucks, the more numerous cars shed copper, lead, zinc, nickel, iron, antimony, and cadmium from wearing parts.

A three-way catalytic converter purifies air in an car's exhaust system, using platinum, palladium, and rhodium as catalysts.

A ceramic biscuit is coated with these metals which speed up the high temperature air purification process. The ceramic catalyst is made from a lightweight, fragile material with a honeycomb structure.

Road debris striking the converter or vibration from broken exhaust pipe supports can cause a catalyst fracture.

When a ceramic catalyst is fractured, the broken pieces can rattle around and grind into powder.

Rhodium, platinum, and palladium content of soils from U.S. roadsides is sometimes dense enough to consider recovery operations.

Mining pollution along the road?

Well, nobody has proposed that, but the point is made, highway roadsides accumulate toxins.

Lead, added to automotive fuels from 1926 to 1984, permeates the soil along any route that carried traffic during those years.

This "legacy lead" may not line recently built interstates, but the older U.S. route running parallel may be loaded.

All pollutants along the highway accumulate and peak just before rains.

A good thunderstorm is an efficient purifier, air is purified and pollutants washed off the right-of-way.

One study found air purity in vehicle interiors was only 24% better than roadside measurements.

That's with windows up.

Heavy stop-and-go traffic means your vehicles' interior is more likely accumulating smog, exhaust, dust, and other impurities.

Smog is Ozone

The nitrogen oxide in diesel exhaust, and volatile organic compounds (VOC), play an important role in the formation of ground-level ozone, otherwise known as smog.

Sunlight is required to produce smog, so ozone levels are highest in the summer.

Since ozone is an even greater part of the air purity problem, I see little purpose for car air purifiers which add ozone while the vehicle is occupied.

Here is a good use for ozone emitting room air purifiers you were thinking of trashing: put the purifier in the auto and plug it in overnight.

Ozone will build up substantially in the interior, oxidizing VOC’s. In the morning, remove the purifier from the car, and ventilate the interior completely before driving.

Carbon monoxide (CO) is a consequence of every combustion process, including cigarette smoking.

CO sticks to vital oxygen carrying hemoglobin in our blood, creating accident causing fatigue.

No car air purifier can filter carbon monoxide, which is concentrated along roads.

Carbon dioxide builds up inside an occupied cabin.

While not directly toxic, it will cause discomfort.

VOC: Unsafe at any Speed

EPA has identified 21 toxic chemicals in highway air.

Some toxic compounds are present in gasoline and are vaporized when gasoline evaporates or passes through the engine unburned.

Benzene, formaldehyde, acetaldehyde, 1,3-butadiene, polycyclic hydrocarbons, and fuel additives such as methyl tertiary butyl ether (MTBE) are present wherever there are autos.

Solvents used in cleaning and repair operations drip onto the pavement.

Leaking antifreeze from radiator hoses is extremely common, as are power steering fluid leaks.

Ions and Ionizers

Ions and their effects on health are discussed under the technology navbar, but the upshot is that rare negative air ions are "good" for particle cleaning and health.

Positive ions and a positive leaning air ion balance are considered "bad."

As air rushes over the exterior metal skin, negative charges are stripped away.

Positive ions build up in interior air, causing stimulation followed by fatigue.

This is why the car air ionizer has become so popular.

Air In Cars

Flow through ventilation is required by law: when the A/C is set to recirculate, all cars still exchange some outside air to maintain adequate oxygen in the vehicle interior.

This admits exhaust fumes and allergens.

Oil leaking on hot engine parts or dripping rubber fuel lines may produce a slight smell of gasoline inside the cab.

Many drivers will not realize this smell is coming from their own ride.

One more phrase has been introduced: "Love that new car smell."

Old automobile smells can be just as bad.

When you appraise a used car ask yourself if the previous owners smoked, used chemical upholstery cleaners, repainted interior metal work, or used solvent containing plastic patching compounds.

Dealers are notorious for using chemicals to makeover a trade in.

Did the doors, window gaskets, or moon-roof ever leak?

Wet carpeting and insulation can make mold very difficult to get rid of.

Some models have incurably wet A/C systems, breeding mold and blowing it in riders faces.

Old heater cores may have tiny anti-freeze leaks, making almost imperceptible smells in the air.

Dust levels in interiors can be far beyond what a small ionizer air purifier can handle.

Ionic air purification is not really air cleaning, it flocks particles into groups too heavy to float in air.

A car has powerful air currents which disturb settled dust. Frequent vacuuming and damp cloth cleaning should accompany installation of an air purifier.

Several manufacturers, mostly from Europe and Asia, have introduced built-in cabin air filters.

Some cleaning products can be toxic in a car's air. Interior air freshener sales continue at a brisk pace.

A vehicle interior is more confined than residential rooms: smoking and side stream smoke are especially unhealthy inside an already toxic car.

Rooms can be painted over, furniture and carpets removed.

Tars and particles from smoking can NEVER BE REMOVED from automobile headliners, upholstery, or AC ducting.

Air Purifiers for the Road

Driving a car can be our single most toxic activity. There are many models of auto air cleaners available. China has thousands of products, which fit the low budget mom and pop electronics explosion there.

Most are small ionizers, and can be plugged into the car's 12v DC cigarette lighter socket.

Few have any ability to actually purify air in cars, with its high impurity levels.

As with indoor air cleaners, better car purifiers have real fans and activated carbon for toxic chemicals.

Some can also double as a travel air purifier, using an optional AC power adapter.

Vehicle Air Purifiers: Reviews

For many car owners, the quickest route to better air in the car is to upgrade their car's cabin air filter with a premium model.

The following page has more on OEM car cabin air filters;

Does Your Car Have an Original Equipment Cabin Air Filter?

I have stopped advising folks whose auto does NOT have an original equipment air filter to buy the hundreds of Chinese ionizers, the choices are stark.

I would get a voltage inverter (12Volt to 120, minimum 1000 watts) and run a room air cleaner in the car.

Site Navigation


End Car Air Purifier, goto Home for air purifier reviews

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