"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 aboutthe target impurities inside our vehicles. The majority of automotive air purification devices on the market, mostly small ionizers without filters, arenot up to the air purifying challenge.
Lost Highway
I remember when you didn't need a car air purifier.
In 1955, I saw the last smoky steam locomotive, just before it retired from service. Not long after that, interstate highway construction began in earnest.
For most of my life, a road trip has been an escape from the monotony of daily life.
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 townsI 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 interiorsis far from pure.
Studies have shown that those living near major highways are more likely tohave 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 outgassingof 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 plasticmodels as kids, and drive wanna be styled pickups as adults. Like the railroads beforethem, 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.
Asthma Cause: Diesel Exhaust?
Latex Allergy Cause: Tire Dust?
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 upalong the highway.
Mechanics working on brakes and clutches are trained to avoid generating cloudsof fibers, but every vehicle on the road raises a huge cloud of roadside dust.
Brake Dust: Another Allergy Cause?
Cars and Purer Air
Clean air standards have made today's landscape look cleaner, and heavy traffic is easierto 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 triggeran inflammatory response, causing serious health problems.
Particlepollution is connected with heartattacks, 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 temperatureair purification process. The ceramic catalyst is made from a lightweight, fragile material with a honeycomb structure.
Road debris striking the converter or vibration frombroken exhaust pipe supports can cause a catalyst fracture. When aceramic catalyst is fractured, the broken pieces canrattle around and grind into powder.
Rhodium, platinum, and palladium content of soils from U.S. roadsides is sometimesdense enough to consider recovery operations.
Mining pollution along the road?
Well, nobody has proposed that, but the point is made, highway roadsidesaccumulate toxins.
Lead, added to automotive fuels from 1926 to 1984, permeates the soil alongany route that carried traffic during those years. This "legacy lead" may not linerecently 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 washedoff 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 knownas smog. Sunlight is required to produce smog, so ozone levels are highest in the summer. I rant at length about ozone (under indoor air quality on navbar).Since ozone is an even greater part of theair 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 autoand plug it in overnight. Ozone will build up substantially in the interior, oxidizing VOC’s. In themorning, remove the purifier from the car, and ventilate the interior before driving.
Carbon monoxide (CO) is a consequence of every combustion process, including cigarette smoking. CO sticks to vital oxygen carryinghemoglobin 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 causediscomfort.
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 whereverthere 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 theupshot is that rare negative air ions are "good" for particle cleaning and health. Positive ions and a positive leaningair 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."
Chemicals Cause New Car Smell
Old automobile smells can be just as bad. When you appraise a used car ask yourselfif the previous owners smoked, used chemical upholstery cleaners, repainted interiormetal 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 difficultto get rid of. Some models have incurably wet A/C systems, breeding mold andblowing it in riders faces. Old heater cores may have tiny anti-freeze leaks, makingalmost imperceptible smells in the air.
Dust levels in interiors can be far beyond what a small ionizer air purifier can handle. Ionicair 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 dampcloth 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 continueat a brisk pace. A vehicle interior is more confined than residential rooms: smoking and side stream smoke areespecially 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 and upholstery.
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
Auto Air Cleaners Evaluation Criteria
Amaircare Roomaid Portable HEPA Filter Review
Aireox D-22 Portable Air Filter Review
Does Your Car Have an Original Equipment Cabin Air Filter? Go to Top of Page
End Car Air Purifier, try Sitemap for navigation
This ain't no technological breakdown
Oh no, this is the road to hell
