Is formaldehyde the sole source of the 'new car smell'? No.
It's more than likely the combined smell of the VOC's (of which formaldehyde is one) emitting from the interior, as there's over a dozen VOC's which are present.
Brown, Stephen K and Min Cheng, 2007. Volatile Organic Compounds (VOCs) in New Car Interiors
They found that the amount of VOCs present is dependent upon the 'delivery time' of the car from the manufacturer. Those cars which didn't have a 'shelf life' at a dealership had the highest amounts of VOCs present. Those which had been on display outside had the lowest.
The chemicals they recorded were:
- acetone + n-pentane
- n-Hexane + MEK (Methyl ethyl ketone)
- MIBK (methyl isobutyl ketone)
- m+p Xylene
- Styrene + o-xylene
- Ethylene glycol butyl ether
- 1,2,4 trimethylbenzene
Of these chemicals, they ranked them from most prevalent to least as follows:
Overall, the more dominant VOCs found in the new cars (highest to
lowest concentrations) were toluene, acetone/pentane,
o-xylene/styrene, 1,2,4-trimethylbenzene, m,p-xylene, various C7–12
alkanes, ethylbenzene, n-hexane and ethylene glycol butyl ether.
They reported the following regarding the toxicity of the VOCs present:
Benzene is a category 1 IARC carcinogen (known human carcinogen) for
which an annual exposure goal of 16 µg/m3 has been recommended (see
Section 1.3). Since urban populations spend an average of one hour per
day in car travel (Newton et al. 2000), these results indicate that
car interiors can be contributors to total exposure to benzene.
Few environmental exposure goals are established for other VOCs. The
NHMRC goal of 250 µg/m3 for any compound was exceeded for many VOCs in
Cars 2 and 3. Toxic effects of some of these VOCs and ambient air
goals (µg/m3 at 0oC/101kPa) based on these effects (Calabrese & Kenyon
- acetone: mucosal irritation (8-hour goal, 39,000)
- cyclohexanone: possible human carcinogen (annual goal, 180)
- ethylbenzene: systemic toxin (24-hour goal, 140);
- MIBK: systemic toxin (8-hour goal, 540)
- n-hexane: neurotoxin (24-hour goal, 540);
- styrene: probable human carcinogen (annual goal, 29)
- toluene: central nervous system dysfunction (8-hour goal, 1600);
xylene isomers: foetal development toxins (24-hour goals: o-xylene
310, m-xylene 3100, p-xylene 62).
It is seen that several of these goals may have been exceeded in the
cars for several weeks after manufacture TVOC concentrations also
occurred at levels that may affect occupants (see Section 1.2) for
weeks to months after car purchase, although not for years. The
effects that could be caused by this TVOC exposure include eye
irritation, and performance and memory factors, all of which may be
important car safety issues, as well as occupant health and comfort
Note, however, that all of the above measurements were made in closed
cars at low ambient temperatures. Lower concentrations may be expected
with greater ventilation of the car interior, while higher
concentrations may be expected under higher ambient temperatures. More
detailed investigation of VOC concentrations under different operating
conditions is needed to decide an appropriate test protocol for
simulating occupant exposure to car interior pollutants.
They conclude the following:
High concentrations of VOCs were found in new cars, especially those
reaching the market soon after manufacture, i.e with minimum
path-to-market. The total VOC (TVOC) levels found have been observed
previously to cause sensory irritation and performance and memory
impairment to human subjects, showing that the pollution of new car
interiors may be a safety issue. Several of the VOCs observed have
potential toxic effects, an aspect that should be explored in further
study under simulated conditions of car usage. The decay of TVOC
concentrations was found to be exponential, at approximately 20% per
week, with the NHMRC indoor air goal being reached after approximately
So yes, that lovely smell you smell in your new car is a bunch of chemicals you really don't want to be smelling. And, if you live where it's warm - you'll smell more of them.