Monday, August 16, 2010

Berkeley Lab news release:Study shows ozone and nicotine a bad combination for asthma

An html version of this press release with images and links to
additional information can be viewed at

Another reason for including asthma on the list of potential health
risks posed by secondhand tobacco smoke, especially for non-smokers, has
been uncovered. Furthermore, the practice of using ozone to remove the
smell of tobacco smoke from indoor environments, including hotel rooms
and the interiors of vehicles, is probably a bad idea.

A new study by researchers with the Lawrence Berkeley National
Laboratory (Berkeley Lab) shows that ozone can react with the nicotine
in secondhand smoke to form ultrafine particles that may become a bigger
threat to asthma sufferers than nicotine itself. These ultrafine
particles also become major components of thirdhand smoke - the residue
from tobacco smoke that persists long after a cigarette or cigar has
been extinguished.

"Our study reveals that nicotine can react with ozone to form secondary
organic aerosols that are less than 100 nanometers in diameter and
become a source of thirdhand smoke," says Mohamad Sleiman, a chemist
with the Indoor Environment Department of Berkeley Lab's Environmental
Energy Technologies Division (EETD) who led this research.

"Because of their size and high surface area to volume ratio, ultrafine
particles have the capacity to carry and deposit potentially harmful
organic chemicals deep into the lower respiratory tract where they
promote oxidative stress," Sleiman says. "It's been well established by
others that the elderly and the very young are at greatest risk."

Results of this study have been reported in the journal /Atmospheric
Environment /in a paper titled "Secondary organic aerosol formation from
ozone-initiated reactions with nicotine and secondhand tobacco smoke."
Co-authoring this paper with Sleiman were Hugo Destaillats and Lara
Gundel, also with EETD's Indoor Environment Department, and Jared Smith,
Chen-Lin Liu, Musahid Ahmed and Kevin Wilson with the Chemical Dynamics
Group of Berkeley Lab's Chemical Sciences Division. The study was
carried out under a grant from the University of California's
Tobacco-Related Disease Research Program.

The dangers of mainstream and secondhand tobacco smoke, which contain
several thousand chemical toxins distributed as particles or gases, have
been well documented. This past February, a study, also spearheaded by
Sleiman, Destaillats and Gundel, revealed the potential health hazards
posed by thirdhand tobacco smoke which was shown to react with nitrous
acid, a common indoor air pollutant, to produce dangerous carcinogens.
Until now, however, in terms of forming ultrafine particles, there have
been no studies on the reaction of nicotine with ozone.

Released as a vapor by the burning of tobacco, nicotine is a strong and
persistent adsorbent onto indoor surfaces that is released back to
indoor air for a period of months after smoking ceased. Ozone is a
common urban pollutant that infiltrates from outdoor air through
ventilation that has been linked to health problems, including asthma
and respiratory ailments.

Says co-author Gundel, "Not only did we find that nicotine from
secondhand smoke reacts with ozone to make ultrafine particles – a new
and stunning development – but we also found that several oxidized
products of ozone and nicotine have higher values on the asthma hazard
index than nicotine itself."

Says co-author Destaillats, "In our previous study, we found that
carcinogens were formed on indoor surfaces, which can lead to exposures
that are likely to be dominated by dermal uptake and dust ingestion.
This study suggests a different exposure pathway to aged secondhand or
thirdhand smoke through the formation and inhalation of ultrafine
particles. Also, our group had previously described the formation of
secondary organic aerosols in reaction of indoor ozone with terpenoids,
commonly present in household products. But this is the first time that
nicotine has been tagged as a potential candidate to form ultrafine
particles or aerosols through a reaction with ozone."

To identify the products formed when nicotine in secondhand smoke is
reacted with ozone, Sleiman and his co-authors utilized the unique
capabilities of Berkeley Lab's Advanced Light Source (ALS), a premier
source of x-ray and ultraviolet light for scientific research. Working
at ALS Beamline 9.0., which is optimized for the study of chemical
dynamics using vacuum ultraviolet (VUV) light and features an aerosol
chemistry experimental station, the researchers found new chemical
compounds forming within one hour after the start of the reaction.

"The tunable VUV light of Beamline 9.0.2's custom-built VUV aerosol mass
spectrometer minimized the fragmentation of organic molecules and
enabled us to chemically characterize the secondhand smoke and identify
individual constituents of secondary organic aerosols," says Sleiman.
"The identification of multifunctional compounds, such as carbonyls and
amines, present in the ultrafine particles, made it possible for us to
estimate the Asthma Hazard Index for these compounds."

While the findings in this study support recommendations from the
California EPA and the Air Resources Board that discourage the use of
ozone-generating "air purifiers," which among other applications, have
been used for the removal of tobacco odors, the Berkeley Lab researchers
caution that the levels of both ozone and nicotine in their study were
at the high end of typical indoor conditions.

Says Sleiman, "In addition, we need to do further investigations to
verify that the formation of ultrafine particles occurs under a range of
real world conditions. However, given the high levels of nicotine
measured indoors when smoking takes place regularly and the significant
yield of ultrafine particles formation in our study, our findings
suggest new link between asthma and exposure to secondhand and thirdhand

Berkeley Lab is a U.S. Department of Energy national laboratory located
in Berkeley, California. It conducts unclassified scientific research
for DOE's Office of Science and is managed by the University of
California. Visit our Website at <>

Mr. Lynn Yarris
Senior science writer
Lawrence Berkeley National Laboratory
Joint BioEnergy Institute
phone: 510-486-5375

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