Page 420 - Book Hosokawa Nanoparticle Technology Handbook

FUNDAMENTALS CH. 7 ENVIRONMENTAL AND SAFETY ISSUES WITH NANOPARTICLES
characterize indoor particles and correlate between 7.2.5.1 Secondary particle formation by gas phase
indoor and outdoor ones from the viewpoint of evalu- ozonolysis
ating the influence of indoor air quality (IAQ) on For particle formation resulting from chemical reac-
human health. tion via ozone, the reaction of terpenes is very com-
As shown in Table 7.2.1, indoor nanoparticles orig- mon in indoor environments as well as atmospheric
inate from the several sources such as products of ones. Terpenes are emitted from fragrance-containing
chemical reactions, nonvolatile residues (NVRs) of vegetable oils such as pine oil and citrus oil, and
liquid droplets, printers/photocopiers, combustion, wooden materials including woody furniture [1].
bioaerosols, and infiltration of outdoor air.
Meanwhile, sources of emission of ozone are air
cleaners, air-conditioners, laser printers using corona
discharge, and infiltration of outdoor air. Terpenes are
generic terms of unsaturated organic compounds that
Table 7.2.1
Main generation sources of indoor nanoparticles. are composed of isoprene as unit (e.g. -pinene and
limonene). These compounds used for household
applications readily react with ozone because they
Chemical reaction by ozone
Terpenes ( -pinene, limonene) – ozone reaction, have one or more double bonds. It has been proposed
formation of irritant products that, as shown in Fig. 7.2.8, the reaction mainly pro-
ceeds to form less volatile pinonic acid via pinon-
Nonvolatile residues (NVRs) of droplets aldehyde of intermediate [2].
Atomization-type air humidifier and cleaner Furthermore, the acid-catalyzed reaction allows the
Printers products to convert into higher molecular weight com-
Satellite particles from ink-jet printer, toner-originated pounds by the polymerization via carbonyl groups in
matters from laser printer the aldehydes and the aldol condensation [3].
It has been reported that the resultant generated
Combustion particles have a size distribution with a peak diame-
Cooking by gas stoves, cigarette smoking, incense ter of about 30 nm, and that the products by terpenes
smoking
ozonolysis irritate human airways [4].
Bioaerosols
Virus 7.2.5.2 Nonvolatile residue (NVR) of liquid droplets
Nanoparticles are also generated from air humidi-
Outdoor sources
Penetration of outdoor nanoparticles through windows fiers or negative air–ion generators in which water is
and other house openings atomized. In general, humidifiers are mainly catego-
rized into vaporization type and atomization type [5].

Figure 7.2.8
Reaction path of -pinene ozonolysis.

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