Handbook of Solvents - George Wypych - ChemTech - Ventech!

18.1 Measurement and estimation of solvents emission and odor 1203
18.1.2 REVIEW OF SOURCES OF SOLVENT EMISSIONS
18.1.2.1 Causes for emissions
The basic human needs include: eating, drinking and breathing. In a 60-year lifetime, human
being takes up about 30 t of food, 60 t of drink and 300 t of air. 12 Thus air pollution may
have a large influence on human health. In comparison with outside air and the ambient air
within public transportation vehicles and terminals, room air quality is of the greatest interest,
since the population in North American cities stays indoors more than 93% time according
to findings by Szalai 13 and more than 91% according to Chapin, 14 of this time > 67 % is
spent in living space and about 4-5 % in the workplace.
Sources for volatile substances in indoor air are diverse and originate, apart from that
brought in with outside air and produced by the living occupants (people, pets) and their activities
(e.g., smoking), from the materials themselves which have been applied for building
and furnishing the room. These include:
• building materials
• glues
• floor covering
• wallpaper
• internal decorative textiles
• paints
• furniture, upholstered furniture, etc.
These materials may contain volatile organic, but also inorganic, compounds, which
are evaporated during use. The emission of these volatile compounds is influenced by a
large number of factors, such as:
• chemical/physical structure of the material (thickness, surface structure)
• volatility, polarity of the volatile compounds
• room temperature and humidity
• room load, i.e., the ratio of the area of emitting surface and the volume of room air
• ventilation, rate of air flow
• load of the external air entering (dust, substances)
The residual monomers from plastics, reactive products (e.g., formaldehyde), degradation
products, flame protection media, softeners etc. may be emitted from building materials.
18.1.2.2 Emissions of VOCs from varnishes and paints
A substantial part of emitted materials are solvents. They preferably originate from varnishes,
paints and glues. Table 18.1.1 shows a survey of the main types of varnishes referring
to their average solvent content.
Table 18.1.1. Solvent share in various types of varnishes
Material Solvent content, wt%
Stain ~95
Cellulose nitrate varnish ~75
PUR varnish 35-70
Polyester varnish 35
UV roller varnish based on acrylate 2-10