marketers about 10¢ per 6oz. can. Perhaps surprisingly, a presentation to a major marketer was initially
rejected because its technical executive thought hydrocarbons had a very bad odor. Later, when
samples were evaluated, that false impression vanished and the company began marketing a kindred
formula very successfully within a year.
The key to the water-based products was to emulsify up to about 32% hydrocarbon propellants
using a non-ionic water-in-oil (w/o) surfactant.
Typical Water-Based Aerosol Air Freshener
n 61.761% Deionized Water or Water USP (U.S. Pharmacopeia grade)
n 05.965% Odorless Mineral Spirits (OMS)
n 00.151% Oleyl Diethanolamide
n 00.014% Octoxynol-9 (as Triton X-100 from Dow Chemical)
n 00.198% Sodium Benzoate
n 00.411% Fragrance
n 31.500% Hydrocarbon Propellant A-46
Unlike the more commonplace non-ionic oil-in-water (o/w) emulsifiers that created foam bubbles
when sprayed, these low hydrophile-lipophile balance (HLB) surfactants provided reasonably small
non-foamy particles. Some commercial formulas worked with as little as 0.12% emulsifier and 30%
isobutane A-31 propellant. Unlike the anhydrous CFC types, these products had to
be shaken before use. The emulsions were meta-stable, with the first sign of propellant
separation taking place in about 90 seconds as a thin, clear top layer.
The stratospheric ozone depletion issue led to a ban of all CFC propellants in
the mid-to-late 1970s. By then, virtually all aerosol air freshener products had been
converted to water-based formulas, so there was almost no direct effect. However, in
1975, the aerosol industry’s product unit volume plummeted about 31% and did not
fully recover for a decade. Some experts, such as the late Douglas Fratz (HCPA Senior
Science Fellow), were of the opinion that the ozone debacle cost the industry about
1.0 billion units per year during every year since 1975. The unit volume of air fresheners
decreased from about 250 million to fewer than 200 million per year during that
trying decade.
Major marketers, such as Colgate, S.C. Johnson, Reckitt & Coleman and Renuzit,
remained guardedly optimistic—launching new fragrances and can designs—but
reducing their advertising to a pessimistic consumer audience. By about 1991, the
California South Coast Air Quality Management District (SCAQMD) began agitating
against aerosols and related products, claiming climatologists were convinced that
they were indirectly contributing to excessive amounts of ozone in the troposphere.
The affected industries fended off the SCAQMD accusations for a few years, until the
State Congress charged the much larger California Air Resources Board (CARB) to
address the problem. During its early years, CARB’s Peter Venturini informally stated
that CARB would have to reduce the volatile organic compound (VOC) content of
aerosols and kindred products by about 85% to meet its ultimate goals and promise
to the U.S. Environmental Protection Agency (EPA) via State Implementation Plans
(SIPS). Today, years later, it would appear that his comment was essentially correct.
CARB began by defining the characteristics of a VOC—the organic substance
would have to exhibit a vapor pressure of over 0.10 mm Hg, have 12 or fewer carbon
atoms per molecule and have a half-life of less than three months in the troposphere.
On that basis, the above water-based formula would have OMS and A-46 as VOCs,
for a total of 37.465%.
About 1994, CARB released its first compendium of mandatory VOC limits.
Water-based air fresheners were identified as two-phase products limited to 30%
Citrus Magic from
Beaumont Products,
Inc.—known for
it fresh, fruity
scents—also releases
a Holiday Limited
Edition spray in
Evergreen and
Peppermint Twist.
VOC content. The industry responded by creating formulas such as:
Water-Based Air Freshener (1st CARB Revision)
n 69.17% Deionized Water or Water USP
n 00.13% Oleyl Diethanolamide (Witcamide 511)
n 00.50% Fragrance
n 00.20% Sodium Benzoate
n 30.00% Hydrocarbon Propellant A-46 (VOC)
26 Spray June 2020