A3.5 Aerosol Products
A3.5.1 Medical Applications
Metered dose inhalers (MDIs) form a reliable and effective therapy for asthma
and chronic obstructive pulmonary disease (COPD).
There are estimated to be 300 million patients with asthma and COPD worldwide.
Approximately 450-500 million MDIs are used annually worldwide with asthma prevalence
increasing as urbanization of developing countries continues. It is estimated
that 10,000 metric tons (tonnes) of CFC and 1000 tonnes of HFCs were used in
MDIs worldwide in 1998 (UNEP, 1998b, 1999b). HFC-based MDIs are essential for
the near-term CFC phaseout, because other available options, including dry powder
inhalers (DPIs) (single or multi-dose), nebulizers (hand held or stationary),
orally administered drugs (tablets, capsules, or oral liquids), and injectable
drugs, which are alternatives for not using CFCs or HFCs, cannot currently replace
CFC products for all patients (UNEP, 1999b). The transition to HFC MDIs began
in 1995, and approximately 5% in 1998 and 10% in 1999 contain HFC (UNEP, 1999b).
HFC-based MDIs and DPIs are expected to help minimize the use of CFCs by 2005
in developed countries, while providing essential medication for patients. Important
factors in the conversion to DPIs will include their acceptance by doctors,
patients, insurance companies, and medical authorities.
Assuming the complete phase-out of CFC MDIs and a continued growth rate in
demand for asthma and COPD treatment of 1.5%3.0%/yr, it is estimated that
HFC consumption and emissions will be 7,500 to 9,000t/yr about 33.6MtCeq
in 2010 (UNEP, 1999b).
DPIs have been formulated successfully for many anti-asthma drugs. Dry powder
inhalers are an immediately available alternative free of CFCs and HFCs; however,
they are not a satisfactory alternative to the pressurized MDIs for some patients
with very low inspiratory flow (e.g., some small children and elderly people,
patients) with acute asthma attacks or with severe respiratory diseases, and
emergency-room patients. Use is likely to accelerate, particularly as they may
be more suitable for young children than the older DPIs (UNEP, 1999b). In Scandinavian
countries, government policies have led to greater use of DPIs than of MDIs
(IPCC/TEAP, 1999; UNEP, 1999b; March, 1998).
The abatement cost estimates to reduce future HFC emissions by replacing MDIs
with DPIs depend on the price of DPIs. The cost per equivalent dose varies between
products and countries, with some CFC-free MDIs being more expensive than CFC-based
MDIs and some DPIs more expensive than both CFC- and HFC-based MDIs (ARCF, 2000).
In Europe, prices are less as much as US$4 higher for a DPI than for a comparable
MDI (Harnisch and Hendriks, 2000). It is estimated that, by 2010, the EU can
reduce HFC emissions by 30% at a cost of about US$460/tCeq and 50%
at about US$490/tCeq (March, 1998), which translates to a differential
cost of US$4 over MDIs; for one country in Europe there is no differential cost
(Harnisch and Hendriks, 2000). It is not currently medically feasible to replace
MDIs by DPIs completely because approximately 25% of MDI use is for patients
who require medication be forced into their respiratory system (Öko-Recherche,
A3.5.2 Cosmetic, Convenience, and Technical Aerosol Propellants
Global 1998 consumption and emissions of HFCs in non-medical aerosol products
was less than 15,000 tonnes (UNEP, 1998d) with two-thirds HFC-134a and one-third
HFC-152a less than 4MtCeq. Emissions of HFCs are projected
to not exceed 20,000 tonnes in 2010 (IPCC/TEAP, 1999) or about 5MtCeq
(calculated assuming equal emissions of HFC-134a and HFC-152a). HFCs have replaced
only about 2% of the aerosol product market that would have used CFCs had there
not been the Montreal Protocol (McFarland, 1999). Hydrocarbon, dimethyl ether
(DME), carbon dioxide, nitrogen propellants, and not-in-kind alternative products
have replaced the remaining 98% of projected demand.
HFCs are used in aerosol products primarily to comply with technical requirements
or environmental regulations. HFC-134a is the propellant of choice for products
that must be completely non-flammable. An example of HFC use based on a technical
requirement is non-flammable, far-reaching insecticide products used on high-voltage
power lines and transformers where workers cannot escape from wasps and hornets.
HFC-152a is the propellant of choice to replace hydrocarbon aerosol propellants
restricted in Southern California and in some applications where hydrocarbons
and dimethyl ether are too flammable but the flammability of HFC-152a is acceptable.
HFC-134a and HFC-152a are the propellants of choice for laboratory, analytical,
and experimental uses where chemical properties are important and flammability
may be a concern.
One source estimates that about 45% of HFC emissions from cosmetic and convenience
applications where flammability is an issue could be eliminated at a cost of
US$70/tCeq and about 70% could be eliminated at a cost of about US$130/tCeq
The aerosol product industry has every incentive to minimize HFC use. HFCs
cost more than other propellants and unnecessary HFC use has the potential to
re-ignite consumer boycotts like the CFC boycotts in the early 1970s that led
to national bans on certain cosmetic products. Boycotts could threaten sales
of all aerosol products because consumers may not be able to distinguish targetted
HFC products from acceptable hydrocarbon products (UNEP, 1999b).
A self-chilling beverage can was designed to achieve refrigeration
through the physics of expanding and emitting approximately 3575g of HFC-134a
directly to the atmosphere for every beverage can chilled. The inventing company
pledged not to manufacture or license the technology and to discourage its use,
the US government banned the use of HFCs in self-chilling beverage cans (US
Federal Register, 1999), and a number of HFC producers have stated publicly
that they will not supply such an application. However, self-chilling cans using
HFC-134a are marketed in at least one country and it is estimated that even
a small market penetration could substantially increase emissions of greenhouse
gases (US Federal Register, 1999).
The UNEP/TEAP HFC and PFC Task Force (UNEP, 1999b) developed principles to
guide the use of HFCs for aerosol products:
- recommend HFCs be used only in applications where they provide technical,
safety, energy, or environmental advantage that are not achieved by not-in-kind
- select the HFC compound with the smallest GWP that still meets the application
Application of these principles justifies the use of HFCs for some products
in some circumstances but these responsible use criteria are not
satisfied when not-in-kind alternatives are technically and economically suitable.
The above-mentioned study (UNEP, 1999b) includes detailed evaluation of alternatives
and substitutes for aerosol safety products (insecticides, boat horns, noise-makers),
cosmetic products (deodorants, hair sprays, shaving creams), convenience products
(room fresheners, dust blowers, tyre inflators, foam caulk, and insulation),
and novelty products (foam party streamers, pneumatic pellet and bait guns).