clothing, for mosquito control, and in agricultural settings. The formulations include
products that have a direct application on the skin of pets for lice treatment,
impregnation of cloth, in sprays, and as part of aerosolizing devices for treatments
of larger areas. Since many pyrethroids are semi-volatile compounds, even applications onto surfaces can result in elevated air concentrations as they volatilize.
Whether these products are used by professionals or purchased for direct use by
the consumer, the result is the same: elevated air concentrations, both indoors and
outdoors, exposing a wide section of the population [8, 9].
A growing application of pyrethroid use is as a mosquito repellent, which can be
applied topically but also released into the air from mosquito coils, electric vaporizers, or aerosol sprays resulting in elevated air levels [10, 11]. These devices, along
with other applications, such as foggers implemented to kill swarming flying insects,
can produce transient high indoor air concentrations (μg/m
3 ) during their application. Many formulations of pyrethrins also include agents that act as synergists, such
as piperonyl butoxide, piperonyl sulfoxide, and sesamex, whose role is to interfere
with the insects’ enzymatic system by degrading pyrethrins, thereby improving the
pyrethroid or permethrin’s effectiveness.
2 Regulation of Pyrethroids
The production and use of pyrethroids, as well as all pesticides, in the USA are
regulated by the US EPA Office of Pesticide Programs under the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA) and the Food Quality Protection Act
(FQPA). Within Europe regulation of pesticides, also referred to as plant protection
products (PPP), can be regulated by the European Union and for food by the
European Food Safety Authority. Regulation can also be implemented through
individual countries that are part of the European Union. Countries and regions
throughout the world have generally developed regulations for pesticide use and
acceptable residual amounts [12]. The regulations are designed to minimize harmful
exposure through the air and other exposure routes by providing direction on
(1) where and how a pesticide can be used and (2) what specific details need to be
included on their labels for their use, storage, and disposal. The label provides
guidance to professional applicators to protect themselves and the general public.
Labels are also required for consumer products to indicate how they can be used
safely. Pyrethroids are permitted pesticides for multiple applications in agricultural
and residential settings. Regulations are based on human health risk assessments and
ecological risk assessments and have been released or are in draft form for many
pyrethroids (i.e., allethrins, bifenthrin, cyfluthrins, cypermethrin, cyphenothrin,
d-phenothrin, deltamethrin, esfenvalerate, etofenprox, fenpropathrin, flumethrin,
gamma-cyhalothrin, imiprothrin, lambda-cyhalothrin, momfluorothrin, permethrin,
prallethrin, pyrethrins, resmethrin, tau-fluvalinate, tefluthrin, tetramethrin, and
tralomethrin and for two synergists often added to the pesticide formulation
piperonyl butoxide and MGK-264) [9]. The regulation for each pyrethroid provides
information on its type (e.g., synthetic pyrethroid, knockdown agent), target
Indoor and Outdoor Pyrethroid Air Concentrations
229
products that have a direct application on the skin of pets for lice treatment,
impregnation of cloth, in sprays, and as part of aerosolizing devices for treatments
of larger areas. Since many pyrethroids are semi-volatile compounds, even applications onto surfaces can result in elevated air concentrations as they volatilize.
Whether these products are used by professionals or purchased for direct use by
the consumer, the result is the same: elevated air concentrations, both indoors and
outdoors, exposing a wide section of the population [8, 9].
A growing application of pyrethroid use is as a mosquito repellent, which can be
applied topically but also released into the air from mosquito coils, electric vaporizers, or aerosol sprays resulting in elevated air levels [10, 11]. These devices, along
with other applications, such as foggers implemented to kill swarming flying insects,
can produce transient high indoor air concentrations (μg/m
3 ) during their application. Many formulations of pyrethrins also include agents that act as synergists, such
as piperonyl butoxide, piperonyl sulfoxide, and sesamex, whose role is to interfere
with the insects’ enzymatic system by degrading pyrethrins, thereby improving the
pyrethroid or permethrin’s effectiveness.
2 Regulation of Pyrethroids
The production and use of pyrethroids, as well as all pesticides, in the USA are
regulated by the US EPA Office of Pesticide Programs under the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA) and the Food Quality Protection Act
(FQPA). Within Europe regulation of pesticides, also referred to as plant protection
products (PPP), can be regulated by the European Union and for food by the
European Food Safety Authority. Regulation can also be implemented through
individual countries that are part of the European Union. Countries and regions
throughout the world have generally developed regulations for pesticide use and
acceptable residual amounts [12]. The regulations are designed to minimize harmful
exposure through the air and other exposure routes by providing direction on
(1) where and how a pesticide can be used and (2) what specific details need to be
included on their labels for their use, storage, and disposal. The label provides
guidance to professional applicators to protect themselves and the general public.
Labels are also required for consumer products to indicate how they can be used
safely. Pyrethroids are permitted pesticides for multiple applications in agricultural
and residential settings. Regulations are based on human health risk assessments and
ecological risk assessments and have been released or are in draft form for many
pyrethroids (i.e., allethrins, bifenthrin, cyfluthrins, cypermethrin, cyphenothrin,
d-phenothrin, deltamethrin, esfenvalerate, etofenprox, fenpropathrin, flumethrin,
gamma-cyhalothrin, imiprothrin, lambda-cyhalothrin, momfluorothrin, permethrin,
prallethrin, pyrethrins, resmethrin, tau-fluvalinate, tefluthrin, tetramethrin, and
tralomethrin and for two synergists often added to the pesticide formulation
piperonyl butoxide and MGK-264) [9]. The regulation for each pyrethroid provides
information on its type (e.g., synthetic pyrethroid, knockdown agent), target
Indoor and Outdoor Pyrethroid Air Concentrations
229