A carregar...
Publicação
Exposição a ozono em cabinas de avião
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 135.34 KB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
RESUMO - O ozono é o principal componente da poluição fotoquímica
do ar. Como agente irritante do aparelho respiratório, os
seus efeitos sobre a saúde caracterizam-se, essencialmente,
por tosse, dispneia, desconforto torácico e alterações da
função pulmonar, encontrando-se também associadas à
exposição ambiental a O3 tanto uma maior frequência e
gravidade de crises de asma como a ocorrência de quadros
clínicos de irritação conjuntival.
É sobretudo a partir dos anos 50, com a descoberta de
concentrações elevadas de ozono em ambientes de trabalho
respeitantes à actividade de soldadura «a arco», que aquele
gás passa a ser encarado como factor profissional de risco.
No início dos anos 60 surgem os primeiros estudos de exposição
a O3 em cabinas de avião, suscitados pela ocorrência,
em tripulantes e passageiros, de queixas clínicas de irritação
do tracto respiratório. Esta sintomatologia era, até
então, atribuída à acção de outros factores, designadamente
o sistema de ventilação e o baixo teor de humidade
do ar. Posteriormente, alguns estudos revelaram que, em
voos comerciais subsónicos, os teores elevados de O3 observados
no interior das cabinas poderiam ser provocados
pela sua insuficiente destruição nos sistemas de entrada
de ar.O presente estudo, efectuado em voos de longo curso realizados
em aeronaves Airbus A340-300 numa única rota
comercial, teve por objectivo avaliar a exposição a ozono
no ar interior em cabina de avião.
Os teores médios de concentração de ozono observados
foram inferiores aos valores susceptíveis de provocarem
efeitos adversos sobre o aparelho respiratório. Como valor
máximo instantâneo, foi atingida a concentração de 152
ppb. Adicionalmente, foi constatada a influência das estações
do ano nos teores de O3.
O conjunto dos resultados obtidos permite concluir que as
concentrações de ozono no ar interior nas cabinas de avião
estudadas são inferiores às correspondentes concentrações
máximas admissíveis, tendo, em todos os voos, sido observado
o cumprimento da norma da FAA respeitante à protecção
da exposição ao ozono em cabinas de aeronaves de
aviação comercial.
ABSTRACT - Ozone is the main component involved in photochemical pollution of the air. As an irritant of the respiratory system, its effects on the health of those exposed to it are characterized essentially by coughing, shortness of breath, chest pain or tightness and alterations to the mechanical pulmonary function. Additionally, a higher frequency and severity of asthmatic exacerbations and the occurrence of eye irritation are linked to environmental exposure to O3 . From the 1950s onwards, with the discovery of high concentrations of ozone in work environments involved in the execution of arc welding, this gas came to be regarded as an occupational risk factor. In the early 1960s the first studies on the exposure to O3 in aircraft cabins appeared, prompted by the occurrence of clinical complaints of irritation of the respiratory tract in crewmembers and passengers. The symptoms had hitherto been attributed to the action of other factors, such as the ventilation system and low level of humidity in the air. Subsequent studies revealed that, in subsonic commercial flights, the high levels of O3 registered inside the cabins could be caused by the insufficient destruction of ozone in the air supply systems. The present study — involving flight personnel in real work situations during long-haul Airbus A340-300 flights on a single commercial route — aims to evaluate the exposure to ozone in the air inside aircraft cabins. The average levels of ozone concentration observed were lower than the values generally considered to provoke adverse effects on the respiratory system. The maximum concentration («ceiling value») measured was that of 152 ppb. In addition to this the influence of the seasons on the O3 levels was also established. The set of findings allows the conclusion that the values for the cabin air quality parameters in the aircraft cabins studied are inferior to the corresponding TLVs. In all flights, compliance with the FAA standards for the protection from exposure to ozone in aircraft cabins in commercial aviation was observed.
ABSTRACT - Ozone is the main component involved in photochemical pollution of the air. As an irritant of the respiratory system, its effects on the health of those exposed to it are characterized essentially by coughing, shortness of breath, chest pain or tightness and alterations to the mechanical pulmonary function. Additionally, a higher frequency and severity of asthmatic exacerbations and the occurrence of eye irritation are linked to environmental exposure to O3 . From the 1950s onwards, with the discovery of high concentrations of ozone in work environments involved in the execution of arc welding, this gas came to be regarded as an occupational risk factor. In the early 1960s the first studies on the exposure to O3 in aircraft cabins appeared, prompted by the occurrence of clinical complaints of irritation of the respiratory tract in crewmembers and passengers. The symptoms had hitherto been attributed to the action of other factors, such as the ventilation system and low level of humidity in the air. Subsequent studies revealed that, in subsonic commercial flights, the high levels of O3 registered inside the cabins could be caused by the insufficient destruction of ozone in the air supply systems. The present study — involving flight personnel in real work situations during long-haul Airbus A340-300 flights on a single commercial route — aims to evaluate the exposure to ozone in the air inside aircraft cabins. The average levels of ozone concentration observed were lower than the values generally considered to provoke adverse effects on the respiratory system. The maximum concentration («ceiling value») measured was that of 152 ppb. In addition to this the influence of the seasons on the O3 levels was also established. The set of findings allows the conclusion that the values for the cabin air quality parameters in the aircraft cabins studied are inferior to the corresponding TLVs. In all flights, compliance with the FAA standards for the protection from exposure to ozone in aircraft cabins in commercial aviation was observed.
Descrição
Palavras-chave
Saúde ocupacional Riscos ocupacionais Exposição ocupacional Medicina do trabalho Ozono Substâncias químicas
Contexto Educativo
Citação
Editora
Escola Nacional de Saúde Pública. Universidade Nova de Lisboa