Am. J. Respir. Crit. Care Med., Vol 155, No. 1, 01 1997, 94-98.
Aerodynamic properties of the major dog allergen Can f 1: distribution in homes, concentration, and particle size of allergen in the air
A Custovic, R Green, A Fletcher, A Smith, CA Pickering, MD Chapman and A Woodcock
North West Lung Centre, Wythenshawe Hospital, Manchester, United Kingdom.
Exposure and sensitization to dog allergen is a significant cause of
asthma. In this study we investigated the distribution, aerodynamic
characteristics, and particle-size distribution of the major dog allergen
Can f 1. Dust samples were collected in 50 homes with a dog and 50 homes
without dogs. Airborne Can f 1 concentration was measured in 28 homes with
dogs and 36 homes without a dog. Particle-size distribution was determined
by using 10 separate Andersen sampler measurements in a dog-handling
facility, and in 10 homes with dogs, and by repeated measurements in a home
with one dog. High levels of Can f 1 (> 10 microg/g) were found in dust
in all but one home with a dog and in eight of 50 homes without dogs.
Airborne Can f 1 levels varied greatly between the homes with dogs (range:
0.3 to 99 ng/m3). Low levels of airborne Can f 1 (range: 0.4 to 1.1 ng/m3)
were detected in 11 of 36 homes without a dog. Can f 1 was predominantly
associated with large particles collected on the first stage of the
Andersen sampler (> 9 microm), which averaged 42 to 49% of the total
allergen recovered in the dog-handling facility and in homes with dogs.
Small particles (< 5 microm diameter) also carried Can f 1, and these
particles comprised approximately 20% of the total airborne allergen load.
There was an excellent concordance between the results obtained in
different sampling areas, and between the total Can f 1 recovered on the
Andersen sampler and on the parallel filter. In conclusion, airborne Can f
1 was detectable in undisturbed conditions in all homes with dogs and in
almost one third of the homes without dogs. In houses with dogs, a
significant proportion (approximately 20%) of airborne Can f 1 was
associated with small particles (< 5 microm diameter). Owing to their
aerodynamic characteristics, these particles would be expected to remain
airborne for a long period and, when inhaled, could penetrate into the
lower airways and initiate asthma attacks.
