Custovic A, Simpson A, Pahdi H, Green R M, Chapman M D, Woodcock A
North West Lung Centre, Wythenshawe Hospital, Manchester, UK.
Thorax. 1998 Jan;53(1):33-8. doi: 10.1136/thx.53.1.33.
Sensitisation to cat allergen (Fel d 1) is an important risk factor for asthma in the UK. A study was undertaken to investigate the distribution of cat allergen in British homes, the aerodynamic characteristics and particle size distribution of airborne Fel d 1, and the method of removing it.
Dust was collected from 50 homes with a cat and from 50 homes without a cat, and airborne levels of Fel d 1 were measured in 50 homes with a cat and 75 homes without a cat. Particle size distribution was determined using an Andersen sampler (8 hours/day) in 10 homes with cats. This was repeated on five separate days in a house with four cats, and then one, two, four, seven, and 14 days after the cats were removed from the living room area. The effect of high efficiency particulate air (HEPA) cleaner on airborne levels of Fel d 1 was investigated in seven homes with cats. Samples were collected on two separate days from two rooms of each house concurrently, one of which contained the cat, one day with the HEPA cleaner on and the other day as a control. Three one hourly samples were collected over a nine hour period (baseline, 4-5 hours, 8-9 hours) using a high volume dust sampler (air flow rate 60 l/min) and the air sample was collected onto a microglass fibre filter (pore size 0.3 micron).
Fel d 1 concentrations were much lower in houses without a cat than in those with a cat (260-fold difference (95% CI 167 to 590) in living room carpets: geometric mean (GM) 0.9 microgram/g (range 0.06-33.93) versus 237 micrograms/g (range 2.8-3000); 314-fold difference (95% CI 167 to 590) in upholstered furniture: 1.21 micrograms/g (range 0.06-61.9) versus 380 micrograms/g (range 7.1-6000); 228-fold difference (95% CI 109 to 478) in bedroom carpets: 0.24 microgram/g (range 0.06-2.24) versus 55 micrograms/g (range 0.06-2304); and 215-fold difference (95% CI 101 to 456) in mattresses: 0.2 microgram/g (range 0.06-2.3) versus 55 micrograms/g (range 0.06-3400). Airborne levels of Fel d 1 were detected in all houses with cats, and the levels varied greatly between the homes (range 0.7-38 ng/m3). Low concentrations of airborne Fel d 1 (range 0.24-1.78 ng/m3) were found in 22 of 75 homes without a cat. Although airborne Fel d 1 was mostly associated with large particles (> 9 microns, approximately 49% of the allergen recovered), small particles (< 4.7 microns) comprised approximately 23% of the total airborne allergen. Total airborne Fel d 1 was reduced by 61.7% two days after removal of the cat but this was due predominantly to the decrease in larger particles (> 4.8 microns) which fell to 13% of their baseline level. Fel d 1 levels associated with small particles (< 4.8 microns) remained largely unchanged on days 1, 2 and 4 and then slowly decreased to 33% of the baseline levels at day 14. With HEPA cleaner a significant reduction in airborne Fel d 1 was observed compared with the control sampling (GM 5.04-0.88 ng/m3 versus 3.79-1.56 ng/m3 at baseline and 8 hours, active versus control group; p = 0.008).
Airborne Fel d 1 was detectable in undisturbed conditions in all homes with cats and in almost a third of homes without cats. In houses with cats a significant proportion (23%) of airborne Fel d 1 was associated with small particles (< 4.7 microns diameter). Removal of the cat from the living room and bedroom areas of the home and the use of HEPA air cleaner reduced airborne levels of cat allergen in homes with cats, but the reduction following cat removal was not evenly spread across the particle size range.
在英国,对猫过敏原(Fel d 1)致敏是哮喘的一个重要风险因素。开展了一项研究,以调查英国住宅中猫过敏原的分布、空气中Fel d 1的空气动力学特性和粒径分布,以及去除它的方法。
从50户养猫家庭和50户未养猫家庭收集灰尘,并在50户养猫家庭和75户未养猫家庭中测量空气中Fel d 1的水平。使用安德森采样器(每天8小时)在10户养猫家庭中测定粒径分布。在一间养了四只猫的房子里,在五个不同的日子重复此操作,然后在猫从客厅区域移走后的第1、2、4、7和14天进行测量。在7户养猫家庭中研究了高效空气过滤器(HEPA)清洁器对空气中Fel d 1水平的影响。从每户的两个房间同时在两个不同的日子采集样本,其中一个房间有猫,一天开启HEPA清洁器,另一天作为对照。使用大容量灰尘采样器(气流速度60升/分钟)在9小时内(基线、4 - 5小时、8 - 9小时)采集三个每小时一次的样本,空气样本采集到微玻璃纤维过滤器(孔径0.3微米)上。
未养猫家庭中的Fel d 1浓度远低于养猫家庭(客厅地毯中相差260倍(95%可信区间167至590):几何均值(GM)0.9微克/克(范围0.06 - 33.93)对237微克/克(范围2.8 - 3000);软垫家具中相差314倍(95%可信区间167至590):1.21微克/克(范围0.06 - 61.9)对380微克/克(范围7.1 - 6000);卧室地毯中相差228倍(95%可信区间109至478):0.24微克/克(范围0.06 - 2.24)对55微克/克(范围0.06 - 2304);床垫中相差215倍(95%可信区间101至456):0.2微克/克(范围0.06 - 2.3)对55微克/克(范围0.06 - 3400)。在所有养猫家庭中均检测到空气中的Fel d 1水平,且各家庭之间差异很大(范围0.7 - 38纳克/立方米)。在75户未养猫家庭中的22户中发现了低浓度的空气中Fel d 1(范围0.24 - 1.78纳克/立方米)。尽管空气中的Fel d 1大多与大颗粒(> 9微米,约占回收过敏原的49%)相关,但小颗粒(< 4.7微米)约占空气中总过敏原的23%。移走猫两天后,空气中总Fel d 1减少了61.7%,但这主要是由于较大颗粒(> 4.8微米)减少至基线水平的13%。与小颗粒(< 4.8微米)相关的Fel d 1水平在第1、2和4天基本保持不变,然后在第14天缓慢降至基线水平的33%。与对照采样相比,使用HEPA清洁器后空气中的Fel d 1显著降低(基线和8小时时,活性组与对照组的几何均值分别为5.04 - 0.88纳克/立方米对3.79 - 1.56纳克/立方米;p = 0.008)。
在所有养猫家庭以及近三分之一未养猫家庭的未受干扰条件下均可检测到空气中的Fel d 1。在养猫家庭中,相当大比例(23%)的空气中Fel d 1与小颗粒(直径< 4.7微米)相关。将猫从家中的客厅和卧室区域移走以及使用HEPA空气清洁器可降低养猫家庭空气中猫过敏原的水平,但移走猫后减少的情况在粒径范围内分布不均。