Current asthma and respiratory symptoms among pupils in relation to dietary factors and allergens in the school environment

The aim was to study asthma and allergy in relation to diet and the school environment. Pupils (5-14 years) in eight schools received a questionnaire, 1014 participated (68%). Settled dust was collected on ALK-filters and analyzed for allergens from cat (Fel d 1), dog (Can f 1), horse (Equ cx), house dust mites (Der p 1, Der f 1), and cockroach (Bla g 1) by ELISA. In total, 6.8% reported cat allergy, 4.8% dog allergy, 7.7% doctor's diagnosed asthma and 5.9% current asthma, and 7.8% reported wheeze. Current asthma was less common among those consuming more fresh milk (P < 0.05) and fish (P < 0.01). Poly-unsaturated fatty acids was associated with more wheeze (P < 0.05), olive oil was associated with less doctors' diagnosed asthma (P < 0.05). Totally, 74% of the classrooms had mean CO(2) <1000 ppm. The median concentration per gram dust was 860 ng/g Fel d 1, 750 ng/g Can f 1 and 954 U/g Equ cx. Horse allergen was associated with more wheeze (P < 0.05), daytime breathlessness (P < 0.05), current asthma (P < 0.05) and atopic sensitization (P < 0.05). Dog allergen was associated with wheeze (P < 0.05) and daytime breathlessness (P < 0.05). The associations between allergens and respiratory symptoms were more pronounced among those consuming margarine, not consuming butter, and with a low intake of milk. In conclusion, cat, dog and horse allergens in schools could be a risk factor for asthma and atopic sensitization, and dietary factors may interact with the allergen exposure. PRACTICAL IMPLICATIONS: Previous school studies performed by us in mid-Sweden, showed that most classrooms did not fulfill the ventilation standards. In this study, most of the classrooms fulfilled the ventilation standard, but despite that had widespread allergen contamination. Most previous studies have focused on cat allergen, but our study has shown that also dog and horse allergens can be risk factors for asthma and allergy in schools. As allergens are transported from other environments, mainly the home environment, the main prevention should be to minimize transfer of allergens. This could be achieved by reducing contacts with furry pets and horses, or using different clothes at home and at school (e.g. school uniforms). Increased cleaning in the schools may reduce allergen levels, but the efficiency of this measure must be evaluated in further intervention studies. Finally, our study supports the view that dietary habits among pupils should not be neglected and interaction between dietary factors and indoor allergen exposure needs to be further investigated.     

A comparative study of asthma, pollen, cat and dog allergy among pupils and allergen levels in schools in Taiyuan city, China, and Uppsala, Sweden

We compared the school environment, asthma and allergy in 10 schools in Taiyuan, China, with eight schools in Uppsala, Sweden. In total 2193 pupils (mean age 13 years) participated. Chinese pupils had more respiratory symptoms, particularly daytime breathlessness after exercise (29.8% vs. 7.1%; P < 0.001), while cat allergy (1.2% vs. 6.6%; P < 0.001) and dog allergy (1.3% vs. 4.0%; P < 0.01) was less common. Cumulative incidence of asthma (1.8% vs. 9.5%; P < 0.001) and doctor's diagnosed asthma (1.2% vs. 9.0%; P < 0.001) were less common in China, indicating an under-diagnosis of asthma. Chinese classrooms were colder (mean 14.7 vs. 21.4 degrees C), more humid (mean 42% vs. 31% RH) and had higher CO2-levels (mean 2211 vs. 761 ppm). Levels of cat (Fel d1), dog (Can f1) allergens were low in settled dust from China (< 200 ng/g dust), but high in airborne dust on Petri-dishes (GM 16.8 ng/m2/day for Fel d1 and 17.7 for Can f1). The Swedish settled dust contained cat, dog and horse allergens in high levels (median 1300 ng/g, 1650 ng/g, 1250 U/g dust, respectively). In conclusion, there were large differences in the school environment, and in respiratory symptom and allergy. Allergen measurements in settled dust only may largely underestimate the classroom exposure. Practical Implications There is a need to improve the school environment, both in China and Sweden. The Swedish schools contained high levels of cat, dog and horse allergens and more amounts of open shelves and textiles that can accumulate dust and allergens. The air measurements indicated that Chinese schools may contain significant amounts of cat and dog allergen, and analysis of settled dust only may not reflect the true allergen exposure. Since the Chinese schools had no mechanical ventilation, they could not fulfill the ventilation standard in winter, and hence there is a need for improving the ventilation. The great discrepancy between respiratory symptoms and reports on asthma, and the high prevalence of attacks of breathlessness without wheeze, may have implication for future questionnaire studies on asthma in China.     

Allergens and endotoxin in settled dust from day-care centers and schools in Oslo, Norway

Allergy to indoor allergens can cause frequent and severe health problems in children. Because little is known about the content of allergens in the indoor environments in Norway, we wanted to assess the levels of cat, dog and mite allergens in schools and day-care centers in Oslo. Allergen levels in dust samples from 155 classrooms and 81 day-care units were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits. Additionally, we measured the levels of endotoxin in 31 day-care units, using the limulus amebocyte lysate test. Most of the dust samples contained detectable amounts of cat and dog allergens. In mattress and floor dust (day-care centers), and curtain and floor dust (schools) the median Fel d 1 levels were 0.17, 0.002, 0.02 and 0.079 microg/m2, while the median Can f 1 levels were 1.7, 0.03, 0.1 and 0.69 microg/m2, respectively. Levels of cat and dog allergens in school floor dust were associated with the number of pupils with animals at home. In contrast, <1% of the samples had measurable levels of the mite allergen Der p 1. Moreover, the levels of endotoxin tended to be higher in dust from floors (1.4 ng/m2) compared with that from mattresses (0.9 ng/m2). PRACTICAL IMPLICATIONS: To reduce allergen exposure, allergic individuals should be placed in the classes/rooms with the fewest pet owners. Moreover, mattresses in day-care centers are major reservoirs of cat and dog allergens and should be cleaned frequently.     

Variability of airborne cat allergen, Fel d1, in a public place

Allergen exposure is a risk to develop an IgE-mediated sensitization. The amount of allergen inhaled per unit time should be related to the amount present in the air, i.e. airborne allergen. Thus, measuring allergen levels in the air would be more relevant than measuring allergen levels in dust. Allergens are present in the air in very minute quantities and usually become airborne after disturbance. Large variation of allergen levels have been found in dust. In this study, we measured variability of airborne cat allergen, Fel d1, in a public place using a high-volume air-sampler. We also studied the distribution and relationship between dust and airborne cat allergens in homes and schools. Air samples were collected at three different airflow rates, i.e. 55, 40, and 30 m3 of air per hour. The concentration of airborne Fel d1 in the community gymnastic hall varied from 1 to 10 pg/m3 within a period of 3 weeks, at airflow rates 55-30 m3/h. The coefficient of variation for repeated samplings was 14-43% (day-to-day variation) and 27-38% (within-day variation). As expected, higher levels of airborne cat allergens were found in homes with cats than in cat-free environments. There was a significant relationship between cat allergen levels in dust and air (r=0.7, P<0.01). Our study demonstrates that when measuring airborne cat allergen a large variation is observed within a day and between days. The large variability of measurement may be explained by the disturbance in the environments. We suggest, that when exposure assessment is made the environment in question should be analyzed, if possible in several occasions.     

Mite and pet allergen exposure in hotels in Uberlândia, Midwestern Brazil

Mite allergens are involved in airway sensitization and allergic diseases. We evaluated the exposure to house dust-mite (Der p 1 and Der f 1) and pet (Fel d 1 and Can f 1) allergens in hotels in Uberlandia, Midwestern Brazil. A total of 140 dust samples were collected from bedding (n = 98) and carpet (n = 42) of bedrooms in 20 hotels enrolled for this study. Geometric mean (GM) levels of Der f 1 (11.30 microg/g of dust; 95% CI: 8.34-15.30 microg/g) were significantly higher than Der p 1 (0.15 microg/g of dust; 95% CI: 0.13-0.18 microg/g) in bedding dust samples (P < 0.001), regardless of the hotel classes. Der f 1 levels were significantly higher in bedding (11.30 microg/g of dust; 95% CI: 8.34-15.30 microg/g) than carpet (6.32 microg/g of dust; 95% CI: 4.31-9.26 microg/g) dust samples (P < 0.05). High levels of Der f 1 (>10 microg/g of dust) were found in 58%, 76%, and 69% of dust samples from Simple, Economical, and Tourist/Superior hotels, respectively, while GM levels of Fel d 1 (0.11 microg/g of dust; 95% CI: 0.09-0.14 microg/g) and Can f 1 (0.30 microg/g of dust; 95% CI: 0.20-0.44 microg/g) were relatively low. These results indicate that Der f 1 is the predominant allergen in hotels in Uberlandia, especially in bedding dust samples, regardless of the hotel classes and could represent an important risk factor for exacerbation of allergic symptoms in previously mite-sensitized guests. PRACTICAL IMPLICATIONS: Mites and pets are important sources of indoor allergens. Most people spend the greatest part of their time indoors. Hotels can constitute an important allergen reservoir of the indoor environment and could represent an important risk for exacerbation of allergic symptoms in previously sensitized guests. Thus, hotels should also be included for planning indoor allergen avoidance as part of a global management strategy, especially in patients with respiratory allergy.     

Relationships between mite allergen levels, mold concentrations, and sick building syndrome symptoms in newly built dwellings in Japan

This study investigated the possible relationships between exposures to mite allergen and airborne fungi with sick building syndrome (SBS) symptoms for residents living in newly built dwellings. We randomly sampled 5709 newly built dwellings in six prefectures from northern to southern Japan. A total of 1479 residents in 425 households participated in the study by completing questionnaire surveys and agreeing to environmental monitoring for mite allergen (Der 1), airborne fungi, aldehydes, and volatile organic compounds. Stepwise logistic regression analyses adjusted for confounders were used to obtain odds ratios (OR) of mite allergen and fungi for SBS symptoms. Der 1 had a significantly high OR for nose symptoms. Rhodotorula had a significantly high OR for any symptoms, and Aspergillus had significantly high OR for eye symptoms. However, the total colony-forming units had a significantly low OR for throat and respiratory symptoms. Eurotium had a significantly low OR for skin symptoms. In conclusion, dust-mite allergen levels and indoor airborne Rhodotorula and Aspergillus concentrations may result in SBS symptoms in newly built dwellings. PRACTICAL IMPLICATIONS: Various factors can cause sick building syndrome symptoms. This study focused on biologic factors such as dust-mite allergen and airborne fungi in newly built dwellings in Japan. Dust-mite allergen levels were significantly associated with higher rates of nose symptoms, airborne Rhodotorula concentrations were significantly associated with higher rates of any symptoms, and Aspergillus concentrations were significantly associated with higher rates of eye symptoms. Measures should be taken to reduce mite allergen levels and fungal concentrations in these dwellings.     

Irritants and allergens at school in relation to furnishings and cleaning

In order to study the influence of furnishings and cleaning on the indoor air quality at school, 181 randomly chosen classrooms were investigated. The amounts of open shelves, textiles and other fittings were noted, data were gathered on cleaning routines, and a number of pollutants were measured in the classrooms. In classrooms with more fabrics there was more settled dust and the concentration of formaldehyde was higher. Classrooms with more open shelves had more formaldehyde, and more pet allergens in settled dust, and classrooms with a white board, instead of a chalk board, were less dusty. Classrooms mainly cleaned through wet mopping had more airborne viable bacteria but less settled dust than classrooms mainly cleaned by dry methods. In rooms where the desks and curtains were more often cleaned, the concentrations of cat and dog allergen in settled dust were lower. It is concluded that furnishings and textiles in the classroom act as significant reservoirs of irritants and allergens and have an impact on the indoor air quality at school.     

Social factors, allergen, endotoxin, and dust mass in mattress

Indoor environment has been associated with allergic disease. Further, it has been observed that the prevalences of allergic sensitization are different in different social groups. We therefore investigated the association between socioeconomic status (SES) and indoor bio-contaminants. House dust samples were collected from parents' and infants' mattress from 2166 families in Munich (62.2%) and Leipzig (37.8%), Germany. Major mite allergen Der p 1 and Der f 1, cat allergen Fel d 1, and endotoxin were extracted and quantified. Parental educational level and family equivalent income were used independently as socioeconomic indicators. Indoor endotoxin, mite allergen Der p 1, and the amount of sampled dust were not associated with the social factors. Mite allergen Der f 1 was slightly associated by family SES but without a consistent pattern. In families who are not cat owners, however, a negative association between the amount of cat allergen and family SES were observed. The observed negative association between cat allergen loads and concentrations in mattress and family SES in non-cat owners' homes indicated that community is an important source of cat allergen exposure. PRACTICAL IMPLICATIONS: The study indicated that community is a major source of cat allergen exposure especially in communities of low SES.     

Mouse and cockroach allergens in the dust and air in northeastern United States inner-city public high schools

Considering that high school students spend a large proportion of their waking hours in the school environment, this could be an important location for exposure to indoor allergens. We have investigated the levels of mouse and cockroach allergens in the settled dust and air from 11 schools in a major northeastern US city. Settled dust samples were vacuumed from 87 classrooms, three times throughout the school year. Two separate air samples (flow = 2.5 lpm) were collected by 53 students over a 5-day period from both their school and their home. Mouse allergen (MUP) in the dust varied greatly between schools with geometric means ranging from 0.21 to 133 microg/g. Mouse allergen was detectable in 81% of the samples collected. Cockroach allergen (Bla g 2) ranged from below limit of detection (<0.003 microg/g) to 1.1 microg/g. Cockroach allergen was detected (>0.003 microg/g) in 71% of the dust samples. Bla g 2 was detected in 22% of airborne samples from the schools. By comparison, mouse allergen was only detected in 5%. These results indicate that the school may be an important location for exposure to allergens from mice and cockroaches and is an indoor environment that should be considered in an overall allergen intervention strategy. PRACTICAL IMPLICATIONS: To date, cockroach and mouse allergen intervention strategies have been mainly focused on the home environment. Considering that children spend a significant amount of time in schools, some studies have assessed cockroach allergen levels in schools. This study provides a clearer picture of the distribution and variability of not only cockroach allergen, but also mouse allergen in the school environment. In addition, this study describes limitations of personal air sampling in a student population. Our results suggest that although cockroach and mouse allergens are commonly recovered in classroom dust samples of inner city schools, cockroach allergens are recovered in the personal air samples with a greater frequency relative to mouse allergens.     

House dust mites (Der p 1, Der f 1), cat (Fel d 1) and cockroach (Bla g 2) allergens in indoor work-places (offices and archives)

BACKGROUND: Exposure to indoor allergens has already been shown to occur in many public places, including workplaces, in several countries. Aim of this study was to measure the levels of house dust mites, cat and cockroach allergens in indoor workplaces (offices and archives) in Italy and to evaluate the possible relationships between allergen levels and building characteristics, type of ventilation, indoor relative humidity and temperature. METHODS: Der f 1 and Der p 1, Fel d 1, Bla g 2 were measured by ELISA in dust samples collected from floors or upholstered seats of 160 workplaces. RESULTS: Detectable Der p 1 levels were found in 86 (54%) workplaces Der f 1 in 87 (55%), Fel d 1 in 86 (54%) and Bla g 2 in 3 (1.9%). Der p 1 allergen concentrations expressed per weight were higher than the proposed sensitization thresholds in 7 samples, Der f 1 in 5, Fel d 1 in 6 and Bla g 2 in 3. The highest allergen levels were detected in samples from upholstered seats. A significant correlation was found between Der f 1 level on floors, expressed per surface, and indoor temperature (r = 0.39; P < 0.01). CONCLUSIONS: In our study we found that upholstered seats in workplaces in Italy may constitute a significant reservoir both of house dust mites and cat allergens. Exposure to these allergens in workplaces may represent a risk factor for elicitation of symptoms and/or induction/maintenance of inflammation in allergic individuals and might also constitute a risk factor for sensitization.     

Effects of furniture polish on release of cat allergen-laden dust from wood surfaces

The purpose of this study was to evaluate the effects of furniture polish (FP) on the release of cat allergen (Fel d 1)-laden dust from wood surfaces and decay of Fel d 1 in dust over time. About 2 g of sieved (150 microm screen) allergen-laden dust was introduced as an aerosol into an experimental chamber by a Pitt-3 generator and allowed to settle onto two finished wood surfaces pre-treated with either distilled water (DW) or FP. After 24 h, each surface was vacuumed into separate plastic cassettes loaded with 37 mm diameter, 0.4 microm pore, polycarbonate filters. The recovered dust was weighed, extracted in phosphate-buffered saline, and assayed for Fel d 1 content using a two-site monoclonal antibody ELISA. After vacuuming, the remaining dust on the wood surfaces was wiped up with a water-moistened swab. The dusts were extracted from the swabs and assayed by ELISA for Fel d 1. More Fel d 1 was recovered by vacuuming from DW-pre-treated surfaces than from FP pre-treated surfaces (100% vs. 69 +/- 66%). On the contrary, more residual Fel d 1 (>99.9%) on the vacuumed surfaces was recovered from FP than from DW pre-treated surfaces by wet swabs. The concentration of Fel d 1 in dust did not change significantly at room temperature over 80 days. In conclusion, FP on wood surfaces makes dust stick to the surface, which likely reduces the release of allergen-laden dust from the wood surface. PRACTICAL IMPLICATIONS: Re-aerosolization of cat allergen-laden dusts from wood surfaces (e.g. wood floor or furniture) significantly increases the concentration of airborne cat allergens. Our study indicates that exposure to airborne cat allergens might be reduced by surface treatment with commercially available FP because cat allergen-laden dusts stuck more tightly to the wood surface treated with FP.     

Comparison of two dust collection methods for reservoir indoor allergens and endotoxin on carpets and mattresses

Variable methods of dust collection may lead to uncertainty in the measurement of biomarkers. The purpose of this study was to examine the effect of two different dust collection devices on dust weight, Der p 1, Fel d 1, and endotoxin levels. We compared: (1) a nylon mesh sock inserted between the furniture attachment and the vacuum hose (the reference method) and (2) the ALK device. Duplicate dust samples were collected for 2 min from 2 m(2) of 37 living room floors and from each longitudinal half of 37 mattresses. Measurement of Der p 1 and Fel d 1 were by double monoclonal antibody enzyme-linked immunosorbent assay (ELISA) and endotoxin by a Limulus Amobocyte Lysate assay. Geometric mean ratios (95% confidence intervals) were calculated to show the differences between sampling devices for each measurement. Compared with the ALK device, the reference method collected significantly more dust from floors (sevenfold) and mattresses (threefold) and more total Der p 1, Fel d 1, and endotoxin in both sites. Floor, but not mattress, Der p 1 concentrations were also significantly higher (threefold) using our reference method. We recommend that, in order to minimize sampling device bias, allergen and endotoxin are expressed as a concentration, and that the bed is considered the major source of allergen exposure. Practical Implications Dust sampling equipment can influence the dust yield. In order to have confidence in comparisons of allergen and endotoxin reservoir levels between centers, standardization in the use of sampling equipment is important.     

Indoor air quality,ventilation and health symptoms in schools: an analysis of existing information

We reviewed the literature on Indoor Air Quality (IAQ), ventilation, and building-related health problems in schools and identified commonly reported building-related health symptoms involving schools until 1999. We collected existing data on ventilation rates, carbon dioxide (CO2) concentrations and symptom-relevant indoor air contaminants, and evaluated information on causal relationships between pollutant exposures and health symptoms. Reported ventilation and CO2 data strongly indicate that ventilation is inadequate in many classrooms, possibly leading to health symptoms. Adequate ventilation should be a major focus of design or remediation efforts. Total volatile organic compounds, formaldehyde (HCHO) and microbiological contaminants are reported. Low HCHO concentrations were unlikely to cause acute irritant symptoms (<0.05 ppm), but possibly increased risks for allergen sensitivities, chronic irritation, and cancer. Reported microbiological contaminants included allergens in deposited dust, fungi, and bacteria. Levels of specific allergens were sufficient to cause symptoms in allergic occupants. Measurements of airborne bacteria and airborne and surface fungal spores were reported in schoolrooms. Asthma and 'sick building syndrome' symptoms are commonly reported. The few studies investigating causal relationships between health symptoms and exposures to specific pollutants suggest that such symptoms in schools are related to exposures to volatile organic compounds (VOCs), molds and microbial VOCs, and allergens.     

Quantitative measurement of airborne cockroach allergen in New York City apartments

We designed and tested a sampling and analysis system for quantitative measurement of airborne cockroach allergen with sufficient sensitivity for residential exposure assessment. Integrated 1-week airborne particle samples were collected at 10-15 LPM in 19 New York City apartments in which an asthmatic child who was allergic to cockroach allergen resided. Four simultaneous air samples were collected in each home: at heights of 0.3 and 1 m in the child's bedroom and in the kitchen. Extracts of air samples were analyzed by ELISA for the cockroach allergen Bla g2, modified by amplifying the colorimetric signal generated via use of AMPLI-Q detection system (DAKO Corporation, Carpinteria, CA, USA). Settled dust samples were quantified by conventional ELISA. Of the homes where cockroach allergen was detected in settled dust, Bla g2 also was detected in 87% and 93% of air samples in the bedroom and kitchen, respectively. Airborne Bla g2 levels were highly correlated within and between the bedroom and kitchen locations (P < 0.001). Expressed as picogram per cubic meter, the room average geometric mean for Bla g2 concentrations was 1.9 pg/m3 (95% CI 0.63, 4.57) and 3.8 pg/m3 (95% CI 1.35, 9.25) in bedrooms and kitchens, respectively. This method offers an attractive supplement to settled dust sampling for cockroach allergen exposure health studies. PRACTICAL IMPLICATIONS: Until now, cockroach allergen exposures have usually been assessed by collection and analysis of settled dust, on the assumption that airborne cockroach allergen cannot be reliably measured. In this study, a sensitive and quantitative method for measuring indoor airborne exposures to cockroach allergens involving a 7-day integrated total suspended particulate (TSP) sample collected at approximately 10-15 l/min was developed. Investigators are now empowered with an alternative exposure assessment method to supplement their studies and the understanding of allergen aerodynamics in the homes of children with asthma. We report airborne cockroach allergen in apartments, suggesting an ongoing burden of inhalation exposure.     

Respiratory symptoms, perceived air quality and physiological signs in elementary school pupils in relation to displacement and mixing ventilation system: an intervention study

Schools may be poorly ventilated and may contain furry pet allergens, particles and microorganisms. We studied health effects when changing from mixing ceiling ventilation to two types of displacement ventilation, front ventilation system (FVS) and floor master system (FMS). The study included pupils in three elementary school classes (N = 61), all with floor heating. One class received blinded interventions; the two others were unchanged (controls). Ventilation flow and supply air temperature was kept constant. The medical investigation included tear film stability (BUT), nasal patency and a questionnaire containing rating scales. When changing from mixing ventilation to FVS, the pupils (N = 26) perceived better air quality (P = 0.006) and less dyspnoea (P = 0.007) as compared to controls (N = 35), and BUT was improved (P = 0.03). At desk level, mean CO(2) was reduced from 867 to 655 ppm. Formaldehyde and viable bacteria were numerically lower, while total bacteria and molds were higher with displacement ventilation. There was no difference in symptoms or signs when changing from FVS to FMS. Cat (Der p1), dog (Can f1) and horse allergen (Equ cx) were common in air at all conditions. In conclusion, displacement ventilation may have certain positive health effects among pupils, as compared to conventional mixing ceiling systems. PRACTICAL IMPLICATIONS: Displacement ventilation may be a suitable ventilation principle for achieving good indoor environment in classrooms. The type of supply air diffuser does not seem to be of major importance. The combination of floor heating and displacement ventilation can be a useful way of avoiding the previously described problem of thermal discomfort.     

Comparing mixing and displacement ventilation in classrooms: pupils' perception and health

Several studies have found that indoor air quality (IAQ) in schools is often poor and may affect the health of the pupils. Building ventilation is a means to reduce pollutants indoors, but different designs should be evaluated for their effectiveness in different environments. In a field experiment performed at four classrooms in one school building, air was supplied either in the mixing or in the displacement mode, and we collected information on exposures, pupils' perception of IAQ and climate, and health symptoms and performed clinical examinations. The room temperature, relative humidity, concentration of CO?, and cat allergen were measured at the breathing height and were similar during each ventilation mode. The children perceived IAQ were similar in the two ventilation regimes, and there were few differences in symptom reports or clinical parameters. However, the pupils reported more eye symptoms during displacement ventilation. PRACTICAL IMPLICATIONS: Both mixing and displacement ventilation may be appropriate in school classrooms as long as the overall design, ventilation rates, and maintenance of systems are satisfactory.     

Teachers' work-related non-literature-known building-related symptoms are also connected to indoor toxicity: A cross-sectional study

A previous study showed that classical building-related symptoms (BRS) were related to indoor dust and microbial toxicity via boar sperm motility assay, a sensitive method for measuring mitochondrial toxicity. In this cross-sectional study, we analyzed whether teachers’ most common work-related non-literature-known BRS (nBRS) were also associated with dust or microbial toxicity. Teachers from 15 schools in Finland completed a questionnaire evaluating 20 nBRS including general, eye, respiratory, hearing, sleep, and mental symptoms. Boar sperm motility assay was used to measure the toxicity of extracts from wiped dust and microbial fallout samples collected from teachers’ classrooms. 231 teachers answered a questionnaire and their classroom toxicity data were recorded. A negative binomial mixed model showed that teachers’ work-related nBRS were 2.9-fold (95% CI: 1.2-7.3) higher in classrooms with highly toxic dust samples compared to classrooms with non-toxic dust samples (p = 0.024). The RR of work-related nBRS was 1.8 (95% CI: 1.1-2.9) for toxic microbial samples (p = 0.022). Teachers’ BRS appeared to be broader than reported in the literature, and the work-related nBRS were associated with toxic dusts and microbes in classrooms.     

粉尘螨第十六类变应原的克隆表达、纯化及免疫原性鉴定

目的 获得大量具有良好IgE结合活性的粉尘螨第十六类变应原（Der f16）的重组变应原,以促进粉尘螨变态反应性疾病的特异性诊断及治疗的研究.方法 挑取经纯培养的粉尘螨,提取总RNA,根据已知Der f16基因序列设计引物,经RT-PCR扩增Der f16基因片段,产物连入pMD32-T载体中.扩增后,利用限制性内切酶EcoR Ⅰ和XhoⅠ双酶切将目的 基因片段连接到pET32a表达载体上,转化到大肠杆菌（E.coli BL21）中经IPTG诱导表达.表达载体经亲和层析纯化,SDS-PAGE检测蛋白纯度,Western bolt检测变应原免疫学活性.结果 以粉尘螨总RNA为模板成功克隆出Der f16基因,与数据库中Der f16基因同源性为100%;经IPTG诱导后,大肠杆菌大量表达Der f16蛋白,所获得的重组蛋白分子质量为73 ku,上清及沉淀物均有蛋白表达,且上清表达量高于沉淀物.重组Der f16能够与螨过敏患者血清中的IgE 反应,而不与健康者血清中的IgE反应.结论成功构建了Der f16的原核表达载体,并高效表达和纯化出具有免疫原性的Der f16重组蛋白.     

Characterization and variability of endotoxin and 3-hydroxy fatty acids in an office building during a particle intervention study

Air and dust samples were collected on two floors of an office building during a double-blind particle intervention study to examine spatial and temporal variability of airborne endotoxin over a period of weeks, and to characterize endotoxin activity and lipopolysaccharide (LPS) content in carpet and chair dust. Air samples were collected on multiple days within and across weeks. Dust samples were collected from carpets and chairs one day per week for three weeks. Endotoxin was measured using a Limulus assay. Dust samples were analyzed for LPS by determination of 3-hydroxy fatty acids (3-OHFAs) using gas chromatography-mass spectrometry. The geometric mean (geometric standard deviation) for 96 indoor air samples was 0.24 (1.6) EU/m3. Significant within-floor spatial variation of airborne endotoxin was found (P < 0.0001, n = 80). Temporal variability of airborne endotoxin was not significant across weeks. Mean (+/- SD) endotoxin levels in carpet dust (59 +/- 9.3 EU/mg dust, n = 12) and in chair dust (38 +/- 7.7 EU/mg dust, n = 10) were significantly different (P < 0.001). Carbon chain length-dependent differences in 3-OHFA levels by dust source and floor were found. Enhanced air filtration did not significantly affect airborne endotoxin (P = 0.62); however, total dust mass and total endotoxin in carpet dust samples increased significantly after enhanced surface cleaning (P < 0.01). These findings suggest that spatial variability, dust source, and surface cleaning may influence building occupant exposures to endotoxin.     

Current asthma and respiratory symptoms among pupils in Shanghai, China: influence of building ventilation, nitrogen dioxide, ozone, and formaldehyde in classrooms

We investigated 10 naturally ventilated schools in Shanghai, in winter. Pupils (13-14 years) in 30 classes received a questionnaire, 1414 participated (99%). Classroom temperatures were 13-21 degrees C (mean 17 degrees C), relative air humidity was 36-82% (mean 56%). The air exchange rate was 2.9-29.4 ac/h (mean 9.1), because of window opening. Mean CO2 exceeded 1000 ppm in 45% of the classrooms. NO2 levels were 33-85 microg/m3 indoors, and 45-80 microg/m3 outdoors. Ozone were 1-9 microg/m3 indoors and 17-28 microg/m3 outdoors. In total, 8.9% had doctors' diagnosed asthma, 3.1% wheeze, 23.0% daytime breathlessness, 2.4% current asthma, and 2.3% asthma medication. Multiple logistic regression was applied. Observed indoor molds was associated with asthma attacks [odds ratio (OR) = 2.40: P < 0.05]. Indoor temperature was associated with daytime breathlessness (OR = 1.26 for 1 C; P < 0.001), and indoor CO2 with current asthma (OR = 1.18 for 100 ppm; P < 0.01) and asthma medication (OR = 1.15 for 100 ppm; P < 0.05). Indoor NO2 was associated with current asthma (OR = 1.51 for 10 microg/m3; P < 0.01) and asthma medication (OR = 1.45 for 10 microg/m3; P < 0.01). Outdoor NO2 was associated with current asthma (OR = 1.44 for 10 microg/m3; P < 0.05). Indoor and outdoor ozone was negatively associated with daytime breathlessness. In conclusion, asthma symptoms among pupils in Shanghai can be influenced by lack of ventilation and outdoor air pollution from traffic. Practical Implications Most urban schools in Asia are naturally ventilated buildings, often situated in areas with heavy ambient air pollution from industry or traffic. The classes are large, and window opening is the only way to remove indoor pollutants, but this results in increased exposure to outdoor air pollution. There is a clear need to improve the indoor environment in these schools. Building dampness and indoor mold growth should be avoided, and the concept of mechanical ventilation should be introduced. City planning aiming to situate new schools away from roads with heavy traffic should be considered.