COVER Ground-based optical astrometric telescopes can be used to precisely measure Earth Rotation Parameters (ERP) and variations of the vertical by observing stars. In the 1980s and 1990s, as a replacement for classical astrometric telescopes, new technical instruments such as very long baseline interferometry (VLBI) were used for ERP measurement because of their greater accuracies. However, these instruments are incapable of measuring plumb line variations. To carry out related research, small-sized charge-coupled device (CCD) camera systems were developed in several European countries at the beginning of the 21st century. These systems can achieve excellent mobile measurements of the vertical deflection. Because there was no such instrument in China, Professor Hongqi Wang and his colleagues at the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) successfully developed the first CCD digital zenith telescope (DZT-1) prototype in China and corresponding data processing software. According to test observation results, the DZT-1 features high accuracy, portability, unattended observation by the remote control, and is suitable for both station and mobile observation, depending on the research purpose. Therefore, the DZT-1 can play a significant role in interdisciplinary studies between astronomy and geoscience. The cover shows the CCD digital zenith telescope prototype (see the articles by Lili Tian et al. on pages 1978 and 1984).

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Materials Science1929 Assessing bacterial magnetotactic behavior by using permanent magnet blocks Tao Song • Hongmiao Pan • Zheng Wang • Tian Xiao • Longfei Wu

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Materials Chemistry1936 Research progress of voltage delay in magnesium battery Lin Chen • Changguo Chen • Chaozhong Guo

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Artic le Environmental Science & Technology

The influence of home environmental factors and life styleon children’s respiratory health in Xi’an

Angui Li • Yuexia Sun • Zhijian Liu •

Xiaoxia Xu • Hongfa Sun • Jan Sundell

Received: 15 April 2013 / Accepted: 21 August 2013 / Published online: 22 March 2014

� Science China Press and Springer-Verlag Berlin Heidelberg 2014

Abstract To assess associations between home indoor air

environments and asthma, allergies and pneumonia, children

aged 1–8 years were surveyed from 12 kindergartens in the

city of Xi’an. 2,020 questionnaires were responded with a

response rate of 83.5 %. The prevalences of doctor diag-

nosed asthma, hay fever, and pneumonia were 2.9 %, 3.6 %,

and 28.3 %, respectively. Living close to a highway was a

risk factor for current rhinitis (AOR 1.5, 95 % CI 1.2–1.8),

eczema (AOR 1.7, 95 % CI 1.2–2.5), and diagnosed pneu-

monia (AOR 1.3, 95 % CI 1.0–1.6). Dampness problems in

the home were associated with 50 %–130 % increases in the

prevalences of asthma and allergy. Airing bed linen under

sun-shine was protective, especially against rhinitis. Pet

avoidance was consistently and significantly associated with

asthma and allergy (AOR 1.3–2.4). Decoration of the home

during children’s early life is a risk factor for current rhinitis

(AOR 1.9, 95 % CI 1.3–2.9) and eczema (AOR 1.9, 95 % CI

1.1–3.6). Risk factors for pneumonia were living in an

apartment (AOR 1.4, 95 % CI 1.1–1.8), latex wall paint

(AOR 1.3, 95 % CI 1.0–1.7), dampness (AOR 1.4–1.5),

breast feeding \3 months (AOR 1.3, 95 % CI 1.0–1.7),

never airing bed linen in sunshine (AOR 1.3, 95 % CI

1.3–1.6), and cleaning children’s room less frequently than

once per day (AOR 1.4, 95 % CI 1.1–1.7). This study dem-

onstrates that home indoor environmental and life style

factors may influence the health of children in Xi’an.

Keywords Children health � Indoor air pollution

(IAP) � Questionnaire survey � Asthma and allergy

1 Introduction

While the World Health Organization estimates that one-

quarter of the total global disease burden is due to environ-

mental factors, that proportion rises to one-third for children

[1]. Children are more adversely impacted by exposure to

environmental factors than adults [2, 3]. Moreover, the burden

is much greater in developing countries, where infant death

from environmental causes is 12 times higher than in devel-

oped countries [1]. Exposures in children’s homes likely have

greater impact than exposures outdoors. In industrialized

countries, people spend over 80 % of their time indoor at

home, school, and office [4, 5]. For preschool children, the time

indoors at home generally exceeds 90 %. Therefore, exposure

to home indoor air pollutants may be critical. Epidemiological

studies of developing countries have consistently confirmed an

association between health and indoor air, particularly for

adverse respiratory illnesses and for vulnerable groups such as

women and children [6, 7]. In their review, Bruce et al. [8] and

Smith et al. [9] found ‘‘consistent evidence’’ that indoor air

pollution increases the risk of acute respiratory infections

(ARI) in childhood, which are the largest cause of death in

children under 5 years of age. Some studies have suggested

that there are positive associations between renovations or

Electronic supplementary material The online version of thisarticle (doi:10.1007/s11434-014-0241-6) contains supplementarymaterial, which is available to authorized users.

A. Li � Z. Liu � X. Xu � H. Sun

School of Environmental and Municipal Engineering, Xi’an

University of Architecture and Technology,

Xi’an 710055, China

Y. Sun (&)

School of Environmental Science and Engineering,

Tianjin University, Tianjin 300072, China

e-mail: yuexiasun@tju.edu.cn

J. Sundell

Department of Building Science, Tsinghua University,

Beijing 100081, China

123

Chin. Sci. Bull. (2014) 59(17):2024–2030 csb.scichina.com

DOI 10.1007/s11434-014-0241-6 www.springer.com/scp

painting and asthma [10–12]. However, others have concluded

that there is no direct relationship between chemical sources

and children’s common disease morbidity [13]. Studies have

reported contradictory effects of cat and dog exposure on

asthma in childhood, resulting in inconsistent recommenda-

tions on animal avoidance [14]. Bornehag et al. [15] reported

that the protective effect of pet keeping is mainly due to a

‘‘Healthy Pet Keeping Effect’’ meaning that families with pets

are the families that are relatively immune to pet allergens.

Of the many studies on associations between children’s

health and indoor air pollution, relatively few have been

performed in China. Wang et al. [16] investigated the effect

of indoor air pollution in dwellings on children’s respiratory

health in Lanzhou city. Niu et al. [17] concluded that the

prevalences of respiratory symptom and diseases were

higher in lower age, for males, and in urban residential areas.

Most Chinese people live in concrete apartment buildings.

Water and heat are supplied by district heating systems, and

biomass or natural gas is used for cooking which may mean

high air pollution. Construction work and housing renova-

tion have increased in the last 10 years in China. With the

improvement of living standards, various new decorative

materials have been used in interior design, furniture, and

textiles. At the same time, pet keeping is becoming more and

more popular in urban areas. All these characteristics may be

associated with respiratory illness in children.

This is the first large-scale investigation conducted in

the Xi’an area. The study aimed at assessing the associa-

tions between indoor air pollution and asthma, allergies,

and respiratory infections in children aged 1–8 years in

Xi’an. The study was conducted in collaboration with the

Government of Xi’an Committee of Municipal and Rural

Construction.

2 Materials and methods

2.1 Participants and survey process

Participants from 12 kindergartens (as shown in Fig. 1) were

randomly chosen in three districts of Xi’an area. A total of

2,420 children (1–8 years old) was enrolled in this study,

and 2,020 questionnaires were completed and returned. This

cross-sectional investigation was carried out between April

and November 2011. The questionnaires were filled out by

parents. Teachers in kindergartens were responsible for the

distribution and collection of questionnaires.

2.2 Questionnaire

The questionnaire used ISAAC questions for health [18],

and questions on home environments from studies modeled

Fig. 1 Geographical distribution of 12 kindergartens investigated. Characters A–L indicate locations of 12 kindergartens

Chin. Sci. Bull. (2014) 59(17):2024–2030 2025

123

on the Sweden DBH study [19]. Home environment

questions were modified so as to be relevant to Chinese

building characteristics and life customs. The questionnaire

is composed of six parts: (i) contact information; (ii)

children and family background information; (iii) health

information for children and family members; (iv) housing

characteristics, and indoor exposures; (v) life style infor-

mation; and (vi) dietary information. Core questions from

the ISAAC questionnaire on health were as follows:

Wheeze current Has your child had wheezing or whis-

tling in the chest in the last 12 months?

Dry cough current In the last 12 months, has your child

had a dry cough at night for more than 2 weeks, apart from

a cough associated with a cold or chest infection?

Diagnosed asthma Has your child been diagnosed with

asthma by doctor?

Rhinitis current In the last 12 months, has your child

had a problem with sneezing, or a runny, or a blocked nose

when he/she did not have a cold or the flu?

Diagnosed hay fever Has your child been diagnosed

with hay fever or allergic rhinitis by a doctor?

Eczema current Has your child had itchy rash at any

time in the last 12 months?

Pneumonia Has your child been diagnosed with pneu-

monia by a doctor?

2.3 Statistical analysis

All statistical analyses were conducted by SPSS 20. Chi

square tests were used to compare differences in health

outcomes among different groups of age, gender, and

allergic families. Logistic regression models were used to

analyze the associations between health and dwelling

related factors and life styles.

All statistical tests were considered statistically signifi-

cant when p values B0.05.

3 Results

3.1 Demographic information

Demographic information for investigated children in

Xi’an in 2011 is shown in Table 1. Due to a limited sample

size of children aged 1, 2, 7, and 8 years, analyses of health

outcomes and home environment focus on children

3–6 years old.

3.2 Health outcomes

Health outcomes for investigated children 3–6 years old in

Xi’an are shown in Table 2.

The influence of gender, age and family allergic history

on wheeze, rhinitis and eczema in the last 12 months,

diagnosed asthma, hay fever, and pneumonia are shown in

Table 3. A history of allergies in the family is significantly

and positively associated with all health outcomes tested.

With increasing age, the symptoms of wheeze, rhinitis, and

eczema in the last 12 months among children decreased,

although only the decrement of wheeze reached significant

level (p \ 0.05). Cumulative diagnosed asthma and hay

fever increased with age, but pneumonia did not. Boys had

a relatively higher prevalence of asthma and incidence of

respiratory infections than girls. However, only the dif-

ference in ‘‘wheeze current’’ reached significance.

Table 1 Demographic information for investigated children

Demographic information n (%)

Age

Age 1–2 30 (1.5)

Age 3–4 948 (47.8)

Age 5–6 959 (48.3)

Age 7–8 46 (2.4)

Gender

Boy 1,068 (53.3)

Girl 936 (46.7)

Allergy in familya

Yes 181 (9.2)

a Whether family member has asthma or allergy

Table 2 Health outcomes of children 3–6 years old in Xi’an

Asthma and allergy Prevalence rate (%)

Wheeze ever 20.2

Wheeze current 13.9

Dry cough current 15.2

Diagnosed asthma 2.9

Rhinitis ever 56.6

Rhinitis current 38.9

Diagnosed hay fever 3.6

Eczema ever 29.0

Eczema current 8.2

Respiratory infections ever Prevalence rate (%)

Croup 4.5

Pneumonia 28.3

Common cold [6 times/year 7.5

Ear infection 7.6

2026 Chin. Sci. Bull. (2014) 59(17):2024–2030

123

3.3 Home environment and life style

Building characteristics and life styles are shown in Sup-

plementary Table 1. 96 % of the investigated children live

in urban or suburban areas. Single family houses and

apartments accounted for 82 % of the dwellings. 17 % of

families had laminated wood floors, and 56 % had latex

wall paint. 4 %–19 % families had dampness-related

problems such as mold/damp spots, flooding, and con-

densation on windowpane in winter. 63 % of children were

exposed to environmental tobacco smoke (ETS) and 21 %

had breast feeding for \3 months. 16 % of families cur-

rently had pets at home, and 20 % of parents reported pet

avoidance (meaning getting rid of or refraining from hav-

ing pets) due to allergic problems.

3.4 The influence of indoor environmental factors

and life style on health of children

Associations between dwelling exposure/life style and

health outcomes are shown in Table 4. Among dwelling

related factors, living close to a highway was a significant

risk factor for current rhinitis and eczema symptoms.

Pneumonia had a higher lifetime-ever incidence rate in

apartments, dwellings built before 2000, or located near to

highway. Dwelling ownership did not have a clear asso-

ciation with health outcomes. Indoor decorations such as

laminated wood and latex wall paint were risk factors for

current rhinitis, current eczema, and lifetime-ever pneu-

monia. Damp problems indoors, especially mold/damp

spots on walls and condensation on windowpane in winter,

were clear and strong risk factors for asthma and allergy.

Among life style factors, avoidance of pets was a signifi-

cant risk factor for both current allergic symptoms and

cumulative diagnosed asthma and hay fever. Decoration

during the child’s early life increased the risk of current

rhinitis and eczema. Airing bedding quilts in sunshine and

no ETS exposure were protective factors. Risk factors for

pneumonia were shorter times of breast feeding, infrequent

airing of bedding quilt, and infrequent cleaning of the

child’s room.

4 Discussion

A questionnaire survey was conducted to find associations

between children’s asthma and allergies and indoor air

factors and life style in Xi’an. The response rate was rel-

atively high (83.5 %), which decreases the risk of selection

and non-response biases.

The prevalence of asthma in our study was 2.9 %. Com-

pared to a Chinese nation-wide survey in 2000, the preva-

lence of asthma in our study demonstrated an increasing

trend (2.9 % in 2011 vs. 1.0 % in 2000 in Xi’an) [20].

We found that living close to a highway was a signifi-

cant risk factor for allergic symptoms and pneumonia. This

suggests that pollutants from heavy traffic may induce

asthma. Other studies have demonstrated that traffic can

precipitate and exacerbate asthma attacks and increase the

incidence of respiratory infections [21].

Indoor use of laminated wood was associated with a

high prevalence of rhinitis and eczema symptoms. Lami-

nated wood is composed of thin layers of wood, or veneers,

that are glued together to make a stronger product. Glues

may emit volatile organic compounds (VOCs) to the indoor

environment. With more new buildings and furnishing

materials, chemical pollutants indoors may be serious.

A South Korean study found VOC and HCHO concentra-

tions after house renovation to be higher than nationally

recommended values [22]. Our study also found that dec-

oration of home in the child’s early life was associated with

an increased prevalence of current rhinitis and eczema.

The relationship between dampness and diseases in our

study is well in accordance with findings in many other

studies summarized in a review [23] and a meta-analysis

[24]. According to Bornehag et al.’s [23] review, ‘‘damp-

ness’’ in buildings appeared to increase the risk for airway

health effects including cough, wheeze, and asthma, with

Table 3 Chi square test on associations between health outcomes and gender, age, family allergic history (N = 1,907)

Health outcomes (%) Age Gender Allergy in family

3 4 5 6 p Boy Girl p Yes No p

Wheeze current 16.6 16.0 11.7 11.6 0.038a 15.6 12.1 0.030 22.5 12.9 0.000

Diagnosed asthma 1.8 2.0 3.6 4.4 0.068 3.7 2.2 0.060 6.9 2.3 0.001

Rhinitis current 41.5 41.7 37.8 33.9 0.066 38.9 38.9 0.977 56.8 36.8 0.000

Diagnosed hay fever 2.9 2.8 3.5 5.7 0.094 4.2 2.9 0.131 10.9 2.9 0.000

Eczema current 9.6 8.5 7.2 7.7 0.582 8.3 8.0 0.817 14.7 7.5 0.001

Pneumonia 29.5 29.6 27.8 26.1 0.639 29.4 27.2 0.281 40.8 26.9 0.000

a Numbers in bold indicate that p values reach significant level

Chin. Sci. Bull. (2014) 59(17):2024–2030 2027

123

odds ratios in the range of 1.4–2.2. The AORs in our study

were in the range of 1.5–2.3. Strategies like airing bed-

quilts under sunshine significantly relieved rhinitis symp-

tom, perhaps because sun-curing can reduce infestations of

house dust mites.

Whether keeping pets in the homes of preschool chil-

dren decreases or increases the risk of allergies and asthma

remains controversial. Remes et al. [25] found that expo-

sure to dogs in childhood might prevent the development of

asthma-like symptoms, at least in low-risk children with no

Table 4 Adjusted odds ratios (95 % confidential interval) of home environment and life style for asthma, hay fever, and pneumonia among

children 3–6 years old in Xi’an (N = 1,907)

Wheeze current Asthma Rhinitis current Hay fever Eczema current Pneumonia

Dwelling related factors

Dwelling location: urban versus (suburban/rural)a

0.80 (0.58, 1.11) 1.63 (0.72, 3.67) 1.19 (0.93, 1.51) 1.27 (0.65, 2.48) 0.74 (0.50, 1.09) 1.25 (0.96, 1.63)

Near to highway (within 200 m)

0.94 (0.69, 1.27) 1.46 (0.80, 2.69) 1.45 (1.17, 1.80)b 0.99 (0.57, 1.73) 1.73 (1.21, 2.47) 1.26 (1.00, 1.59)

House type: apartment versus (single family house)

1.08 (0.79, 1.48) 1.37 (0.73, 2.58) 1.10 (0.88, 1.36) 0.86 (0.49, 1.53) 0.83 (0.56, 1.21) 1.40 (1.10, 1.77)

House constructed period: before 2000 versus (after 2000)

1.01 (0.76, 1.33) 1.12 (0.62, 2.03) 1.18 (0.97, 1.44) 0.96 (0.57, 1.61) 0.76 (0.54, 1.08) 1.38 (1.11, 1.70)

Ownership: rent versus (owner)

1.44 (1.08, 1.92) 1.31 (0.72, 2.39) 0.77 (0.63, 0.94) 0.86 (0.52, 1.44) 1.23 (0.86, 1.75) 0.96 (0.78, 1.19)

Indoor decoration

Floor covering: laminated wood versus (cement)

0.85 (0.51, 1.40) 1.38 (0.55, 3.50) 1.45 (1.02, 2.05) 1.68 (0.64, 4.44) 2.75 (1.34, 5.68) 1.29 (0.89, 1.86)

Wall covering: latex paint versus (lime)

0.80 (0.57, 1.11) 1.06 (0.52, 2.19) 1.31 (1.03, 1.67) 1.84 (0.91, 3.74) 1.22 (0.79, 1.87) 1.28 (0.99, 1.66)

Indoor dampness

Mold/dampness spot: yes versus (no)

1.71 (1.11, 2.64) 1.16 (0.45, 3.00) 1.45 (1.03, 2.04) 1.64 (0.78, 3.43) 1.67 (0.99, 2.81) 1.54 (1.08, 2.20)

Condensation on window pane in winter: [5 versus (\5 cm)

1.26 (0.88, 1.81) 1.24 (0.61, 2.51) 1.70 (1.30, 2.22) 1.45 (0.76, 2.76) 2.26 (1.50, 3.43) 1.39 (1.05, 1.84)

Moldy odor: yes versus (no)

1.35 (0.89, 2.06) 1.27 (0.52, 3.08) 1.76 (1.28, 2.41) 0.98 (0.43, 2.21) 1.53 (0.93, 2.52) 1.31 (0.94, 1.83)

Life style

Home decoration during pregnancy or child 0–1 year: yes versus (no)

1.56 (0.90, 2.68) 1.29 (0.39, 4.31) 1.93 (1.26, 2.94) 1.94 (0.79, 4.81) 1.94 (1.06, 3.56) 1.21 (0.78, 1.90)

Breast feeding: less versus (more than 3 months)

1.09 (0.78, 1.51) 0.85 (0.41, 1.77) 1.10 (0.87, 1.39) 0.88 (0.46, 1.68) 1.04 (0.69, 1.56) 1.30 (1.02, 1.67)

Environmental tobacco smoke: yes versus (no)

1.11 (0.84, 1.47) 1.35 (0.74, 2.48) 1.12 (0.92, 1.36) 1.47 (0.84, 2.55) 1.78 (1.21, 2.60) 0.90 (0.73, 1.11)

Air quilt under sunshine: never/sometimes versus (often)

1.00 (0.76, 1.32) 1.18 (0.67, 2.08) 1.42 (1.17, 1.72) 0.93 (0.56, 1.55) 0.82 (0.58, 1.16) 1.28 (1.04, 1.58)

Pets at current home: yes versus (no)

1.46 (1.04, 2.05) 1.44 (0.72, 2.86) 1.23 (0.95, 1.60) 1.39 (0.75, 2.59) 1.47 (0.97, 2.23) 1.34 (1.02, 1.77)

Avoidance of petsc: yes versus (no)

1.84 (1.34, 2.53) 2.36 (1.26, 4.46) 1.27 (0.99, 1.64) 1.87 (1.07, 3.28) 1.99 (1.35, 2.94) 1.04 (0.79, 1.37)

Cleaning child’s room: less than once per day versus (everyday)

0.89 (0.67, 1.17) 1.35 (0.77, 2.37) 1.19 (0.98, 1.45) 1.25 (0.75, 2.08) 1.05 (0.75, 1.49) 1.39 (1.13, 1.71)

Odds ratios were adjusted with gender, age, and family allergic historya Factors in parentheses are used as referencesb Numbers in bold indicate that p values reach significant levelc Get rid of or refrain from pets due to allergy among family members

2028 Chin. Sci. Bull. (2014) 59(17):2024–2030

123

family history of asthma. However, Svanes et al. [26]

reported that selective avoidance of cat keeping could

contribute to preventing children from having asthma and

Bornehag et al. [15] reported that the protective effect of

pet keeping is mainly due to a ‘‘Healthy Pet Keeping

Effect’’, meaning that families with pets are self-aware that

they do not have allergic responses to pets. Our study

shows that avoidance behavior of pets (that is, getting rid

of, or refraining from having pets because of allergies

among family members) was a significant risk factor for

asthma and allergies (AOR: 1.3-2.4). This confirms that the

apparent protective effect of pets is not real; it is instead a

manifestation of ‘‘selection’’ behavior.

The overall pneumonia-ever incidence for Xi’an

children was 28.3 %, which is four times as high as for

children in Texas (12.5 %) [27]. This ‘‘relative risk’’ is

consistent with a report from WHO, which shows that

the incidence of pneumonia in children aged \5 years

in developing is 6 times as high as in developed

countries (0.29 vs. 0.05 episodes per child-year) [28].

Previous studies have reported that breast feeding dur-

ing the first year of life [29, 30] could reduce pneu-

monia infections, while ETS and mold in child’s

bedroom increased the risk of pneumonia [31]. Our

study supports these findings. However, the explanation

for why children living in modern apartment in the

urban area of Xi’an had higher pneumonia-ever rates

compared to those living in single family houses in

rural areas need further investigation.

5 Conclusions

The prevalences of asthma, hay fever, and pneumonia of

children 3–6 years old in Xi’an were 2.9 %, 3.6 %, and

28.3 %, respectively. Dwelling and life style related factors

influenced respiratory health of the Xi’an’s children.

Laminated wood floor, latex wall paint, and decoration in

early life of the children were associated with increased

prevalences of asthma and allergies. Airing bed-quilts

under sunshine was found to be protective against allergic

symptoms. Living close to a highway increased the pneu-

monia-ever incidence, as did living in an apartment in an

urban area, dampness, latex wall paint, short time of breast

feeding, infrequent airing of the bed-quilt, and infrequent

cleaning of the child’s room.

Acknowledgments This work was supported by the National Nat-

ural Science Foundation of China (51178374), the Specialized

Research Fund for the Doctoral Program of Higher Education

(20106120110008) and Xi’an Urban and Rural Construction Com-

mittee of Science and Technology Project (2011023). We appreciate

Louise B. Weschler for her thorough language checking and valuable

comments on this article.

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