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China has implemented two national clean air actions in 2013-2017 and 2018-2020, respectively, with the aim of reducing primary emissions and hence improving air quality at a national level. It is important to examine the effectiveness of such emission reductions and assess the resulting changes in air quality. However, such evaluation is difficult as meteorological factors can amplify, or obscure the changes of air pollutants, in addition to the emission reduction. In this study, we applied the random forest machine learning technique to decouple meteorological influences from emissions changes, and examined the deweathered trends of air pollutants in 12 Chinese mega-cities during 2013-2020. The observed concentrations of all criteria pollutants except O 3 showed significant declines from 2013 to 2020, with PM 2.5 annual decline rates of 6-9% in most cities. In contrast, O 3 concentrations increased with annual growth rates of 1-9%. Compared with the observed results, all the pollutants showed smoothed but similar variation in trend and annual rate-of-change after weather normalization. The response of O 3 to NO 2 concentrations indicated significant regional differences in photochemical regimes, and the differences between observed and deweathered results provided implications for volatile organic compound emission reductions in O 3 pollution mitigation. We further evaluated the effectiveness of first and second clean air actions by removing the meteorological influence. We found that the meteorology can make negative or positive contribution in reducing pollutant concentrations from emission reduction, depending on type of pollutants, locations, and time period. Among the 12 mega-cities, only Beijing showed a positive meteorological contribution in amplifying reductions in main pollutants except O 3 during both clean air action periods. Considering the large and variable impact of meteorological effects in changing air quality, we suggest that similar deweathered analysis is needed as a routine policy evaluation tool on a regional basis., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

We investigated associations between prenatal and postnatal environmental factors and onset and remission of preschool childhood eczema across China. The study population was preschoolers in randomized day care centers in seven cities (N = 39,782). Data on eczema and prenatal and postnatal indoor and outdoor environment were obtained from a cross-sectional questionnaire sent to parents or other guardians. Reports on eczema in the first 2 years and in the past year was used to retrospectively calculate onset and remission (changes of reported eczema). Prenatal and postnatal outdoor temperature, NO 2 and PM 10 were modelled from official air pollution data. Associations were estimated by two-level logistic regression. Calculated onset rate was 3.2%/y and remission rate 29.2%/y. Exposure to NO 2 during pregnancy was associated with onset of eczema, similarly for all trimesters. Postnatal PM 10 and NO 2 were related to decreased remission. Postnatal outdoor temperature was associated with onset of eczema. Pre-natal and current redecoration or buying new furniture, and perinatal as well as current dampness and indoor mould, were associated with increased onset and decreased remission. Cockroaches in current home was another indoor risk factors. Prenatal exposure to farm environment and large family size were all negatively associated with eczema. In conclusion, a warmer climate and prenatal NO 2 can be associated with increased onset of eczema in Chinese preschoolers. Postnatal PM 10 and NO 2 can be associated with reduced remission. Perinatal and current dampness, indoor mould and cockroaches may increase onset and decrease remission. Exposure to chemical emissions from indoor materials after first year of life may increase onset. Prenatal exposure to farm environment and large family size could be protective., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

Given a large fraction of people's exposure to urban PM 2.5 occur indoors, reducing indoor PM 2.5 levels may offer a more feasible and immediate way to save substantial lives and economic losses attributable to PM 2.5 exposure. We aimed to estimate the premature mortality and economic loss reductions associated with achieving the newly established Chinese indoor air guideline and a few hypothetical indoor PM 2.5 guideline values. We used outdoor PM 2.5 concentrations from 1497 monitoring sites in 339 Chinese cities in 2015, coupled with a steady-state mass balance model, to estimate indoor concentrations of outdoor-infiltrated PM 2.5 . Using province-specific time-activity patterns for urban residents, we estimated outdoor and indoor exposures to PM 2.5 of outdoor origin. We then proceeded to use localized census-based concentration-response models and the value of statistical life estimates to calculate premature deaths and economic losses attributable to PM 2.5 exposure across urban China. Finally, we estimated potentially avoidable mortality and corresponding economic losses by meeting the current 24-hour based guideline and various hypothetical indoor limits for PM 2.5 . In 2015 in urban areas of mainland China, the city-specific annual mean outdoor and indoor PM 2.5 concentrations ranged 9-108 μg/m 3 and 5-56 μg/m 3 , respectively. Indoor exposures contributed 62%-91% daily and 68%-83% annually to the total time-weighted exposures. The potential reductions in total deaths and economic losses for the scenario in which daily indoor concentrations met the current guideline of 75 μg/m 3 , 37.5 μg/m 3 , and 25 μg/m 3 were 16.9 (95% CI: 0.7-62.1) thousand, 87.7 (95% CI: 9.7-197.7) thousand, and 165.5 (95% CI: 30.8-304.0) thousand, respectively. The corresponding reductions in economic losses were 5.7 (95% CI: 0.2-34.8) billion, 29.4 (95% CI: 2.4-109.6) billion, and 55.2 (95% CI: 7.7-168.0) billion US Dollars, respectively. Deaths and economic losses would be reduced exponentially within the range of 0-75 μg/m 3 for hypothetical indoor PM 2.5 limits. The findings demonstrate the effectiveness of reducing indoor concentrations of outdoor-originated PM 2.5 in saving substantial lives and economic losses in China. The analysis provides quantitative evidence to support the implementation of an indoor air quality guideline or standard for PM 2.5 ., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

We estimated associations between ambient air pollution, home environment and asthma as well as rhinitis among adults across China. A total of 40,279 young adults from eight Chinese cities participated in a questionnaire survey (participation rate 75%). There were questions on health and home environment. Information on city level gross domestic product (GDP) per capita, ambient temperature and PM 10 and NO 2 were collected from registers. Two-level logistic regression models were used to study health associations. Totally 1.6% reported asthma and 6.6% reported allergic rhinitis (AR). Higher temperature was associated with more asthma but less AR. Higher GDP was associated with less asthma but more AR. Higher degree of urbanization, higher level of NO 2 and living near heavily trafficked road were risk factors for asthma and AR. Participants in older buildings reported more asthma. Redecoration and buying new furniture were related to more asthma and AR (OR = 1.15-1.91). Using natural gas (OR = 1.34) and biomass (OR = 1.35) for cooking were risk factors for AR. Burning mosquito coils and incense increased the risk of asthma and AR. Cat keeping (OR = 2.88), dog keeping (OR = 2.04), cockroaches (OR = 1.54) and rats or mice (OR = 1.46) were associated with asthma. Cockroaches increased the risk of AR (OR = 1.22). Air humidifier and air cleaner were linked to asthma and AR. Frequent cleaning and exposing bedding to sunshine were protective. In conclusion, urbanization, NO 2 and traffic exhaust can increase the risk of adult asthma and AR. Higher ambient temperature was related to more asthma but less AR. Indoor animals such as cats, dogs, rats/mice and presence of cockroaches were associated with asthma or AR. Indoor chemical sources such as redecoration and new furniture were other risk factors. Cooking with natural gas or biomass and burning mosquito coils and incense were associated with asthma or AR. Frequent cleaning and exposing bedding to sunshine were protective., Competing Interests: Declaration of competing interest The authors declare that they have no known competing interest., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

The long-term effects of ambient PM 2.5 and chemical constituents on childhood pneumonia were still unknown. A cross-sectional study was conducted in 30,315 children in the China Children, Homes, Health (CCHH) project, involving 205 preschools in six cities in China, to investigate the long-term effects of PM 2.5 constituents on lifetime-ever diagnosed pneumonia. Information on the lifetime-ever pneumonia and demographics were collected by validated questionnaires. The lifetime annual average ambient PM 2.5 , ozone and five main PM 2.5 constituents, including SO 4 2- , NO 3 , organic matter (OM) and black carbon (BC), were estimated according to preschool addresses by a combination of satellite remote sensing, chemical transport modeling and ground-based monitors. The prevalence of lifetime-ever diagnosed pneumonia was 34.5% across six cities and differed significantly among cities (p = 0.004). The two-level logistic regression models showed that the adjusted odds ratio for PM - , NH 4 + , organic matter (OM) and black carbon (BC), were estimated according to preschool addresses by a combination of satellite remote sensing, chemical transport modeling and ground-based monitors. The prevalence of lifetime-ever diagnosed pneumonia was 34.5% across six cities and differed significantly among cities (p = 0.004). The two-level logistic regression models showed that the adjusted odds ratio for PM 2.5 (per 10 µg/m 3 ) and its constituents (per 1 µg/m 3 )-SO 4 2- , NO 3 - , NH 4 + , and OM were 1.12 (95% CI:1.07-1.18), 1.02 (1.00-1.04), 1.06 (1.04-1.09), 1.05 (1.03-1.07) and 1.09 (1.06-1.12), respectively. Children in urban area, aged < 5 years and breastfeeding time < 6 months enhanced the risks of pneumonia. Our study provided robust results that long-term levels of ambient PM 2.5 and its constituents increased the risk of childhood pneumonia, especially NH 4 + , NO 3 - and OM., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

This paper studied associations between reported common cold and home dampness and mould, cleaning habits and ventilation, climate and outdoor air pollution in China among young adults without asthma or allergic rhinitis. Parents of children attending day care in eight Chinese cities answered a questionnaire on their health and home environment (75% response rate). We restricted the population to subject without asthma or allergic rhinitis (N = 37,275). Temperature and air pollution data was obtained from monitoring stations. Associations were estimated by multilevel logistic regression. Totally 12.5% reported common cold (≥3 colds) and 1.6% frequent common cold (≥5 colds) in the past 12 months. Female gender (OR = 1.53; 95% CI 1.37-1.71), residents in southern China (OR = 1.89; 95% CI 1.16-3.07) and living in homes with water leakage (OR = 1.32; 95% CI 1.16-1.50), mould odour (OR = 1.48; 95% CI 1.28-1.72), indoor mould (OR = 1.47; 95% CI 1.28-1.70), condensation on window panes (OR = 1.42; 95% CI 1.32-1.52) and damp bed clothing (OR = 1.19; 95% CI 1.11-1.28) were associated with common cold. Having many signs of dampness increased ORs. Daily cleaning (OR = 0.91; 95% CI 0.85-0.97) and mechanical ventilation in kitchen or bathroom (OR = 0.75; 95% CI 0.64-0.89) were protective. Higher mean ambient temperature (OR = 1.11 per °C; 95% CI 1.02-1.21), PM 10 (OR = 1.17 per 10 μg/m 3 ; 95% CI 1.14-1.21) and PM 2.5 (OR = 1.28 per 10 μg/m 3 ; 95% CI 1.20-1.37) were associated with common cold. The association with particulate air pollution was stronger in southern China. Similar associations were found for frequent common cold. In conclusion, indoor dampness and mould, a warmer climate and PM 10 and PM 2.5 can be associated with reported common cold. Further intervention and prospective studies are needed to verify causality of observed association in this cross-sectional study., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Few Chinese population studies exist on early life risk factors for furry pet allergy., Objectives: We studied childhood respiratory symptoms when in contact with furry pets in relation to early life exposure. Moreover, we studied similar environmental associations for rhinitis not related to furry pets., Methods: Children aged 3-6 y from day care centres in seven Chinese cities participated (N = 39,782). Parents answered a questionnaire on home environment and children's health, including rhinoconjunctivitis and wheeze when in contact with furry pets, and diagnosed rhinitis. Prenatal and postnatal outdoor temperature, PM 2.5 , PM 10 , and NO 2 were calculated using data from monitoring stations. Associations were estimated by multilevel logistic regression., Results: Totally 2% had cats, 4% dogs, and 3.2% had rhinoconjunctivitis or wheeze when in contact with furry pets (FP symptoms). Moreover, 1.1% had furry pet related diagnosed rhinitis and 7.5% had diagnosed rhinitis not related to furry pets (other diagnosed rhinitis). Prenatal PM 2.5 and PM 10 , especially in second trimester, and a colder climate were risk factors for FP symptoms. ETS, dampness and mould, condensation on windows in wintertime, and cats and dog keeping were associated with FP symptoms. Breast feeding and frequent window opening were protective. Similar indoor associations were found for furry pet related diagnosed rhinitis. ETS, dampness and mould, window condensation, urbanization and mechanical exhaust ventilation were risk factors for other diagnosed rhinitis. Cooking with an electric stove and early life exposure to animals (cats, dogs, farm environment during pregnancy) were protective for diagnosed rhinitis not related to furry pets., Conclusions: Prenatal outdoor PM 10 and PM 2.5 can be risk factors for symptoms suggestive of furry pet allergy. Early life dampness and mould can be risk factors for rhinitis related and not related to furry pets. Exposure to animals (cats, dogs, farm environment) may reduce diagnosed rhinitis not related to furry pets., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

We surveyed 40 010 three- to six-year-old children in seven Chinese cities (Beijing, Taiyuan, Urumqi, Shanghai, Nanjing, Changsha, and Chongqing) during 2010-2012 so as to investigate possible links between home renovation and childhood eczema. Their parents responded to questions on home renovation and childhood eczema. Multivariate and two-level (city-child) logistic regression analyses yielding odds ratios with 95% confidence intervals were performed. Sensitivity analyses stratifying data for region, climate, and income level were also performed. The prevalences of childhood eczema in children with different floor and wall covering materials were significantly different and were significantly higher with home renovation during early lifetime. Exposure to synthetic materials significantly increased the risk of childhood eczema by 20%-25%. The risks (AOR, 95% CI) of current eczema among children in families with solid wood flooring and oil paint wall covering were 1.25 (1.04-1.49) and 1.35 (1.14-1.60), respectively. Home renovation during pregnancy was related to children's lifetime and current eczema., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

We studied indoor sources of indoor particulate matter (PM), outdoor air pollution and antibiotic use in relation to asthma, rhinitis and eczema among pre-school children and investigated synergistic effects between PM and antibiotics use. Children (3-6y) from randomly selected day care centres in seven cities across China were included (n = 39,782). Data on ambient temperature and air pollution were collected from local monitoring stations. Data on indoor PM sources (ETS, burning of incense or mosquito coils and biomass for cooking), antibiotics use and health (doctor diagnosed asthma and rhinitis, lifetime eczema, current wheeze and current rhinitis) were assessed by a parental questionnaire. Associations were calculated by multilevel logistic regression. Asthma diagnosis was associated with outdoor temperature, NO 2 and burning mosquito coils. Rhinitis diagnosis was associated with NO 2 , ETS, gas cooking and burning biomass for cooking. Lifetime eczema was associated with temperature, PM 10, NO 2 , ETS, biomass cooking and burning mosquito coils. Burning incense was associated with current wheeze and current rhinitis. Children using antibiotics had more asthma, wheeze, rhinitis, and eczema. Excluding children with respiratory infections did not change associations with antibiotics use. Antibiotics use enhanced the effects of ETS and PM 10 (a synergistic effect). In conclusion, a warmer climate, outdoor NO 2 and PM 10, ETS, gas cooking and burning biomass, incense and mosquito coils can increase the risk of asthma, wheeze, rhinitis and eczema among pre-school children in China. Antibiotics use is a risk factor for childhood asthma, wheeze, rhinitis and eczema and ETS and outdoor PM 10 can enhance the effect., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study estimates adult mortalities attributed to PM 2.5 across urban China in 2015 and the corresponding mortalities that might be avoided by meeting the yearly averaged indoor PM 2.5 threshold in the newly established Assessment Standard for Healthy Building (ASHB) and seven other potential thresholds. We use outdoor PM 2.5 concentrations from ∼1500 monitoring sites in 339 Chinese cities, coupled with a detailed exposure model, to estimate outdoor and indoor exposures to PM 2.5 originating outdoors. We proceed to calculate premature mortality attributable to PM 2.5 exposure using an integrated exposure-response model. Results indicate that indoor exposures accounted for 66%-87% of total exposure to PM 2.5 of outdoor origin and 81% (95% confidence interval (CI), 71%-87%), i.e., 316 000 (95% CI, 176 000-435 000), of the 389 000 (95% CI, 245 000-501 000) mortalities attributable to "outdoor PM 2.5 " for the urban population ≥25 years of age in China in 2015. Potentially 14 000 (95% CI, 8000-20 000) deaths might be avoided if indoor PM 2.5 of outdoor origin met the ASHB guideline of 35 μg/m 3 for annual mean indoor PM 2.5 , and 162 000 (95% CI, 79 000-237 000) deaths might be avoided by meeting a 10 μg/m 3 threshold. The analysis in this work should be helpful in formulating indoor air quality policies.

Objective: Few longitudinal studies exist on childhood exposure to indoor and outdoor air pollution and respiratory illness in China. We studied associations between indoor and outdoor environment and prevalence, onset and remission of wheeze and rhinitis among children across China., Methods: Children (3-6 y) were recruited from randomized day care centres in six cities. The main data analysis was restricted to children not moving since birth (N = 17,679). Data on wheeze, rhinitis and the home environment were assessed by a parental questionnaire. Prevalence in the first two years of life (baseline) and the last year (follow-up) was used to calculate onset and remission. Outdoor PM 2.5 , PM 10 , and NO 2 at the day care centre were modelled from monitoring station data. Associations were calculated by multilevel logistic regression., Results: Prenatal NO 2 was associated with decreased remission of wheeze and increased prevalence and increased onset of rhinitis. Prenatal PM 2.5 was associated with increased prevalence of wheeze. Postnatal NO 2 and postnatal PM 10 were associated with increased prevalence and lower remission of wheeze and rhinitis. Mould, window pane condensation, renovation and cockroaches at home were associated with increased prevalence and increased onset of wheeze and rhinitis. Gas cooking was associated with increased onset of rhinitis. Children of mothers with industrial work had more wheeze., Conclusions: Outdoor PM 2.5 , PM 10 and NO 2 can increase childhood wheeze and rhinitis. Dampness and mould can increase onset and decrease remission. Crowdedness, cockroaches at home and emissions from new building materials and gas cooking can be risk factors for wheeze and rhinitis., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Biomass burning is associated with childhood pneumonia but few studies exist on other indoor factors., Aim: To study pneumonia in relation to pre-natal and post-natal exposure among children across China., Methods: Children (3-6 y) (n = 39,782) from randomized day care centres in seven cities in China. Information on pneumonia and pre-natal and post-natal exposure to home environment factors were assessed by a parental questionnaire. Life-time outdoor temperature and GDP per capita were assessed on city level. Associations were calculated by multilevel logistic regression adjusting for fourteen co-variates., Results: Totally 32.0% had ever had pneumonia diagnosed by a physician. Children of farmer mothers (OR = 0.65), with breastfeeding (OR = 0.91) and living in rural (OR = 0.85) or suburban (OR = 0.90) areas had less pneumonia. Buying new furniture one year before conception (OR = 1.11) and after first year of life (OR = 1.10) increased the risk. Redecoration one year before conception (OR = 1.20), during pregnancy (OR = 1.18) and after first year of life (OR = 1.17) increased pneumonia risk. Children with mould (OR = 1.17), window pane condensation (WPC) (OR = 1.20) and mould odour (OR = 1.15) at home at birth only had a higher risk of pneumonia. Similar associations were seen for dampness and mould in the current home. Children in the oldest and newest homes had less pneumonia. Cockroaches (OR = 1.08), mosquitos or flies in the current home (OR = 1.18), an exhaust fan in the bathroom (OR = 1.10) and higher economic development level, measured as GDP per capita on city level (OR 1.11 per 10,000 RMB/year) were associated with childhood pneumonia., Conclusions: Perinatal and postnatal exposure to mould, mould odour and window pane condensation at home can be early life risk factors for childhood pneumonia in China. Moreover, pre-natal and post-natal exposure to chemical emissions from new furniture and renovation could increase the risk of childhood pneumonia. Breastfeeding, farm exposure, and living in rural or suburban areas could be protective., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Children's pneumonia is a heavy health burden. Few studies have been carried out on residential risk factors for pneumonia in children. Potential risks associated with dwelling characteristics are still unknown., Methods: A cross-sectional study was conducted among children in 8 cities in China during 2010-2011 and 41,176 valid data on children aged 3-8 years old were used in this analysis. To obtain the lifetime-ever incidence of pneumonia in children and identify associations between pneumonia and residential risk factors, chi-square analysis and logistic regression methods were employed. Adjusted odds ratios were used as measures of effect with a 95% confidence interval. Confounding variables in the regression model include children's gender, birthweight, breastfeeding duration, parental smoking and family history of atopy., Results: The average lifetime-ever incidence of childhood pneumonia was 32.3%. Urban children (33.6%) had more pneumonia than suburban (29.9%) and rural children (24.9%). More residential risk factors were found in urban-dwellings. Boys, low birthweight (<2500 g), breastfeeding duration <6 months, family allergic history, and exposure to parental smoking were found to be associated with higher pneumonia lifetime-ever incidences. Various indicators of dampness, including visible mold spots, damp stains, water damage, water condensation, damp clothing or bedding and mold odor, were also positively associated with pneumonia. Pneumonia incidence increased as the number of dampness indicators increased. Both natural gas and solid cooking fuels were positively associated with pneumonia compared with electricity. Compared with cement, construction materials including synthetic fiber, laminated wood, real wood, paint, emulsion paint and wall paper were positively associated with pneumonia. Daily living habits such as putting bedding to sunshine frequently and cleaning the child's bedroom every day could be effective preventive strategies. A dose-response relationship between the number of residential risk factors and pneumonia was observed when the risk factors number ranged from 7 to 11. Residences with more risk factors had higher lifetime-ever pneumonia odds ratios., Conclusions: Indoor environmental factors including dampness, use of solid fuels or natural gas for cooking and use of new construction materials are risk factors for childhood pneumonia. This study gives evidence for the importance of home environment exposures in the occurrence of childhood pneumonia. Actions against the residential risk factors described in this study may help to prevent pneumonia in children., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Childhood asthma is prevalent in China. However, there is a lack of evidence on whether household renovation, including the materials used and the periods, are associated with the disease., Objectives: To investigate the associations between household decoration materials and renovation periods, and childhood asthma and its related symptoms., Methods: During 2010-2012, a retrospective cohort study was initiated in seven cities of China, and 40,010 children, aged 3-6 years, were recruited. Data on demographics, health status, and home decoration conditions were collected using a parent-administered questionnaire. Two-level (city-child) logistic regression analyses with adjusted odds ratios (AORs) and 95% confidence intervals (CIs) were performed to show the target associations. Sensitivity analysis was performed by stratifying data for children in the southern and northern cities., Results: Children whose homes underwent renovation or the addition of new furniture within 1 year before pregnancy, during pregnancy, at age 0-1 year, and after age 1 year had significantly (p < 0.05) higher prevalence of childhood asthma and its related symptoms. The use of solid wood floors and wallpaper had significant associations (cement: AOR, 95% CI: 1.59, 1.17-2.17; lime: AOR, 95% CI: 1.31, 1.00-1.71) with an increased risk of lifetime asthma. Household renovation and the addition of new furniture during pregnancy had significant associations with lifetime asthma (renovation: AOR, 95% CI: 1.23, 1.01-1.51); lifetime wheeze (renovation: AOR, 95% CI: 1.21, 1.05-1.39; furniture: AOR, 95% CI: 1.24, 1.14-1.36), current wheeze (renovation: AOR, 95% CI, 1.21 1.05-1.40; furniture: AOR, 95% CI: 1.23, 1.12-1.34), and current dry cough (renovation: AOR, 95% CI: 1.41, 1.23-1.63; furniture: AOR, 95% CI: 1.28, 1.17-1.41). Similar associations were found between the addition of new furniture during early childhood and lifetime asthma and its related symptoms. Except for the association between lifetime wheeze and flooring materials, the studied associations were generally stronger among children from the northern cities., Conclusions: We confirmed that using cellulose based materials in home decoration and renovation, and adding new furniture during early childhood and pregnancy could be risk factors for childhood asthma. The association between household decoration during early childhood and childhood asthma may be stronger in the northern cities of China., (Copyright © 2018 Elsevier Ltd. All rights reserved.)