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, NO2 and burning mosquito coils. Rhinitis diagnosis was associated with NO2, ETS, gas cooking and burning biomass for cooking. Lifetime eczema was associated with temperature, PM10, NO2, 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 PM10 (a synergistic effect). In conclusion, a warmer climate, outdoor NO2 and PM10, 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 PM10 can enhance the effect.

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. 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 PM2.5, PM10, and NO2 at the day care centre were modelled from monitoring station data. Associations were calculated by multilevel logistic regression. Prenatal NO2 was associated with decreased remission of wheeze and increased prevalence and increased onset of rhinitis. Prenatal PM2.5 was associated with increased prevalence of wheeze. Postnatal NO2 and postnatal PM10 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. Outdoor PM2.5, PM10 and NO2 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.

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 PM₁₀ and NO₂ 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 NO₂ 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, NO₂ 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.

During 2010-2012, we conducted an observational study on household environment and health outcomes among 40,010 preschool children from seven cities of China. Here we examined associations of six dampness-related indicators (visible mold spots, visible damp stains, damp clothing and/or bedding, water damage, condensation on windowpane, moldy odor) in the current residence and three dampness-related indicators (visible mold spots, condensation on windowpane, moldy odor) in the early residence with childhood asthma and rhinitis. In the multi-level logistic regression analyses, visible mold spots and visible damp stains in the current residence were significantly associated with the increased odds of doctor-diagnosed asthma and allergic rhinitis during lifetime-ever (adjusted odd ratios (AORs) range: 1.18-1.35). All dampness-related indicators were significantly associated with increased odds of wheeze and rhinitis during lifetime-ever and in the past 12 months (AORs range: 1.16-2.64). The cumulative numbers of damp indicators had positively dose-response relationships with the increased odds of the studied diseases. These associations for wheeze and rhinitis were similar between northern children and southern children. Similar results were found in the sensitive analyses among children without a family history of allergies and among children without asthma and allergic rhinitis. For 3-6 years-old children in mainland of China in 2011, we speculated that about 90,000 (2.02%) children with asthma and about 59,000 (1.09%) children with allergic rhinitis could be attributable to exposing to visible mold spots in the current residence. Our results suggested that early and lifetime exposures to household dampness indicators are risk factors for childhood asthma and rhinitis.