RESUMO
Indoor semivolatile organic compounds (SVOCs) pose a substantial threat to human health. However, identifying the sources of these emissions has been challenging owing to the scarcity of convenient and practical on-site methodologies. Herein, a novel method for source screening was proposed using aluminum silicate sampling strips to adsorb SVOCs from the surface air of indoor materials. The adsorbed SVOC levels indicate the emission intensity of these materials into indoor environments. Additionally, compact sampling strips can be readily fixed to any vertical surface using a static sticker, facilitating the characterization of various materials in practical settings. Laboratory-simulated experiments demonstrated the capability of the proposed method to differentiate between source and non-source materials within a 10-cm distance in the same space. In practical scenarios, the primary emission sources identified via this method exhibited a consistent correlation with the contents of the corresponding materials obtained from the traditional solvent-extraction method. As the adsorbed SVOCs were directly transferred to a GC-MS through thermal desorption instead of the solvent-extraction procedure, the proposed method demonstrated several-fold improvements in analytical sensitivity and efficiency. Using this versatile screening technique, some emerging and important SVOC species were identified within specific indoor materials. Eliminating these sources has been demonstrated as an effective approach to mitigate SVOC pollution. Overall, the proposed method offers a powerful tool for managing indoor pollutants and safeguarding human health.
Assuntos
Poluição do Ar em Ambientes Fechados , Monitoramento Ambiental , Compostos Orgânicos Voláteis , Poluição do Ar em Ambientes Fechados/análise , Compostos Orgânicos Voláteis/análise , Monitoramento Ambiental/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Poluentes Atmosféricos/análise , HumanosRESUMO
BACKGROUND: High-level exposure to indoor air pollutants (IAPs) and their corresponding adverse health effects have become a public concern in China in the past 10 years. However, neither national nor provincial level burden of disease attributable to multiple IAPs has been reported for China. This is the first study to estimate and rank the annual burden of disease and the financial costs attributable to targeted residential IAPs at the national and provincial level in China from 2000 to 2017. METHODS: We first did a systematic review and meta-analysis of 117 articles from 37â231 articles identified in major databases, and obtained exposure-response relationships for the candidate IAPs. The exposure levels to these IAPs were then collected by another systematic review of 1864 articles selected from 52â351 articles. After the systematic review, ten IAPs with significant and robust exposure-response relationships and sufficient exposure data were finally targeted: PM2·5, nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide, radon, formaldehyde, benzene, toluene, and p-dichlorobenzene. The annual exposure levels in residences were then evaluated in all 31 provinces in mainland China continuously from 2000 to 2017, using the spatiotemporal Gaussian process regression model to analyse indoor originating IAPs, and the infiltration factor method to analyse outdoor originating IAPs. The disability-adjusted life-years (DALYs) attributable to the targeted IAPs were estimated at both national and provincial levels in China, using the population attributable fraction method. Financial costs were estimated by an adapted human capital approach. FINDINGS: From 2000 to 2017, annual DALYs attributable to the ten IAPs in mainland China decreased from 4620 (95% CI 4070-5040) to 3700 (3210-4090) per 100â000. Nevertheless, in 2017, IAPs still ranked third among all risk factors, and their DALYs and financial costs accounted for 14·1% (95% CI 12·3-15·6) of total DALYs and 3·45% (3·01-3·82) of the gross domestic product. Specifically, the rank of ten targeted IAPs in order of their contribution to DALYs in 2017 was PM2·5, carbon monoxide, radon, benzene, nitrogen dioxide, ozone, sulphur dioxide, formaldehyde, toluene, and p-dichlorobenzene. The DALYs attributable to IAPs were 9·50% higher than those attributable to outdoor air pollution in 2017. For the leading IAP, PM2·5, the DALYs attributable to indoor origins are 18·3% higher than those of outdoor origins. INTERPRETATION: DALYs attributed to IAPs in China have decreased by 20·0% over the past two decades. Even so, they are still much higher than those in the USA and European countries. This study can provide a basis for determining which IAPs to target in various indoor air quality standards and for estimating the health and economic benefits of various indoor air quality control approaches, which will help to reduce the adverse health effects of IAPs in China. FUNDING: The National Key Research and Development Program of China and the National Natural Science Foundation of China.
Assuntos
Poluentes Atmosféricos , Ozônio , Radônio , Humanos , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Monóxido de Carbono/análise , Dióxido de Enxofre/análise , Benzeno/efeitos adversos , Benzeno/análise , Dióxido de Nitrogênio/efeitos adversos , Dióxido de Nitrogênio/análise , Formaldeído/análise , Efeitos Psicossociais da Doença , Material Particulado/análise , Radônio/análise , Ozônio/análise , Tolueno/análiseRESUMO
Indoor radon exposure is thought to be associated with adverse health effect as lung cancer. Lung cancer incidences in China have been the highest worldwide during the past two decades. It is important to quantitively address indoor radon exposure and its health effect, especially in countries like China. In this paper, we have conducted a meta-analysis based on indoor radon and its health effect studies from a systematic review between 2000 and 2020. A total of 8 studies were included for lung cancer. We found that the relative risk (RR) was 1.01 (95% CI: 1.01-1.02) per 10 Bq/m3 increase of indoor radon for lung cancer in China. The subgroup analysis found no significant difference between the conclusions from the studies from China and other regions. The health effect of indoor radon exposure is relatively consistent for the low-exposure and high-exposure groups in the subgroup analysis. With a better understanding of exposure level of indoor radon, the outcomes and conclusions of this study will provide supports for next phase of researches on estimation of environmental burden of disease by indoor radon exposures in countries like China.
Assuntos
Poluição do Ar em Ambientes Fechados , Neoplasias Pulmonares , Radônio , Humanos , Poluição do Ar em Ambientes Fechados/efeitos adversos , Poluição do Ar em Ambientes Fechados/análise , Fatores de Risco , Radônio/efeitos adversos , Radônio/análise , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/etiologia , China/epidemiologiaRESUMO
The burden of disease attributed to the indoor exposure to sulfur dioxide (SO2 ), nitrogen dioxide (NO2 ), ozone (O3 ), and carbon monoxide (CO) is not clear, and the quantitative concentration-response relationship is a prerequisite. This is a systematic review to summarize the quantitative concentration-response relationships by screening and analyzing the polled effects of population-based epidemiological studies. After collecting literature published between 1980 and 2019, a total of 19 health outcomes in 101 studies with 182 health risk estimates were recruited. By meta-analysis, the leave-one-out sensitivity analysis and Egger's test for publication bias, the robust and reliable effects were found for SO2 (per 10 µg/m3 ) with chronic obstructive pulmonary diseases (COPD) (pooled relative risks [RRs] 1.016, 95% CI: 1.012-1.021) and cardiovascular diseases (CVD) (RR 1.012, 95%CI: 007-1.018), respectively. NO2 (per 10 µg/m3 ) had the pooled RRs for childhood asthma, preterm birth, lung cancer, diabetes, and COPD by 1.134 (1.084-1.186), 1.079 (1.007-1.157), 1.055 (1.010-1.101), 1.019 (1.009-1.029), and 1.016 (1.012-1.120), respectively. CO (per 1 mg/m3 ) was significantly associated with Parkinson's disease (RR 1.574, 95% CI: 1.069-2.317) and CVD (RR 1.024, 95% CI: 1.011-1.038). No robust effects were observed for O3 . This study provided evidence and basis for further estimation of the health burden attributable to the four gaseous pollutants.
Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Poluição do Ar , Doenças Cardiovasculares , Ozônio , Nascimento Prematuro , Doença Pulmonar Obstrutiva Crônica , Recém-Nascido , Feminino , Humanos , Criança , Dióxido de Nitrogênio , Monóxido de Carbono , Dióxido de Enxofre , Poluição do Ar/análise , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , EnxofreRESUMO
Exposure to formaldehyde causes a variety of adverse health outcomes, while the distributions of indoor formaldehyde in different building types are still not clear in China. In this study, based on the systematic review of previously published data and Monte Carlo simulation, we assessed geographical and temporal distributions of indoor formaldehyde concentrations in residences, schools, and offices across China. A total of 397 studies covered 34 provincial-level regions since 1986 were collected. The results showed that indoor formaldehyde concentrations in residences, schools, and offices in nationwide were decreasing over years due to the publishment of indoor air quality standards since 2002. During 2011 to 2015, the median concentrations of indoor formaldehyde in newly renovated residences, schools, and offices were 153 µg/m3 , 163 µg/m3 , and 94 µg/m3 , with an exceeding rate of 82%, 46%, and 91% considering a standard threshold of 100 µg/m3 at that time, while the exceeding rate was less than 5% for buildings that were renovated beyond one year. Our findings release the temporal trends and geographic distributions of indoor formaldehyde concentrations in residences, schools, and offices in China in the past 30 years, and provide basic data for the comprehensive evaluation of disease burden attributable to indoor formaldehyde exposure.
Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Hipersensibilidade Respiratória , Humanos , Poluição do Ar em Ambientes Fechados/análise , Formaldeído/análise , Habitação , Instituições Acadêmicas , Hipersensibilidade Respiratória/induzido quimicamente , China , Poluentes Atmosféricos/análiseRESUMO
The last two decades have witnessed rapid urbanization and economic growth accompanied by severe indoor air pollution of volatile organic compounds (VOCs) in China. However, indoor VOC pollution across China has not been well characterized and documented. This study is a systematic review of field measurements of eight target VOCs (benzene, toluene, xylenes, acetaldehyde, p-dichlorobenzene, butadiene, trichloroethylene, and tetrachloroethylene) in residences, offices, and schools in China from 2000 to 2021. The results show that indoor pollution of benzene, toluene, and xylenes has been more serious in China than in other countries. Spatiotemporal distribution shows lower indoor VOC levels in east and south-east regions and a declining trend from 2000 to 2021. Moving into a dwelling more than 1 year after decoration and improving ventilation could significantly reduce exposure to indoor VOCs. Reducing benzene exposure is urgently needed because it is associated with greater health risks (4.5 × 10-4 for lifetime cancer risk and 8.3 for hazard quotient) than any other VOCs. The present study enriches the database of indoor VOC levels and provides scientific evidence for improving national indoor air quality standards as well as estimating the attributable disease burden caused by VOCs in China.
Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Tetracloroetileno , Tricloroetileno , Compostos Orgânicos Voláteis , Acetaldeído , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Benzeno/análise , Butadienos , China , Monitoramento Ambiental , Medição de Risco , Instituições Acadêmicas , Tolueno , Compostos Orgânicos Voláteis/análise , Xilenos/análiseRESUMO
BACKGROUND: Several studies have reported that childhood prevalence of eczema has been increasing worldwide. However, none study quantitatively evaluated prevalence trends of eczema among children and adults in the last 30 years in China. METHODS AND FINDINGS: Via a systematic review of literature databases in English and Chinese, we summarized all studies reporting eczema prevalences from 1985 to 2015 in China as well as diagramed prevalence and eczematous population trends against year for different age groups. A total of 93 studies and 17 studies (16 for children and one for adults) were selected for qualitative and quantitative synthesis, respectively. Childhood lifetime-ever eczema prevalences ranged from 10.0% to 30.0%. Prevalences among 3-12-year-olds children showed increasing trends in most specific cities, but national lifetime-ever eczema prevalences among 13-14-year-olds children decreased from 10.6% in 2001 to 8.6% in 2009 in mainland China. We estimated that about 1.5 million children aged 13-14-year-olds in 2009 and 15.5 million children aged 3-6-year-olds in 2012 had lifetime-ever eczema in mainland China. Similar studies were too few to ascertain time-trends of eczema prevalence among adults. About 39.4, 20.0, and 11.6 million adults aged 15-86-year-olds in 2010 had contact dermatitis, seborrheic dermatitis, and atopic dermatitis in the mainland China, respectively. CONCLUSIONS: The burden of eczema became heavier in young children, whereas perhaps had been reduced in adolescent in China. More studies for eczema prevalence in adults are warranted.
Assuntos
Asma , Dermatite Atópica , Eczema , Adolescente , Adulto , Asma/epidemiologia , Criança , Pré-Escolar , China/epidemiologia , Dermatite Atópica/epidemiologia , Eczema/epidemiologia , Humanos , PrevalênciaRESUMO
Exposure to volatile organic compounds (VOCs) indoors is thought to be associated with several adverse health effects. However, we still lack concentration-response (C-R) relationships between VOC levels in civil buildings and various health outcomes. For this paper, we conducted a systematic review and meta-analysis of observational studies to summarize related associations and C-R relationships. Four databases were searched to collect all relevant studies published between January 1980 and December 2017. A total of 39 studies were identified in the systematic review, and 32 of these were included in the meta-analysis. We found that the pooled relative risk (RR) for leukemia was 1.03 (95% CI: 1.01-1.05) per 1 µg/m3 increase of benzene and 1.25 (95%CI: 1.14-1.37) per 0.1 µg/m3 increase of butadiene. The pooled RRs for asthma were 1.08 (95% CI: 1.02-1.14), 1.02 (95% CI: 1.00-1.04), and 1.04 (95% CI: 1.02-1.06) per 1 µg/m3 increase of benzene, toluene, and p-dichlorobenzene, respectively. The pooled RR for low birth weight was 1.12 (95% CI: 1.05-1.19) per 1 µg/m3 increase of benzene. Our findings provide robust evidence for associations between benzene and leukemia, asthma, and low birth weight, as well as for health effects of some other VOCs.
Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Asma , Leucemia , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/efeitos adversos , Poluição do Ar em Ambientes Fechados/análise , Benzeno/análise , Humanos , Leucemia/epidemiologia , Leucemia/etiologia , Estudos Observacionais como Assunto , Compostos Orgânicos Voláteis/análiseRESUMO
China's profoundly rapid modernization in the past two decades has resulted in dramatic changes in indoor environmental exposures. Among these changes, exposure to phthalates has attracted increasing attention. We aimed to characterize indoor phthalate exposure and to estimate the disease burden attributable to indoor phthalate pollution from 2000 to 2017 in China. We integrated the national exposure level of indoor phthalates from literature through systematic review and Monte Carlo simulation. Dose-response relationships between phthalate exposure and health outcomes were obtained by systematic review and meta-analysis. Based on existing models for assessing probabilities of causation and a comprehensive review of available data, we calculated the disability-adjusted life years (DALYs) among the general Chinese population resulting from exposure to indoor phthalate pollution. We found that DnBP, DiBP, and DEHP were the most abundant phthalates in indoor environments of residences, offices, and schools with medians of national dust phase concentration from 74.5 µg/g to 96.3 µg/g, 39.6 µg/g to 162.5 µg/g, 634.2 µg/g to 1,394.7 µg/g, respectively. The national equivalent exposure for children to phthalates in settled dust was higher than that of adults except for DiBP and DnOP. Dose-response relationships associated with DEP, DiBP, DnBP, BBzP, and DEHP exposures were established. Between 2000 and 2017, indoor phthalate exposure in China has led to 3.32 million DALYs per year, accounting for 0.90% of total DALYs across China. The annual DALY associated with indoor phthalate pollution in China was over 2000 people per million, which is about 2~3 times of the DALY loss due to secondhand smoke (SHS) in six European countries or the sum of the DALY loss caused by indoor radon and formaldehyde in American homes. Our study indicates a considerable socioeconomic impact of indoor phthalate exposure for a modernizing human society. This suggest the need for relevant national standard and actions to reduce indoor phthalate exposure.
Assuntos
Poluição do Ar em Ambientes Fechados , Dietilexilftalato , Adulto , Poluição do Ar em Ambientes Fechados/efeitos adversos , Poluição do Ar em Ambientes Fechados/análise , Criança , China/epidemiologia , Efeitos Psicossociais da Doença , Dietilexilftalato/análise , Poeira/análise , Humanos , Ácidos Ftálicos , Estados UnidosRESUMO
OBJECTIVE: Phthalate acid esters (PAEs) have been identified to be associated with children's health. Present study was conducted to assess associations between PAEs in household dust and childhood rhinitis. METHODS: Based on phase II of CCHH study (China, Children, Home, Health) conducted in Shanghai, China, 266 indoor dust samples were collected from participants' families. Concentrations of PAEs in dust samples were measured by chemical treatment and gas chromatograph-mass spectrometer. Information about individuals and residences was surveyed by questionnaires. Logistic regression models were applied to obtain the associations between PAEs and childhood rhinitis. RESULTS: Higher concentrations of benzyl butyl phthalate (BBP) were found in those families with children who had diagnosed rhinitis. Significantly higher concentrations of bis(2-ethylhexyl) phthalate (DEHP) and PAEs with high molecular weight (HMW-PAEs) were found in the positive group of lifetime rhinitis. Using the multiple and ordinal logistic regression models adjusted by covariates, dibutyl phthalate (DBP), DEHP, and HMW-PAEs were found to be significantly associated with diagnosed rhinitis. Boys who exposure to higher concentrations of DBP, DEHP, HMW-PAEs, and total PAEs have significant associations with diagnosed rhinitis compared with girls who exposure to lower concentration of PAEs. CONCLUSIONS: Present observational study indicated that exposure to high concentrations of DBP, DEHP, and HMW-PAEs in house settled dust was a risk factor for rhinitis for children, especially for boys.
Assuntos
Ácidos Ftálicos , Rinite , Criança , China/epidemiologia , Poeira/análise , Ésteres/análise , Humanos , Ácidos Ftálicos/análise , Rinite/epidemiologiaRESUMO
After decades of development, the indoor environment in China has changed. A systematic review was conducted from peer-reviewed scientific papers with field test data of indoor radon in China from 2000 to 2020 for three types of buildings. The mean concentrations of indoor radon for dwellings, school buildings, and office buildings are 54.6, 56.1, and 54.9 Bq/m3 . The indoor radon concentration was related to seasons, climate regions, ventilation, decoration, and other factors such as soil and outdoor air. Colder seasons, especially in severe colder areas of China, newer decorated buildings, closed windows, and doors were all associated with higher indoor radon concentrations. Variables like climate region and ventilation showed statistical significance in the correlation analysis. Regarding the increasing trend of indoor radon concentration in China during the last two decades, further study of indoor radon is necessary especially for school buildings and office buildings, and will help access its environmental burden of disease in China more accurately.
Assuntos
Poluentes Radioativos do Ar , Poluição do Ar em Ambientes Fechados , Monitoramento de Radiação , Radônio , Poluentes Radioativos do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , China , Habitação , Radônio/análise , Instituições AcadêmicasRESUMO
Phthalic acid esters (PAEs) have a negative impact on human health and are widely distributed in China. As part of the China, Children, Home, Health (CCHH) study, we investigated the associations between childhood asthmatic symptoms and PAEs in settled house dust in Shanghai, China. We found that di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DiBP) were abundant in the indoor environment. A total of 27 % of children suffered from diagnosed asthma. The Mann-Whitney U test and multiple logistic regression were used to obtain the associations between PAEs and childhood asthmatic symptoms. Stratification analysis was performed to reveal the influence of gender on the associations between PAE exposure and target symptoms. Compared with low concentrations of PAEs, high concentrations of high molecular weight PAEs (HMW-PAEs) were significantly associated with childhood diagnosed asthma (adjusted odds ratios (AORs) > 1, P < 0.05). Moreover, significantly negative associations were found between high concentrations of DiBP and current cough (AORs<1, P < 0.05). All significantly positive associations were observed among girls, and most of the associations of dimethyl phthalate (DMP) and diethyl phthalate (DEP) exposure with the studied symptoms among girls were higher than those among boys. Exposure to PAEs may be a risk factor for asthmatic symptoms in children, especially in girls.
Assuntos
Asma , Ácidos Ftálicos , Asma/induzido quimicamente , Asma/epidemiologia , Criança , China/epidemiologia , Poeira/análise , Ésteres/análise , Humanos , Ácidos Ftálicos/análise , Ácidos Ftálicos/toxicidadeRESUMO
Indoor ammonia (NH3 ) pollution has been paid more and more attention in view of its health risk. However, few studies have investigated the exposure level in the non-occupational environment in China. This study systematically reviewed the indoor ammonia exposure level in different regions, the equivalent exposure concentration of different populations, and the factors that influence indoor air ammonia in residences, offices, and schools in China. The literature published in 1980-2019 from main databases was searched and detailed screened, and finally, 56 related studies were selected. The results illustrated that the median concentration of indoor air ammonia in residences, offices, and school buildings was 0.21 mg/m3 , 0.26 mg/m3 , and 0.15 mg/m3 . There were 46.4%, 71.4%, and 40% of these samples exceeding the NH3 standard, respectively. The national concentrations and the equivalent exposure levels of adults and children were calculated and found to be higher than 0.20 mg/m3 . The concentration of ammonia varied greatly in different climate zones and economic development regions. Higher concentrations were found in the severe cold zone and the regions with higher economic level. This review reveals a high exposure risk of indoor air ammonia and the crucial impact of human emission, indoor air temperature, new concrete, and economic level, suggesting further investigation on indoor air ammonia evaluation and health effects.
Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Adulto , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Amônia/análise , Criança , China , Monitoramento Ambiental , Humanos , Instituições AcadêmicasRESUMO
Findings for impacts of outdoor air pollutants on birth outcomes were controversial. We performed a retrospective observational study in 2527 preschoolers of Shanghai, China and investigated associations of duration-averaged concentrations of outdoor sulphur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter with an aerodynamic diameter ≤ 10 µm (PM10) in different months and trimesters of gestation, with preterm birth (PB), low birth weight (LBW), term low birth weight (T-LBW), and small for gestational age (SGA). Daily concentrations of outdoor air pollutants were collected in each residence-located district. Parents reported health information. In the multivariate logistic regression analyses, exposures to outdoor NO2 were consistently associated with the higher odds of LBW and T-LBW. These associations were generally stronger for early months than for later months of the gestation. Adjusted odds ratios generally were larger in multi-pollutant model than in single-pollutant model. Exposure to NO2 in the first month of the gestation was significantly associated with T-LBW (adjusted OR, 95%CI: 1.91, 1.02-3.58 for increment of interquartile range (18.5 µg/m3); p-value = 0.044) in multi-pollutant model. This association was stronger in girls, renters, and children whose mothers ≥30 years-old, with household dampness-related exposures, and with parental smoking during pregnancy. Our results indicate that exposure to NO2 during gestation perhaps is a risk factor for LBW and T-LBW, and effects of NO2 exposures could be greater during early periods than during later periods of gestation.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Nascimento Prematuro , Adulto , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Peso ao Nascer , Criança , China/epidemiologia , Feminino , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Exposição Materna/efeitos adversos , Dióxido de Nitrogênio/toxicidade , Material Particulado/análise , Material Particulado/toxicidade , GravidezRESUMO
Social distancing and ventilation were emphasized broadly to control the ongoing pandemic COVID-19 in confined spaces. Rationales behind these two strategies, however, were debated, especially regarding quantitative recommendations. The answers to "what is the safe distance" and "what is sufficient ventilation" are crucial to the upcoming reopening of businesses and schools, but rely on many medical, biological, and engineering factors. This study introduced two new indices into the popular while perfect-mixing-based Wells-Riley model for predicting airborne virus related infection probability - the underlying reasons for keeping adequate social distance and space ventilation. The distance index Pd can be obtained by theoretical analysis on droplet distribution and transmission from human respiration activities, and the ventilation index Ez represents the system-dependent air distribution efficiency in a space. The study indicated that 1.6-3.0â¯m (5.2-9.8â¯ft) is the safe social distance when considering aerosol transmission of exhaled large droplets from talking, while the distance can be up to 8.2â¯m (26â¯ft) if taking into account of all droplets under calm air environment. Because of unknown dose response to COVID-19, the model used one actual pandemic case to calibrate the infectious dose (quantum of infection), which was then verified by a number of other existing cases with short exposure time (hours). Projections using the validated model for a variety of scenarios including transportation vehicles and building spaces illustrated that (1) increasing social distance (e.g., halving occupancy density) can significantly reduce the infection rate (20-40 %) during the first 30â¯min even under current ventilation practices; (2) minimum ventilation or fresh air requirement should vary with distancing condition, exposure time, and effectiveness of air distribution systems.
RESUMO
Microbes in buildings have attracted extensive attention from both the research community and the general public due to their close relationship with human health. However, there still lacks comprehensive information on the indoor exposure level of microbes in China. This study systematically reviews exposure levels, the community structures, and the impact factors of airborne bacteria and fungi in residences, schools, and offices in China. We reviewed the major literature databases between 1980 and 2019 and selected 55 original studies based on a set of criteria. Results show that the concentration of indoor bacteria varies from 72.5 to 7500 CFU/m3 , with a median value of 1000 CFU/m3 , and the concentration of fungi varies from 12 to 9730 CFU/m3 , with a median value of 526 CFU/m3 . The concentration level of microbes varies in different climate zones, with higher bacterial concentrations in the severe cold zone, and higher fungal concentrations in the hot summer and warm winter zone. Among different buildings, classrooms have the highest average bacteria and fungi levels. This review reveals that a unified assessment system based on health effects is needed for evaluating the exposure levels of bacteria and fungi.
Assuntos
Microbiologia do Ar , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Bactérias , Monitoramento Ambiental , Fungos , Habitação , Humanos , Instituições Acadêmicas , Estações do Ano , Local de TrabalhoRESUMO
Background: Associations of early antibiotics exposures with childhood asthma, allergies, and airway illnesses are debated. Objectives: We aimed to investigate associations of first-year antibiotics exposure with childhood asthma, allergies, and airway illnesses. Methods: A cross-sectional study was conducted among preschoolers in Shanghai, China during 2011-2012. A questionnaire regarding household environment and lifestyles and childhood health outcomes was reported by the child's parents. Results: In total, 13,335 questionnaires (response rate: 85.3%) were analyzed and 3049 (24.1%) children had first-year antibiotics exposure. In the multivariate logistic regression analyses, first-year antibiotics exposure had significant associations with the higher odds of lifetime-ever pneumonia (adjusted OR, 95% CI: 2.15, 1.95-2.37), croup (1.46, 1.24-1.73), wheeze (1.44, 1.30-1.60), asthma (1.38, 1.19-1.61), food allergy (1.29, 1.13-1.46), and allergic rhinitis (1.23, 1.07-1.41), and as well as current (one year before the survey) common cold (≥3 times) (1.38, 1.25-1.52), dry cough (1.27, 1.13-1.42), atopic dermatitis (1.25, 1.09-1.43), wheeze (1.23, 1.10-1.38), and rhinitis symptoms (1.15, 1.04-1.26). These associations were different in children with different individual characteristics (age, sex, family history of atopy, and district) and other early exposures (breastfeeding, home decoration, pet-keeping, and environmental tobacco smoke). Conclusions: Our results indicate that first-year antibiotics exposure could be a strong risk factor for childhood pneumonia, asthma, allergies, and their related symptoms. The individual characteristics and other early exposures may modify effects of early antibiotic exposure on childhood allergies and airway illnesses.
Assuntos
Antibacterianos/efeitos adversos , Asma/epidemiologia , Dermatite Atópica/epidemiologia , Antibacterianos/uso terapêutico , Asma/induzido quimicamente , Pré-Escolar , China/epidemiologia , Estudos Transversais , Eczema , Feminino , Hipersensibilidade Alimentar/epidemiologia , Humanos , Lactente , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Inquéritos e QuestionáriosRESUMO
Studies have shown that acupuncture is very effective in treating chronic stress depression. However, little is known about the therapeutic mechanism of electro-acupuncture. Metabolomics, on the other hand, is a technology that determines the metabolic changes of organisms caused by various interventions as a whole and is related to the overall effect of electro-acupuncture (EA). 1HNMR, serum sample analysis, and histopathology and molecular biology analysis were used to evaluate the effects of EA. The results show that electro-acupuncture points can regulate the heat pain threshold of chronic stress model rats and change the morphology of adrenal cortex cells Structure, and regulate the contents of corticotropin-releasing hormone, Corticosterone (CORT), glucose, alanine and valine in the samples. These findings help to clarify the therapeutic mechanism of electro-acupuncture on heterologous chronic stress model rats. The effect of electro-acupuncture on improving chronic stress is likely to be achieved by regulating glucose metabolism, which can provide a reference for clinical acupuncture treatment of chronic stress depression.
Assuntos
Glicemia/metabolismo , Eletroacupuntura , Estresse Fisiológico , Córtex Suprarrenal/metabolismo , Glândulas Suprarrenais/citologia , Alanina/química , Animais , Comportamento Animal , Peso Corporal , Corticosterona/química , Espectroscopia de Ressonância Magnética , Masculino , Limiar da Dor , Ratos , Ratos Sprague-Dawley , Valina/químicaRESUMO
It's inconsistent about associations of early exposures to outdoor air pollutants with allergies and airway diseases in childhood. Here, we investigated associations of prenatal and postnatal exposures to outdoor nitrogen dioxide (NO2), sulphur dioxide (SO2), and PM10 (particulate matter with an aerodynamic diameter ≤ 10 µm) with asthma, wheeze, hay fever, rhinitis, pneumonia, and eczema in childhood. We surveyed 3,177 preschoolers who never change residences since birth in Shanghai, China. Parents reported information regarding children's health status. Daily-averaged concentrations of these pollutants in the children's gestation and in the first year of lifetime for district where children lived were collected by Shanghai Environmental Monitoring Center. After adjusting for covariates, exposures to higher level of NO2 during different trimesters of gestation and of the first year of lifetime had significant associations with the increased odds of asthma, hay fever, rhinitis, pneumonia, and eczema in childhood. Associations of NO2 exposures in the early trimesters of gestation and of the first year of lifetime with pneumonia were stronger than in the later trimesters, whereas associations of NO2 exposures in the early trimesters with hay fever and eczema were weaker than in the later trimesters. Our results indicated that prenatal and postnatal exposures to outdoor NO2 could be risk factors for allergies and airway diseases in childhood. Both dose and duration were related with the influence degree of early NO2 exposure on childhood allergies and airway diseases.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Hipersensibilidade , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Criança , China/epidemiologia , Feminino , Humanos , Hipersensibilidade/epidemiologia , Hipersensibilidade/etiologia , Dióxido de Nitrogênio/análise , Material Particulado/análise , GravidezRESUMO
Associations of household airborne fungi with allergies in childhood were inconsistent in the epidemiologic studies. During 2013-2014, we conducted a case-control study (phase two), which was nested in a cross-sectional study (phase one) during 2011-2012 in Shanghai, China. We inspected indoor air quality of 454 residences for 5-10 years old children. We defined cases as those children who were reported illnesses in the questionnaire of phase one or phase two and defined controls as those children who were not reported illnesses in both phases. A total of 436 living rooms and 445 bedrooms had valid data of household airborne fungi, and their mean concentrations were 301 cfu/m3 and 310 cfu/m3, respectively. In the multiple logistic regression analyses with adjusting for potential confounders, most associations of 16 studied illnesses with airborne fungi concentration were not statistically significant. Taking children in the 1st quartile that was stratified according to airborne fungi concentration in the living room as reference, only children in the 3rd quartile were significantly associated with a higher odd of lifetime-ever ear infections (adjusted OR, 95% CI 3.05, 1.29-7.21), and children in the 4th quartile were significantly associated with a higher odd of lifetime-ever wheeze (2.72, 1.28-5.75); but children in the 3rd quartile (0.33, 0.17-0.68) and in the 4th quartile (0.47, 0.23-0.97) were significantly associated with a lower odd of rhinitis in the past 12 months prior to the home inspection. Our results indicate that exposures to indoor airborne fungi in low concentrations seemingly have no significant impacts on the risks of most allergic and airway illnesses in childhood. Since families with sick participants might pay more attention to improve indoor air quality, effects of "avoidance behavior" on associations between indoor pollutants and childhood health should be considered in the data analysis and design of the nested case-control study.