Reanalysis of residential radon surveys in China from 1980 to 2019

Analysis of indoor radon concentration levels and trends in China

A systematic review of publicly available papers on indoor radon data from 1980 to 2023 was conducted to provide a preliminary understanding of indoor radon concentration levels and trends in China. Keywords were used to collect literature on indoor radon surveys in China during the periods of before 2000, 2000-2010 and after 2010 in the CNKI, WANFANG, VIP and PubMed databases. This paper also collected indoor radon concentration data from WHO, UNSCEAR publications and PubMed databases for other countries. A total of 37,886 indoor radon concentration data points were collected in China, covering 31 provinces. The results showed that the weighted and arithmetic mean radon concentrations in China were 29.4 Bq/m3 and 33.2 Bq/m3 (n = 17,940) before 2000, 44.7 Bq/m3 and 43.3 Bq/m3 (n = 10,692) in 2000-2010, 57.6 Bq/m3 and 60.8 Bq/m3(n = 9,254) after 2010, respectively. It indicated an increasing trend in indoor radon concentrations in China. The differences in mean indoor radon concentrations across time periods were significant (p < 0.001). In the regional analysis, the differences in indoor radon concentrations between different administrative geographic regions for each time period were significant (p < 0.05). Furthermore, the differences in indoor radon concentrations among climatic areas were significant for the periods 2000-2010 and after 2010 (p < 0.05). Additionally, this paper collected indoor radon data from 63 countries worldwide. The mean radon concentrations across the three periods-before 2000, 2000-2010 and after 2010-were 56.5 Bq/m3, 67.9 Bq/m3 and 81 Bq/m3, respectively. Meanwhile, a comparison of indoor radon concentration was made before and after 2000 among 26 countries, of which 16 countries showed an increasing trend. So, it can be seen the increase in indoor radon concentration in China is not an isolated phenomenon, and the issue of indoor radon pollution still requires further attention.

Determination of representative elementary surface for accurately measuring radon exhalation rate in masonry wall

The average radon exhalation rate of the building wall surface is a key factor affecting indoor radon concentration, and its accurate measurement is of great significance for the evaluation and design of radon protection for walls. The main layer of the masonry walls is composed of bricks and bonded cement mortar. Due to the possible differences in radon exhalation rates from brick surfaces and cement mortar joints. General methods for measuring radon exhalation rate of the wall (such as the closed-loop method, the opened-loop method and the local static collection method) all involve the use of radon collection hoods. However, the measurement results of radon exhalation rate are significantly affected by the position and size of the radon collection hood covering the wall surface. Therefore, the Computational Fluid Dynamics (CFD) method was used to study the radon exhalation rules on the surface of masonry wall under diffusion and seepage-diffusion conditions, respectively. The simulation results show that the radon exhalation rates on the brick surfaces and cement mortar joints of masonry walls are different, and a representative elementary surface (RES) should be selected when accurately measuring the radon exhalation rate of the wall surface. It is worth noting that the shape of the RES is not restricted, and the representative surface for measuring radon exhalation rate is not unique; it can be an integer multiple surface of RES area. Furthermore, experiments have confirmed the accuracy and effectiveness of the determined RES. The proposed RES achieves accurate measurement of the average radon exhalation rate of walls by integrating the radon exhalation rates at the joints between bricks and cement mortar.

Indoor Radon Concentrations in Severe Cold Area and Cold Area and Impact of Energy-saving Design on Indoor Radon in China

ABSTRACT

This study investigated indoor radon concentrations in modern residential buildings in the Cold Area and Severe Cold Area in China. A total of 19 cities covering 16 provinces were selected with 1,610 dwellings measured for indoor radon concentration. The arithmetic mean and geometric mean of indoor radon concentration were 68 Bq m -3 and 57 Bq m -3 , respectively. It was found that indoor radon concentrations were much higher in the Severe Cold Area than those in the Cold Area. The indoor radon concentrations showed an increasing trend for newly constructed buildings. It was estimated that the average effective dose from inhalation of indoor radon is 2.15 mSv and 1.60 mSv for the Severe Cold Area and Cold Area, respectively. The more and more rigid energy-saving design for residential buildings in the Severe Cold Area and Cold Area has an obvious impact on the increased trend of indoor radon due to extremely low air exchange rate in China.

Estimation of radon progeny concentration based on track morphological parameters

As the integrated measurements of radon progeny are essential to its risk assessment, a new method based on the morphological analysis of tracks on CR-39 was established for the discrimination of alpha particles emitted from different progenies. The preliminary experiment confirmed its feasibility and revealed its potential for application in long-term surveys of indoor radon progeny. This new attempt was expected be benefit to the improvement of integrated measurements of radon progeny.

Disease Burden and Prediction Analysis of Tracheal, Bronchus, and Lung Cancer Attributable to Residential Radon, Solid Fuels, and Particulate Matter Pollution Under Different Sociodemographic Transitions From 1990 to 2030

BACKGROUND

This study investigated the impact of epidemiologic and sociodemographic changes in tracheal, bronchus, and lung cancer associated with residential radon, solid fuels, and particulate matter.

RESEARCH QUESTION

What are the influencing factors of tracheal, bronchus, and lung cancer disease burden attributable to the three pollutants?

STUDY DESIGN AND METHODS

Data were obtained from the Global Burden of Disease 2019. Age-standardized mortality rate (ASMR) and sociodemographic index (SDI) values were collected from 21 regions, and restricted cubic splines and quantile regression were used to investigate the relationship between ASMR or age-standardized disability-adjusted life years rate (ASDR), and SDI. Additionally, five countries with different SDIs were selected, and the Bayesian age-period-cohort model was used to predict the ASMR trends from 2020 to 2030.

RESULTS

High SDI quintiles were associated with increased residential radon pollution. The disease burden attributed to these three pollutants was particularly severe in the middle SDI quintiles. Older adults aged 80 to 89 years had the highest age-specific mortality, and the disease burden was greater in male patients than in female patients with these cancers attributed to the pollutants. The highest ASMR attributable to particulate matter when the SDI was 0.7. As the SDI increased, the disease burden caused by radon increased, whereas the burden caused by solid fuels decreased. Projections have indicated a rise in the death burden in patients with this cancer from particulate pollution in China, India, and Uganda over the next decade.

INTERPRETATION

The disease burden of tracheal, bronchus, and lung cancer attributed to the three pollutants was influenced by SDI, sex, and age. Older men are more susceptible to be affected. More preventive interventions may be required for men at younger ages to reduce the high death burden of older men. However, it is necessary to give due attention to women in specific countries in the future.

Evolutionary game analysis of indoor radon mitigation with local government involvement

Radon is the second leading risk factor for lung cancer after smoking. As a public policy, radon mitigation not only involves radon control technology or its cost-benefit analysis, but also includes the decision-making process of local governments. In this study, the evolutionary game theory was used to analyse the interaction between local governments and residents based on the subsidy of the central government. Considering the practical data in China, factors influencing the behaviour of local governments and residents were discussed using numerical simulations. The results indicated that radon mitigation is a fully government-promoted action; thus, its implementation largely depends on the subsidy of the central government and the share of radon control costs borne by the local government. The financial burden for both local governments and residents is a more important determinant than long-term health effects. The relatively poor local economic situation could limit the implementation of radon control. There would be a public policy paradox wherein cities or regions with higher radon risk would have lower willingness for radon control, mainly due to the significantly higher costs of radon control. This work provides reference data for decision-making to implement radon control and is expected to offer some suggestions for local governments.

Lung cancer as adverse health effect by indoor radon exposure in China from 2000 to 2020: A systematic review and meta-analysis

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.

A global burden assessment of lung cancer attributed to residential radon exposure during 1990-2019

This study aimed to explore the spatial and temporal trends of lung cancer burden attributable to residential radon exposure at the global, regional, and national levels. Based on the Global Burden of Disease Study (GBD) 2019, we collected the age-standardized mortality rate (ASMR) and age-standardized disability-adjusted life rate (ASDR) of lung cancer attributable to residential radon exposure from 1990 to 2019. The Joinpoint model was used to calculate the annual average percentage change (AAPC) to evaluate the trend of ASMR and ASDR from 1990 to 2019. The locally weighted regression (LOESS) was used to estimate the relationship of the socio-demographic index (SDI) with ASMR and ASDR. In 2019, the global ASMR and ASDR for lung cancer attributable to residential radon exposure were 1.03 (95% CI: 0.20, 2.00) and 22.66 (95% CI: 4.49, 43.94) per 100 000 population, which were 15.6% and 23.0% lower than in 1990, respectively. According to the estimation, we found the lung cancer burden attributable to residential radon exposure declined significantly in high and high-middle SDI regions, but substantially increased in middle and low-middle SDI regions from 1990 to 2019. Across age and sex, the highest burden of lung cancer attributable to residential radon exposure was found in males and elderly groups. In conclusion, the global burden of lung cancer attributable to residential radon exposure showed a declining trend from 1990 to 2019, but a relatively large increase was found in the middle SDI regions. In 2019, the burden of lung cancer attributable to residential radon exposure remained high, particularly in males, the elderly, and high-middle SDI regions compared with other groups.

Status of radon exposure in Bangladeshi locations and dwellings

Potentially higher cancer risk due to exposure from natural background radiation was indicated for the Bangladeshi population by estimations based on the countrywide study. Several regions with elevated natural background exhibited higher soil radium and thorium contents than the world average. Being the decay products of these radioactive elements, natural radon isotopes could constitute environmental risk factors for internal radiation exposure to the lungs of people living in these areas. Although lung cancer is one of the most prevalent types of cancer in Bangladesh, its status and features are still unclear. To clarify the present status of one of the potential risk factors for lung cancer in the country, this review intends to ascertain the countrywide radon exposure, and its pathways by types of local dwelling and by regions, which would provide an indication of the internal exposures in areas of elevated natural background radiation and radionuclides of soil as well as an understanding of the preliminary contribution of environmental radon on the country's lung cancer prevalence. In this review, countrywide monitored air radon exposures for Bangladeshi dwellings and workplaces are organized from peer-reviewed published papers. Radon has been identified as one of influential sources of radiation dose in Bangladesh with its higher radon exhalation and emanation rate from soil. A novel nationwide depiction of the overall assessed indoor and soil radon levels for Bangladesh has been made through radiation maps. This would be helpful for designing future systematic radon/radiological monitoring and research on the country's lung cancer prevalence.