Mountainous Area Of Southwest China Research Articles

Study on Comprehensive Treatment Technology of High-speed Railway Passing Through Giant Karst Tunnel

In the mountainous areas of Southwest China, a karst landscape is well developed. There, exposed giant karst caves in the construction of high-speed railway tunnels cause great construction difficulties and safety risks for the tunnel crossing. In this paper, the study object is the project on giant karst cave of the Qianjiang–Changde railway high-mountain tunnel. After the karst cave was revealed, unmanned aerial vehicle detection, three-dimensional laser scanning, and blasting vibration monitoring were used to study the stability of the karst cave. It was found that the karst cave has a higher risk of falling rocks. On the basis of careful consideration of construction, operation safety, and economy, the “backfill cave ballast + grouting to reinforce on the upper part” scheme was determined for the treatment of the karst cave. During the process of disposal, the surface and layered settlement of backfill were monitored, in which it showed that the surface settlement control was reasonable, and the settlement mainly came from the bottom of the grouting layer, the top of non-grouting backfill, and original accumulation. To prevent the risk of falling rocks, we performed permanent safety protection of the wall and the roof for the karst cave and temporary safety protection of the mobile scaffold. Finally, the backfill treatment of the giant karst cave of high-mountain tunnel was smooth, the settlement after construction was controllable, and it met the design requirements.

Integrating multisource RS data and GIS techniques to assist the evaluation of resource-environment carrying capacity in karst mountainous area

The karst mountainous area is an ecologically fragile region with prominent human-land contradictions. The resource-environment carrying capacity (RECC) of this region needs to be further clarified. The development of remote sensing (RS) and geographic information system (GIS) provides data sources and processing platform for RECC monitoring. This study analyzed and established the evaluation index system of RECC by considering particularity in the karst mountainous area of Southwest China; processed multisource RS data (Sentinel-2, Aster-DEM and Landsat-8) to extract the spatial distributions of nine key indexes by GIS techniques (information classification, overlay analysis and raster calculation); proposed the methods of index integration and fuzzy comprehensive evaluation of the RECC by GIS; and took a typical area, Guangnan County in Yunnan Province of China, as an experimental area to explore the effectiveness of the indexes and methods. The results showed that: (1) The important indexes affecting the RECC of karst mountainous area are water resources, tourism resources, position resources, geographical environment and soil erosion environment. (2) Data on cultivated land, construction land, minerals, transportation, water conservancy, ecosystem services, topography, soil erosion and rocky desertification can be obtained from RS data. GIS techniques integrate the information into the RECC results. The data extraction and processing methods are feasible on evaluating RECC. (3) The RECC of Guangnan County was in the mid-carrying level in 2018. The mid-carrying and low-carrying levels were the main types, accounting for more than 80.00% of the total study area. The areas with high carrying capacity were mainly distributed in the northern regions of the northwest-southeast line of the county, and other areas have a low carrying capacity comparatively. The coordination between regional resource-environment status and socioeconomic development is the key to improve RECC. This study explores the evaluation index system of RECC in karst mountainous area and the application of multisource RS data and GIS techniques in the comprehensive evaluation. The methods can be applied in related fields to provide suggestions for data/information extraction and integration, and sustainable development.

Exploring cultivated land evolution in mountainous areas of Southwest China, an empirical study of developments since the 1980s

Exploring cultivated land evolution in mountainous areas of Southwest China, an empirical study of developments since the 1980s

Susceptibility mapping of damming landslide based on slope unit using frequency ratio model

In the mountainous area of southwest China, there is a large number of large hydropower stations that have already been built or under construction. The construction and the safety of the operation of hydropower stations directly affect the residents’ safety of life and property on both sides of the downstream river. Landslide hazards are one of the main problems affecting the construction and operation of hydropower stations. Therefore, it is currently more urgent to evaluate landslide susceptibility within the basin. The goal of this paper is to carry out landslide susceptibility mapping that affects the construction and operation of hydropower stations. In the case of a large research area and lack of landslide hazard data, this paper selects the sample of blocking river landslide in a larger area with similar topography and geological conditions and applies the quantitative method to carry out landslide sensitivity mapping. In this paper, the slope unit works as the evaluation unit, 191 landslide sample data were obtained, and nine landslide conditioning factors (slope, aspect, curvature, lithology, distance to fault, distance to the river, land use, soil, and the topographic wetness index (TWI)) were obtained. Combined with the quantitative frequency model (FR model), the landslide susceptibility map was obtained. The research process and results show that (1) when the study area is large, the landslide data is scarce, and it is difficult to get the landslide inventory map; the landslide samples can be selected in a larger area with similar topography and geological conditions. It is feasible to use the analysis data of landslide samples to evaluate the landslide susceptibility; (2) for specific industry applications such as hydropower station operation safety, the landslide evaluation range can be reduced by the spatial correlation between landslide aspect and river flow direction, which is beneficial to the management department to reduce the scope of attention; and (3) the verification results show that the slope unit can be used for quantitative evaluation of landslide sensitivity based on the FR model and can obtain the highest evaluation accuracy. The main advantage of this method is its capability to carry out landslide susceptibility mapping with quantitative methods and to ensure that higher mapping accuracy is obtained in areas where landslide hazard data is lacking.

基于仿真分析和田间试验的电动微耕机操作舒适性提高

Now the engine mini-tiller has become indispensable agricultural machinery in vast hilly and mountainous areas of Southwest China. Many researches have been made to improve its operating comfort, but little effects have been obtained. As an alternative, a new type of electric mini-tiller was developed. For further improvement of its operating comfort, simulation analysis and field test were integrated to decrease the vertical force and vibration RMS values at the handle. The results showed that when the position of centre of gravity moved 19.78 cm, the vertical force was reduced from 154.24 N to 0 N, and vibration RMS values decreased by 20.16% under working condition.

Spatial Agglomeration Characteristics of Rural Settlements in Poor Mountainous Areas of Southwest China

The rural settlements in poverty-stricken mountainous areas are the "living fossils" of an economic society with the characteristics of spatial dispersion and are slowly changing. Spatial agglomeration is the development direction of rural settlements. In-depth exploration of the spatial agglomeration characteristics and influencing factors of rural settlements in poverty-stricken mountainous areas is a way to provide a basis for rural settlement restructuring. We selected Pengshui County, a national poverty-stricken county in the southwestern mountainous area of China, as the research area. Spatial buffer and kernel density analysis were used to analyze the agglomeration characteristics of rural settlements and influencing factors. The results show that: (1) The rural settlements are small in scale and the space is evenly dispersed. 55.63% of the rural settlements’ sizes are less than 1000 m2, 84.15% of the rural settlements’ sizes are less than 2500 m2, and 92.81% of the rural settlements are within 200 m. (2) The elevation and slope of topographic factors have a significant agglomeration effect on rural settlements. However, the slope direction has no agglomeration effect. 85.41% of rural settlements (52.75% of rural settlements are gathered between 400 and 800 m above sea level) are gathered at an altitude of 1000 m or less, and 77.59% of rural settlements are gathered with a slope of 6~25°. Additionally, there are few rural settlements with a slope of 0~2°. Moreover, the distribution of residential areas has no agglomeration effect on rural settlements. (3) The cultivated land exerts the most significant effect on rural settlements followed by roads and water sources, while the role of urban land is weak. 99.48% of rural settlements are concentrated in the 100 m area of cultivated land. Therefore, in the poverty-stricken mountainous areas in the southwestern mountainous areas of China, convenient farming is the primary condition for production and living. Rural settlements are highly correlated with cultivated land. Rural settlements are scattered and concentrated with the scattered cultivated land. The rural settlements were leaded by the distribution of cultivated land. Less high-quality cultivated land with less slope were occupied or not by rural residential areas’ people.

Relationship between area size and elevational distribution pattern of cryptic pheasant species in Mts. Gaoligong, China

The size of a geographic area is believed to be one of the most important factors that drive patterns of species richness. Studies have shown that mountains have a diverse range of patterns (area, species distribution, etc.) along an elevation gradient. Therefore, an understanding of the relationship between the distribution patterns of mountainous species and the area of altitudinal bands is of great importance to accurately determine and monitor global patterns of species diversity. However, the effects of area size on the distribution of species depends on taxon-specific idiosyncrasies. Few studies have assessed such effects on the secretive terrestrial pheasant species. In this study, we conducted three-dimensional map-based interview survey (3DIS) with local human communities that inhabit the same environments as the pheasants in Mts. Gaoligong, Western China. We obtained distributional information for 15 pheasant species, which enabled further analyses to be conducted. The area sizes of the different elevation bands were determined using a Digital Elevation Model database, and the altitudinal range of each species was calculated via interpolation. The area sizes at different altitudes showed a unimodal hump-shaped pattern that matched the diversity distribution of the pheasants. This study confirmed that the pattern of biodiversity of cryptic pheasants in the mountainous areas of Southwest China was hump-shaped, which is a very typical biodiversity pattern for most biotaxa. Regression analysis also revealed that area size was a key factor that affects the diversity and distribution of pheasant species, and may act concurrently with other factors, such as climate, energy, geometric constraints, and human disturbance.

Three new compounds with nitric oxide inhibitory activity from Tirpitzia sinensis, an ethnomedicinal plant from Southwest China

The medicinal plant Tirpitzia sinensis has been used by the Zhuang ethnic people in mountainous areas of Southwest China to stop bleeding, invigorate blood circulation, and treat inflammation and wounds. In order to further explore its traditional medicinal uses, the phytochemical constituents of this species were examined. Three new compounds, the lignan tirpitzin (1), the flavonoid tirpitzoside (2), and the furan-glycoside tirpitziol (3), along with five known compounds were isolated from the aerial part of T. sinensis for the first time. The structures of these compounds were elucidated by 1D and 2D NMR, LC/MS, IR spectrometric methods and compared with published data. The results of an in silico pharmacophore-based analysis showed potential targets of the new compounds, including ERBB2, IRAK4, LCK, JAK2, MAPK14, and MMP-12. These targets suggested that 1–3 may be involved with wound-healing and/or inflammation, leading to an in vitro assay of nitric oxide (NO) inhibition assays with lipopolysaccharide-induced BV-2 cells. All three new compounds displayed moderate NO inhibitory activity with the IC50 values of 14.97 ± 0.87, 26.63 ± 1.32, and 17.09 ± 2.3 μM, respectively.

Creep Characteristics Of Concrete Used In Long-Span Arch Bridge

The reinforced concrete arch bridge with concrete-filled steel tubular stiffened skeleton is extensively used in the mountainous area of southwest China due to their long span and high stability. Beibanjiang Bridge located in Shanghai- Kunming high-speed railway, which had a record span of 445 m, has recently been completed in 2016. However, concrete creep and shrinkage have pronounced effects on the long-term deflection and stress redistribution of this bridge. Several concrete creep and shrinkage specimens in the natural environment were made to predict the long-term behaviour of this bridge accurately. They were used to measure the concrete creep and shrinkage of the core concrete and surrounding concrete used in the arch bridge. The test results were compared to ACI209 R-92 Prediction of Creep, Shrinkage and Temperature Effects in Concrete Structures model, 1990 CEB-FIP Model Code 1990: Design Code model, fib Model Code for Concrete Structures 2010 model and Creep and Shrinkage Prediction Model for Analysis and Design of Concrete Structures-Model B3. Based on the numerical fitting method, the fib Model Code for Concrete Structures 2010 model was modified to suit the concrete creep and shrinkage experimental results. Then, the modified fib Model Code for Concrete Structures 2010 model was used to predict the timedependent behaviour of a concrete arch bridge.

The study of transcriptome sequencing for flower coloration in different anthesis stages of alpine ornamental herb (Meconopsis ‘Lingholm’)

Meconopsis (Papaveraceae) is an interesting alpine herb, mainly distributed in the mountainous area of southwest China and high altitude zone in Tibetan-Himalaya. Different Meconopsis species showed a flower color alteration in different anthesis stages, Meconopsis ‘Lingholm’ is one of the localized species whose petal color changes from purple to blue during the flowering process. In general, the blue color flower is a rare kind, and usually hard to cultivate artificially. The molecular mechanism of flower color formation and color alteration of alpine flowers were reported by many research workers. To find critical genes that regulate Meconopsis ‘Lingholm’ color alteration and the mechanism of environmental adaptation, the current study performed transcriptome sequencing by using Meconopsis ‘Lingholm’ petals from different anthesis stages. There were totally 91,615 unigenes obtained from 31.4 Gb sequencing data, and differentially expressed genes between two consecutive flowering stages were obtained. Bioinformatics studies showed genes regulating petal color alteration were activated. Moreover, the functional analysis showed that Meconopsis ‘Lingholm’ showed a stress response to mechanical damage, non-biological stimulation and water deficiency in the bud stage, as well as showed a stress response to the cold from cracking stage to blooming stage. Furthermore, RNA-Seq results were verified using nine randomly selected genes by qPCR, which showed same expression trend with sequencing results. During this study, 20 candidate genes identified for further studies, which included five petal color related genes and 15 environmental response genes.

A simplified procedure for estimating nonlinear seismic demand of tall piers

More than 40% of the bridges in mountainous areas of Southwest China are constructed with piers having a height of over 40 m. The seismic response of such tall pier structures is usually estimated by nonlinear response history analysis and/or adaptive pushover procedures; while providing satisfactory results, these methods can be quite time consuming and computational demanding. Therefore, this paper proposes a simplified procedure for estimating the nonlinear seismic response of tall piers. The influence of plastic deformation at the base on dynamic properties (natural periods and mode shapes) of a linearized system for the tall piers is first investigated, using a numerical model of the prototype bridge, based on an equivalent linearization technique. Using these results, a simplified procedure is proposed to predict the distribution of seismic shear force and bending moment along the pier height, as well as the curvature ductility ratio at the pier base. The efficiency of the proposed procedure is verified with numerical examples of tall piers subjected to recorded ground motions, through comparing the seismic demands determined by this method with rigorous nonlinear response history analysis. The results show that the proposed method can efficiently estimate the distribution of both shear force and bending moment along the height of the tall pier; the curvature ductility ratio at pier base can be predicted with errors around 10%.

Effect of the soil-implement contact area on soil translocation under hoeing tillage

Hoeing tillage is widely performed in mountainous areas of Southwest China, as a result of patchy and steep cropland. The effect of the soil-implement contact area on soil translocation by manual hoeing needs to be addressed to better understand the relationship between tillage implement and tillage erosion. This study aimed to explore the mechanism on the effect of soil-implement contact area on soil translocation under hoeing tillage. A series of tillage experiments were conducted with four fixed tillage depths (0.05, 0.10, 0.15 and 0.20 m) on 9 slopes ranging from 0.09 to 0.58 m m−1, respectively, and the subsequent data were compared with those acquired previously by different hoe blade widths. Tillage depth is a significant factor reflecting the soil-implement contact area especially for a constant width of hoe blade. Mean soil displacement distance increased with increasing tillage depth, and this effect is more pronounced for greater slope gradients. Tillage translocation rates were linearly related to slope gradient, but quadratically to tillage depth. As another factor reflecting the soil-implement contact area, the hoe blade width is also a significant factor influencing tillage erosion. Tillage transport coefficients (k4) can be predicted by the soil-implement contact area. It is suggested that minimizing the soil-implement contact area by either decreasing tillage depth or reducing the width of hoe blades are effective measures for combating tillage erosion.

Genetic Diversity and Drug Susceptibility of Mycobacterium tuberculosis Isolates in a Remote Mountain Area of China

ObjectiveWe determined the genetic diversity of Mycobacterium tuberculosis (MTB) in a remote mountainous area of southwest China and evaluated the resolving ability of single nucleotide polymorphism (SNP) genotyping combined with variable number tandem repeat (VNTR) genotyping for Beijing family strains in association with drug resistance status. MethodsThree hundred thirty-one MTB strains were isolated from patients living in mountainous regions of southwest China, and 8-loci SNP, VNTR-15 genotyping assays, and drug susceptibility testing of 9 drugs were performed. ResultsA total of 183 [55.29% (183/331)] strains were classified into the Beijing family. Of the 183 strains, 111 (60.66%) were defined as modern Beijing strains. The most predominant modern Beijing sub-lineage and ancient Beijing sub-lineage were Bmyc10 [39.34% (72/183)] and Bmyc25 [20.77% (38/183)], respectively. Of the isolates, 19.64% (65/331) were resistant to at least 1 of the 9 anti-TB drugs and 17 [4.98% (17/331)] MTB isolates were multi-drug resistant tuberculosis (MDR-TB). Two hundred sixty-one isolates showed a clustering rate of 14.18% (37/261) and a discriminatory index of 0.9990. The Beijing lineage exhibited a significantly higher prevalence of MDR-TB, as well as resistance to isoniazid (INH), rifampin (RIF), and para-aminosalicylic acid (PAS) when analyzed independently (P = 0.005, P = 0.017, P = 0.014, and P = 0.006 respectively). The Beijing lineage was not associated with genetic clustering or resistance to any drug. In addition, genetic clustering was not associated with drug resistance. ConclusionMTB strains demonstrate high genetic diversity in remote mountainous areas of southwest China. Beijing strains, especially modern Beijing strains, are predominant in remote mountainous area of China. The combination of 8-loci SNPs and VNTR-15 genotyping is a useful tool to study the molecular epidemiology of MTB strains in this area.

Experimental study on the dynamic response and stability of bedding rock slopes with weak interlayers under heavy rainfall

Rainfall-induced landslides are notable geological hazards that occur frequently in the mountainous areas of Southwest China. Heavy rainfall in the wet season often causes landslides in mountainous areas, posing a threat to the infrastructure and human safety. For rock slopes, the sliding surface often occurs along a weak interlayer which plays a key role in controlling the mechanism of slope failure during the wet season. Typical bedding rock slope in the Maoergai reservoir was taken as the prototype to determine the physical modeling test materials and parameters, and a three-layered slope model was used to simulate a rock slope with a weak interlayer. A series of laboratory tests were carried out to study the dynamic response and stability of the bedding rock slope with a weak interlayer under heavy rainfall. The experimental results showed that the shear strength of the weak interlayer decreased due to a water softening effect. The changes of pore water pressure and rainfall erosion were the two dominant dynamic factors inducing the gradual decrease of shear resistance of the weak interlayer. In addition, the limit equilibrium method (Janbu’s method) was used to analyze the stability of the slope model and investigate the relationship between shear strength and slope stability. The obtained correlation between shear parameters and the safety factor indicated that the safety factor of the slope model decreased with the softening of the weak interlayer, and its internal friction angle was the key parameter influencing slope stability.

The Evaluation of Land Use Status in Mountainous Counties of Southwest China Based on Comprehensive Evaluation Models: A Case Study of Baoxing County, Sichuan Province

In mountainous areas of Southwest China, the land resources are scarce, and the ecological environment is fragile, so it is particularly important to carry out the evaluation of land use status for the sustainability of land development. Taking Baoxing County in Sichuan Province, the typical mountainous county in Southwest China, as an instance, this study refers to the existing research frameworks to establish the evaluation system of land use status. Meanwhile, the comprehensive evaluation models are used to evaluate land use status. As indicated from the results, in Baoxing County, the comprehensive evaluation score of the overall status of land use, the evaluation score of the development degree of land, the evaluation score of the intensive management degree of land and the evaluation score of the comprehensive benefits of land were 83.5, 108.24, 72.25 and 80.77, respectively. Land use status is generally at the relatively rational use stage, and the main problems are the lack of land investment and the low mechanization level of agricultural production. It is suggested to increase the financial investment in land and enhance the intensive degree and comprehensive benefits of land in the future.

Numerical simulation of a high-speed landslide in Chenjiaba, Beichuan, China

High-speed landslide is a catastrophic geological disaster in the mountainous area of southwest China. To predict the movement process of landslide reactivation in Chenjiaba town, Beichuan county, Sichuan province, China, we simulated the movement process of two landslide failures in Chenjiaba via rapid mass movement simulation and unmanned aerial vehicle images (UAV), and obtained the movement characteristic parameters of the landslides. According to a back analysis, the most remarkable fitting rheological parameters were friction coefficient (μ = 0. 18) and turbulence (ξ = 400 m · s-2). The parameter of landslide pressure was applied as the zoning index of landslide hazard to obtain the influence zone and hazard zoning map of the Chenjiaba landslide. Results show that the Duba River was blocked quickly with a landslide accumulation at the maximum height of 44.14 m when the Chenjiaba deposits lost stability. The hazard zoning map indicated that the landslide hazard degree is positively correlated with the slope. This landslide assessment is a quantitative hazard assessment method based on a landslide movement process and is suitable for high-speed landslide. Such method can provide a scientific basis for urban construction and planning in the landslide hazard area to avoid hazards effectively.

Identification and estimation of landslide-debris flow disaster risk in primary and middle school campuses in a mountainous area of Southwest China

In China, school campuses are greatly affected by natural disasters such as landslide-debris flows in mountainous areas. To minimize disaster losses, it is very important to identify and assess disaster risks for every relevant subsystem. By comprehensive consideration of natural and human activities, landslide-debris flow hazard, environmental susceptibility, and exposure of primary and middle school campuses were identified in Chuxiong, a mountainous area of southwest China. These factors were assessed by applying the Analytic Hierarchy Process method and k-means Clustering Algorithm. A risk index was also proposed, and a risk map was developed based on it. The results show that hazard density and extreme precipitation intensity were the key hazard-inducing factors. The distributions of rivers, faults, slopes, and soil erosion were the key environmental susceptibility factors, and this finding is consistent with the intensive risk distribution. The increasing amounts of human disturbance, such as serious soil erosion due to farming on steep slopes, degradation of vegetation caused by changes in land use, and highway construction due to rapid urbanization, also play important roles in increasing the risk. We conclude that the environmental factors determine the distribution and intensity of the landslide-debris flow hazard risk to some extent. However, the exposure of primary and middle school campuses, including the density of schools and their contribution, leads to potential losses in landslide-debris flow hazard zones. We highlight the integrated risk assessment including hazard-inducing factors, environment susceptibility, and campus exposure. The results have practical implications for sustainable campus management, planning, and disaster insurance.

CFD and Experimental Studies on Wind Turbines in Complex Terrain by Improved Actuator Disk Method

In this paper, an onshore wind farm in mountainous area of southwest China was investigated through numerical and experimental methods. An improved actuator disk method, taking rotor data (i.e. blade geometry information, attack angle, blade pitch angle) into account, was carried out to investigate the flow characteristic of the wind farm, especially the wake developing behind the wind turbines. Comparing to the classic AD method and the situ measurements, the improved AD shows better agreements with the measurements. The turbine power was automatically predicted in CFD by blade element method, which agreed well with the measurement results. The study proved that the steady CFD simulation with improved actuator disk method was able to evaluate wind resource well and give good balance between computing efficiency and accuracy, in contrary to much more expensive computation methods such as actuator-line/actuator-surface transient model, or less accurate methods such as linear velocity reduction wake model.

Climatic Characteristics and Determination Method for Freezing Rain in China

The climatic characteristics and temperature profiles of freezing rain in China are analyzed based on the observational data at 650 stations in China from 2000 to 2015. The freezing rain of China is generally in stripe-shape spatial distribution. The stations with freezing rain over 100 station-hours are mainly concentrated at the southeast areas of Southwest China and high-elevation mountainous areas of Eastern China. There are mainly two types of freezing rain temperature profiles, including single-warm-layer profile and double-warm-layer profile. The freezing rain profiles of mountainous area and urban area in Southwest China are similar to each other, and the freezing rain in Central and East China shares the similar single-warm-layer profile. The profiles in South China show the characteristics of freezing rain’s profile in both Southwest China and Central/East China as the position of stations. PA of freezing rain’s profiles is negatively correlated with NA, with correlation coefficients ranging from −0.36 to −0.70. The configuration of weak cold/warm layer (both smaller than 150°C·hPa) is one of major reasons causing frequent freezing rain at mountainous areas of Southwest China. The more obvious the change of NA with the variations of PA is, the more the freezing rain is likely to occur.

Couple's infertility in relation to male smoking in a Chinese rural area.

Smoking is a well-known risk factor of reproductive health. However, the effect of paternal smoking on fertility has been less extensively examined. We conducted a cross-sectional study in a mountainous area of South-West China to assess the effect of male smoking on couples’ fertility. A total of 8200 couples aged 18–49 years in the study area were invited to participate in the study. An in-person interview was performed to collect demographic characteristics of the couples, and husbands’ life style factors including smoking and drinking habits. Information on time to pregnancy (TTP) was collected retrospectively. Infertility was defined as failure to achieve clinical pregnancy after regular unprotected intercourse for ≥12 months. Logistic regression model was used to estimate the association between male smoking and infertility. A total of 7025 couples were included in the final analysis. After adjusting for potential confounders, the couples were more likely to suffer from infertility if the husbands smoked (adjusted odds ratio [aOR] =1.28, 95% CI: 1.08–1.52) before the first pregnancy. After the analyses were performed according to husbands’ smoking duration, an increased risk started at a relatively longer smoking duration of 5–10 years (aOR = 1.58, 95% CI: 1.26–1.99) and a stronger association (aOR = 3.34, 95% CI: 2.45–4.56) was observed in the group of ≥10 years. Similar patterns were found for the number of cigarettes smoked per day and the total amount of cigarettes smoked. From our findings, we conclude that male smoking may have an adverse impact on couples’ infertility.