Households In City Research Articles

Local affordable housing dynamics in two global cities: patterns and possible lessons?

ABSTRACT This paper compares how New York and London, two major global cities, have developed policies and programmes to help ensure affordable housing for their citizens. It clarifies how, starting from relatively limited local regulatory powers in the nineteenth century, each city has used local resources as well as centrally authorized programmes, to create unique mixes of rental housing support, mostly based on instruments that enable sub-market rents. It goes on to discuss how the legacies arising from these interventions, both positive and negative, have influenced affordability in these cities’ current, more internationally open and generally more privatized, housing systems. The relative success of both cities has depended on the management of this pastiche of programmes and financing. Even so, while large proportions of lower income households in both cities (although larger in London) are assisted, there remains significant, and, in current economic circumstances, potentially growing numbers of households, facing unaffordable market rents. In the foreseeable future it can only be an amalgam of these local and nationally supported policies together with local initiatives that can help limit, although not resolve, the continuing problems of ensuring adequate affordable homes for lower income households in both New York and London.

Chemical-Free Greywater Treatment Using Aeration, Sedimentation, Followed by Granular Activated Carbon Filter (GAC) -A Case Study of Baghdad city household

Greywater is a possible water source that can be improved for meeting the quality required for irrigation. Treatment of greywater can range from uncomplicated coarse filtration to advanced biological treatment. This article presents a simple design of a small scale greywater treatment plant, which is a series of physical and natural processes including screening, aeration, sedimentation, and filtration using granular activated carbon filter and differentiates its performance with sand filter. The performance of these units with the dual filter media of (activated carbon with sand) in treatment of greywater from Iraqi house in Baghdad city during 2019 and that collected from several points including washbasins, kitchen sink, bathrooms, and laundry, was recorded in terms of removal efficiency of particular pollutants like Turbidity 94%, chemical oxygen demand (COD) 93%, and oil 91%. Dual filter was the most effective filter for decreasing these pollutants, while sand indicates the lowest removal efficiency. In general, granular activated carbon media seemed to be the most proper medium to improve greywater quality for reaching the quality of irrigation within the terms of organic matter decrease. Accordingly, this technology may be reliable for greywater treatment in a residential area.

Choleraepidemien in den Städten der österreichischen Alpenländer in den 1830er Jahren

In 1831 the first European cholera epidemic hit most parts of Lower Austria hard. The traditional system of fighting plague epidemics based on advance warning, cordons sanitaire and quarantine proved to be ineffective in the case of cholera. Shocked by the sudden death of many cholera victims the imperial government tried to push forward investments in sewers and the water supply at least in the capital Vienna. Unfortunately these investments showed no improving effect on cholera morbidity and mortality in the 1830s, because the quality of filtered water from the river Danube that supplied the Kaiser-Ferdinand-Wasserleitung build in 1836-1843 was inadequate and the new sewer-system, the so called Cholera-sewers, lacked functional capability in summer and during floods. Due to the fact that most of the cholera epidemics entered the Habsburg monarchy from the east or from the Adriatic sea, the inner Alpine provinces with the exception of South Tyrol remained almost untouched by cholera epidemics of that era. The east-west-gradient in mortality cannot be explained by any measures to improve the water supply or sewer system in these parts of Austria. Most households in cities of these provinces were supplied with drinking water by domestic wells and sanitation was dominated by cesspools, which was the case even in most parts of Vienna. What might explain the difference in mortality is the lower population density correlated with the better quality of water from the wells in the Alpine zone.

Urban-regional patterns of food purchasing behaviour: a cross-sectional analysis of the 2015-2016 Australian Household Expenditure Survey.

In many high-income countries people living in regional (rural) areas have higher rates of chronic disease compared to people living in urban areas. Food purchasing behaviour provides a potential pathway linking residential location with dietary intake and health outcomes. This study examined the relationship between geographic location and food expenditure on a range of foods. Data from the 2015-2016 Australian Household Expenditure Survey (number of households = 9827) were used to examine weekly household food expenditure and proportion of total food expenditure on 14 categories of food items. Foods were classified using the Australian Guide to Healthy Eating. Two-part models and zero-one inflated beta regression models were used to assess the association between geographic area and food expenditure. Average proportion of total food expenditure on fruit was estimated to be more for households located in major cities compared to households located in inner and outer regional areas. Households located in inner and outer regional areas allocated less to fresh fruit, fish and meals out compared to households in major cities. Households located in inner regional areas allocated a greater proportion of their food budget to sweet cakes, biscuits, puddings, desserts, chocolate and ice-cream compared to households in major cities and outer regional areas. The geographic patterns in food purchasing suggest those in regional areas may be at risk of diets less aligned with healthy guidelines. Given the findings of this study suggesting geographic differences in food purchasing, further research is warranted to enhance contextual understanding of food purchasing behaviours in regional areas.

Study on the effect of rural population aging on Farmers’ participation in collective management, protection of small-scale irrigation and water conservancy facilities: Taking Sichuan Province as an example

In recent years, a large number of infrastructure construction including small-scale farmland and water conservancy facilities have been carried out in rural areas of China. However, with the acceleration of urbanization process, a large number of young and middle-aged labor force has been transferred from rural areas to urban areas. Rural areas in China are facing serious aging problems, and the supply lack of labor force is insufficient, resulting in the collective management and protection of small-scale agricultural water conservancy facilities in a dilemma. Based on the survey data of 918 rural households in Jintang County, Meishan City and Chongzhou City, Sichuan Province, this paper uses ordered probit model to analyze the impact of rural population aging on rural households’ participation in collective management and protection of small-scale farmland water conservancy facilities. The results show that the aging degree of rural population is high, and it has a significant negative impact on the participation of farmers in the collective management and protection of farmland and water conservancy facilities. The increase of the cultivated land area of farmers has a alleviating negative effect of rural population aging.

Rural residential energy carrier structure and primary PM<sub>2.5</sub> emissions from the Qinghai-Tibet Plateau

Solid fuels, including various types of crop residue, wood, animal dung, and coal, are widely used for daily cooking and space heating in many rural households in developing countries, resulting in significant adverse impacts on regional air quality, indoor air quality, and human health. The Qinghai-Tibet Plateau (QTP) region is considered to be one of the areas with the cleanest air in the world; however, due to reliance on solid fuels in the residential sector, and due to lower air pollutant emissions from other sectors like industry and transportation, solid fuel burning has become a main issue affecting energy use and the environment in this area. It has been recognized that local solid fuel burning contributes significantly to regional climate change resulting in increased average ambient temperature and changes in the glaciers in the QTP area. However, information on household fuel use, residential energy carrier data, and air pollutant emissions in this area is very scarce. In the present study, rural household energy use in Tibet and Qinghai provinces were investigated based on a field survey and questionnaires, and primary fine particulate matter (PM2.5) emissions were estimated. Heavy reliance on solid fuels for both daily cooking and space heating was found in the QTP area. The study showed that for daily cooking activity, the time fractions of use of clean energy carriers including gas and electricity were 27% and 8% in rural Tibet and Qinghai provinces, respectively, and the time fractions of use of biomass fuels, mainly woody fuel and animal dung, were 72% and 35%, respectively. Qinghai has high reliance on coal, but Tibet has low use of coal. For space heating demand, only solid fuels were used in these two provinces. Biomass fuels, primarily wood and animal dung, were also the main fuel used to heat animal foods. Total residential fuel consumption was estimated at 3.88 (3.80−3.96 as the interquartile range) and 4.28 (3.28−5.31) million tones in rural Tibet and Qinghai, respectively, including only 1.76 million tons and 663 tons of gas fuels, respectively. The consumed fuels for cooking and heating activities were nearly equal. In rural Tibet, woody fuels and animal dung comprised up to 44% and 53%, respectively, of the total mass of rural residential fuels consumed, while in rural Qinghai, these two fuels contributed to 17% and 37% of the total mass. Annual residential fuel consumption per household was 7.91 and 5.87 tons/household, respectively, equivalent to about 122 and 129 GJ/household. For each fuel type, there was no statistically significant relationship between the consumption amount and the number of persons in the household ( P> 0.05), however, the total residential fuel consumption was positively correlated with the population at the city level ( P 0.001). This suggested that the fuel consumption per household, which reflects the basic need for each family, was similar for households in different cities, although the residential energy carrier structures were significantly different. Because of heavy reliance on traditional solid fuels, the residential sector is a main source of PM2.5. The estimated total emissions associated with the rural residential sector were 32.1 (31.9−33.4 as the inter-quartile range) and 42.7 (33.1−53.7) Gg, respectively, for Tibet and Qinghai provinces. Air pollutant emissions from the Qinghai-Tibet Plateau have obvious impacts on the ecosystem, including, but not limited to, outdoor and indoor air quality, public health, and regional radiative forcing. Relatively small sample size is a limitation of the present study, and in the emission estimation, emission factors were obtained from an existing database, while localized emission factors would be preferable in estimating air pollutant emissions. In future works, it is recommended to address historic changes of residential energy and the driving factors of the transition. Under the urbanization in this area, future field-based surveys and case studies would be valuable in exploring the impacts of urbanization on residential energy use, air pollutant emissions, human health and regional climate change.

Relationship of Self-Differentiation and Social Intelligence with Happiness by Mediating Role of Difficulty in Cognitive Emotion Regulation Among Female-Headed Households

Background: Female-headed households are one of the vulnerable classes of society that are exposed to serious social problems. Happiness constitutes part of human emotions with different functional consequences in the personal, social, mental, cognitive, and emotional characteristics of female-headed households. Objectives: This study aimed to investigate the mediating role of difficulty in cognitive emotion regulation in the relationships of self-differentiation and social intelligence with happiness among female-headed households in Ahvaz city in 2018. Methods: This cross-sectional study included 261 female-headed households, which were selected by a purposive sampling method. The research instruments included the Oxford Happiness Inventory (OHI), the Tromso Social Intelligence Scale (TSIS), the Differentiation of Self Inventory (DSI), and the Difficulties in Emotion Regulation Scale (DERS). Results: The results showed that the relationship between difficulties in cognitive emotion regulation and happiness was significant, direct, and negative (β = -0.50, P = 0.000). Also, the relationship between social intelligence and happiness was significant, direct, and positive (β = 0.21, P = 0.000). There was no direct and significant relationship between self-differentiation and happiness (β = 0.04, P = 0.545). Path analysis results showed that difficulties in cognitive emotion regulation had a mediating role in the relationship of social intelligence (β = -0.16, P = 0.000) and self-differentiation (β = -0.03, P = 0.019) with happiness. Conclusions: The research findings suggest the important mediating role of difficulty in cognitive emotion regulation in the relationships between social intelligence, happiness, and self-differentiation.

Smart grids, prosumers and energy management within a smart city integrated system

Abstract Due to a significant increase in electricity consumption globally, governments have to look and to identify better, more efficient and effective alternatives and sustainable energy sources to meet this high demand. This becomes more and more important in the context of implementing modern approaches such as those that might be applied in cases of smart cities and cultural and creative communities. Electricity can be produced based on conventional sources, but also on an emergent use of renewable sources. The electricity grid is usually designed as unidirectional. We consider that in case of smart cities and creative-innovative communities there is a need to implement mostly new smart grids that are bidirectional. This may allow and support the emergency of a new type of electricity user, called “prosumers”, who produces electricity from renewable sources, next uses & shares them smartly within the smart grid and finally stores them. Globally, photovoltaic energy prosumers are considered one of the most important actors in the energy transition and seem to be ready to introduce significant amounts of electricity within the grid. We anticipate that people living in households in smart cities and communities among most regions of the world will tend in the future to improve their self-consumption from the production of smart energy. This paper supports the idea that using mostly electricity from renewable alternative sources, especially solar, can be also developed with the help of households acting within smart cities and communities. The paper will also present briefly an overview of the scientific literature dedicated to this topic. We will also provide further interesting insights through a number of case studies representing good practices regarding prosumers in Italy and Romania.

Nickel and dimed: Parking fees at NCI-designated cancer centers.

2029 Background: Nonmedical costs from cancer treatment can be a significant out-of-pocket expense. As treatment may span over months, parking costs can become a significant burden on patients and caregivers. This cross-sectional study aims to report parking fees at National Cancer Institute (NCI)-designated cancer centers and to project parking costs for the treatment duration of certain cancers. Methods: Parking fees from NCI treatment centers were obtained via online search or phone call in Fall of 2019. City cost of living, median city household income, and discount availability were documented. Pearson correlation was used between parking costs and city variables. Parking costs were estimated for treatment of node positive breast cancer (12 daily rates plus 20 1-hr rates), definitive head and neck cancer (35 1-hr rates) and acute myeloid leukemia (AML) (42 daily rates). RStudio Version 1.2.5033 was used for analyses. Results: Parking costs were obtained for 100% of the 63 NCI centers included. Median city cost of living relative to New York City was 75.0 (out of 100); median city household income was $55,295 (range $28,974-$120,573). Twenty-five (40%) of NCI centers did not have detailed parking cost information online. Average parking costs were $3.55/hr (median $2, range 0-$15) and $7.79/day (median $5, range 0-$40). Twenty centers (32%) offered completely free parking for patients. Free parking was available at 43 (68%) centers for radiation appointments and 34 (54%) centers for chemotherapy appointments. Averaged estimated parking costs including discounts for a course of treatment for breast cancer was $122.03 (range 0-$800); head and neck cancer, $85.56 (range 0-$665); and AML hospitalization, $327.33 (range 0-$1470). City cost of living was positively correlated with daily parking costs (R = 0.7, p < 0.01) and negatively correlated with both free daily parking (R = -0.33, p = 0.02) and free parking during radiation (R = -0.34, p = 0.02) or chemotherapy (R = -0.37, p < 0.01). The median city household income was correlated with the daily parking costs (R = 0.30 p = 0.02) but not with free daily parking (R = -0.19, p = 0.16), free parking for patients on radiation (R = -0.23, p = 0.09) or on chemotherapy (R = -0.21, p = 0.14). Conclusions: Patients may face significant nonmedical costs through parking fees, even at centers that reflect the highest standard of care. There was high variability in costs with the potential for patients to pay hundreds of dollars in parking in order to receive their care. Efforts to minimize financial toxicity should focus on this potentially under-reported patient concern.

Uncovering the allergen-specific modulation in non-allergic laboratory mouse workers – understanding health versus disease

Abstract Mouse allergies are prevalent in inner city households and laboratory workers. Mouse allergens trigger allergic symptoms from atopic dermatitis/conjunctivitis to rhinitis and asthma, thus their research is of great clinical value. The aim of this study was to characterize the mouse-specific T cell response changes in non-allergic laboratory workers before and after vacation. Peripheral blood mononuclear cells (PBMC) were collected pre-break, pre re-exposure (after break), and after re-exposure to mouse, and were stimulated with peptides identified from high molecular weight fractions of mouse allergen extracts (HiMO). Non-allergics had sizeable reacitivity and majority had decreased T cell responses upon re-exposure. In addition, the decreased magnitudes were positively correlated with time of re-exposure but not length of break. Interestingly, the suppressive activity was dominant and specific for mouse responses and did not affect bystander responses. CD4 T cell responses was down-regulated temporally for a period of time (40–160 days) and eventually went back to baseline. Ex vivo immunophenotyping revealed a trend towards down-regulation of B cells and classical Tregs. Mouse-specific CD4 effector cells were reduced while total CD4 effector cells were not. The results indicate that non-allergic status is an active process which involves allergen-specific modulation of responses upon re-exposure to allergens. Uncovering the molecular programs associated with this modulation by transcriptomic study will be the next step to better understand health and allergic diseases.

Economic analysis of the solar thermal and air source heat pump combined system for energy demand of buildings in China

This study focus on the economy of the solar thermal and air source heat pump combined system supplying the same demand of SH and DHW for a city household at different locations in China, namely; Beijing, Xi’an and Nanjing. These three locations represent the climatic conditions variety in China with different outdoor temperatures and solar radiation. At each location, the optimized simulations are carried out to recognize the most economical configurations. The results show that, for a 15-year running time, the system comprising 10m2 solar collectors and 5 kW air source heat pump is the best configuration having the minimum cost for all three cities, but the minimum cost of which is different for each location. At Nanjing, the system has the lowest cost of all the three cities, and the payback time of which is also the shortest. However, the payback time of the optimum system in Beijing is 15.9 years exceeding its running time, due to the lowest central heating fee included in the cost of the traditional heating method.

Migrants' choice of household split or reunion in China's urbanisation process: The effect of objective and subjective socioeconomic status

The past practice of migrant households' split based on ‘economic rationality’ has caused many social problems in China, and the settlement of entire migrant households in cities has become an important social issue. Using 2014 China Migrants Dynamic Survey data and a multilevel regression method, this study found that objective socioeconomic status (SES) significantly impacts migrants' choice of household reunion. Migrants with higher monthly household income and homeownership are more likely to choose household reunion in cities compared to those with lower income and no homeownership. Additionally, migrants with higher subjective SES are more likely to choose household reunion in cities compared to those with lower subjective SES. Furthermore, subjective SES plays a significant mediating role in the relationship between objective SES and migrants' choice of city household reunion. We argue that unlike the early period of China's reform and opening-up, actively choosing household split has transformed into a passive choice for migrant households in current China. We also suggest that promoting migrant households' reunion in cities is significant to China's sustainable urbanisation process.

Vegetable Consumption Pattern and Health Consciousness of Urban Terrace Garden Farmers

A study was conducted to analyse the vegetable consumption pattern and health consciousness of urban households practicing terrace gardening at their homes. The survey was conducted among randomly selected 90 households in Pune city i.e., Pune Municipal Corporation and Pimpri - Chinchwad Municipal Corporation. The study revealed that among the urban wellers doing terrace gardening, everyone showed either moderate or high level of health consciousness and no one showed low level. The amount of vegetables consumed per household per day was taken in to consideration while collecting details regarding general consumption pattern of vegetables. As per the study, it was found that, 70 per cent were consuming moderate amount of vegetables on daily basis.

Distribution characteristics, source appointment, and health risk assessment of Cd exposure via household dust in six cities of China

This study investigated the characteristics and health risks of cadmium (Cd) in household dust in urban and rural areas during heating and non-heating periods. Seven hundred and sixty-two dust samples and 381 questionnaires were collected from households in the Chinese cities of Dalian, Taiyuan, Lanzhou, Shanghai, Wuhan, and Chengdu. The Cd concentration results of household dust indicated higher levels in urban areas and in heating periods because of the complex mankind activities and environmental influence factors. A correlation analysis and redundancy analysis demonstrated that smoking, cooking, and ventilation time were vital influencing factors for Cd levels in household dust. Cd in the indoor air, outdoor air, traffic air, and soil also contributed to the Cd in the household dust, among which soil contributed the most. The non-carcinogenic and carcinogenic risks of Cd in the household dust were acceptable. Ingestion was the primary pathway for residents’ exposure to Cd in household dust. And the different exposure behavior patterns of population in the study areas had a great impact on the health risk assessment results.

Urban poor families access to assets and implication on household’s food security, the situation of low-income households in City of Kigali, Rwanda

Urban poor families access to assets and implication on household’s food security, the situation of low-income households in City of Kigali, Rwanda

Households’ participation in solid waste management system of Homs city, Syria

Solid waste management practice is a matter of concern for public health and environmental protection and has become a major challenge in Syria. Improper waste management can bear adverse consequences on public health, environment, and natural resources. The current study focuses on households' participation in solid waste management in Homs city. Waste management plans can only be successful if the community support and actively participate in it, and as the largest stakeholder, households have an important role by reduction of waste volume and increasing the recovery rate. In respect to this issue, this study presents the findings of the research concerning the waste management practices applied by households at the local level in Homs city as well as the attitude of households (as service users) to the current solid waste management system. Data were assembled by a questionnaire survey conducted on 300 households in Homs city as well as formal interviews with officials and supervisors in related departments. We found that composting activities were not applied in the studied areas as well as waste separation practices were spurred by economic revenues earned without prior knowledge of the environmental benefits. Moreover, residents had to practice improper ways to remove their waste from residential areas in cases of inadequate and unreliable waste collection services.

Measuring the effect of a program of waste separation at source in Da Nang City, Vietnam

This study focused on the waste separation behavior of households in areas with a waste separation at source (WSS) program to understand the effect of the program and identify suggestions for improving the participation rate. A questionnaire survey was conducted through face-to-face interviews with 402 households in Da Nang City, Vietnam. To measure the effect of the WSS program on waste separation behavior, the authors conducted a comparison between waste separation behavior before and after implementing the program. The authors developed a model of waste separation behavior to clarify the factors. The differences in participation rates and influencing factors as they related to respondents’ level of involvement in the WSS program were also examined by Chi-squared test and ANOVA. The participation rate before the WSS program was 70.0% for plastic bottles, 70.1% for cardboard, and 71.4% for aluminum cans. After the WSS program, these rates significantly increased by 14.2% for plastic bottles, 12.6% for cardboard, and 12.3% for aluminum cans. Through behavior modeling, the factors influencing waste separation behavior were clarified. The attendance of respondents at an explanatory meeting and the recognition of the leaflets would positively promote the participation rate and the factors influencing waste separation behavior.

Recycling Behaviour of Malaysian Urban Households and Upcycling Prospects

Households remain the main generator of municipal solid waste in Malaysia. Malaysians produce an average of 30,000 tons of waste per day and only 5 per cent of it is recycled. Malaysian urbanites throw away waste more than normal. The solid waste generated continues to be a costly affair with about two-thirds of the local councils’ total collected annual assessment fees being spent to manage waste. Yet at the same time, Malaysia’s waste recycling rate is way below the average levels. Hence the perennial question remains as to why Malaysian households are not recycling or recycling enough. This study investigates recycling behavior of urban households in a green city. Methodology utilized survey questionnaire approach to 100 households to determine residents’ willingness to participate in recycling activities. Results revealed proactive and reactive behaviors indicating two distinct recycling groups. Analysis generated factors of convenience of recycling facilities and services, environmental involvement recycling benefits and habitual recycling in the two groups. Willingness to recycle differed across the two groups. Recycling benefits and convenience to recycling facilities significantly influenced the behavior of proactive group while only habitual recycling was significant for the reactive group. Findings had implications on policy making and implementation of recycling programs. Upcycling prospects highlighted proactive roles of households to convert useless wastes into quality and marketable products to benefit the environment.

Factors Affecting Demand and Utilization of Dental Services: Evidence from a Developing Country

Background: To achieve evidence-based policymaking to improve access to dental services and reduce inequality in the utilization of these services, the identification of effective factors on the use of dental services is essential. Objectives: Therefore, the present study was conducted to investigate the most important socioeconomic factors affecting the demand and utilization of dental services among households in Khorramabad, Iran. Methods: This cross-sectional study was performed among 500 households in Khorramabad city in 2017. The participants were selected using a randomized stratified sampling method. Logistic regression was used to determine the most important factors affecting the utilization of dental services and linear regression to examine income elasticity. To measure inequality among income groups, the concentration index was employed. Data analysis was performed using STATA-14 software and the inequality measurement was carried out using DASP-2.3 in STATA software. Results: The mean number of visits by the respondents was 2.78 ± 1.8. Income elasticity and concentration index for these services were estimated to be 0.31 and 0.207, respectively. Increasing household income, advancing age, higher education level of the head of the household, and having complementary insurance coverage (OR = 1.72) had positive relationships with the increased utilization of dental services. Also, a female head of the household (OR = 0.39) and increased household size (OR = 0.9) led to a reduction in the utilization of these services. Conclusions: Inequality is observed in the use of dental services between different socioeconomic groups. Therefore, health policymakers should implement interventions such as dental health insurance to reduce this inequality in such a way that inequalities between socioeconomic groups are reduced.

A fresh look at contemporary perspectives on urban housing affordability

ABSTRACT The literature on housing affordability has grown rapidly since Hulchanski [1995, p. 489. The concept of housing affordability: six contemporary uses of the housing expenditure-to-income ratio. Housing Studies, 10(4), 471–491] declared that housing researchers should avoid using the term since it is not a robust concept and measurement often lacks validity. In the ensuing 24 years, however, scholars have continued to debate the definition and measurement of housing affordability as well as the prevalence and type of ‘housing affordability problems’ in various countries. This paper is a think piece which takes a fresh look at housing affordability as a concept which has persisted despite considerable contestation and scepticism about its use. It provides a critical and multi-disciplinary assessment of housing affordability starting with early conceptualization of the nexus between economic principles and social norms about housing and living standards to a reworking of housing affordability in the twenty-first century as an urban issue affecting lower and middle-income households in cities, as a consequence of the financialization of housing and urban restructuring. It argues that the housing affordability concept has been repurposed such that the focus is less on understanding housing expenditures in contributing to poverty and disadvantage within the domain of social policy and more on the urban policy challenges of growing inequities in access to urban resources. The paper highlights the challenges for urban policy in adopting and adapting rather than rejecting a multi-dimensional concept of housing affordability and consequently the importance of new ways of measuring urban housing affordability.