Light pollution in USA and Europe: The good, the bad and the ugly.

Light pollution is a worldwide problem that has a range of adverse effects on human health and natural ecosystems. Using data from the New World Atlas of Artificial Night Sky Brightness, VIIRS-recorded radiance and Gross Domestic Product (GDP) data, we compared light pollution levels, and the light flux to the population size and GDP at the State and County levels in the USA and at Regional (NUTS2) and Province (NUTS3) levels in Europe. We found 6800-fold differences between the most and least polluted regions in Europe, 120-fold differences in their light flux per capita, and 267-fold differences in flux per GDP unit. Yet, we found even greater differences between US counties: 200,000-fold differences in sky pollution, 16,000-fold differences in light flux per capita, and 40,000-fold differences in light flux per GDP unit. These findings may inform policy-makers, helping to reduce energy waste and adverse environmental, cultural and health consequences associated with light pollution.

Modeling long-term effects attributed to nitrogen dioxide (NO2) and sulfur dioxide (SO2) exposure on asthma morbidity in a nationwide cohort in Israel.

Studies have provided extensive documentation that acutely elevated environmental exposures contribute to chronic health problems. However, only attention has been paid to the effects of modificate of exposure assessment methods in environmental health investigations, leading to uncertainty and gaps in our understanding of exposure- and dose-response relationships. The goal of the present study was to evaluate whether average or peak concentration exerts a greater influence on asthma outcome, and which of the exposure models may better explain various physiological responses generated by nitrogen dioxide (NO2) or sulfur dioxide (SO2) air pollutants. The effects of annual NO2 and SO2 exposures on asthma prevalence were determined in 137,040 17-year-old males in Israel, who underwent standard health examinations before induction to military service during 1999-2008. Three alternative models of cumulative exposure were used: arithmetic mean level (AM), average peak concentration (APC), and total number of air pollution exposure episodes (NEP). Air pollution data for NO2 and SO2 levels were linked to the residence of each subject and asthma prevalence was predicted using bivariate logistic regression. There was significant increased risk for asthma occurrence attributed to NO2 exposure in all models with the highest correlations demonstrated using the APC model. Data suggested that exposure-response is better correlated with NO2 peak concentration than with average exposure concentration in subjects with asthma. For SO2, there was a weaker but still significant exposure response association in all models. These differences may be related to differences in physiological responses including effects on different regions of the airways following exposure to these pollutants. NO2, which is poorly soluble in water, penetrates deep into the bronchial tree, producing asthmatic manifestations such as inflammation and increased mucus production as a result of high gaseous concentrations in the lung parenchyma. In contrast, SO2, which is highly water soluble, exerts its effects rapidly in the upper airways, leading to similar limited correlations at all levels of exposure with fewer asthmatic manifestations observed. These data indicate that differing exposure assessment methods may be needed to capture specific disease consequences associated with these air pollutants.

Does artificial light-at-night exposure contribute to the worldwide obesity pandemic?

BACKGROUND: Worldwide overweight and obesity rates are on the rise, with about 1 900 billion adults being defined as overweight and about 600 million adults being defined as obese by the World Health Organization (WHO). Increasing exposure to artificial light-at-night (ALAN) may influence body mass, by suppression of melatonin production and disruption of daily rhythms, resulting in physiological or behavioral changes in the human body, and may thus become a driving force behind worldwide overweight and obesity pandemic. METHODS: We analyzed most recent satellite images of night time illumination, available from the US Defense Meteorological Satellite Program (DMSP), combining them with country-level data on female and male overweight and obesity prevalence rates, reported by the WHO. The study aims to identify and measure the strength of association between ALAN and country-wide overweight and obesity rates, controlling for per capita GDP, level of urbanization, birth rate, food consumption and regional differences. RESULTS: ALAN emerged as a statistically significant and positive predictor of overweight and obesity (t>1.97; P<0.05), helping to explain, together with other factors, about 70% of the observed variation of overweight and obesity prevalence rates among females and males in more than 80 countries worldwide. Regional differences in the strength of association between ALAN and excessive body mass are also noted. CONCLUSIONS: This study is the first population-level study that confirms the results of laboratory research and cohort studies in which ALAN was found to be a contributing factor to excessive body mass in humans.

The effect of housing on migrations in Israel: 1988-1994.

"The analysis of 1988-1994 statistical data indicates that the population of Israel simultaneously moves in two opposite directions: while the initial distribution of new immigrants is primarily focused on the areas where jobs are available, the existing population of these areas tends to move outward, to the less populated districts where housing is more available and affordable. The paper thus argues that the heterogeneity of the population is indeed a crucial consideration for the proper modeling of migration behavior."

The effect of housing construction on population migrations in Israel.

"Population migrations in Israel simultaneously move in two opposite directions: while the initial distribution of new immigrants is primarily focused on big cities of the country's central core, the existing population of these centres tends to move outward, to small settlements where housing is more readily available. The effect of housing construction on population migrations appears to be delayed and tends to become visible with the passage of time. The initial low attractiveness of urban settlements in peripheral districts of the country to the new immigrants is mainly caused by [the] small size of the population in the settlements and an inferior state of urban development rather than by a lack of new housing or the harsh climatic conditions of these areas."

Sustainability of population growth: a case study of urban settlements in Israel.

"One of the most sensitive criteria for gauging the degree of socio-economic prosperity of an urban settlement is the ability to sustain stable rates of population growth by attracting newcomers and retaining existing population. The present paper argues that after reaching a particular size (on the average, 20-30,000 residents), urban localities in Israel tend to experience substantial changes in components of their annual population growth. Starting with this inflection point, the growth of settlements gradually becomes less dependent on natural causes (birth and death rates) than on the ability to attract newcomers and retain current residents. On the basis of this conclusion, a strategy of ¿redirecting priorities' to developing the peripheral regions of the country is suggested."

Investigating the effect of clustering of the urban field on sustainable population growth of centrally located and peripheral towns.

In a previous study (Portnov and Erell, 1998a), an Index of Clustering was defined, which allowed an analysis of the combined effect of spatial isolation and remoteness of peripheral towns on the long-term patterns of their population growth. In the present paper, the analysis of the effect of clustering of the urban field on the patterns of population growth is extended to centrally located urban places, and the validity of this index is tested in two unevenly populated countries--Israel and Norway. In both countries, the effect of clustering of the urban field on the patterns of urban growth is twofold. In sparsely populated areas, the presence of neighboring towns appears to increase their chances of attracting potential migrants due to inter-urban exchanges, while in more densely populated areas, increasing clustering tends to reduce migration influx to a given locality due to inter-town competition. Following this conclusion, a strategy of "redirecting priorities" leading to the formation of urban clusters is proposed, which may enhance the potential of urban growth in geographical areas where this is desirable.