Abstract
Nineteen years have passed since our previous review in this journal in 1999 regarding estrogen receptors. At that time, we described the current assessments of the physiological activities ...of estrogen and estrogen receptors. Since that time there has been an explosion of progress in our understanding of details of estrogen receptor-mediated processes from the molecular and cellular level to the whole organism. In this review we discuss the basic understanding of estrogen signaling and then elaborate on the progress and current understanding of estrogen receptor actions that have developed using new models and continuing clinical studies.
As evidence for the devastating impacts of air pollution on human health continues to increase, improving urban air quality has become one of the most pressing tasks facing policy makers world-wide. ...Increasingly, and very often on the basis of conflicting and/or weak evidence, the introduction of green infrastructure (GI) is seen as a win–win solution to urban air pollution, reducing ground-level concentrations without imposing restrictions on traffic and other polluting activities. The impact of GI on air quality is highly context dependent, with models suggesting that GI can improve urban air quality in some situations, but be ineffective or even detrimental in others. Here we set out a novel conceptual framework explaining how and where GI can improve air quality, and offer six specific policy interventions, underpinned by research, that will always allow GI to improve air quality. We call GI with unambiguous benefits for air quality GI4AQ. However, GI4AQ will always be a third-order option for mitigating air pollution, after reducing emissions and extending the distance between sources and receptors.
The greenhouse gas (GHG) emissions embodied in 66 different food categories together with self-reported dietary information are used to show how consumer choices surrounding food might lead to ...reductions in food-related GHG emissions. The current UK-average diet is found to embody 8.8kgCO2eperson−1day−1. This figure includes both food eaten and food wasted (post-purchase). By far the largest potential reduction in GHG emissions is achieved by eliminating meat from the diet (35% reduction), followed by changing from carbon-intensive lamb and beef to less carbon-intensive pork and chicken (18% reduction). Cutting out all avoidable waste delivers an emissions saving of 12%. Not eating foods grown in hot-houses or air-freighted to the UK offers a 5% reduction in emissions. We show how combinations of consumer actions can easily lead to reductions of 25% in food related GHG emissions. If such changes were adopted by the entire UK population this would be equivalent to a 71% reduction in the exhaust pipe emissions of CO2 from the entire UK passenger car fleet (which totalled 71MtCO2eyear−1 in 2009).
•UK-average diet embodies 8.8kgCO2eperson−1day−1 (including avoidable waste).•Eliminating meat from the diet reduces food-related GHG emissions by 35%.•Changing from GHG-intensive meats to less intensive meats reduces emissions by 18%.•Cutting out all avoidable food waste reduces emissions by 12%.•Avoiding hot-housed food or food air-freighted to the UK reduces emissions by 5%.
Street-level concentrations of nitrogen dioxide (NO2) and particulate matter (PM) exceed public health standards in many cities, causing increased mortality and morbidity. Concentrations can be ...reduced by controlling emissions, increasing dispersion, or increasing deposition rates, but little attention has been paid to the latter as a pollution control method. Both NO2 and PM are deposited onto surfaces at rates that vary according to the nature of the surface; deposition rates to vegetation are much higher than those to hard, built surfaces. Previously, city-scale studies have suggested that deposition to vegetation can make a very modest improvement (<5%) to urban air quality. However, few studies take full account of the interplay between urban form and vegetation, specifically the enhanced residence time of air in street canyons. This study shows that increasing deposition by the planting of vegetation in street canyons can reduce street-level concentrations in those canyons by as much as 40% for NO2 and 60% for PM. Substantial street-level air quality improvements can be gained through action at the scale of a single street canyon or across city-sized areas of canyons. Moreover, vegetation will continue to offer benefits in the reduction of pollution even if the traffic source is removed from city centers. Thus, judicious use of vegetation can create an efficient urban pollutant filter, yielding rapid and sustained improvements in street-level air quality in dense urban areas.
The greenhouse gas (GHG) emissions embodied in 61 different categories of food are used, with information on the diet of different groups of the population (omnivorous, vegetarian and vegan), to ...calculate the embodied GHG emissions in different dietary scenarios. We calculate that the embodied GHG content of the current UK food supply is 7.4kg CO2eperson−1day−1, or 2.7tCO2eperson−1y−1. This gives total food-related GHG emissions of 167MtCO2e (1Mt=106 metric tonnes; CO2e being the mass of CO2 that would have the same global warming potential, when measured over 100 years, as a given mixture of greenhouse gases) for the entire UK population in 2009. This is 27% of total direct GHG emissions in the UK, or 19% of total GHG emissions from the UK, including those embodied in goods produced abroad. We calculate that potential GHG savings of 22% and 26% can be made by changing from the current UK-average diet to a vegetarian or vegan diet, respectively. Taking the average GHG saving from six vegetarian or vegan dietary scenarios compared with the current UK-average diet gives a potential national GHG saving of 40MtCO2ey−1. This is equivalent to a 50% reduction in current exhaust pipe emissions from the entire UK passenger car fleet. Hence realistic choices about diet can make substantial differences to embodied GHG emissions.
► We calculate the greenhouse gas emissions embodied in different diets. ► The embodied GHG content of the current UK food supply is 7.4kgCO2eperson−1day−1. ► Changing to a vegetarian or vegan diet reduces GHG emissions by 22–26%. ► Changing to a vegetarian or vegan diet would reduce UK GHG emissions by 40MtCO2ey−1.
We estimate the amount of carbon dioxide embodied in bi-lateral trade between the UK and China in 2004. Developing and applying the method of Shui and Harriss 2006. The role of CO
2 embodiment in ...US–China trade. Energy Policy 34, 4063–4068, the most recently available data on trade and CO
2 emissions have been updated and adjusted to calculate the CO
2 emissions embodied in the commodities traded between China and the UK. It was found that through trade with China, the UK reduced its CO
2 emissions by approximately 11% in 2004, compared with a non-trade scenario in which the same type and volume of goods are produced in the UK. In addition, due to the greater carbon-intensity and relatively less efficient production processes of Chinese industry, China–UK trade resulted in an additional 117
Mt of CO
2 to global CO
2 emissions in the same one year period, compared with a non-trade scenario in which the same type and volume of goods are produced in the UK. This represents an additional 19% to the reported national CO
2 emissions of the UK (555
Mt/y in 2004) and 0.4% of global emissions. These findings suggest that, through international trade, very significant environmental impacts can be shifted from one country to another, and that international trade can (but does not necessarily) result in globally increased greenhouse gas emissions. These results are additional to the environmental consequences of transporting goods, which are not robustly quantified here.
The emissions of BVOCs from oilseed rape (Brassica napus), both when the plant is exposed to clean air and when it is fumigated with ozone at environmentally-relevant mixing ratios (ca. 135 ppbv), ...were measured under controlled laboratory conditions. Emissions of BVOCs were recorded from combined leaf and root chambers using a recently developed Selective Reagent Ionisation-Time of Flight-Mass Spectrometer (SRI-ToF-MS) enabling BVOC detection with high time and mass resolution, together with the ability to identify certain molecular functionality. Emissions of BVOCs from below-ground were found to be dominated by sulfur compounds including methanethiol, dimethyl disulfide and dimethyl sulfide, and these emissions did not change following fumigation of the plant with ozone. Emissions from above-ground plant organs exposed to clean air were dominated by methanol, monoterpenes, 4-oxopentanal and methanethiol. Ozone fumigation of the plants caused a rapid decrease in monoterpene and sesquiterpene concentrations in the leaf chamber and increased concentrations of ca. 20 oxygenated species, almost doubling the total carbon lost by the plant leaves as volatiles. The drop in sesquiterpenes concentrations was attributed to ozonolysis occurring to a major extent on the leaf surface. The drop in monoterpene concentrations was attributed to gas phase reactions with OH radicals deriving from ozonolysis reactions. As plant-emitted terpenoids have been shown to play a role in plant-plant and plant-insect signalling, the rapid loss of these species in the air surrounding the plants during photochemical pollution episodes may have a significant impact on plant-plant and plant-insect communications.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Surface ozone is a major pollutant threatening public health, agricultural production and natural ecosystems. While measures to improve air quality in megacities such as Delhi are typically aimed at ...reducing levels of particulate matter (PM), ozone could become a greater threat if these measures focus on PM alone, as some air pollution mitigation steps can actually lead to an increase in surface ozone. A better understanding of the factors controlling ozone production in Delhi and the impact that PM mitigation measures have on ozone is therefore critical for improving air quality. Here, we combine
in situ
observations and model analysis to investigate the impact of PM reduction on the non-linear relationship between volatile organic compounds (VOC), nitrogen oxides (NO
x
) and ozone.
In situ
measurements of NO
x
, VOC, and ozone were conducted in Delhi during the APHH-India programme in summer (June) and winter (November) 2018. We observed hourly averaged ozone concentrations in the city of up to 100 ppbv in both seasons. We performed sensitivity simulations with a chemical box model to explore the impacts of PM on the non-linear VOC-NO
x
-ozone relationship in each season through its effect on aerosol optical depth (AOD). We find that ozone production is limited by VOC in both seasons, and is particularly sensitive to solar radiation in winter. Reducing NO
x
alone increases ozone, such that a 50% reduction in NO
x
emissions leads to 10-50% increase in surface ozone. In contrast, reducing VOC emissions can reduce ozone efficiently, such that a 50% reduction in VOC emissions leads to ∼60% reduction in ozone. Reducing PM alone also increases ozone, especially in winter, by reducing its dimming effects on photolysis, such that a 50% reduction in AOD can increase ozone by 25% and it also enhances VOC-limitation. Our results highlight the importance of reducing VOC emissions alongside PM to limit ozone pollution, as well as benefitting control of PM pollution through reducing secondary organic aerosol. This will greatly benefit the health of citizens and the local ecosystem in Delhi, and could have broader application for other megacities characterized by severe PM pollution and VOC-limited ozone production.
Quantify the influence of aerosol light extinction on surface ozone photochemistry, highlight controlling VOC for improving air quality in Delhi.
Biogenic volatile organic compounds produced by plants are involved in plant growth, development, reproduction and defence. They also function as communication media within plant communities, between ...plants and between plants and insects. Because of the high chemical reactivity of many of these compounds, coupled with their large mass emission rates from vegetation into the atmosphere, they have significant effects on the chemical composition and physical characteristics of the atmosphere. Hence, biogenic volatile organic compounds mediate the relationship between the biosphere and the atmosphere. Alteration of this relationship by anthropogenically driven changes to the environment, including global climate change, may perturb these interactions and may lead to adverse and hard-to-predict consequences for the Earth system.
Particle nucleation is one of the main sources of atmospheric particulate
matter by number, with new particles having great relevance for human health
and climate. Highly oxidized multifunctional ...organic molecules (HOMs) have
been recently identified as key constituents in the growth and, sometimes,
in initial formation of new particles. While there have been many studies of
HOMs in atmospheric chambers, flow tubes, and clean environments, analyses of
data from polluted environments are scarce. Here, measurements of HOMs and
particle size distributions down to small molecular clusters are presented
alongside volatile organic compounds (VOCs) and trace-gas data from a
campaign in June 2017, in Beijing. Many gas-phase HOMs have been
characterized and their temporal trends and behaviours analysed in the
context of new particle formation. The HOMs identified have a
degree of oxidation comparable to that seen in other, cleaner, environments, likely
due to an interplay between the higher temperatures facilitating rapid
hydrogen abstractions and the higher concentrations of NOx and other
RO2⚫ terminators ending the autoxidation sequence more rapidly.
Our data indicate that alkylbenzenes, monoterpenes, and isoprene are
important precursor VOCs for HOMs in Beijing. Many of the C5 and
C10 compounds derived from isoprene and monoterpenes have a slightly
greater degree of average oxidation state of carbon compared to those from
other precursors. Most HOMs except for large dimers have daytime peak
concentrations, indicating the importance of OH⚫ chemistry in the
formation of HOMs, as O3 tends to be lower on days with higher HOM
concentrations; similarly, VOC concentrations are lower on the days with
higher HOM concentrations. The daytime peaks of HOMs coincide with the
growth of freshly formed new particles, and their initial formation
coincides with the peak in sulfuric acid vapours, suggesting that the
nucleation process is sulfuric-acid-dependent, with HOMs contributing to
subsequent particle growth.
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