Concentration-response Functions Research Articles

Air quality improvements and health benefits from China’s clean air action since 2013

Aggressive emission control measures were taken by the Chinese government after the promulgation of the ‘Air Pollution Prevention and Control Action Plan’ in 2013. Here we evaluated the air quality and health benefits associated with this stringent policy during 2013–2015 by using surface PM2.5 concentrations estimated from a three-stage data fusion model and cause-specific integrated exposure–response functions. The population-weighted annual mean PM2.5 concentrations decreased by 21.5% over China during 2013–2015, reducing from 60.5 in 2013 to 47.5 μg m−3 in 2015. Subsequently, the national PM2.5-attributable mortality decreased from 1.22 million (95% CI: 1.05, 1.37) in 2013 to 1.10 million (95% CI: 0.95, 1.25) in 2015, which is a 9.1% reduction. The limited health benefits compared to air quality improvements are mainly due to the supralinear responses of mortality to PM2.5 over the high concentration end of the concentration–response functions. Our study affirms the effectiveness of China’s recent air quality policy; however, due to the nonlinear responses of mortality to PM2.5 variations, current policies should remain in place and more stringent measures should be implemented to protect public health.

Interplay of ventilation and filtration: Differential analysis of cost function combining energy use and indoor exposure to PM2.5 and ozone

This study investigated the effects of ventilation and filtration on building energy consumption and exposure to PM2.5 and ozone in U.S. offices. Energy use and indoor PM2.5 and ozone concentrations were predicted in 15 locations for a typical office with either a constant air volume (CAV) or variable air volume (VAV) mechanical system. For each office and location, annual simulations were performed with combinations of fixed ventilation ranging 20–100 CFM/occ (9.4–47 L/s/occ) and filters ranging in efficiency corresponding to MERV 8–16 and HEPA. Energy use was monetized using historic costs, and PM2.5 and ozone exposures were monetized using incidence valuations and concentration-response functions. These outcomes were combined into a singular cost function, which was characterized empirically as a function of ventilation and filtration. Various partial derivatives of the cost function were calculated to observe trends and interdependencies. Exposure cost was 5.5 times higher than energy cost for cases with common filters (MERV 8–11). Even with high filter efficiency, exposure cost was greater than energy cost on average. Filtration had a much stronger effect than ventilation on indoor contaminant levels and the total cost function. The differential analysis revealed that ventilation and filtration complement each other: Implementing a high efficiency filter can mitigate negative effects of ventilation, and higher ventilation rates can increase the efficacy of filtration (e.g. increasing ventilation from 20 to 60 CFM/occ increased filtration efficacy by 1.2–1.5 for VAV offices).

Tackling the mortality from long-term exposure to outdoor air pollution in megacities: Lessons from the Greater Cairo case study

ObjectiveThe poor outdoor air quality in megacities of the developing world and its impact on health is a matter of concern for both the local populations and the decision-makers. The objective of this work is to quantify the mortality attributable to long-term exposure to PM2.5, NO2, and O3 in Greater Cairo (Egypt). MethodsWe analyze the temporal and spatial variability of the three pollutants concentrations measured at 18 stations of the area. Then, we apply the method recommended by the WHO to estimate the excess mortality. In this assessment, three different shapes (log-linear, linear, and log-log) of the concentration-response functions (CRF) are used. ResultsWith PM2.5 concentrations varying from 50 to more than 100µg/m3 in the different sectors of the megacity, the spatial variability of this pollutant is found to be one important cause of uncertainty on the excess mortality associated with it. Also important is the choice of the CRF. With the average (75µg/m3) PM2.5 concentration and the most favorable log-log shape of the CRF, 11% (CI, 9–14%) of the non-accidental mortality in the population older than 30 years can still be attributed to PM2.5, which corresponds to 12520 (CI, 10240–15930) yearly premature deaths. Should the Egyptian legal 70µg/m3 PM10 limit (corresponding to approximately 37.5µg/m3 for PM2.5) be met, this number would be reduced to 7970, meaning that 4550 premature deaths could be avoided each year.Except around some industrial or traffic hot spots, NO2 concentration is found to be below the 40µg/m3 air quality guideline of the WHO. However, the average concentration (34µg/m3) of this gas exceeds the stricter 10µg/m3 recommendation of the HRAPIE project and it is thus estimated that from 7850 to 10470 yearly deaths can be attributed to NO2.Finally, with the ozone concentration measured at one station only, it is found that, depending on the choice of the CRF, between 2.4% and 8.8% of the mortality due to respiratory diseases can be attributed to this gas. ConclusionIn Greater Cairo, PM2.5 and NO2 constitute major health risks. The best estimate is that in the population older than 30 years, 11% and 8% of the non-accidental mortality can be attributed to these two pollutants, respectively.

Associations between fine particulate matter and mortality in the 2001 Canadian Census Health and Environment Cohort

BackgroundLarge cohort studies have been used to characterise the association between long-term exposure to fine particulate matter (PM2.5) air pollution with non-accidental, and cause-specific mortality. However, there has been no consensus as to the shape of the association between concentration and response. MethodsTo examine the shape of this association, we developed a new cohort based on respondents to the 2001 Canadian census long-form. We applied new annual PM2.5 concentration estimates based on remote sensing and ground measurements for Canada at a 1km spatial scale from 1998 to 2011. We followed 2.4 million respondents who were non-immigrants aged 25–90 years and did not reside in an institution over a 10 year period for mortality. Exposures were assigned as a 3-year mean prior to the follow-up year. Income tax files were used to account for residential mobility among respondents using postal codes, with probabilistic imputation used for missing postal codes in the tax data. We used Cox survival models to determine hazard ratios (HRs) for cause-specific mortality. We also estimated Shape Constrained Health Impact Functions (a concentration-response function) for selected causes of death. ResultsIn models stratified by age, sex, airshed, and population centre size, and adjusted for individual and neighbourhood socioeconomic variables, HR estimates for non-accidental mortality were HR = 1.18 (95% CI: 1.15–1.21) per 10μg/m3 increase in concentration. We observed higher HRs for cardiovascular disease (HR=1.25; 95% CI: 1.19–1.31), cardio-metabolic disease (HR = 1.27; 95% CI: 1.21–1.33), ischemic heart disease (HR = 1.36; 95% CI: 1.28–1.44) and chronic obstructive pulmonary disease (COPD) mortality (HR = 1.24; 95% CI: 1.11–1.39) compared to HR for all non-accidental causes of death. For non-accidental, cardio-metabolic, ischemic heart disease, respiratory and COPD mortality, the shape of the concentration-response curve was supra-linear, with larger differences in relative risk for lower concentrations. For both pneumonia and lung cancer, there was some suggestion that the curves were sub-linear. ConclusionsAssociations between ambient concentrations of fine particulate matter and several causes of death were non-linear for each cause of death examined.

Impacts of ozone air pollution and temperature extremes on crop yields: Spatial variability, adaptation and implications for future food security

Ozone air pollution and climate change pose major threats to global crop production, with ramifications for future food security. Previous studies of ozone and warming impacts on crops typically do not account for the strong ozone-temperature correlation when interpreting crop-ozone or crop-temperature relationships, or the spatial variability of crop-to-ozone sensitivity arising from varietal and environmental differences, leading to potential biases in their estimated crop losses. Here we develop an empirical model, called the partial derivative-linear regression (PDLR) model, to estimate the spatial variations in the sensitivities of wheat, maize and soybean yields to ozone exposures and temperature extremes in the US and Europe using a composite of multidecadal datasets, fully correcting for ozone-temperature covariation. We find generally larger and more spatially varying sensitivities of all three crops to ozone exposures than are implied by experimentally derived concentration-response functions used in most previous studies. Stronger ozone tolerance is found in regions with high ozone levels and high consumptive crop water use, reflecting the existence of spatial adaptation and effect of water constraints. The spatially varying sensitivities to temperature extremes also indicate stronger heat tolerance in crops grown in warmer regions. The spatial adaptation of crops to ozone and temperature we find can serve as a surrogate for future adaptation. Using the PDLR-derived sensitivities and 2000–2050 ozone and temperature projections by the Community Earth System Model, we estimate that future warming and unmitigated ozone pollution can combine to cause an average decline in US wheat, maize and soybean production by 13%, 43% and 28%, respectively, and a smaller decline for European crops. Aggressive ozone regulation is shown to offset such decline to various extents, especially for wheat. Our findings demonstrate the importance of considering ozone regulation as well as ozone and climate change adaptation (e.g., selecting heat- and ozone-tolerant cultivars, irrigation) as possible strategies to enhance future food security in response to imminent environmental threats.

Sodium Carbonate is Saltier Than Sodium Chloride to Sodium-Depleted Rats.

In a series of behavioral experiments in the 1960s, G.R. Morrison identified several unique features of the taste of Na2CO3 to rats; namely, it is 1) considerably more intense than NaCl at isomolar concentrations, 2) avoided at 10 times lower concentrations than NaCl to thirsty rats, 3) preferred at 10 times lower concentrations than NaCl in sodium-depleted rats. He also demonstrated its qualitatively similarity to NaCl. In Experiment 1, we confirmed and extended many of Morrison's observations. Rats were injected with furosemide on 3 occasions to stimulate a sodium appetite. After each depletion, rats were given a brief-access taste test in a lickometer presenting, in random order, water and 7 concentrations of salt. One test used NaCl (0.028-0.89 M, quarter log steps), another used Na2CO3, and the third used Na2CO3, but at a tenfold lower concentration range (0.0028-0.089 M). Rats licked NaCl in an inverted-U shaped concentration-response function peaking at 0.158-0.281 M. As Morrison's results predicted, rats licked Na2CO3 in nearly identical fashion, but at a tenfold lower concentration range (peak at 0.0158-0.028 M). In a second experiment, furosemide-treated rats were repeatedly tested with the lower Na2CO3 range but mixed in the epithelial sodium channel blocker amiloride at various concentrations (3-300 μM, half log steps). Amiloride reduced licking for Na2CO3 and shifted the peak response rightward up to about half a log unit. Thus, this "super-saltiness" of Na2CO3 to rats is at least partly amiloride-dependent.

입자상 대기오염물질의 건강 위해성 평가를 위한 국내 농도반응함수 도출

Objectives: HRA (Health Risk Assessment) is an important tool for measuring the health impacts of air pollution. HRA is already being used widely as an important reference for crafting air pollution policies. However, the absence of a domestic CRF (Concentration Response Function) standard, which is a main component for HRA, could cause confusion amongst policy-makers. The purpose of this study is to tabulate a domestic CRF standard for a PM (Particulate Matter)-related HRA. Methods: This study suggested a domestic CRF standard for HRA thorough a literature review. The literature review for meta-analysis was limited to the English language for epidemiological studies published from January 1980 to March 2016. This meta-analysis was conducted by assuming both fixed- and random-effects of CRF. In addition, studies that reported HRA of air pollution for WHO (World Health Organization), the EC (European Commission), and the EPA (Environmental Protection Agency) were reviewed to compare the CRFs of South Korea to the recommended CRFs of WHO, the EC, or the EPA. Additionally, a domestic CRF standard was supplemented by these. Results: Nineteen studies were selected for the CRF for South Korea. Fifty-three CRFs were derived for meta-analysis. CRFs with a standard for PM-related HRA were divided according to the following four criteria: air pollution, exposure characteristics, type of health impact, and age group. Finally, a domestic CRF standard was created comprised of 21 CRFs. Among these, six CRFs were derived from the results of foreign HRA studies. Conclusions: This study is important in that a domestic CRF standard is first suggested. In addition, this study suggests a further area of study for using HRA as a policy tool and a direction of epidemiological study.

Integrated Uncertainty Analysis for Ambient Pollutant Health Risk Assessment: A Case Study of Ozone Mortality Risk.

The U.S. Environmental Protection Agency (EPA) uses health risk assessment to help inform its decisions in setting national ambient air quality standards (NAAQS). EPA's standard approach is to make epidemiologically-based risk estimates based on a single statistical model selected from the scientific literature, called the "core" model. The uncertainty presented for "core" risk estimates reflects only the statistical uncertainty associated with that one model's concentration-response function parameter estimate(s). However, epidemiologically-based risk estimates are also subject to "model uncertainty," which is a lack of knowledge about which of many plausible model specifications and data sets best reflects the true relationship between health and ambient pollutant concentrations. In 2002, a National Academies of Sciences (NAS) committee recommended that model uncertainty be integrated into EPA's standard risk analysis approach. This article discusses how model uncertainty can be taken into account with an integrated uncertainty analysis (IUA) of health risk estimates. It provides an illustrative numerical example based on risk of premature death from respiratory mortality due to long-term exposures to ambient ozone, which is a health risk considered in the 2015 ozone NAAQS decision. This example demonstrates that use of IUA to quantitatively incorporate key model uncertainties into risk estimates produces a substantially altered understanding of the potential public health gain of a NAAQS policy decision, and that IUA can also produce more helpful insights to guide that decision, such as evidence of decreasing incremental health gains from progressive tightening of a NAAQS.

Modeling variability in air pollution-related health damages from individual airport emissions

In this study, we modeled concentrations of fine particulate matter (PM2.5) and ozone (O3) attributable to precursor emissions from individual airports in the United States, developing airport-specific health damage functions (deaths per 1000t of precursor emissions) and physically-interpretable regression models to explain variability in these functions. We applied the Community Multiscale Air Quality model using the Decoupled Direct Method to isolate PM2.5- or O3-related contributions from precursor pollutants emitted by 66 individual airports. We linked airport- and pollutant-specific concentrations with population data and literature-based concentration-response functions to create health damage functions. Deaths per 1000t of primary PM2.5 emissions ranged from 3 to 160 across airports, with variability explained by population patterns within 500km of the airport. Deaths per 1000t of precursors for secondary PM2.5 varied across airports from 0.1 to 2.7 for NOx, 0.06 to 2.9 for SO2, and 0.06 to 11 for VOCs, with variability explained by population patterns and ambient concentrations influencing particle formation. Deaths per 1000t of O3 precursors ranged from −0.004 to 1.0 for NOx and 0.03 to 1.5 for VOCs, with strong seasonality and influence of ambient concentrations. Our findings reinforce the importance of location- and source-specific health damage functions in design of health-maximizing emissions control policies.

A chronology of ratios between black smoke and PM10 and PM2.5 in the context of comparison of air pollution epidemiology concentration-response functions

BackgroundFor many air pollution epidemiological studies in Europe, ‘black smoke’ (BS) was the only measurement available to quantify ambient particulate matter (PM), particularly for exposures prior to the mid-1990s when quantification via the PM10 and/or PM2.5 metrics was introduced. The aim of this work was to review historic BS and PM measurements to allow comparison of health concentration-response functions (CRF) derived using BS as the measure of exposure with CRFs derived using PM10 or PM2.5.MethodsThe literature was searched for quantitative information on measured ratios of BS:PM10, BS:PM2.5, and chemical composition of PM; with specific focus on the United Kingdom (UK) between 1970 and the early 2000s when BS measurements were discontinued.ResultsThe average BS:PM10 ratio in urban background air was just below unity at the start of the 1970s, decreased rapidly to ≈ 0.7 in the mid-1970s and to ≈ 0.5 at the end of the 1970s, with continued smaller declines in the 1980s, and was within the range 0.2–0.4 by the end of the 1990s. The limited data for the BS:PM2.5 ratio suggest it equalled or exceeded unity at the start of the 1970s, declined to ≈ 0.7 by the end of the 1970s, with slower decline thereafter to a range 0.4–0.65 by the end of the 1990s. For an epidemiological study that presents a CRFBS value, the corresponding CRFPM10 value can be estimated as RBS:PM10 × CRFBS where RBS:PM10 is the BS:PM10 concentration ratio, if the toxicity of PM10 is assumed due only to the component quantified by a BS measurement. In the general case of some (but unknown) contribution of toxicity from non-BS components of PM10 then CRFPM10 > RBS:PM10 × CRFBS, with CRFPM10 exceeding CRFBS if the toxicity of the other components in PM10 is greater than the toxicity of the component to which the BS metric is sensitive. Similar analyses were applied to relationships between CRFPM2.5 and CRFBS.ConclusionsApplication of this analysis to example published CRFBS values for short and long-term health effects of PM suggest health effects from other components in the PM mixture in addition to the fine black particles characterised by BS.

RISK ASSESSMENT OF THE AIR POLLUTION FOR INDUSTRIAL & RESIDENTIAL AREA CASE STUDY: EL-MAX AREA, ALEXANDRIA CITY

This papers introduces the concept of air pollution risk assessment (APRA) or health risk assessment (AP-HRA), describes in broad terms how the health risks of outdoor air pollution and its sources are estimated, and gives an overview of the general principles for the proper conduct of an AP-HRA for various scenarios and purposes The main purpose of an AP-HRA is to estimate and communicate the health impact of exposure to air pollution or changes in air pollution in different socioeconomic, environmental, and policy circumstances. The first step of an AP-HRA is to assess the exposure of the target population to specific air pollutants. Monitoring data may be used to estimate the past and current exposure to air pollution for populations living near the monitoring site. In addition, air quality modelling is often used to estimate differences in exposure for different socioeconomic and environmental conditions within the geographical area of interest, and to predict changes in exposure in future policy scenarios. The second step of an AP-HRA is to estimate the health risk associated with the exposure to air pollution. This requires the use of concentration–response functions (CRFs), which quantify the health impact per concentration unit of a particular air pollutant. The third step of an AP-HRA is to quantify and express the uncertainty of the generated estimate of health impact. This is an important and integral component of the results, and it is vital to ensure both that the main message is not lost and that the results produced are understandable by policy-makers and others who do not necessarily have a technical background or expertise in AP-HRA. Results of AP-HRAs are often reported in terms of numbers of attributable deaths or cases of disease, years of life lost, disability-adjusted life years, or change in life expectancy attributable to exposure or a change in exposure to air pollution. These health impacts can then be used to evaluate costs and benefits of policy change in monetary terms.

Challenges in estimating health effects of indoor exposures to outdoor particles: Considerations for regional differences

Ambient air pollution is a leading environmental risk factor causing substantial losses of life and significant morbidity. Concentration-response (CR) functions used globally to estimate such effects are largely based on ambient epidemiology, using centrally monitored outdoor air quality as an exposure indicator and various indices of population health as an outcome. Similar common understanding is mostly missing regarding indoor exposures. Less studied are health impact modifying factors such as particle size, infiltration, time-activity and population differences. In this discussion paper we aim at looking at one of these, infiltration.The sensitivity of overall personal exposure to indoor exposures was quantified by a simple probabilistic time-activity model to calculate fractional exposures for indoor, outdoor and in traffic time-activity. To demonstrate the potential regional differences in epidemiological C-R relationships we re-analysed the ESCAPE results for natural-cause mortality, focusing on geographical grouping of the cohorts: pooled estimates were calculated for the Nordic, Central European and Southern European cohorts.When comparing the relative differences in the regional hazard ratio increments, the Central European value (7%) is 1.75 times higher than the Nordic one, and Southern European value (12%) 3 times higher, respectively. While towards the expected direction when aiming to explain these differences at least partly with differences in PM2.5 infiltration, the differences are not statistically significant and only the Central European and the all cohorts combined estimates reach borderline statistical significance. As the analysis of PM2.5 infiltration factors by similar regions yielded only 10–15% differences, it seems possible that that the available data could also accommodate other regional factors, such as those originating from regional differences in population and contribution of indoor sources of PM, time-activity, behaviour, or compositional differences in the particulate matter.

Public health impacts of excess NOx emissions from Volkswagen diesel passenger vehicles in Germany

In September 2015, the Volkswagen Group (VW) admitted the use of ‘defeat devices’ designed to lower emissions measured during VW vehicle testing for regulatory purposes. Globally, 11 million cars sold between 2008 and 2015 are affected, including about 2.6 million in Germany. On-road emissions tests have yielded mean on-road NOx emissions for these cars of 0.85 g km−1, over four times the applicable European limit of 0.18 g km−1. This study estimates the human health impacts and costs associated with excess emissions from VW cars driven in Germany. A distribution of on-road emissions factors is derived from existing measurements and combined with sales data and a vehicle fleet model to estimate total excess NOx emissions. These emissions are distributed on a 25 by 28 km grid covering Europe, using the German Federal Environmental Protection Agency’s (UBA) estimate of the spatial distribution of NOx emissions from passenger cars in Germany. We use the GEOS-Chem chemistry-transport model to predict the corresponding increase in population exposure to fine particulate matter and ozone in the European Union, Switzerland, and Norway, and a set of concentration-response functions to estimate mortality outcomes in terms of early deaths and of life-years lost. Integrated over the sales period (2008–2015), we estimate median mortality impacts from VW excess emissions in Germany to be 1200 premature deaths in Europe, corresponding to 13 000 life-years lost and 1.9 billion EUR in costs associated with life-years lost. Approximately 60% of mortality costs occur outside Germany. For the current fleet, we estimate that if on-road emissions for all affected VW vehicles in Germany are reduced to the applicable European emission standard by the end of 2017, this would avert 29 000 life-years lost and 4.1 billion 2015 EUR in health costs (median estimates) relative to a counterfactual case with no recall.

Preterm birth associated with maternal fine particulate matter exposure: A global, regional and national assessment

Reduction of preterm births (<37 completed weeks of gestation) would substantially reduce neonatal and infant mortality, and deleterious health effects in survivors. Maternal fine particulate matter (PM2.5) exposure has been identified as a possible risk factor contributing to preterm birth. The aim of this study was to produce the first estimates of ambient PM2.5-associated preterm births for 183 individual countries and globally. To do this, national, population-weighted, annual average ambient PM2.5 concentration, preterm birth rate and number of livebirths were combined to calculate the number of PM2.5-associated preterm births in 2010 for 183 countries. Uncertainty was quantified using Monte-Carlo simulations, and analyses were undertaken to investigate the sensitivity of PM2.5-associated preterm birth estimates to assumptions about the shape of the concentration-response function at low and high PM2.5 exposures, inclusion of provider-initiated preterm births, and exposure to indoor air pollution.Globally, in 2010, the number of PM2.5-associated preterm births was estimated as 2.7 million (1.8–3.5 million, 18% (12–24%) of total preterm births globally) with a low concentration cut-off (LCC) set at 10μgm−3, and 3.4 million (2.4–4.2 million, 23% (16–28%)) with a LCC of 4.3μgm−3. South and East Asia, North Africa/Middle East and West sub-Saharan Africa had the largest contribution to the global total, and the largest percentage of preterm births associated with PM2.5. Sensitivity analyses showed that PM2.5-associated preterm birth estimates were 24% lower when provider-initiated preterm births were excluded, 38–51% lower when risk was confined to the PM2.5 exposure range in the studies used to derive the effect estimate, and 56% lower when mothers who live in households that cook with solid fuels (and whose personal PM2.5 exposure is likely dominated by indoor air pollution) were excluded. The concentration-response function applied here derives from a meta-analysis of studies, most of which were conducted in the US and Europe, and its application to the areas of the world where we estimate the greatest effects on preterm births remains uncertain. Nevertheless, the substantial percentage of preterm births estimated to be associated with anthropogenic PM2.5 (18% (13%–24%) of total preterm births globally) indicates that reduction of maternal PM2.5 exposure through emission reduction strategies should be considered alongside mitigation of other risk factors associated with preterm births.

Benefits on public health from transport-related greenhouse gas mitigation policies in Southeastern European cities.

Climate change is a major environmental threat of our time. Cities have a significant impact on greenhouse gas emissions as most of the traffic, industry, commerce and more than 50% of world population is situated in urban areas. Southern Europe is a region that faces financial turmoil, enhanced migratory fluxes and climate change pressure. The case study of Thessaloniki is presented, one of the only two cities in Greece with established climate change action plans. The effects of feasible traffic policies in year 2020 are assessed and their potential health impact is compared to a business as usual scenario. Two types of measures are investigated: operation of underground rail in the city centre and changes in fleet composition. Potential co-benefits from reduced greenhouse gas emissions on public health by the year 2020 are computed utilizing state-of-the-art concentration response functions for PMx, NO2 and C6H6. Results show significant environmental health and monetary co-benefits when the city metro is coupled with appropriate changes in the traffic composition. Monetary savings due to avoided mortality or leukaemia incidence corresponding to the reduction in PM10, PM2.5, NO2 and C6H6 exposure will be 56.6, 45, 37.7 and 1.0 million Euros respectively. Promotion of 'green' transportation in the city (i.e. the wide use of electric vehicles), will provide monetary savings from the reduction in PM10, PM2.5, NO2 and C6H6 exposure up to 60.4, 49.1, 41.2 and 1.08 million Euros. Overall, it was shown that the respective GHG emission reduction policies resulted in clear co-benefits in terms of air quality improvement, public health protection and monetary loss mitigation.

Global burden of mortalities due to chronic exposure to ambient PM2.5 from open combustion of domestic waste

Uncontrolled combustion of domestic waste has been observed in many countries, creating concerns for air quality; however, the health implications have not yet been quantified. We incorporate the Wiedinmyer et al (2014 Environ. Sci. Technol. 48 9523–30) emissions inventory into the global chemical-transport model, GEOS-Chem, and provide a first estimate of premature adult mortalities from chronic exposure to ambient PM2.5 from uncontrolled combustion of domestic waste. Using the concentration-response functions (CRFs) of Burnett et al (2014 Environ. Health Perspect. 122 397–403), we estimate that waste-combustion emissions result in 270 000 (5th–95th: 213 000–328 000) premature adult mortalities per year. The confidence interval results only from uncertainty in the CRFs and assumes equal toxicity of waste-combustion PM2.5 to all other PM2.5 sources. We acknowledge that this result is likely sensitive to choice of chemical-transport model, CRFs, and emission inventories. Our central estimate equates to 9% of adult mortalities from exposure to ambient PM2.5 reported in the Global Burden of Disease Study 2010. Exposure to PM2.5 from waste combustion increases the risk of premature mortality by more than 0.5% for greater than 50% of the population. We consider sensitivity simulations to uncertainty in waste-combustion emission mass, the removal of waste-combustion emissions, and model resolution. A factor-of-2 uncertainty in waste-combustion PM2.5 leads to central estimates ranging from 138 000 to 518 000 mortalities per year for factors-of-2 reductions and increases, respectively. Complete removal of waste combustion would only avoid 191 000 (5th–95th: 151 000–224 000) mortalities per year (smaller than the total contributed premature mortalities due to nonlinear CRFs). Decreasing model resolution from 2° × 2.5° to 4° × 5° results in 16% fewer mortalities attributed to waste-combustion PM2.5, and over Asia, decreasing resolution from 0.5° × 0.666° to 2° × 2.5° results in 21% fewer mortalities attributed to waste-combustion PM2.5. Owing to coarse model resolution, our global estimates of premature mortality from waste-combustion PM2.5 are likely a lower bound.

Assessment of health burden caused by particulate matter in southern China using high-resolution satellite observation

As the major engine of economic growth in China, the Pearl River Delta (PRD) region is one of the most urbanized regions in the world. Rapid development has brought great wealth to its citizens; however, at the same time, increasing emissions of ambient pollutants from vehicles and industrial combustions have caused considerable air pollution and negative health effects for the region's residents. In this study, the concentration response function method was applied together with satellite-retrieved particulate matter (PM10 and PM2.5) concentration data to estimate the health burden caused by this pollutant from 2004 to 2013. The value of statistical life was used to calculate the economic loss due to the negative health effects of particulate matter pollution. Our results show that in the whole PRD region, the estimated number of deaths from the four diseases attributable to PM2.5 was the highest in 2012, at 45,000 (19,000–61,000); the number of all-cause hospital admissions due to PM10 was the highest in 2013, reaching up to 91,000 (0–270,000) (excluding Hong Kong). Among the 10 cities, the capital city Guangzhou suffered the most from ambient particulate matter pollution and had the highest mortality and morbidity over the 10years. The cost of mortality in this region was the highest in 2012, at 46,000 million USD, or around 6.1% of local total gross domestic product (GDP). The positive spatial relationship between the degree of urbanization and the particulate matter concentration proves that the urbanization process does worsen air quality and hence increases the health risks of local urban citizens. It is recommended that local governments further enhance their control policies to better guarantee the health and wealth benefits of local residents.

Alterations of consciousness and mystical-type experiences after acute LSD in humans

RationaleLysergic acid diethylamide (LSD) is used recreationally and in clinical research. Acute mystical-type experiences that are acutely induced by hallucinogens are thought to contribute to their potential therapeutic effects. However, no data have been reported on LSD-induced mystical experiences and their relationship to alterations of consciousness. Additionally, LSD dose- and concentration-response functions with regard to alterations of consciousness are lacking.MethodsWe conducted two placebo-controlled, double-blind, cross-over studies using oral administration of 100 and 200 μg LSD in 24 and 16 subjects, respectively. Acute effects of LSD were assessed using the 5 Dimensions of Altered States of Consciousness (5D-ASC) scale after both doses and the Mystical Experience Questionnaire (MEQ) after 200 μg.ResultsOn the MEQ, 200 μg LSD induced mystical experiences that were comparable to those in patients who underwent LSD-assisted psychotherapy but were fewer than those reported for psilocybin in healthy subjects or patients. On the 5D-ASC scale, LSD produced higher ratings of blissful state, insightfulness, and changed meaning of percepts after 200 μg compared with 100 μg. Plasma levels of LSD were not positively correlated with its effects, with the exception of ego dissolution at 100 μg.ConclusionsMystical-type experiences were infrequent after LSD, possibly because of the set and setting used in the present study. LSD may produce greater or different alterations of consciousness at 200 μg (i.e., a dose that is currently used in psychotherapy in Switzerland) compared with 100 μg (i.e., a dose used in imaging studies). Ego dissolution may reflect plasma levels of LSD, whereas more robustly induced effects of LSD may not result in such associations.

The Perceptual Characteristics of Sodium Chloride to Sodium-Depleted Rats.

Three experiments assessed potential changes in the rat's perception of sodium chloride (NaCl) during a state of sodium appetite. In Experiment 1, sodium-sufficient rats licking a range of NaCl concentrations (0.028-0.89M) in 15s trials showed an inverted U-shaped concentration response function peaking at 0.281M. Depleted rats (furosemide) showed an identical function, merely elevated, suggesting altered qualitative or hedonic perception but no change in perceived intensity. In Experiment 2, sodium-depleted rats were tested with NaCl, sodium gluconate, and potassium chloride (KCl; 0.028-0.89M) similar to Experiment 1. KCl was licked at the same rate as water except for a slight elevation at 0.158; sodium gluconate and NaCl were treated similarly, but rats showed more licking for hypertonic sodium gluconate than hypertonic NaCl. Sodium-depleted rats were also tested with NaCl mixed in amiloride (10-300 μM). Amiloride reduced licking but did not alter the shape of the concentration-response function. Collectively, these results suggest that transduction of sodium by epithelial sodium channels (which are blocked by amiloride and are more dominant in sodium gluconate than NaCl transduction) is crucial for the perception of sodium during physiological sodium depletion. In Experiment 3, sodium-deplete rats were tested with NaCl as in Experiment 1 but after taste aversion conditioning to 0.3M NaCl or sucrose. Rats conditioned to avoid NaCl but not sucrose failed to express a sodium appetite, strongly suggesting that NaCl does not undergo a change in taste quality during sodium appetite-rats show no confusion between sucrose and NaCl in this paradigm.

Mortality benefits of vigorous air quality improvement interventions during the periods of APEC Blue and Parade Blue in Beijing, China

Vigorous air pollution control measures were implemented during the 2014 Asia-Pacific Economic Cooperation and a large-scale military parade (described here as “APEC Blue” and “Parade Blue” periods) in Beijing, China. A natural experiment was conducted in a health impact assessment framework to estimate the number of deaths attributable to PM2.5, using concentration-response functions derived from previous studies conducted in Beijing, combined with the differences in PM2.5 concentrations between intervention and reference periods. Substantial reductions in daily PM2.5 concentrations were observed during both intervention periods. Using the same dates from the prior year as a reference, daily PM2.5 concentration decreased from 98.57 μg/m3 to 47.53 μg/m3 during “APEC Blue”, and from 59.15 μg/m3 to 17.07 μg/m3 during the “Parade Blue”. We estimated that 39–63 all-cause deaths (21–51 cardiovascular, 6–13 respiratory deaths) have been prevented during the APEC period; and 41–65 deaths (22–52 cardiovascular, 6–13 respiratory deaths) have been prevented during the Parade period. This study shows that substantial mortality reductions could be achieved by implementing stringent air pollution mitigation measures.