Particulate air pollution as a predictor of mortality in a prospective study of U.S. adults

Retrieval of high-resolution aerosol optical depth (AOD) using Landsat 8 imageries over different LULC classes over a city along Indo-Gangetic Plain, India

Aerosol optical depth (AOD) serves as a crucial indicator for assessing regional air quality. To address regional and urban pollution issues, there is a requirement for high-resolution AOD products, as the existing data is of very coarse resolution. To address this issue, we retrieved high-resolution AOD over Kanpur (26.4499°N, 80.3319°E), located in the Indo-Gangetic Plain (IGP) region using Landsat 8 imageries and implemented the algorithm SEMARA, which combines SARA (Simplified Aerosol Retrieval Algorithm) and SREM (Simplified and Robust Surface Reflectance Estimation). Our approach leveraged the green band of the Landsat 8, resulting in an impressive spatial resolution of 30 m of AOD and rigorously validated with available AERONET observations. The retrieved AOD is in good agreement with high correlation coefficients (r) of 0.997, a low root mean squared error of 0.035, and root mean bias of - 4.91%. We evaluated the retrieved AOD with downscaled MODIS (MCD19A2) AOD products across various land classes for cropped and harvested period of agriculture cycle over the study region. It is noticed that over the built-up region of Kanpur, the SEMARA algorithm exhibits a stronger correlation with the MODIS AOD product compared to vegetation, barren areas and water bodies. The SEMARA approach proved to be more effective for AOD retrieval over the barren and built-up land categories for harvested period compared with the cropping period. This study offers a first comparative examination of SEMARA-retrieved high-resolution AOD and MODIS AOD product over a station of IGP.

Comparison Between Smoked Tobacco and Medical Cannabis Cigarettes Concerning Particulate Matter

Introduction: Cannabis is a widely used drug like tobacco and alcohol. In the meantime, it is also prescribed for medical treatment in some countries. Tobacco smoke contains chemical carcinogens and particulate matter (PM) that are both harmful to health. Method: In this study, we investigated PM levels in second-hand smoke (SHS) of hand-tamped cannabis cigarettes compared to cigarettes with tubing tobacco and the 3R4F reference cigarette. Results: It could be demonstrated that the largest proportion of the particle mass is attributable to particles with a diameter of less than 1μm and that every tested cigarette emitted more PM than the 3R4F reference cigarette. In addition, our data clearly revealed that cannabis smoke contains higher PM levels in SHS than tobacco cigarettes. Compared to the reference cigarette, the PM1 emissions of cannabis were 105% higher. Also, the cannabis mixed cigarettes had higher PM levels than the 3R4F cigarettes. For instance, the PM10 emissions were 93% higher. Also, the Gauloises Mélange tubing tobacco also reached higher PM concentrations than the 3R4F cigarette. Discussion: Regardless of negative health effects, cannabis is seen as a harmless drug in the public eye. We found strong indications for potential health risks by PM from cannabis products and, therefore, the public should be educated about a potential harm.

A Long Way from Steubenville: Environmental Epidemiology in a Rapidly Changing World

This commentary focuses on research that has long been at the core of environmental epidemiology: studies of the health effects of air pollution. It highlights publications in the American Journal of Epidemiology going back more than 50 years that have contributed to the debate about the validity of this research and its meaning for public policy. Technological advances have greatly expanded the toolbox of environmental epidemiologists in terms of measuring and analyzing complex exposures in large populations. Yet, discussions about biases in estimating air pollution health effects have always been and remain intense. Epidemiologists have brought new methodologies and concepts to this research, alleviating some but not all concerns. Here, the focus is on seminal epidemiologic work that established valid links between air pollution exposures and health outcomes and generated data for environmental policies and prevention. With this commentary, I hope to inspire epidemiologists to address many more of the burning environmental health questions-wildfires included-with a similar scientific doggedness. The rapidly changing conditions of our planet are challenging us to innovate and offer solutions, albeit perhaps a little bit faster this time around.

Environmental impacts of Indian coal thermal power plants and associated human health risk to the nearby residential communities: A potential review

Worldwide, harmful emissions from coal power plants cause many illnesses contribute to premature deaths burden. Despite its high impact on human health and being a major source of toxic pollutants, coal has been considered a component of global energy for decades. Hence, this work was envisaged to understand the rising environmental and multiple health issues from coal power plants. Studies on the adverse impacts of coal power plants on the environment, including soil, surface water, groundwater and air, were critically evaluated. The health risk from exposure to different pollutants and toxic metals released from the power plant was also demonstrated. The study also highlighted the government initiatives and policies regarding coal power operation and generation. Lastly, the study focused on guiding coal power plant owners and policymakers in identifying the essential cues for the risk assessment and management. The current study found an association between environmental and human health risks due to power generation, which needs intervention from the scientific and medical fields to jointly address public concerns. It is also suggested that future research should concentrate on exposure assessment techniques by integrating source-identification and geographic information systems to assess the health effects of different contaminants from power plants and to mitigate their adverse impact.

Aiming to Improve Equity in Pulmonary Health: Cystic Fibrosis

This review summarizes the evidence of health disparities in cystic fibrosis (CF), an autosomal recessive genetic disorder with substantial variation in disease progression and outcomes. We review disparities by race, ethnicity, socioeconomic status, geographic location, gender identity, or sexual orientation documented in the literature. We outline the mechanisms that generate and perpetuate such disparities across levels and domains of influence and assess the implications of this evidence. We then recommend strategies for improving equity in CF outcomes, drawing on recommendations for the general population and considering approaches specific to people living with CF.

In vitro bio-characterization of solid lipid nanoparticles of favipiravir in A549 human lung epithelial cancer cells

Objectives

Lung cancer is a leading cause of mortality worldwide. In lung cancer treatment, nebulized solid lipid nanoparticles may be a viable drug delivery method, helping the drug reach sites of action, and improving its inhalation efficiency and pulmonary deposition. This research focused on evaluating the effectiveness of solid lipid nanoparticles of favipiravir (Fav-SLNps) in facilitating drug delivery to sites of action in lung cancer treatment.

Methods

The hot-evaporation method was used to formulate Fav-SLNps. The in vitro cell viability, anti-cancer effects, and cellular uptake activity were evaluated in A549 human lung adenocarcinoma cells treated with the Fav-SLNp formulation.

Results

The Fav-SLNps were formulated successfully. Importantly, Fav-SLNps at a concentration of 322.6 μg/ml were found to be safe and non-toxic toward A549 cells in vitro. The formulation had potential anti-proliferative properties via increasing the proportions of cells in G2/M and G0/G1 phases to 1.20 and 1.13 times those in untreated cells. Additionally, Fav-SLNp treatment significantly induced necrosis in A549 cells. Furthermore, the use of SLNps in the Fav formulation resulted in a macrophage drug uptake 1.23 times that of the free drug.

Conclusion

Our results confirmed the internalization and anti-cancer activity of the Fav-SLNp formulation in the A549 lung cancer cell line. Our findings suggest that Fav-SLNps could potentially be used as lung cancer treatment to facilitate drug delivery to sites of action in the lungs.

Information entropy tradeoffs for efficient uncertainty reduction in estimates of air pollution mortality

Implementing effective policy to protect human health from the adverse effects of air pollution, such as premature mortality, requires reducing the uncertainty in health outcomes models. Here we present a novel method to reduce mortality uncertainty by increasing the amount of input data of air pollution and health outcomes, and then quantifying tradeoffs associated with the different data gained. We first present a study of long-term mortality from fine particulate matter (PM_2.5) based on simulated data, followed by a real-world application of short-term PM_2.5-related mortality in an urban area. We employ information yield curves to identify which variables more effectively reduce mortality uncertainty when increasing information. Our methodology can be used to explore how specific pollution scenarios will impact mortality and thus improve decision-making. The proposed framework is general and can be applied to any real case-scenario where knowledge in pollution, demographics, or health outcomes can be augmented through data acquisition or model improvements to generate more robust risk assessments.

Socioeconomic determinants of respiratory health in patients with cystic fibrosis: implications for treatment strategies

INTRODUCTION

Great variation exists in the progression and outcomes of cystic fibrosis (CF) lung disease, due to both genetic and environmental influences. Social determinants mediate environmental exposures and treatment success; people with CF from socioeconomically disadvantaged backgrounds have worse health and die younger than those in more advantaged positions.

AREAS COVERED

This paper reviews the literature on the mechanisms that are responsible for generating and sustaining disparities in CF health, and the ways by which social determinants translate into health advantages or disadvantages in people with CF. The authors make recommendations for addressing social risk factors in CF clinical practice.

EXPERT OPINION

Socioeconomic factors are not dichotomous and their impact is felt at every step of the social ladder. CF care programs need to adopt a systematic protocol to screen for health-related social risk factors, and then connect patients to available resources to meet individual needs. Considerations such as daycare, schooling options, living and working conditions, and opportunities for physical exercise and recreation as well as promotion of self-efficacy are often overlooked. In addition, advocacy for changes in public policies on health insurance, environmental regulations, social welfare, and education would all help address the root causes of CF health inequities.

Health impact assessment of air pollution in an area of the largest coal mine in Brazil

Coal exploration and burning activities are among the activities with the greatest potential to cause atmospheric pollution due to the combustion process of this mineral and the consequent release of particles that, in significant quantities, can pose a potential health risk, mainly respiratory and cardiovascular diseases. The Candiota region, in the extreme south of Brazil, concentrates 40% of the national reserves of mineral coal, and its burning is capable of releasing air pollutants, including particulate matter (PM). Some environmental and epidemiological studies have been carried out in the region, but so far, there is no investigation to estimate the impact of PM on health outcomes. The current study aimed to estimate the mortality attributed to the PM, as well as the benefits in health indicators associated with the reduction of air pollution to the limits set forth in local legislation and the WHO. Daily data on PM levels collected from an air quality monitoring station over a year were used, as well as population data and health indicators from 7 cities influenced by mining activities, such as total mortality and cardiovascular diseases and hospitalizations for cardiac and respiratory problems. In a scenario where PM levels are within legal limits, a percentage greater than 11% of cardiovascular deaths was attributed to pollution by PM2.5, and the reduction in PM10 and PM2.5 levels may be responsible for the increase in the expectation of life in up to 17 months and monetary gains of more than $ 24 million, due to the reduction in hospitalizations and mortality. Studies of this nature should be important tools made available to decision-makers, with a view to improving environmental laws and a consequent improvement in the quality of life and health indicators of the population.

Particle formation due to brake wear, influence on the people health and measures for their reduction: a review

For achieving the desired vehicle speed, the IC engine is very important, while for further vehicle speed maintaining and adaptation to road conditions, the braking system is important. With each brake's activation, wear products are forming, which are very harmful to the environment, because they can contain heavy metals. The braking working parameters (initial speed and braking pressure) are beside the achieved temperature in contact par, the most responsible, for particle formation and their release into the air. The particles forming can be divided by size on coarse, fine, and ultrafine particles, and which were observed in the paper. However, the greatest accent was placed on coarse and fine particles. For the determination of the composition of wear products, most often, laboratory tests were used. Particle composition greatly depends on the composition of brake pads, which can consist of about 30 components, and where some of these components have very unfavourable effects on people's health. So today, many researches are focused on finding such composition for brake pads, which will wear as less as possible, without disturbing the basic tribological properties. The conclusion of this paper shows that the applied materials for manufacturing the braking system are very important, as well as the construction, for the reduction of particle emission.

Design and Characterization of Atorvastatin Dry Powder Formulation as a potential Lung Cancer Treatment

Lung cancer is the leading cause of cancer death. Many studies have shown the beneficial effects of Atorvastatin in decreasing the mortality risk and improving survival among patients with lung cancer. This research paper focuses on improving AVT cytotoxic activity and cellular uptake by developing mannitol microcarriers as a promising drug delivery system for lung cancer treatment and, studying the impact of improving inhalation deposition on the delivery and Dry Powder formulations efficiency. The AVT loaded mannitol (AM) microparticles (AVT-AM) formulation was prepared by spray drying and characterized for its physicochemical properties and aerodynamic deposition. The results revealed that the AVT-AM formulation has good flow properties and aerosol deposition with a particle size of 3418 nm ± 26.86. The formulation was also assessed in vitro for cytotoxicity effects (proliferation, apoptosis, and cell cycle progression) on A549 human lung adenocarcinoma. Compared with free AVT, the AVT-AM formulation has significantly higher cellular uptake and anti-cancer properties by disrupting cell cycle progression via either apoptosis or cell cycle arrest in the G2/M phase. This study shows that AVT loaded mannitol microcarriers may provide a potentially effective and sustained pulmonary drug delivery for lung cancer treatment.

Assessing the value of complex refractive index and particle density for calibration of low-cost particle matter sensor for size-resolved particle count and PM2.5 measurements

Low-cost optical scattering particulate matter (PM) sensors report total or size-specific particle counts and mass concentrations. The PM concentration and size are estimated by the original equipment manufacturer (OEM) proprietary algorithms, which have inherent limitations since particle scattering depends on particles' properties such as size, shape, and complex index of refraction (CRI) as well as environmental parameters such as temperature and relative humidity (RH). As low-cost PM sensors are not able to resolve individual particles, there is a need to characterize and calibrate sensors' performance under a controlled environment. Here, we present improved calibration algorithms for Plantower PMS A003 sensor for mass indices and size-resolved number concentration. An aerosol chamber experimental protocol was used to evaluate sensor-to-sensor data reproducibility. The calibration was performed using four polydisperse test aerosols. The particle size distribution OEM calibration for PMS A003 sensor did not agree with the reference single particle sizer measurements. For the number concentration calibration, the linear model without adjusting for the aerosol properties and environmental conditions yields an absolute error (NMAE) of ~ 4.0% compared to the reference instrument. The calibration models adjusted for particle CRI and density account for non-linearity in the OEM's mass concentrations estimates with NMAE within 5.0%. The calibration algorithms developed in this study can be used in indoor air quality monitoring, occupational/industrial exposure assessments, or near-source monitoring scenarios where field calibration might be challenging.

The Built Environment and Health in Low- and Middle-Income Countries: a Review on Quantitative Health Impact Assessments

PURPOSE OF REVIEW

Features and attributes of the built environment (BE) impact positively and negatively on health, especially in cities facing unprecedented urban population growth and mass motorization. A common approach to assess the health impacts of built environment is health impact assessment (HIA), but it is rarely used in low- and middle-income countries (LMICs) where urbanization rates are fastest. This article reviews selected HIA case studies from LMICs and reports the methods and tools used to support further implementation of quantitative HIAs in cities of LMICs.

RECENT FINDINGS

In total, 24 studies were reviewed across Algeria, Brazil, China, India, Iran, Kenya, Thailand, Turkey, and Mauritius. HIAs examine specific pathways through which the built environment acts: air pollution, noise, physical activity, and traffic injury. Few HIAs of BE addressed more than one exposure pathway at a time, and most studies focused on air pollution across the sectors of transport and energy. A wide number of tools were used to conduct exposure assessment, and different models were applied to assess health impacts of different exposures. Those HIAs rely on availability of local concentration data and often use models that have set exposure-response functions (ERFs). ERFs were not adapted to local populations except for HIAs conducted in China. HIAs of BE are being successfully conducted in LMICs with a variety of tools and datasets. Scaling and expanding quantitative health impact modeling in LMICs will require further study on data availability, adapted models/tools, low technical capacity, and low policy demand for evidence from modeling studies. As case studies with successful use of evidence from modeling emerge, the uptake of health impact modeling of BE is likely to increase in favor of people and planet.

Long-Term Effects of Fine Particles on Mortality: Insights from 1984

I review an important study that Professor Evans published early in his career examining the role of cross-sectional mortality studies in air pollution risk assessment. At a time when both risk assessment and particle effects on mortality were controversial, John's thoughtful analysis of the issues and data relevant to assessing long-term mortality risks from airborne particles provides a comprehensive primer that is still relevant today. The paper includes a critical literature review, a meta-analysis of published particle effect estimates, and a reanalysis of landmark cross-sectional mortality data set. EPA criteria documents and related literature had largely discounted the cross-sectional mortality findings on the basis of criticisms about exposure assessment and control for confounding. John's analysis reached a different conclusion, that is, "we are of the opinion that the cross-sectional studies reflect a causal relationship between exposure to airborne particles and premature mortality. From our point of view it is as likely that parameters have been underestimated … as that they are overestimated due to confounding." The paper acknowledged the impossibility of precisely quantifying the long-term mortality effect of particle air pollution, and that there is a need for further research utilizing alternative approaches. These conclusions foreshadow the emergence, a decade later, of the influential particulate matter (PM) mortality findings from the Harvard Six Cities and American Cancer Society cohort studies. I conclude by suggesting that well designed cross-sectional studies could play a role in identifying exposure-response associations in resource-poor settings where there is a paucity of local evidence to support air pollution regulations.

Mortality Benefits and Control Costs of Improving Air Quality in Mexico City: The Case of Heavy Duty Diesel Vehicles

Diesel vehicles are significant contributors to air pollution in Mexico City. We estimate the costs and mortality benefits of retrofitting heavy-duty vehicles with particulate filters and oxidation catalysts. The feasibility and cost-effectiveness of controls differ by vehicle model-year and type. We evaluate 1985 to 2014 model-year vehicles from 10 vehicle classes and five model-year groups. Our analysis shows that retrofitting all vehicles with the control that maximizes expected net benefits for that vehicle type and model-year group has the potential to reduce emissions of primary fine particles (PM_2.5 ) by 950 metric tons/year; cut the population-weighted annual mean concentration of PM_2.5 in Mexico City by 0.90 µg/m³ ; reduce the annual number of deaths attributable to air pollution by over 80; and generate expected annual health benefits of close to 250 million US$. These benefits outweigh expected costs of 92 million US$ per year. Diesel retrofits are but one step that should viewed in the context of other efforts--such as development of an integrated public transportation system, promotion of the rational use of cars, reduction of emissions from industrial sources and fires, and redesign of the Mexico City Metropolitan Area to reduce urban sprawl--that must be analyzed and implemented to substantially control air pollution and protect public health. Even if considering other potential public health interventions, which would offer greater benefits at the same or lower costs, only by conducting, promoting, and publishing this sort of analyses, we can make strides to improve public health cost-effectively.

Reproducible Research: A Retrospective

Advances in computing technology have spurred two extraordinary phenomena in science: large-scale and high-throughput data collection coupled with the creation and implementation of complex statistical algorithms for data analysis. These two phenomena have brought about tremendous advances in scientific discovery but have raised two serious concerns. The complexity of modern data analyses raises questions about the reproducibility of the analyses, meaning the ability of independent analysts to recreate the results claimed by the original authors using the original data and analysis techniques. Reproducibility is typically thwarted by a lack of availability of the original data and computer code. A more general concern is the replicability of scientific findings, which concerns the frequency with which scientific claims are confirmed by completely independent investigations. Although reproducibility and replicability are related, they focus on different aspects of scientific progress. In this review, we discuss the origins of reproducible research, characterize the current status of reproducibility in public health research, and connect reproducibility to current concerns about the replicability of scientific findings. Finally, we describe a path forward for improving both the reproducibility and replicability of public health research in the future.

Guidance to Reduce the Cardiovascular Burden of Ambient Air Pollutants: A Policy Statement From the American Heart Association

In 2010, the American Heart Association published a statement concluding that the existing scientific evidence was consistent with a causal relationship between exposure to fine particulate matter and cardiovascular morbidity and mortality, and that fine particulate matter exposure is a modifiable cardiovascular risk factor. Since the publication of that statement, evidence linking air pollution exposure to cardiovascular health has continued to accumulate and the biological processes underlying these effects have become better understood. This increasingly persuasive evidence necessitates policies to reduce harmful exposures and the need to act even as the scientific evidence base continues to evolve. Policy options to mitigate the adverse health impacts of air pollutants must include the reduction of emissions through action on air quality, vehicle emissions, and renewable portfolio standards, taking into account racial, ethnic, and economic inequality in air pollutant exposure. Policy interventions to improve air quality can also be in alignment with policies that benefit community and transportation infrastructure, sustainable food systems, reduction in climate forcing agents, and reduction in wildfires. The health care sector has a leadership role in adopting policies to contribute to improved environmental air quality as well. There is also potentially significant private sector leadership and industry innovation occurring in the absence of and in addition to public policy action, demonstrating the important role of public-private partnerships. In addition to supporting education and research in this area, the American Heart Association has an important leadership role to encourage and support public policies, private sector innovation, and public-private partnerships to reduce the adverse impact of air pollution on current and future cardiovascular health in the United States.

Mitigating the air pollution effect? The remarkable decline in the pollution-mortality relationship in Hong Kong

Using transboundary pollution from mainland China as an instrument, we show that air pollution leads to higher cardio-respiratory mortality in Hong Kong. However, the air pollution effect has dramatically decreased over the past two decades: before 2003, a 10-unit increase in the Air Pollution Index could lead to a 3.1% increase in monthly cardio-respiratory mortality, but this effect has declined to 0.5% using recent data and is no longer statistically significant. Exploratory analyses suggest that a well-functioning medical system and immediate access to emergency services can help mitigate the contemporaneous effects of pollution on mortality.

Evaluation of Aldehydes, Polycyclic Aromatic Hydrocarbons, and PM2.5 Levels in Food Trucks: A Pilot Study

Background: The food truck industry has rapidly expanded in the United States and kitchen environments can contain harmful contaminants from cooking emissions. The objective of this study was to examine the levels of aldehydes, polycyclic aromatic hydrocarbons (PAHs), and Particulate Matter (PM)_2.5 generated from cooking process in food trucks. Methods: Area sampling was performed twice at two participating food trucks during work shifts. Nine aldehydes and eighteeen PAHs were analyzed according to the relevant standard methods while PM_2.5 was measured with a real time monitor. Ventilation performance of the food truck exhaust hoods was also investigated using a thermal anemometer. Findings: Formaldehyde was the only aldehyde detected in all samples with a concentration range of 7.16 to 53.68 µg/m³. No PAHs were detected above the limit of quantification. Average PM_2.5 concentrations ranged from 0.65 to 7.03 mg/m³. Food Trucks 1 and 2 have an average exhaust flow rate of 211 and 215 L/s per linear meter of hood, respectively. Conclusions/Application to practice: Overall, Food Truck 2 had consistently higher levels of aldehydes and PM_2.5 with comparable ventilation performance as Food Truck 1. The higher exposure levels of Food Truck 2 could possibly be attributed to a larger volume of food orders and the heavy duty cooking equipment with an exhaust flow rate below the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommendations. Although more investigations need to be performed, the findings could be used to raise awareness of food truck workers and health practitioners to reduce potential exposure risks.

Fine particulate air pollution and human mortality: 25+ years of cohort studies

Much of the key epidemiological evidence that long-term exposure to fine particulate matter air pollution (PM_2.5) contributes to increased risk of mortality comes from survival studies of cohorts of individuals. Although the first two of these studies, published in the mid-1990s, were highly controversial, much has changed in the last 25 + years. The objectives of this paper are to succinctly compile and summarize the findings of these cohort studies using meta-analytic tools and to address several of the key controversies. Independent reanalysis and substantial extended analysis of the original cohort studies have been conducted and many additional studies using a wide variety of cohorts, including cohorts constructed from public data and leveraging natural experiments have been published. Meta-analytic estimates of the mean of the distribution of effects from cohort studies that are currently available, provide substantial evidence of adverse air pollution associations with all-cause, cardiopulmonary, and lung cancer mortality.

The impact of long-term PM2.5 exposure on specific causes of death: exposure-response curves and effect modification among 53 million U.S. Medicare beneficiaries

BACKGROUND

The shape of the exposure-response curve for long-term ambient fine particulate (PM_2.5) exposure and cause-specific mortality is poorly understood, especially for rural populations and underrepresented minorities.

METHODS

We used hybrid machine learning and Cox proportional hazard models to assess the association of long-term PM_2.5 exposures on specific causes of death for 53 million U.S. Medicare beneficiaries (aged ≥65) from 2000 to 2008. Models included strata for age, sex, race, and ZIP code and controlled for neighborhood socio-economic status (SES) in our main analyses, with approximately 4 billion person-months of follow-up, and additionally for warm season average of 1-h daily maximum ozone exposures in a sensitivity analysis. The impact of non-traffic PM_2.5 on mortality was examined using two stage models of PM_2.5 and nitrogen dioxide (NO₂).

RESULTS

A 10 μg /m³ increase in 12-month average PM_2.5 prior to death was associated with a 5% increase in all-cause mortality, as well as an 8.8, 5.6, and 2.5% increase in all cardiovascular disease (CVD)-, all respiratory-, and all cancer deaths, respectively, in age, gender, race, ZIP code, and SES-adjusted models. PM_2.5 exposures, however, were not associated with lung cancer mortality. Results were not sensitive to control for ozone exposures. PM_2.5-mortality associations for CVD- and respiratory-related causes were positive and significant for beneficiaries irrespective of their sex, race, age, SES and urbanicity, with no evidence of a lower threshold for response or of lower Risk Ratios (RRs) at low PM_2.5 levels. Associations between PM_2.5 and CVD and respiratory mortality were linear and were higher for younger, Black and urban beneficiaries, but were largely similar by SES. Risks associated with non-traffic PM_2.5 were lower than that for all PM_2.5 and were null for respiratory and lung cancer-related deaths.

CONCLUSIONS

PM_2.5 was associated with mortality from CVD, respiratory, and all cancer, but not lung cancer. PM_2.5-associated risks of CVD and respiratory mortality were similar across PM_2.5 levels, with no evidence of a threshold. Blacks, urban, and younger beneficiaries were most vulnerable to the long-term impacts of PM_2.5 on mortality.

Short-Term Elevation of Fine Particulate Matter Air Pollution and Acute Lower Respiratory Infection

RATIONALE

Nearly 60% of U.S. children live in counties with particulate matter less than or equal to 2.5 μm in aerodynamic diameter (PM_2.5) concentrations above air quality standards. Understanding the relationship between ambient air pollution exposure and health outcomes informs actions to reduce exposure and disease risk.

OBJECTIVES

To evaluate the association between ambient PM_2.5 levels and healthcare encounters for acute lower respiratory infection (ALRI).

METHODS

Using an observational case-crossover design, subjects (n = 146,397) were studied if they had an ALRI diagnosis and resided on Utah's Wasatch Front. PM_2.5 air pollution concentrations were measured using community-based air quality monitors between 1999 and 2016. Odds ratios for ALRI healthcare encounters were calculated after stratification by ages 0-2, 3-17, and 18 or more years.

MEASUREMENTS AND MAIN RESULTS

Approximately 77% (n = 112,467) of subjects were 0-2 years of age. The odds of ALRI encounter for these young children increased within 1 week of elevated PM_2.5 and peaked after 3 weeks with a cumulative 28-day odds ratio of 1.15 per +10 μg/m³ (95% confidence interval, 1.12-1.19). ALRI encounters with diagnosed and laboratory-confirmed respiratory syncytial virus and influenza increased following elevated ambient PM_2.5 levels. Similar elevated odds for ALRI were also observed for older children, although the number of events and precision of estimates were much lower.

CONCLUSIONS

In this large sample of urban/suburban patients, short-term exposure to elevated PM_2.5 air pollution was associated with greater healthcare use for ALRI in young children, older children, and adults. Further exploration is needed of causal interactions between PM_2.5 and ALRI.

Toxicity potential of particles caused by particle-bound polycyclic aromatic hydrocarbons (PPAHs) at two roadside locations and relationship with traffic

This study assessed exposure by the roadside to highly toxic particle-bound polycyclic aromatic hydrocarbons (PPAHs) that are known to adsorb preferentially on fine particles, aerodynamic diameter (d_p ≤ 1 μm). The real-time air quality measurements were conducted in March, April, and May 2015 in Kanpur at two busy roadside locations: one outside IIT Kanpur main gate, IG, and another by a residential area, M3. The locations show varying land use type and traffic density. Higher averaged daily concentrations of PM₁₀, PM_2.5, and PM₁ were observed at IG (PM₁₀ 700-800 μg/m³) owing to nature and high density of traffic, and occurrence of biomass burning nearby. Statistically significant relation (R² > 90%, p < 0.05) between PM₁ and PM_2.5 highlights the influence of mobile sources on particle load at IG. IG, the busier location, had higher daily averaged concentration of aggregate PPAHs (104 ng/m³) than M3 which is located near a residential area (38 ng/m³). In contrast, the higher average daily value of PC/DC ratio (mass per unit surface area of PPAHs on nanoparticles) at M3 (4.87 ng/mm²) than at IG (4.08 ng/mm²) suggests that PAHs of greater mass occur on particles at M3. Finer particles are known to adsorb pollutants of a larger mass that are likely to be more toxic in case of PAHs suggest that ambient air at M3 has more toxicity potential. However, this inference is not based on chemical analyses, and chemical characteristics must also be taken into account for the detailed assessment of health risk. The multiple path dosimetry model (MPPD-v3.04) reveals that the 99.02% of PM₁₀ inhaled, 77.01% of PM_2.5 and 34.54% of PM₁ are deposited in the outermost (head) region of the human respiratory tract.

Positive association between moderate altitude and chronic lower respiratory disease mortality in United States counties

For patients with chronic lower respiratory disease, hypobaric hypoxia at a high altitude is considered a risk factor for mortality. However, the effects of residing at moderately high altitudes remain unclear. We investigated the association between moderate altitude and chronic lower respiratory disease mortality. In particular, we examined the lower 48 United States counties for age-adjusted chronic lower respiratory disease mortality rates, altitude, and socioeconomic factors, including tobacco use, per capita income, population density, sex ratio, unemployment, poverty, and education between 1979 and 1998. The socioeconomic factors were incorporated into the correlation analysis as potential covariates. Considerable positive (R = 0.235; P <0.001) and partial (R = 0.260; P <0.001) correlations were observed between altitude and chronic lower respiratory disease mortality rate. In the subgroup with high COPD prevalence subgroup, even stronger positive (R = 0.346; P <0.001) and partial (R = 0.423, P <0.001) correlations were observed. Multivariate regression analysis of all available socioeconomic factors revealed that additional knowledge on altitude improved the adjusted R2 values from 0.128 to 0.186 for all counties and from 0.301 to 0.421 for counties with high COPD prevalence. We concluded that in the lower 48 United States counties, even a moderate altitude may pose considerable risks in patients with chronic lower respiratory disease.

Assessment and economic valuation of air pollution impacts on human health over Europe and the United States as calculated by a multi-model ensemble in the framework of AQMEII3

The impact of air pollution on human health and the associated external costs in Europe and the United States (US) for the year 2010 are modeled by a multi-model ensemble of regional models in the frame of the third phase of the Air Quality Modelling Evaluation International Initiative (AQMEII3). The modeled surface concentrations of O3, CO, SO2 and PM2.5 are used as input to the Economic Valuation of Air Pollution (EVA) system to calculate the resulting health impacts and the associated external costs from each individual model. Along with a base case simulation, additional runs were performed introducing 20 % anthropogenic emission reductions both globally and regionally in Europe, North America and east Asia, as defined by the second phase of the Task Force on Hemispheric Transport of Air Pollution (TF-HTAP2). Health impacts estimated by using concentration inputs from different chemistry-transport models (CTMs) to the EVA system can vary up to a factor of 3 in Europe (12 models) and the United States (3 models). In Europe, the multi-model mean total number of premature deaths (acute and chronic) is calculated to be 414 000, while in the US, it is estimated to be 160 000, in agreement with previous global and regional studies. The economic valuation of these health impacts is calculated to be EUR 300 billion and 145 billion in Europe and the US, respectively. A subset of models that produce the smallest error compared to the surface observations at each time step against an all-model mean ensemble results in increase of health impacts by up to 30 % in Europe, while in the US, the optimal ensemble mean led to a decrease in the calculated health impacts by ~ 11 %. A total of 54 000 and 27 500 premature deaths can be avoided by a 20 % reduction of global anthropogenic emissions in Europe and the US, respectively. A 20 % reduction of North American anthropogenic emissions avoids a total of ~ 1000 premature deaths in Europe and 25 000 total premature deaths in the US. A 20 % decrease of anthropogenic emissions within the European source region avoids a total of 47 000 premature deaths in Europe. Reducing the east Asian anthropogenic emissions by 20 % avoids ~ 2000 total premature deaths in the US. These results show that the domestic anthropogenic emissions make the largest impacts on premature deaths on a continental scale, while foreign sources make a minor contribution to adverse impacts of air pollution.

Relationship between fine particulate matter, weather condition and daily non-accidental mortality in Shanghai, China: A Bayesian approach

There are concerns that the reported association of ambient fine particulate matter (PM_2.5) with mortality might be a mixture of PM_2.5 and weather conditions. We evaluated the effects of extreme weather conditions and weather types on mortality as well as their interactions with PM_2.5 concentrations in a time series study. Daily non-accidental deaths, individual demographic information, daily average PM_2.5 concentrations and meteorological data between 2012 and 2014 were obtained from Shanghai, China. Days with extreme weather conditions were identified. Six synoptic weather types (SWTs) were generated. The generalized additive model was set up to link the mortality with PM_2.5 and weather conditions. Parameter estimation was based on Bayesian methods using both the Jeffreys’ prior and an informative normal prior in a sensitivity analysis. We estimate the percent increase in non-accidental mortality per 10 μg/m³ increase in PM_2.5 concentration and constructed corresponding 95% credible interval (CrI). In total, 336,379 non-accidental deaths occurred during the study period. Average daily deaths were 307. The results indicated that per 10 μg/m³ increase in daily average PM_2.5 concentration alone corresponded to 0.26–0.35% increase in daily non-accidental mortality in Shanghai. Statistically significant positive associations between PM_2.5 and mortality were found for favorable SWTs when considering the interaction between PM_2.5 and SWTs. The greatest effect was found in hot dry SWT (percent increase = 1.28, 95% CrI: 0.72, 1.83), followed by warm humid SWT (percent increase = 0.64, 95% CrI: 0.15, 1.13). The effect of PM_2.5 on non-accidental mortality differed under specific extreme weather conditions and SWTs. Environmental policies and actions should take into account the interrelationship between the two hazardous exposures.

A review of the impact of fireworks on particulate matter in ambient air

To determine the impact of fireworks (FW) and firecrackers (FC) on particulate matter (PM) in ambient air, we reviewed evidence related to ambient PM during FW/FC periods; specifically, PM concentration, size, morphology, chemical components, including water-soluble ions and trace metals, and associated human health risks caused by exposure to FW/FC PM were reviewed. A large body of research suggests that outdoor ambient PM levels increase significantly during FW/FC displays. Furthermore, FW/FC PM remains suspended in the air, contributing to high PM concentrations for a long period. Increased PM from burning FW and FC mainly comprises fine and ultrafine spherical particles. Elevated levels of various trace metals, ions, elemental carbon (EC), organic carbon (OC), and organics in PM are present during FW/FC periods.

IMPLICATIONS

Unique physical and chemical properties of ambient PM during short-term FW/FC burning can lead to a substantial increase in adverse health effects compared with during non-FW/FC periods. Further epidemiological and toxicological research into the potential health effects resulting from exposure to various pollutants from FW/FC is vital. Geographical distributions of PM concentrations during FW displays highlight the importance of implementing PM controls at the regional level and formulating stricter protective environmental legislation, particularly in Asian (e.g., India, China, or Taiwan) where festivals are not the only periods celebrated with FW/FC.

Caracterización química de material particulado PM10 en la atmósfera de La Guajira Colombia

Durante el año 2013, se realizó un estudio en La Guajira, Colombia, con el fin de determinar  la composición química del  material particulado PM10, producto de las actividades mineras de carbón a cielo abierto que ocupan casi 30% del territorio; también se evaluó su asociación a fuentes naturales y antropogénicas. La recolección de filtros se realizó por medio de un sistema de monitoreo conformado por catorce estaciones mediante equipos muestreadores de alto volumen PM10 (Thermo Scientific VFC-PM10 High Volume Air Sampler). Para el análisis, los filtros de cuarzo fueron sometidos a extracción acuosa en caliente y se determinaron los iones por espectrofotometría UV-VIS e ICP-MS. Las concentraciones más altas corresponden a la especies SO42- (0,25 µg/m3), Cl- (0,19 µg/m3), NH4+ (0,032 µg/m3), Na+ (1,98µg/m3), Ca2+ (0,40 µg/m3) y Mg2+ (0,31 µg/m3). Los resultados indican que las principales fuentes responsables del material particulado corresponden al aerosol marino impulsado por las corrientes (Cl- y Na+) de origen natural, y las actividades agrícolas, pecuarias (NH4+) y mineras (SO42-, Ca2+ y Mg2+) de origen antropogénico.

Characterizing the Long-Term PM2.5 Concentration-Response Function: Comparing the Strengths and Weaknesses of Research Synthesis Approaches

The magnitude, shape, and degree of certainty in the association between long-term population exposure to ambient fine particulate matter (PM2.5 ) and the risk of premature death is one of the most intensely studied issues in environmental health. For regulatory risk analysis, this relationship is described quantitatively by a concentration-response (C-R) function that relates exposure to ambient concentrations with the risk of premature mortality. Four data synthesis techniques develop the basis for, and derive, this function: systematic review, expert judgment elicitation, quantitative meta-analysis, and integrated exposure-response (IER) assessment. As part of an academic workshop aiming to guide the use of research synthesis approaches, we developed criteria with which to evaluate and select among the approaches for their ability to inform policy choices. These criteria include the quality and extent of scientific support for the method, its transparency and verifiability, its suitability to the policy problem, and the time and resources required for its application. We find that these research methods are both complementary and interdependent. A systematic review of the multidisciplinary evidence is a starting point for all methods, providing the broad conceptual basis for the nature, plausibility, and strength of the associations between PM exposure and adverse health effects. Further, for a data-rich application like PM2.5 and premature mortality, all three quantitative approaches can produce estimates that are suitable for regulatory and benefit analysis. However, when fewer data are available, more resource-intensive approaches such as expert elicitation may be more important for understanding what scientists know, where they agree or disagree, and what they believe to be the most important areas of uncertainty. Whether implicitly or explicitly, all require considerable judgment by scientists. Finding ways for all these methods to acknowledge, appropriately elicit, and examine the implications of that judgment would be an important step forward for research synthesis.

Chemical composition of PM2.5 from two tunnels with different vehicular fleet characteristics

The chemical compositions of PM2.5 including OC, EC, water soluble ions, elements, and organic components such as polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes, emitted in Wuzushan (WZS) and Kuixinglou (KXL) tunnels were determined. WZS tunnel is a major route for diesel vehicles traveling, while KXL tunnel has limited to diesel vehicles. The results showed that the proportions of the different constituents of PM2.5 in the Wuzushan (WZS) tunnel were OC (27.7%), EC (32.1%), elements (13.9%), and water soluble ions (9.2%). Whereas the chemical profile of PM2.5 in the Kuixinglou (KXL) tunnel was OC (17.7%), EC (10.4%), elements (8.90%), and water soluble ions (8.87%). The emission factors (EFs) of PM2.5 and proportions of SO4(2-) and Pb were decreased by vehicle emission standards and fuel quality policy in China, and the higher molecular weight PAHs (4+5+6 rings) were more abundant than the lower molecular weight PAHs (2+3 rings) in the two tunnels. The proportions of 17A(H)-21B(H)-30-Norhopane and 17A(H)-21B(H)-Hopane in the hopane and sterane were not dependent on the vehicles types. In addition, specific composition profiles for PM2.5 from gasoline-fueled vehicles (GV) and diesel-fueled vehicles (DV) emissions were drafted, which indicated that OC (0.974mg·veh(-1)·km(-1)) was the most abundant component in PM2.5, followed by Fe, Cl(-), and Mg for GV. The relative proportions of the different constituents in the PM2.5 for DV were EC (35.9%), OC (27.2%), elements (12.8%), and water soluble ions (11.7%). Both the PM2.5 EFs and EC proportions in DV were higher than those in GV, and the HMW PAHs were the dominant PAHs for both GV and DV. The PM2.5 emissions from the vehicles in Yantai were 581±513tons to 1353±1197tons for GV, and 19,627±2477tons to 23,042±2887tons for DV, respectively.

Seasonal Variability of Carbon Monoxide (CO) in the Ambient Environment of IMO State, Nigeria

The air quality of four areas in Imo State with a total of twenty two locations was monitored for a period six months with respect to CO level using Gasman air monitor (Crowcon Instruments Ltd, England. The air quality monitoring was conducted in the morning, afternoon and evening hours within dry and wet seasons in order to elucidate the variability of this atmospheric pollutant in the study locations. The results obtained showed significant variation of the air pollutant in the morning, afternoon and evening including within the twenty four weeks, and between dry and wet seasons. The mean values of CO in the dry season are in the order Egbema > Okigwe > Owerri > Orlu, while the order for the mean CO level in wet season is Okigwe > Orlu > Egbema > Owerri. Elevated concentration of CO was observed in the study areas above 10 ppm, the Nigerian National ambient air quality standard. This observation calls for health and environmental concern. Hence, anthropogenic activities and fugitive emission sources of atmospheric pollutants such as increased vehicular traffic, biomass combustion, use of electric power generating sets, leakages from incinerators and flare stacks should be seriously monitored.

The Effects of Climate Change on Patients With Chronic Lung Disease. A Systematic Literature Review

BACKGROUND

Ever since higher overall mortality rates due to heat stress were reported during the European heat waves of 2003 and 2006, the relation between heat waves and disease-specific events has been an object of scientific study. The effects of heat waves on the morbidity and mortality of persons with chronic lung disease remain unclear.

METHODS

We conducted a systematic search using PubMed, the Cochrane Library, and Google Advanced Search to identify relevant studies published between 1990 and 2015. The reference lists of the primarily included articles were searched for further pertinent articles. All articles were selected according to the PRISMA guidelines. The heat-wave-related relative excess mortality was descriptively expressed as a mean daily rate ratio ([incidence 1]/[incidence 2]), and the cumulative excess risk (CER) was expressed in percent.

RESULTS

33 studies with evaluable raw data concerning the effect of heat waves on patients with chronic lung disease (chronic obstructive pulmonary disease, bronchial asthma, pulmonary arterial hypertension, and idiopathic pulmonary fibrosis) were analyzed in this review. By deriving statistics from the overall data set, we arrived at the conclusion that future heat waves will-with at least 90% probability-result in a mean daily excess mortality (expressed as a rate ratio) of at least 1.018, and-with 50% probability-in a mean daily excess mortality of at least 1.028. These figures correspond, respectively, to 1.8% and 2.8% rises in the daily risk of death.

CONCLUSION

Heat waves significantly increase morbidity and mortality in patients with chronic lung disease. The argument that the excess mortality during heat waves is compensated for by a decrease in mortality in the subsequent weeks/months (mortality displacement) should not be used as an excuse for delay in implementing adaptive strategies to protect lung patients from this risk to their health.

Dynamics of Particle Size on Inhalation of Environmental Aerosol and Impact on Deposition Fraction

Inhalation of elevated levels of particulate air pollution has been shown to elicit the onset of adverse health effects in humans, where the magnitude of the response is a product of where in the lung the particulate dose is delivered. At any point in time during inhalation the depositional flux of the aerosol is a function of the radius of the droplet, thus a detailed understanding of the rate and magnitude of the mass flux of water to the droplet during inhalation is crucial. In this study, we assess the impact of aerosol hygroscopicity on deposited dose through the inclusion of a detailed treatment of the mass flux of water to account for the dynamics of particle size in a modified version of the standard International Commission on Radiological Protection (ICRP) whole lung deposition model. The ability to account for the role of the relative humidity (RH) of the aerosol prior to, and during, inhalation on the deposition pattern is explored, and found to have a significant effect on the deposition pattern. The model is verified by comparison to previously published measurements, and used to demonstrate that ambient RH affects where in the lung indoor particulate air pollution is delivered.

Estimating PM2.5 Concentrations in Xi'an City Using a Generalized Additive Model with Multi-Source Monitoring Data

Particulate matter with an aerodynamic diameter <2.5 μm (PM2.5) represents a severe environmental problem and is of negative impact on human health. Xi'an City, with a population of 6.5 million, is among the highest concentrations of PM2.5 in China. In 2013, in total, there were 191 days in Xi'an City on which PM2.5 concentrations were greater than 100 μg/m3. Recently, a few studies have explored the potential causes of high PM2.5 concentration using remote sensing data such as the MODIS aerosol optical thickness (AOT) product. Linear regression is a commonly used method to find statistical relationships among PM2.5 concentrations and other pollutants, including CO, NO2, SO2, and O3, which can be indicative of emission sources. The relationships of these variables, however, are usually complicated and non-linear. Therefore, a generalized additive model (GAM) is used to estimate the statistical relationships between potential variables and PM2.5 concentrations. This model contains linear functions of SO2 and CO, univariate smoothing non-linear functions of NO2, O3, AOT and temperature, and bivariate smoothing non-linear functions of location and wind variables. The model can explain 69.50% of PM2.5 concentrations, with R2 = 0.691, which improves the result of a stepwise linear regression (R2 = 0.582) by 18.73%. The two most significant variables, CO concentration and AOT, represent 20.65% and 19.54% of the deviance, respectively, while the three other gas-phase concentrations, SO2, NO2, and O3 account for 10.88% of the total deviance. These results show that in Xi'an City, the traffic and other industrial emissions are the primary source of PM2.5. Temperature, location, and wind variables also non-linearly related with PM2.5.

Is Carbon Black a Suitable Model Colloidal Substrate for Diesel Soot?

Soot formation in diesel engines is known to cause premature engine wear. Unfortunately, genuine diesel soot is expensive to generate, so carbon blacks are often used as diesel soot mimics. Herein, the suitability of a commercial carbon black (Regal 250R) as a surrogate for diesel soot dispersed in engine base oil is examined in the presence of two commonly used polymeric lubricant additives. The particle size, morphology, and surface composition of both substrates are assessed using BET surface area analysis, TEM, and XPS. The extent of adsorption of a poly(ethylene-co-propylene) (dOCP) statistical copolymer or a polystyrene-block-poly(ethylene-co-propylene) (PS-PEP) diblock copolymer onto carbon black or diesel soot from n-dodecane is compared indirectly using a supernatant depletion assay technique via UV spectroscopy. Thermogravimetric analysis is also used to directly determine the extent of copolymer adsorption. Degrees of dispersion are examined using optical microscopy, TEM, and analytical centrifugation. SAXS studies reveal some structural differences between carbon black and diesel soot particles. The mean radius of gyration determined for the latter is significantly smaller than that calculated for the former, and in the absence of any copolymer, diesel soot suspended in n-dodecane forms relatively loose mass fractals compared to carbon black. SAXS provides evidence for copolymer adsorption and indicates that addition of either copolymer transforms the initially compact agglomerates into relatively loose aggregates. Addition of dOCP or PS-PEP does not significantly affect the structure of the carbon black primary particles, with similar results being observed for diesel soot. In favorable cases, remarkably similar data can be obtained for carbon black and diesel soot when using dOCP and PS-PEP as copolymer dispersants. However, it is not difficult to identify simple copolymer-particle-solvent combinations for which substantial differences can be observed. Such observations are most likely the result of dissimilar surface chemistries, which can profoundly affect the colloidal stability.

Effects of fine particles on children's hospital admissions for respiratory health in Seville, Spain

This study analyzes the influence of fine particles PM2.5 on nonprogrammed children's hospital admissions that occurred in the city of Seville between 2007 and 2011, and makes an economic assessment of the cost of the children's hospital admissions for respiratory causes due to particle pollution. The PM2.5 dose-response functions for each type of hospital admission were used to quantify the cost of the hospital admissions. It can be concluded that the PM2.5 concentrations have negative effects on bronchiolitis, pneumonia, asthma, and bronchitis and other causes. A reduction of the daily average annual PM2.5 concentration from the existing levels to 10 µg/m3 would show an annual average reduction of children's hospital admissions due to respiratory diseases of 0.09 cases. This paper shows that the daily average cost for children hospital admissions due to respiratory reasons in the city of Seville, associated with daily average annual levels of PM2.5 above 10 µg/m3, was almost 200€.

IMPLICATIONS

Elevated PM2.5 concentrations in Seville have negative effects on children's bronchiolitis, pneumonia, asthma, and bronchitis and other causes. A reduction of the daily average annual PM2.5 concentration from the existing levels to 10 μg/m3 would suppose an annual mean reduction of children's hospital admissions due to respiratory diseases of 0.09 cases.

Historical Perspectives of the Causation of Lung Cancer: Nursing as a Bystander

Lung cancer is the leading cause of cancer deaths worldwide. Less-known forces are involved in the etiology of lung cancer and have relevant implications for providers in ameliorating care. The purpose of this article is to discuss theories of causation of lung cancer using historical analyses of the evolution of the disease and incorporating related explanations integrating the relationships of science, nursing, medicine, and society. Literature from 160 years was searched and Thagard's model of causation networks was used to exhibit how nursing and medicine were significant influences in lung cancer causation theory. Disease causation interfaces with sociological norms of behavior to form habits and rates of health behavior. Historically, nursing was detrimentally manipulated by the tobacco industry, engaging in harmful smoking behaviors, thus negatively affecting patient care. Understanding the underlying history behind lung cancer causation may empower nurses to play an active role in a patient's health.

Reduced-Rank Spatio-Temporal Modeling of Air Pollution Concentrations in the Multi-Ethnic Study of Atherosclerosis and Air Pollution

There is growing evidence in the epidemiologic literature of the relationship between air pollution and adverse health outcomes. Prediction of individual air pollution exposure in the Environmental Protection Agency (EPA) funded Multi-Ethnic Study of Atheroscelerosis and Air Pollution (MESA Air) study relies on a flexible spatio-temporal prediction model that integrates land-use regression with kriging to account for spatial dependence in pollutant concentrations. Temporal variability is captured using temporal trends estimated via modified singular value decomposition and temporally varying spatial residuals. This model utilizes monitoring data from existing regulatory networks and supplementary MESA Air monitoring data to predict concentrations for individual cohort members. In general, spatio-temporal models are limited in their efficacy for large data sets due to computational intractability. We develop reduced-rank versions of the MESA Air spatio-temporal model. To do so, we apply low-rank kriging to account for spatial variation in the mean process and discuss the limitations of this approach. As an alternative, we represent spatial variation using thin plate regression splines. We compare the performance of the outlined models using EPA and MESA Air monitoring data for predicting concentrations of oxides of nitrogen (NO _x )-a pollutant of primary interest in MESA Air-in the Los Angeles metropolitan area via cross-validated R². Our findings suggest that use of reduced-rank models can improve computational efficiency in certain cases. Low-rank kriging and thin plate regression splines were competitive across the formulations considered, although TPRS appeared to be more robust in some settings.

Individual-level concentrations of fine particulate matter chemical components and subclinical atherosclerosis: a cross-sectional analysis based on 2 advanced exposure prediction models in the multi-ethnic study of atherosclerosis

Long-term exposure to outdoor particulate matter with an aerodynamic diameter less than or equal to 2.5 µm (PM2.5) has been associated with cardiovascular morbidity and mortality. The chemical composition of PM2.5 that may be most responsible for producing these associations has not been identified. We assessed cross-sectional associations between long-term concentrations of PM2.5 and 4 of its chemical components (sulfur, silicon, elemental carbon, and organic carbon (OC)) and subclinical atherosclerosis, measured as carotid intima-media thickness (CIMT) and coronary artery calcium, between 2000 and 2002 among 5,488 Multi-Ethnic Study of Atherosclerosis participants residing in 6 US metropolitan areas. Long-term concentrations of PM2.5 components at participants' homes were predicted using both city-specific spatiotemporal models and a national spatial model. The estimated differences in CIMT associated with interquartile-range increases in sulfur, silicon, and OC predictions from the spatiotemporal model were 0.022 mm (95% confidence interval (CI): 0.014, 0.031), 0.006 mm (95% CI: 0.000, 0.012), and 0.026 mm (95% CI: 0.019, 0.034), respectively. Findings were generally similar using the national spatial model predictions but were often sensitive to adjustment for city. We did not find strong evidence of associations with coronary artery calcium. Long-term concentrations of sulfur and OC, and possibly silicon, were associated with CIMT using 2 distinct exposure prediction modeling approaches.

Size-resolved deposition rates for ultrafine and submicrometer particles in a residential housing unit

We estimated the size-resolved particle deposition rates for the ultrafine and submicrometer particles using a nonlinear regression method with unknown particle background concentrations during nonsourced period following a controlled sourced period in a well-mixed residential environment. A dynamic adjustment method in conjunction with the constant injection of tracer gas was used to maintain the air exchange rate at three target levels across the range of 0.61-1.24 air change per hour (ACH). Particle deposition was found to be highly size dependent with rates ranging from 0.68 ± 0.10 to 5.03 ± 0.20 h(-1) (mean ± s.e.). Our findings also suggest that the effect of air exchange on the particle deposition under enhanced air mixing was relatively small when compared to both the strong influence of size-dependent deposition mechanisms and the effects of mechanical air mixing by fans. Nonetheless, the significant association between air exchange and particle deposition rates for a few size categories indicated potential influence of air exchange on particle deposition. In the future, the proposed approach can be used to explore the separate or composite effects between air exchange and air mixing on particle deposition rates, which will contribute to improved assessment of human exposure to ultrafine and submicrometer particles.

Health and air quality benefits of policies to reduce coal-fired power plant emissions: a case study in North Carolina

We analyzed sulfur dioxide (SO2) emissions and fine particulate sulfate (PM2.5 sulfate) concentrations in the southeastern United States during 2002-2012, in order to evaluate the health impacts in North Carolina (NC) of the NC Clean Smokestacks Act of 2002. This state law required progressive reductions (beyond those mandated by federal rules) in pollutant emissions from NC's coal-fired power plants. Although coal-fired power plants remain NC's leading SO2 source, a trend analysis shows significant declines in SO2 emissions (-20.3%/year) and PM2.5 sulfate concentrations (-8.7%/year) since passage of the act. Emissions reductions were significantly greater in NC than in neighboring states, and emissions and PM2.5 sulfate concentration reductions were highest in NC's piedmont region, where 9 of the state's 14 major coal-fired power plants are located. Our risk model estimates that these air quality improvements decreased the risk of premature death attributable to PM2.5 sulfate in NC by about 63%, resulting in an estimated 1700 (95% CI: 1500, 1800) deaths prevented in 2012. These findings lend support to recent studies predicting that implementing the proposed federal Cross-State Air Pollution Rule (recently upheld by the U.S. Supreme Court) could substantially decrease U.S. premature deaths attributable to coal-fired power plant emissions.

Structured expert judgment to characterize uncertainty between PM2.5 exposure and mortality in Chile

To further the understanding and implementation of expert elicitation methods in the evaluation of public policies related to air pollution, the present study's main goal was to explore the potential strengths and weaknesses of structured expert judgment (SEJ) methodology as a way to derive a C-R function for chronic PM(2.5) exposure and premature mortality in Chile. Local experts were classified in two groups according to background and experience: physicians (Group 1) and engineers (Group 2). Experts were required to provide an estimate of the true percent change in nonaccidental mortality resulting from a permanent 1 μg/m(3) reduction in PM2.5 annual average ambient concentration across the entire Chilean territory. Cooke's Classical Model was used to combine the individual experts' assessments. Experts' mortality estimations varied markedly across groups: while experts in Group 1 delivered higher estimations than those reported in major international cohort studies, estimations from Group 2 were, to varying degrees, anchored to previous studies. Accordingly, combined distributions for each group and all experts were significantly different, due to the high sensitivity of the weighted distribution to experts' performance in calibration variables. Results of this study suggest that, while the use of SEJ has great potential for estimating C-R functions for chronic exposure to PM2.5 and premature mortality and its major sources of uncertainty in countries where no studies are available, its successful implementation is conditioned by a number of factors, which are analyzed and discussed.

Spatial and temporal variation in fine particulate matter mass and chemical composition: the Middle East Consortium for Aerosol Research Study

Ambient fine particulate matter (PM_2.5) samples were collected from January to December 2007 to investigate the sources and chemical speciation in Palestine, Jordan, and Israel. The 24-h PM_2.5 samples were collected on 6-day intervals at eleven urban and rural sites simultaneously. Major chemical components including metals, ions, and organic and elemental carbon were analyzed. The mass concentrations of PM_2.5 across the 11 sites varied from 20.6 to 40.3 μg/m³, with an average of 28.7 μg/m³. Seasonal variation of PM_2.5 concentrations was substantial, with higher average concentrations (37.3 μg/m³) in the summer (April–June) months compared to winter (October–December) months (26.0 μg/m³) due mainly to high contributions of sulfate and crustal components. PM_2.5 concentrations in the spring were greatly impacted by regional dust storms. Carbonaceous mass was the most abundant component, contributing 40% to the total PM_2.5 mass averaged across the eleven sites. Crustal components averaged 19.1% of the PM_2.5 mass and sulfate, ammonium, and nitrate accounted for 16.2%, 6.4%, and 3.7%, respectively, of the total PM_2.5 mass. The results of this study demonstrate the need to better protect the health and welfare of the residents on both sides of the Jordan River in the Middle East.