Air pollution interventions and their impact on public health

Tailoring ammonia capture in MOFs and COFs: A multi-scale and machine learning comprehensive investigation of functional group modification

Our study aims to examine the impact of ligand functionalization on the ammonia adsorption properties of MOFs and COFs, by combining multi-scale calculations with machine learning techniques. Density Functional Theory calculations were performed to investigate the interactions between ammonia (NH3) and a comprehensive set of 48 strategically chosen functional groups. In all of the cases, it is observed that functionalized rings exhibit a stronger interaction with ammonia molecule compared to unfunctionalized benzene, while -O2Mg demonstrates the highest interaction energy with ammonia (15 times stronger than the bare benzene). The trend obtained from the thorough DFT screening is verified via Grand Canonical Monte-Carlo calculations by employing interatomic potentials derived from quantum chemical calculations. Isosteric heat of adsorption plots provide a comprehensive elucidation of the adsorption process, and important insights can be taken for studies in fine-tuning materials for ammonia adsorption. Furthermore, a proof of concept machine learning (ML) analysis is conducted, which demonstrates that ML can accurately predict NH3 binding energies despite the limited amount of data. The findings derived from our multi-scale methodology indicate that the functionalization strategy can be utilized to guide synthesis towards MOFs, COFs, or other porous materials for enhanced NH3 adsorption capacity.

Urban policy interventions to reduce traffic-related emissions and air pollution: A systematic evidence map

BACKGROUND

Urban areas are hot spots for human exposure to air pollution, which originates in large part from traffic. As the urban population continues to grow, a greater number of people risk exposure to traffic-related air pollution (TRAP) and its adverse, costly health effects. In many cities, there is a need and scope for air quality improvements through targeted policy interventions, which continue to grow including rapidly changing technologies.

OBJECTIVE

This systematic evidence map (SEM) examines and characterizes peer-reviewed evidence on urban-level policy interventions aimed at reducing traffic emissions and/or TRAP from on-road mobile sources, thus potentially reducing human exposures and adverse health effects and producing various co-benefits.

METHODS

This SEM follows a previously peer-reviewed and published protocol with minor deviations, explicitly outlined here. Articles indexed in Public Affairs Index, TRID, Medline and Embase were searched, limited to English, published between January 1, 2000, and June 1, 2020. Covidence was used to screen articles based on previously developed eligibility criteria. Data for included articles was extracted and manually documented into an Excel database. Data visualizations were created in Tableau.

RESULTS

We identified 7528 unique articles from database searches and included 376 unique articles in the final SEM. There were 58 unique policy interventions, and a total of 1,139 unique policy scenarios, comprising these interventions and different combinations thereof. The policy interventions fell under 6 overarching policy categories: 1) pricing, 2) land use, 3) infrastructure, 4) behavioral, 5) technology, and 6) management, standards, and services, with the latter being the most studied. For geographic location, 463 policy scenarios were studied in Europe, followed by 355 in Asia, 206 in North America, 57 in South America, 10 in Africa, and 7 in Australia. Alternative fuel technology was the most frequently studied intervention (271 times), followed by vehicle emission regulation (134 times). The least frequently studied interventions were vehicle ownership taxes, and studded tire regulations, studied once each. A mere 3 % of studies addressed all elements of the full-chain-traffic emissions, TRAP, exposures, and health. The evidence recorded for each unique policy scenario is hosted in an open-access, query-able Excel database, and a complementary interactive visualization tool. We showcase how users can find more about the effectiveness of the 1,139 included policy scenarios in reducing, increasing, having mixed or no effect on traffic emissions and/or TRAP.

CONCLUSION

This is the first peer-reviewed SEM to compile international evidence on urban-level policy interventions to reduce traffic emissions and/or TRAP in the context of human exposure and health effects. We also documented reported enablers, barriers, and co-benefits. The open-access Excel database and interactive visualization tool can be valuable resources for practitioners, policymakers, and researchers. Future updates to this work are recommended.

PROTOCOL REGISTRATION

Sanchez, K.A., Foster, M., Nieuwenhuijsen, M.J., May, A.D., Ramani, T., Zietsman, J. and Khreis, H., 2020. Urban policy interventions to reduce traffic emissions and traffic-related air pollution: Protocol for a systematic evidence map. Environment international, 142, p.105826.

Airborne estimation of SO2 emissions rates from a coal-fired power plant using two top-down methods: A mass balance model and Gaussian footprint approach

In this study, two top-down methods-mass balance and Gaussian footprint-were used to determine SO₂ emissions rates via three airborne sampling studies over Korea's largest coal power plant in October 2019 and 2020. During the first two flights in October 2019, mass balance approaches significantly underestimated the SO₂ emissions rates by 75 % and 28 %, respectively, as obtained from the real-time stack monitoring system. Notably, this large discrepancy accounted for the insufficient number of transects altitudes and high levels of background SO₂ along the upwind side. Alternatively, the estimated SO₂ emissions rates of the third flight (October 2020) displayed a difference of <10 % from rea-time monitoring data (630 vs. 690 kg·hr^-1), owing to the enhanced vertical resolution with increased transects and lower background SO₂ levels. In contrast to the mass balance method, Gaussian footprints offered significantly improved accuracy (relative error: 41 %, 32 %, and 2 % for Flights 1, 2, and 3, respectively). This relatively good performance was attributed to prior emissions knowledge via the Clean Air Policy Support System (CAPSS) emissions inventory and its unique ability to accurately estimate stack-level SO₂ emissions rates. Theoretically, the Gaussian footprint was less prone to sparse transects and upwind background levels. However, it can be substantially influenced by atmospheric stability and consequently by effective stack heights and dispersion parameters; basically, all factors with minimal-to-no influence on the mass balance approach. Conversely, the mass balance method was the only plausible approach to estimate unidentified source emissions rates when well-defined prior emission information was unknown. Here, the footprint approach supplemented the mass balance method when the emission inventories were known, and employing both strategies approaches greatly enhanced the integrity of top-down emissions inventories from the power plant sources, thus, supporting their potential for ensuring operational compliance with SO₂ emissions regulation.

A Real-Time Approach to Detect PM2.5 in a Seriously Polluted Environment Based on Pressure Drop

A differential pressure-based low-cost PM2.5 detection system was developed for particulate matter measurement in polluted environments. The PM2.5 monitor consists of a sampling device, a pump, a pressure sensor, and a control circuit. Two sampling devices including a foam penetration-filter tube and a cyclone-filter holder were applied. Tests were conducted in a haze environment and laboratory particle chambers with varying PM2.5 concentration. The pressure data were related to the PM2.5 concentration recorded by Dusttrak to show the calibration process and the performance of this instrument. Results showed the concentration information given by the instrument was consistent with the actual concentration in the experiment, and this instrument was more suitable for seriously polluted environment detection. Concentration oscillation of the pressure-based PM2.5 monitor caused by turbulent flow could be reduced by a longer calculation interval and data averaging in the calculation process. As a low-cost sensor, the pressure-based PM2.5 monitor still has good performance and application value for detecting high-concentration PM2.5 in atmospheric environments or workplaces.

Understanding NO2 Concentration Dynamics within Tema Metropolitan Area of Ghana Using Generalized Linear Model

The concentration of nitrogen dioxide (NO2) is worsening across the globe alongside growth in industrial and general anthropogenic activities. Due to its serious health implications with long-term exposure, studies on NO2 concentration have gained space in the academic literature. In this study, awareness is created on the levels of NO2 across four (4) locations within the Tema Metropolitan area, with specific interest in selecting locations and periods significantly saturated with NO2 within the study area. NO2 was measured using RKI Eagle, an instrument with a built-in sensor for a specific gas measurement. Measurements were taken day and night at sampling points around 100 meters apart in each location. Data collection was performed over a nine (9)-month period. The Generalized Linear model is explored for selecting locations and periods significantly affected by NO2. From the results, the fourth week (26th–31st) of July 2020, the fourth week (27th–31st) of December 2020, the first week (1st–7th) of January 2021, and the fourth week (24th–31st) of January 2021 recorded severe concentrations of NO2. Additionally, the lives of residents in the Oil Jetty and the VALVO hospital areas were found to be the most endangered, as they recorded significantly high concentrations of NO2. In a developing country such as Ghana, this study is useful for monitoring NO2 concentrations in similar areas to inform decision making and environmental policy formulation.

The effect of using personal-level indoor air cleaners and respirators on biomarkers of cardiorespiratory health: a systematic review

BACKGROUND

Emerging studies have investigated potential cardiovascular and respiratory health impacts from the use of personal-level intervention equipment against air pollution exposure. The objective of this systematic review is to assess the efficacy of personal-level air pollution intervention on mitigating adverse health effects from air pollution exposure by using portable air cleaner or wearing respirator.

METHODS

In this systematic review, we searched PubMed and Web of Science for published literatures up to May 31, 2020, focusing on personal-level air pollution intervention studies. Among these studies, we investigated the impacts on cardio-respiratory responses to the use of these interventions. The intervention of review interest was the use of personal-level equipment against air pollution, including using portable air cleaner indoors or wearing respirator outdoors. The outcome of review interest was impacts on cardio-respiratory health endpoints following interventions, including level changes in blood pressure, heart rate variability (HRV), lung function, and biomarkers of inflammation and oxidative stress. Weighted mean differences or percent changes were pooled in meta-analyses for these health endpoints. The heterogeneity across studies was assessed using the Cochran's Q-statistic test, and the individual study quality was assessed using the Cochrane risk of bias tool version 2 (RoB 2). We further applied the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method to evaluate the certainty of evidence.

RESULTS

From systematic literature search and screening, we identified 29 related eligible intervention studies, including 21 studies on indoor portable air cleaner use and 8 studies on respirator use. For portable air cleaner intervention, we observed suggestive evidence of beneficial changes on cardio-respiratory health endpoints. Collectively in these studies, we found significantly beneficial changes of 2.01% decreases (95% CI: 0.50%, 3.52%) in systolic blood pressure, as well as non-significantly beneficial changes of 3.04% increases (95% CI: -2.65%, 8.74%) in reactive hyperemia index and 0.24% increases (95% CI: -0.82%, 1.31%) in forced expiratory volume in 1 s. We also observed non-significant reductions in levels of inflammation and oxidative stress biomarkers, including C-reactive protein, interleukin-6, fibrinogen, fractional exhaled nitric oxide and malondialdehyde. For respirator intervention, we observed some beneficial changes on cardiovascular health endpoints, such as significant increases in HRV parameters [SDNN (2.20%, 95% CI: 0.54%, 3.86%)], as well as non-significant decreases in blood pressure [SBP (0.63 mmHg, 95% CI: -0.39, 1.66)]; however, no sufficient data were available for meta-analyses on lung function and biomarkers. RoB 2 assessments suggested that most intervention studies were with a moderate to high overall risk of bias. The certainty of evidence for intervention outcome pairs was graded very low for either portable air cleaner or respirator intervention. The common reasons to downgrade study evidence included loss to follow-up, lack of blinding, lack of washout period, small sample size, and high heterogeneity across studies.

CONCLUSIONS

The uses of indoor portable air cleaner and respirator could contribute to some beneficial changes on cardiovascular health, but with much limited evidence on respiratory health. Low certainty of the overall study evidence shed light on future research for larger sample size trials with more rigorous study design.

A review on reducing indoor particulate matter concentrations from personal-level air filtration intervention under real-world exposure situations

Improving air quality in indoor environments where people live is of importance to protect human health. In this systematic review, we assessed the effectiveness of personal-level use of air filtration units in reducing indoor particulate matters (PM) concentrations under real-world situations following systematic review guidelines. A total of 54 articles were included in the review, in which 20 randomized controlled/crossover trials that reported the changes in indoor fine PM (PM_2.5 ) concentrations were quantitatively assessed in meta-analysis. Standardized mean differences (SMDs) were calculated for changes in indoor PM concentrations following air filtration interventions. Moderate-to-large reductions of 11%-82% in indoor PM_2.5  concentrations were observed with SMD of -1.19 (95% CI: -1.50, -0.88). The reductions in indoor PM concentrations varied by geographical locations, filtration technology employed, indoor environmental characteristics, and air pollution sources. Most studies were graded with low-to-moderate risk of bias; however, the overall certainty of evidence for indoor PM concentration reductions was graded at very low level. Considering the effectiveness of indoor air filtration under practical uses, socio-economic disparities across study populations, and costs of air filter replacement over time, our results highlight the importance of reducing air pollution exposure at the sources.

Changes in criteria air pollution levels in the US before, during, and after Covid-19 stay-at-home orders: Evidence from regulatory monitors

The widespread and rapid social and economic changes from Covid-19 response might be expected to dramatically improve air quality. However, national monitoring data from the US Environmental Protection Agency for criteria pollutants (PM_2.5, ozone, NO₂, CO, PM₁₀) provide inconsistent support for that expectation. Specifically, during stay-at-home orders, average PM_2.5 levels were slightly higher (~10% of its multi-year interquartile range [IQR]) than expected; average ozone, NO₂, CO, and PM₁₀ levels were slightly lower (~30%, ~20%, ~27%, and ~1% of their IQR, respectively) than expected. The timing of peak anomaly, relative to the stay-at-home orders, varied by pollutant (ozone: 2 weeks before; NO₂, CO: 3 weeks after; PM₁₀: 2 weeks after); but, by 5-6 weeks after stay-at-home orders, the concentration anomalies appear to have ended. For PM_2.5, ozone, CO, and PM₁₀, no US state had lower-than-expected pollution levels for all weeks during stay-at-home-orders; for NO₂, only Arizona had lower-than-expected levels for all weeks during stay-at-home orders. Our findings show that the enormous changes from the Covid-19 response have not lowered PM_2.5 levels across the US beyond their normal range of variability; for ozone, NO₂, CO, and PM₁₀ concentrations were lowered but the reduction was modest and transient.

Impact of temporary traffic bans on the risk of acute coronary syndromes in a large metropolitan area

BACKGROUND

Strong epidemiologic evidence has highlighted the role of pollution, on top of adverse climate features, as a novel cardiovascular risk factor. However, mechanistic proof that reducing pollution may be beneficial to prevent atherothrombotic events is limited. We aimed at appraising the impact of temporary traffic bans in a large metropolitan area on the risk of acute coronary syndromes.

METHODS

Aggregate and anonymized data from 15 tertiary cardiac care centers were obtained detailing precoronavirus disease 2019 (COVID-19) daily cases of ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI), including those treated with percutaneous coronary intervention (PCI). Data on pollutants and climate were sought for the same days. Mixed level regression was used to compare the week before vs after the traffic ban (Fortnight analysis), the 3 days before vs. after (Weekly analysis) and the Sunday before vs. after (Sunday analysis).

RESULTS

A total of 8 days of temporary traffic bans were included, occurring between 2017 and 2020, totaling 802 STEMI and 1196 NSTEMI in the Fortnight analysis, 382 STEMI and 585 in the Weekly analysis, and 148 STEMI and 210 NSTEMI in the Sunday analysis.Fortnight and Sunday analyses did not disclose a significant impact of traffic ban on STEMI or NSTEMI (all P>0.05). Conversely, Weekly analysis showed non-significant changes for STEMI, but a significant decrease in daily NSTEMI when comparing the 3 days before the traffic ban with the ban day (P=0.043), as well as the 3 days before vs. the 3 days after the ban (P=0.025). No statistically significant effect of traffic ban was found at Fortnight, Weekly or Sunday analyses for daily mean concentrations of benzene, carbon monoxide, nitric oxide, nitrogen dioxide, ozone, sulfur dioxide, particulate matter (PM) <2.5 µm or PM <10 µm (all P>0.05). However, minimum daily concentrations showed a significant reduction of ozone during the ban in comparison to the week preceding it (P=0.034), nitric oxide during the ban in comparison to the 3 days preceding it (P=0.046), and an increase in benzene during the ban in comparison to the Sunday before (P=0.039).

CONCLUSIONS

Temporary traffic ban may favorably reduce coronary atherothrombotic events, and in particular NSTEMI, even if not globally and immediately impacting on environmental pollution. Further controlled studies are required to confirm and expand this hypothesis-generating results.

Model for assessing health damage from air pollution in quarrying area - Case study at Tan Uyen quarry, Ho Chi Minh megapolis, Vietnam

Vietnam has a great demand for stone exploitation for the development of the country's infrastructure, reaching 181 million m³ in 2020. Mining activities are always accompanied by environmental pollution, negatively affecting public health. To accurately assess the level of pollution, as well as quantify the effect of air pollution on human health, a number of structures, methods, and models provide tools to assess the benefits of this control for public health and related economic values. However, there has been no research in Vietnam applied specifically to this type of stone exploitation. This study offers a model to evaluate the economic damage caused by dust exposure from activities related to quarrying, overcoming the lack of continuous monitoring data. The area selected for research is Binh Duong province, in the Ho Chi Minh megapolis, Vietnam, which has two construction quarries, Thuong Tan and Tan My, with a current annual production of approximately 4–5 million m³. The calculation results show that the damage to human health is estimated at approximately 9,643 billion dong a year, equivalent to 15.03 million USD. In addition, if the standard criteria are tightened, damage will continue to increase. This study also analyses some of the difficulties and limitations in the modelling process.

The Molecular Mechanisms of Adaptive Response Related to Environmental Stress

The exposure of living organisms to environmental stress triggers defensive responses resulting in the activation of protective processes. Whenever the exposure occurs at low doses, defensive effects overwhelm the adverse effects of the exposure; this adaptive situation is referred to as “hormesis”. Environmental, physical, and nutritional hormetins lead to the stimulation and strengthening of the maintenance and repair systems in cells and tissues. Exercise, heat, and irradiation are examples of physical hormetins, which activate heat shock-, DNA repair-, and anti-oxidative-stress responses. The health promoting effect of many bio-actives in fruits and vegetables can be seen as the effect of mildly toxic compounds triggering this adaptive stimulus. Numerous studies indicate that living organisms possess the ability to adapt to adverse environmental conditions, as exemplified by the fact that DNA damage and gene expression profiling in populations living in the environment with high levels of air pollution do not correspond to the concentrations of pollutants. The molecular mechanisms of the hormetic response include modulation of (a) transcription factor Nrf2 activating the synthesis of glutathione and the subsequent protection of the cell; (b) DNA methylation; and (c) microRNA. These findings provide evidence that hormesis is a toxicological event, occurring at low exposure doses to environmental stressors, having the benefit for the maintenance of a healthy status.

Urban policy interventions to reduce traffic emissions and traffic-related air pollution: Protocol for a systematic evidence map

INTRODUCTION

Cities are the world's engines of economic growth, innovation, and social change, but they are also hot spots for human exposure to air pollution, mainly originating from road traffic. As the urban population continues to grow, a greater quantity of people risk exposure to traffic-related air pollution (TRAP), and therefore also risk adverse health effects. In many cities, there is scope for further improvement in air quality through targeted urban policy interventions. The objective of this protocol is to detail the methods that will be used for a systematic evidence map (SEM) which will identify and characterize the evidence on policy interventions that can be implemented at the urban-level to reduce traffic emissions and/or TRAP from on-road mobile sources, thus reducing human exposures and adverse health impacts.

METHODS

Articles will be searched for and selected based on a predetermined search strategy and eligibility criteria. A variety of databases will be searched for relevant articles published in English between January 1, 2000 and June 1, 2020 to encompass the interdisciplinary nature of this SEM, and articles will be stored and screened using Rayyan QCRI. Predetermined study characteristics will be extracted and coded from included studies in a Microsoft Excel sheet, which will serve as an open access, interactive database, and two authors will review the coded data for consistency. The database will be queryable, and various interactive charts, graphs, and maps will be created using Tableau Public for data visualization. The results of the evidence mapping will be detailed via narrative summary.

CONCLUSION

This protocol serves to increase transparency of the SEM methods and provides an example for researchers pursuing future SEMs.

Health Effects of Air-Quality Regulations in Seoul Metropolitan Area: Applying Synthetic Control Method to Controlled-Interrupted Time-Series Analysis

Despite enormous investment in air-quality regulations, there are only a few studies about the health effects of the air-quality regulations. By applying synthetic control methods to controlled-interrupted time-series analysis, this study aimed to test whether air-quality regulations implemented in Seoul metropolitan area since 2005 had reduced cardiovascular mortality rate in Seoul and Incheon. Each synthetic control for Seoul and Incheon was constructed to predict the counterfactual cardiovascular mortality rate through synthetic control methods. By using a synthetic control as a control group in controlled-interrupted time-series analysis, we tested whether the air-quality regulations had changed the trend of cardiovascular mortality rate in Seoul and Incheon after the intervention. The results showed a significant slope change in cardiovascular mortality rate in Seoul (coefficient: −0.001, 95% confidence interval (CI): −0.0015, −0.0004) and Incheon (coefficient: −0.0006, 95% CI: −0.0012, 0). This study suggests additional evidence that air-quality regulations implemented in the Seoul metropolitan areas since 2005 had beneficial effects on cardiovascular mortality rate in Seoul and Incheon.

Attributable Risk to Assess the Health Impact of Air Pollution: Advances, Controversies, State of the Art and Future Needs

Despite the increased attention given to the health impact assessment of air pollution and to the strategies to control it in both scientific literature and concrete interventions, the results of the implementations, especially those involving traffic, have not always been satisfactory and there is still disagreement about the most appropriate interventions and the methods to assess their effectiveness. This state-of-the-art article reviews the recent interpretation of the concepts that concern the impact assessment, and compares old and new measurements of attributable risk and attributable fraction. It also summarizes the ongoing discussion about the designs and methods for assessing the air pollution impact with particular attention to improvements due to spatio-temporal analysis and other new approaches, such as studying short term effects in cohorts, and the still discussed methods of predicting the values of attributable risk (AR). Finally, the study presents the more recent analytic perspectives and the methods for directly assessing the effects of not yet implemented interventions on air quality and health, in accordance with the suggestion in the strategic plan 2020-2025 from the Health Effect Institute.

The atmospheric impacts of initiatives advancing shifts towards low-emission mobility: A scoping review

In an urban environment, people's daily traffic choices are reflected in emissions and the resulting local air composition, or air quality. Traffic contributes to the emissions of both carbon dioxide (CO₂), affecting climate, and particulate matter (PM), affecting atmospheric chemistry and human health. While the development of city infrastructure is not in the hands of individuals, it is their transport mode choices that constitute traffic. In this scoping review we analyse 108 initiatives from around the world potentially influencing individual travel behaviour and producing changes in the shares of different transport modes (modal shifts). The targets, types and techniques of initiatives are identified. Examples of economic, regulative, structural and persuasive initiatives are included. Special focus is on whether the impacts on CO₂ emissions, PM emissions and/or PM concentrations have been quantitatively evaluated, and on the quality and results of the evaluations. We observe that a variety of targets can motivate actions that lead to modal shifts and emission reductions. The results indicate that the level of atmospheric evaluations is low: absolute or relative changes in emissions and/or concentrations had been evaluated for only 31% (N = 34) of the reviewed initiatives, with substantial heterogeneity in quality. Sanctions, such as congestion charge and restrictions, have more likely been evaluated in peer reviewed analyses than incentives. Scientific evaluations of impacts on ambient PM concentrations are especially scarce (N = 4), although Air Quality is the primary target of 13% of actions and secondary target for at least 12%. We discuss the determinants of success and failure, when it comes to different types of initiatives, emission reductions and evaluations. A high-quality evaluation of atmospheric impacts captures the following: correct data about the modal shift (rate and direction), exclusion of external factors affecting the shift and emissions, and possible indirect impacts of the shift.

Comparing the lung cancer burden of ambient particulate matter using scenarios of air quality standards versus acceptable risk levels

OBJECTIVES

Ambient particulate matter (PM) is regulated with science-based air quality standards, whereas carcinogens are regulated with a number of "acceptable" cases. Given that PM is also carcinogenic, we identify differences between approaches.

METHODS

We assessed the lung cancer deaths for Switzerland attributable to exposure to PM up to 10 µm (PM10) and to five particle-bound carcinogens. For PM10, we used an epidemiological approach based on relative risks with four exposure scenarios compared to two counterfactual concentrations. For carcinogens, we used a toxicological approach based on unit risks with four exposure scenarios.

RESULTS

The lung cancer burden using concentrations from 2010 was 10-14 times larger for PM10 than for the five carcinogens. However, the burden depends on the underlying exposure scenarios, counterfactual concentrations and number of carcinogens. All scenarios of the toxicological approach for five carcinogens result in a lower burden than the epidemiological approach for PM10.

CONCLUSIONS

Air quality standards-promoted so far by the WHO Air Quality Guidelines-provide a more appealing framework to guide health risk-oriented clean air policymaking than frameworks based on a number of "acceptable" cases.

Interventions to reduce ambient air pollution and their effects on health: An abridged Cochrane systematic review

BACKGROUND

A broad range of interventions have been implemented to improve ambient air quality, and many of these have been evaluated. Yet to date no systematic review has been conducted to identify and synthesize these studies. In this systematic review, we assess the effectiveness of interventions in reducing ambient particulate matter air pollution and improving adverse health outcomes.

METHODS

We searched a range of electronic databases across multiple disciplines, as well as grey literature databases, trial registries, reference lists of included studies and the contents of relevant journals, through August 2016. Eligible for inclusion were randomized and cluster randomized controlled trials, as well as several non-randomized study designs often used for evaluating air quality interventions. We included studies that evaluated interventions targeting industrial, residential, vehicular and multiple sources, with respect to their effect on mortality, morbidity and the concentrations of particulate matter (PM - including PM₁₀, PM_2.5, coarse particulate matter and combustion-related PM), as well as several criteria pollutants, including ozone, carbon monoxide, nitrogen oxides, nitrogen dioxide, nitric oxide and sulphur dioxide. We did not restrict studies based on the population, setting or comparison. Two authors independently assessed studies for inclusion, extracted data and assessed risk of bias. We assessed risk of bias using the Graphic Appraisal Tool for Epidemiological studies (GATE) for correlation studies, as modified and employed by the UK National Institute for Health and Care Excellence. We synthesized evidence narratively, as well as graphically using harvest plots. We assessed the certainty of evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

RESULTS

We included 42 studies assessing 38 unique interventions. These comprised a heterogeneous mix of interventions, including those aiming to address industrial sources (n = 5; e.g. the closure of a factory), residential sources (n = 7; e.g. coal ban), vehicular sources (n = 22; e.g. low emission zones), and multiple sources (n = 4; e.g. tailored measures that target both local traffic and industrial polluters). Evidence for effectiveness was mixed. Most included studies observed either no significant association or an association favoring the intervention, with little evidence that the assessed interventions might be harmful.

CONCLUSIONS

Given the heterogeneity across interventions, outcomes, and methods, it was difficult to derive overall conclusions regarding the effectiveness of interventions in terms of improved air quality or health. Some evidence suggests that interventions are associated with improvements in air quality and human health, with very little evidence suggesting interventions were harmful. The evidence base highlights the challenges related to establishing the effectiveness of specific air pollution interventions on outcomes. It also points to the need for improved study design and analysis methods, as well as more uniform evaluations. The prospective planning of evaluations and an evaluation component built into the design and implementation of interventions may also be particularly beneficial.

Biochemical changes among municipal solid waste sorting workers: implications for personal protective equipment availability and use

Background. Solid waste management has emerged as one of the greatest challenges facing human and environmental health. Municipal solid waste workers are potentially exposed to a variety of occupational biohazards and safety risks in the workplace. Objective. This study aimed to evaluate the availability and use of personal protective equipment (PPE) and some biochemical changes among solid waste sorting workers. Methods. A group of solid waste sorting workers was interviewed and checked for availability, use and appropriateness of PPE using a structured questionnaire and checklist. Workers were tested for hepatic and renal function parameters and biomarkers of allergy and inflammation. Results. The level of high-sensitivity C-reactive protein (hsCRP) as a biomarker of inflammation was elevated in 12.9% while total serum immunoglobulin E was obviously high among most workers (79.2%). Workers with inadequately available, used or effective PPE were more likely to have morbidities and showed elevated serum levels of serum glutamic pyruvic transaminase, serum glutamic-oxaloacetic transaminase, urea, creatinine, hsCRP and total immunoglobulin E. Conclusions. Elevated biomarkers of allergy and inflammation herald preclinical disease risks that should be included in basic health surveillance. Use of PPE should be emphasized for workers involved in solid waste sorting to effectively protect their health.

Emission from open burning of municipal solid waste in India

Open burning of Municipal Solid Waste (MSW) is a potential non-point source of emission, which causes greater concern especially in developing countries such as India. Lack of awareness about environmental impact of open burning, and ignorance of the fact, i.e. 'Open burning is a source of emission of carcinogenic substances' are major hindrances towards an appropriate municipal solid waste management system in India. The paper highlights the open burning of MSW practices in India, and the current and projected emission of 10 major pollutants (dioxin, furans, particulate matter, carbon monoxide, sulphur oxides, nitrogen oxides, benzene, toluene, ethyl benzene and 1-hexene) emitted due to the open burning of MSW. Waste to Energy potential of MSW was also estimated adopting effective biological and thermal techniques. Statistical techniques were applied to analyse the data and current and projected emission of various pollutants were estimated. Data pertaining to population, MSW generation and its collection efficiency were compiled for 29 States and 7 Union Territories. Thereafter, emission of 10 pollutants was measured following methodology prescribed in Intergovernmental Panel on Climate Change guideline for National Greenhouse Gas Inventories, 2006. The study revealed that people living in Metropolitan cities are more affected by emissions from open burning.

Interventions to reduce ambient particulate matter air pollution and their effect on health

BACKGROUND

Ambient air pollution is associated with a large burden of disease in both high-income countries (HICs) and low- and middle-income countries (LMICs). To date, no systematic review has assessed the effectiveness of interventions aiming to reduce ambient air pollution.

OBJECTIVES

To assess the effectiveness of interventions to reduce ambient particulate matter air pollution in reducing pollutant concentrations and improving associated health outcomes.

SEARCH METHODS

We searched a range of electronic databases with diverse focuses, including health and biomedical research (CENTRAL, Cochrane Public Health Group Specialised Register, MEDLINE, Embase, PsycINFO), multidisciplinary research (Scopus, Science Citation Index), social sciences (Social Science Citation Index), urban planning and environment (Greenfile), and LMICs (Global Health Library regional indexes, WHOLIS). Additionally, we searched grey literature databases, multiple online trial registries, references of included studies and the contents of relevant journals in an attempt to identify unpublished and ongoing studies, and studies not identified by our search strategy. The final search date for all databases was 31 August 2016.

SELECTION CRITERIA

Eligible for inclusion were randomized and cluster randomized controlled trials, as well as several non-randomized study designs, including controlled interrupted time-series studies (cITS-EPOC), interrupted time-series studies adhering to EPOC standards (ITS-EPOC), interrupted time-series studies not adhering to EPOC standards (ITS), controlled before-after studies adhering to EPOC standards (CBA-EPOC), and controlled before-after studies not adhering to EPOC standards (CBA); these were classified as main studies. Additionally, we included uncontrolled before-after studies (UBA) as supporting studies. We included studies that evaluated interventions to reduce ambient air pollution from industrial, residential, vehicular and multiple sources, with respect to their effect on mortality, morbidity and several air pollutant concentrations. We did not restrict studies based on the population, setting or comparison.

DATA COLLECTION AND ANALYSIS

After a calibration exercise among the author team, two authors independently assessed studies for inclusion, extracted data and assessed risk of bias. We conducted data extraction, risk of bias assessment and evidence synthesis only for main studies; we mapped supporting studies with regard to the types of intervention and setting. To assess risk of bias, we used the Graphic Appraisal Tool for Epidemiological studies (GATE) for correlation studies, as modified and employed by the Centre for Public Health Excellence at the UK National Institute for Health and Care Excellence (NICE). For each intervention category, i.e. those targeting industrial, residential, vehicular and multiple sources, we synthesized evidence narratively, as well as graphically using harvest plots.

MAIN RESULTS

We included 42 main studies assessing 38 unique interventions. These were heterogeneous with respect to setting; interventions were implemented in countries across the world, but most (79%) were implemented in HICs, with the remaining scattered across LMICs. Most interventions (76%) were implemented in urban or community settings.We identified a heterogeneous mix of interventions, including those aiming to address industrial (n = 5), residential (n = 7), vehicular (n = 22), and multiple sources (n = 4). Some specific interventions, such as low emission zones and stove exchanges, were assessed by several studies, whereas others, such as a wood burning ban, were only assessed by a single study.Most studies assessing health and air quality outcomes used routine monitoring data. Studies assessing health outcomes mostly investigated effects in the general population, while few studies assessed specific subgroups such as infants, children and the elderly. No identified studies assessed unintended or adverse effects.The judgements regarding the risk of bias of studies were mixed. Regarding health outcomes, we appraised eight studies (47%) as having no substantial risk of bias concerns, five studies (29%) as having some risk of bias concerns, and four studies (24%) as having serious risk of bias concerns. Regarding air quality outcomes, we judged 11 studies (31%) as having no substantial risk of bias concerns, 16 studies (46%) as having some risk of bias concerns, and eight studies (23%) as having serious risk of bias concerns.The evidence base, comprising non-randomized studies only, was of low or very low certainty for all intervention categories and primary outcomes. The narrative and graphical synthesis showed that evidence for effectiveness was mixed across the four intervention categories. For interventions targeting industrial, residential and multiple sources, a similar pattern emerged for both health and air quality outcomes, with essentially all studies observing either no clear association in either direction or a significant association favouring the intervention. The evidence base for interventions targeting vehicular sources was more heterogeneous, as a small number of studies did observe a significant association favouring the control. Overall, however, the evidence suggests that the assessed interventions do not worsen air quality or health.

AUTHORS' CONCLUSIONS

Given the heterogeneity across interventions, outcomes, and methods, it was difficult to derive overall conclusions regarding the effectiveness of interventions in terms of improved air quality or health. Most included studies observed either no significant association in either direction or an association favouring the intervention, with little evidence that the assessed interventions might be harmful. The evidence base highlights the challenges related to establishing a causal relationship between specific air pollution interventions and outcomes. In light of these challenges, the results on effectiveness should be interpreted with caution; it is important to emphasize that lack of evidence of an association is not equivalent to evidence of no association.We identified limited evidence for several world regions, notably Africa, the Middle East, Eastern Europe, Central Asia and Southeast Asia; decision-makers should prioritize the development and implementation of interventions in these settings. In the future, as new policies are introduced, decision-makers should consider a built-in evaluation component, which could facilitate more systematic and comprehensive evaluations. These could assess effectiveness, but also aspects of feasibility, fidelity and acceptability.The production of higher quality and more uniform evidence would be helpful in informing decisions. Researchers should strive to sufficiently account for confounding, assess the impact of methodological decisions through the conduct and communication of sensitivity analyses, and improve the reporting of methods, and other aspects of the study, most importantly the description of the intervention and the context in which it is implemented.

Competing Forces of Socioeconomic Development and Environmental Degradation on Health and Happiness for Different Income Groups in China

China's rapid socioeconomic growth in recent years and the simultaneous increase in many forms of pollution are generating contradictory pictures of residents' well-being. This paper applies multilevel analysis to the 2013 China General Social Survey data on social development and health to understand this twofold phenomenon. Multilevel models are developed to investigate the impact of socioeconomic development and environmental degradation on self-reported health (SRH) and self-reported happiness (SRHP), differentiating among lower, middle, and higher income groups. The results of the logit multilevel analysis demonstrate that income, jobs, and education increased the likelihood of rating SRH and SRHP positively for the lower and middle groups but had little or no effect on the higher income group. Having basic health insurance had an insignificant effect on health but increased the likelihood of happiness among the lower income group. Provincial-level pollutants were associated with a higher likelihood of good health for all income groups, and community-level industrial pollutants increased the likelihood of good health for the lower and middle income groups. Measures of community-level pollution were robust predictors of the likelihood of unhappiness among the lower and middle income groups. Environmental hazards had a mediating effect on the relationship between socioeconomic development and health, and socioeconomic development strengthened the association between environmental hazards and happiness. These outcomes indicate that the complex interconnections among socioeconomic development and environmental degradation have differential effects on well-being among different income groups in China.

Adaptation of the human population to the environment: Current knowledge, clues from Czech cytogenetic and "omics" biomonitoring studies and possible mechanisms

The human population is continually exposed to numerous harmful environmental stressors, causing negative health effects and/or deregulation of biomarker levels. However, studies reporting no or even positive impacts of some stressors on humans are also sometimes published. The main aim of this review is to provide a comprehensive overview of the last decade of Czech biomonitoring research, concerning the effect of various levels of air pollution (benzo[a]pyrene) and radiation (uranium, X-ray examination and natural radon background), on the differently exposed population groups. Because some results obtained from cytogenetic studies were opposite than hypothesized, we have searched for a meaningful interpretation in genomic/epigenetic studies. A detailed analysis of our data supported by the studies of others and current epigenetic knowledge, leads to a hypothesis of the versatile mechanism of adaptation to environmental stressors via DNA methylation settings which may even originate in prenatal development, and help to reduce the resulting DNA damage levels. This hypothesis is fully in agreement with unexpected data from our studies (e.g. lower levels of DNA damage in subjects from highly polluted regions than in controls or in subjects exposed repeatedly to a pollutant than in those without previous exposure), and is also supported by differences in DNA methylation patterns in groups from regions with various levels of pollution. In light of the adaptation hypothesis, the following points may be suggested for future research: (i) the chronic and acute exposure of study subjects should be distinguished; (ii) the exposure history should be mapped including place of residence during the life and prenatal development; (iii) changes of epigenetic markers should be monitored over time. In summary, investigation of human adaptation to the environment, one of the most important processes of survival, is a new challenge for future research in the field of human biomonitoring that may change our view on the results of biomarker analyses and potential negative health impacts of the environment.

Impact of light rail transit on traffic-related pollution and stroke mortality

OBJECTIVES

This paper evaluates the changes in vehicle exhaust and stroke mortality for the general public residing in the surrounding area of the light rail transit (LRT) in Houston, Texas, after its opening.

METHODS

The number of daily deaths due to stroke for 2002-2005 from the surrounding area of the original LRT line (exposure group) and the control groups was analyzed using an interrupted time-series analysis. Ambient concentrations of acetylene before and after the opening of LRT were also compared.

RESULTS

A statistically significant reduction in the average concentration of acetylene was observed for the exposure sites whereas the reduction was negligible at the control site. Poisson regression models applied to the stroke mortality data indicated a significant reduction in daily stroke mortality after the opening of LRT for the exposure group, while there was either an increase or a considerably smaller reduction for the control groups.

CONCLUSIONS

The findings support the idea that LRT systems provide health benefits for the general public and that the reduction in motor-vehicle-related air pollution may have contributed to these health benefits.

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 PM_2.5, using concentration-response functions derived from previous studies conducted in Beijing, combined with the differences in PM_2.5 concentrations between intervention and reference periods. Substantial reductions in daily PM_2.5 concentrations were observed during both intervention periods. Using the same dates from the prior year as a reference, daily PM_2.5 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.

"Exposure Track"-The Impact of Mobile-Device-Based Mobility Patterns on Quantifying Population Exposure to Air Pollution

Air pollution is now recognized as the world's single largest environmental and human health threat. Indeed, a large number of environmental epidemiological studies have quantified the health impacts of population exposure to pollution. In previous studies, exposure estimates at the population level have not considered spatially- and temporally varying populations present in study regions. Therefore, in the first study of it is kind, we use measured population activity patterns representing several million people to evaluate population-weighted exposure to air pollution on a city-wide scale. Mobile and wireless devices yield information about where and when people are present, thus collective activity patterns were determined using counts of connections to the cellular network. Population-weighted exposure to PM2.5 in New York City (NYC), herein termed "Active Population Exposure" was evaluated using population activity patterns and spatiotemporal PM2.5 concentration levels, and compared to "Home Population Exposure", which assumed a static population distribution as per Census data. Areas of relatively higher population-weighted exposures were concentrated in different districts within NYC in both scenarios. These were more centralized for the "Active Population Exposure" scenario. Population-weighted exposure computed in each district of NYC for the "Active" scenario were found to be statistically significantly (p < 0.05) different to the "Home" scenario for most districts. In investigating the temporal variability of the "Active" population-weighted exposures determined in districts, these were found to be significantly different (p < 0.05) during the daytime and the nighttime. Evaluating population exposure to air pollution using spatiotemporal population mobility patterns warrants consideration in future environmental epidemiological studies linking air quality and human health.

Survey of Ambient Air Pollution Health Risk Assessment Tools

Designing air quality policies that improve public health can benefit from information about air pollution health risks and impacts, which include respiratory and cardiovascular diseases and premature death. Several computer-based tools help automate air pollution health impact assessments and are being used for a variety of contexts. Expanding information gathered for a May 2014 World Health Organization expert meeting, we survey 12 multinational air pollution health impact assessment tools, categorize them according to key technical and operational characteristics, and identify limitations and challenges. Key characteristics include spatial resolution, pollutants and health effect outcomes evaluated, and method for characterizing population exposure, as well as tool format, accessibility, complexity, and degree of peer review and application in policy contexts. While many of the tools use common data sources for concentration-response associations, population, and baseline mortality rates, they vary in the exposure information source, format, and degree of technical complexity. We find that there is an important tradeoff between technical refinement and accessibility for a broad range of applications. Analysts should apply tools that provide the appropriate geographic scope, resolution, and maximum degree of technical rigor for the intended assessment, within resources constraints. A systematic intercomparison of the tools' inputs, assumptions, calculations, and results would be helpful to determine the appropriateness of each for different types of assessment. Future work would benefit from accounting for multiple uncertainty sources and integrating ambient air pollution health impact assessment tools with those addressing other related health risks (e.g., smoking, indoor pollution, climate change, vehicle accidents, physical activity).

Quantifying the impact of PM2.5 and associated heavy metals on respiratory health of children near metallurgical facilities

The aim of this study was to link the concentrations of particulate matter with an aerodynamic diameter below 2.5 μm (PM2.5) and associated heavy metals with occurrence of wheezing and hospitalizations due to wheezing in 111 children who live near metallurgical plants in Targoviste City, Romania. A group of 72 children with high levels of immunoglobulin E (IgE) and eosinophils, as well as frequent wheezing episodes, was geolocated on digital thematic maps. Monitoring campaigns and medical assessments were performed over two consecutive years (2013-2014). The multiannual average concentrations of PM2.5 ranged from 4.6 to 22.5 μg m(-3), up to a maximum value of 102 μg m(-3). Significant correlations (p < 0.01) were observed between the locations of the children with respiratory issues and the PM2.5 multiannual average (r = 0.985) and PM2.5 maximum (r = 0.813). Fe, Ni, Cd, and Cr were the main marker elements of the emissions from steel production and metal-working facilities in the Targoviste area. The results support the hypothesis that increased PM2.5 levels directly influence wheezing symptom and asthma attacks in the analyzed group. IgE, eosinophils, and wheezing episodes may be considered key indicators with which to evaluate the adverse effects of PM2.5 air pollution on children's health.

Impact of air quality guidelines on COPD sufferers

Background

COPD is one of the leading causes of morbidity and mortality in both high- and low-income countries and a major public health burden worldwide. While cigarette smoking remains the main cause of COPD, outdoor and indoor air pollution are important risk factors to its etiology. Although studies over the last 30 years helped reduce the values, it is not very clear if the current air quality guidelines are adequately protective for COPD sufferers.

Objective

This systematic review was to summarize the up-to-date literature on the impact of air pollution on the COPD sufferers.

Methods

PubMed and Google Scholar were utilized to search for articles related to our study’s focus. Search terms included “COPD exacerbation”, “air pollution”, “air quality guidelines”, “air quality standards”, “COPD morbidity and mortality”, “chronic bronchitis”, and “air pollution control” separately and in combination. We focused on articles from 1990 to 2015. We also used articles prior to 1990 if they contained relevant information. We focused on articles written in English or with an English abstract. We also used the articles in the reference lists of the identified articles.

Results

Both short-term and long-term exposures to outdoor air pollution around the world are associated with the mortality and morbidity of COPD sufferers even at levels below the current air quality guidelines. Biomass cooking in low-income countries was clearly associated with COPD morbidity in adult nonsmoking females.

Conclusion

There is a need to continue to improve the air quality guidelines. A range of intervention measures could be selected at different levels based on countries’ socioeconomic conditions to reduce the air pollution exposure and COPD burden.

Urinary biomarkers of exposure and of oxidative damage in children exposed to low airborne concentrations of benzene

The aim of this work was to evaluate the oxidative damage to nucleic acids in children (5-11 years) associated with exposure to environmental pollutants and tobacco smoke (ETS). For each subject, urinary sampling was done twice (evening and next morning) to measure by tandem LC-MS-MS such oxidated products of nucleic acids as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and 8-oxo-7,8-dihydroguanine (8-oxoGua). Methyl tert-butyl ether (U-MTBE), benzene (U-Benz), and its metabolites (t,t-muconic and S-phenylmercapturic acids, t,t-MA and S-PMA, respectively) were determined as biomarkers of exposure to air pollution, and cotinine as a biomarker of exposure to ETS. Biomarkers of exposure (S-PMA and U-MTBE) and of DNA oxidation (8-oxodGuo) were dependent on the urbanization and industrialization levels and increased in the evening sample as compared to next morning (p<0.05). In both evening and next morning samples, 8-oxodGuo and 8-oxoGuo correlated with each other (r=0.596 and r=0.537, respectively, p<0.01) and with biomarkers of benzene exposure, particularly S-PMA (r=0.59 and r=0.45 for 8-oxodGuo and r=0.411 and r=0.383 for 8-oxoGuo, p<0.01). No such correlations were observed for U-MTBE and cotinine. Multiple linear regression analyses showed that 8-oxodGuo was positively associated with S-PMA at both sampling times (β=0.18 and β=0.14 for evening and next morning sampling, respectively; p<0.02) and weakly with U-MTBE (β=0.07, p=0.020) only in the evening urines. These results suggest that the selected biomarkers of exposure to benzene, particularly S-PMA, are good tracers of exposure to complex mixtures of oxidative pollutants and that the associated oxidative damage to nucleic acids is detectable even at very low levels of exposure.

Identifying potential exposure reduction priorities using regional rankings based on emissions of known and suspected carcinogens to outdoor air in Canada

BACKGROUND

Emissions inventories aid in understanding the sources of hazardous air pollutants and how these vary regionally, supporting targeted reduction actions. Integrating information on the relative toxicity of emitted pollutants with respect to cancer in humans helps to further refine reduction actions or recommendations, but few national programs exist in North America that use emissions estimates in this way. The CAREX Canada Emissions Mapping Project provides key regional indicators of emissions (total annual and total annual toxic equivalent, circa 2011) of 21 selected known and suspected carcinogens.

METHODS

The indicators were calculated from industrial emissions reported to the National Pollutant Release Inventory (NPRI) and estimates of emissions from transportation (airports, trains, and car and truck traffic) and residential heating (oil, gas and wood), in conjunction with human toxicity potential factors. We also include substance-specific annual emissions in toxic equivalent kilograms and annual emissions in kilograms, to allow for ranking substances within any region.

RESULTS

For provinces and territories in Canada, the indicators suggest the top five substances contributing to the total toxic equivalent emissions in any region could be prioritized for further investigation. Residents of Quebec and New Brunswick may be more at risk of exposure to industrial emissions than those in other regions, suggesting that a more detailed study of exposure to industrial emissions in these provinces is warranted. Residential wood smoke may be an important emission to control, particularly in the north and eastern regions of Canada. Residential oil and gas heating, along with rail emissions contribute little to regional emissions and therefore may not be an immediate regional priority.

CONCLUSIONS

The developed indicators support the identification of pollutants and sources for additional investigation when planning exposure reduction actions among Canadian provinces and territories, but have important limitations similar to other emissions inventory-based tools. Additional research is required to evaluate how the Emissions Mapping Project is used by different groups and organizations with respect to informing actions aimed at reducing Canadians' potential exposure to harmful air pollutants.

Land use regression models for crustal and traffic-related PM2.5 constituents in four areas of the SAPALDIA study

Many studies have documented adverse health effects of long-term exposure to fine particulate matter (PM2.5), but there is still limited knowledge regarding the causal relationship between specific sources of PM2.5 and such health effects. The spatial variability of PM2.5 constituents and sources, as a exposure assessment strategy for investigating source contributions to health effects, has been little explored so far. Between 2011 and 2012, three measurement campaigns of PM and nitrogen dioxide (NO2) were performed in 80 sites across four areas of the Swiss Study on Air Pollution and Lung and heart Diseases in Adults (SAPALDIA). Reflectance analysis and energy dispersive X-ray fluorescence (XRF) were performed on PM2.5 filter samples to estimate light absorbance and trace element concentrations, respectively. Three air pollution source factors were identified using principal-component factor analysis: vehicular, crustal, and long-range transport. Land use regression (LUR) models were developed for temporally-adjusted scores of each factor, combining the four study areas. Model performance was assessed using two cross-validation methods. Model explained variance was high for the vehicular factor (R(2)=0.76), moderate for the crustal factor (R(2)=0.46), and low for the long-range transport factor (R(2)=0.19). The cross-validation methods suggested that models for the vehicular and crustal factors moderately accounted for both the between and within-area variability, and therefore can be applied to the four study areas to estimate long-term exposures within the SAPALDIA study population. The combination of source apportionment techniques and LUR modelling may help in identifying air pollution sources and disentangling their contribution to observed health effects in epidemiologic studies.

Using wavelet-feedforward neural networks to improve air pollution forecasting in urban environments

The paper presents the screening of various feedforward neural networks (FANN) and wavelet-feedforward neural networks (WFANN) applied to time series of ground-level ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM10 and PM2.5 fractions) recorded at four monitoring stations located in various urban areas of Romania, to identify common configurations with optimal generalization performance. Two distinct model runs were performed as follows: data processing using hourly-recorded time series of airborne pollutants during cold months (O3, NO2, and PM10), when residential heating increases the local emissions, and data processing using 24-h daily averaged concentrations (PM2.5) recorded between 2009 and 2012. Dataset variability was assessed using statistical analysis. Time series were passed through various FANNs. Each time series was decomposed in four time-scale components using three-level wavelets, which have been passed also through FANN, and recomposed into a single time series. The agreement between observed and modelled output was evaluated based on the statistical significance (r coefficient and correlation between errors and data). Daubechies db3 wavelet-Rprop FANN (6-4-1) utilization gave positive results for O3 time series optimizing the exclusive use of the FANN for hourly-recorded time series. NO2 was difficult to model due to time series specificity, but wavelet integration improved FANN performances. Daubechies db3 wavelet did not improve the FANN outputs for PM10 time series. Both models (FANN/WFANN) overestimated PM2.5 forecasted values in the last quarter of time series. A potential improvement of the forecasted values could be the integration of a smoothing algorithm to adjust the PM2.5 model outputs.

Health impacts and economic losses assessment of the 2013 severe haze event in Beijing area

Haze is a serious air pollution problem in China, especially in Beijing and surrounding areas, affecting visibility, public health and regional climate. In this study, the Weather Research and Forecasting-Chemistry (WRF-Chem) model was used to simulate PM2.5 (particulate matters with aerodynamic diameter≤2.5 μm) concentrations during the 2013 severe haze event in Beijing, and health impacts and health-related economic losses were calculated based on model results. Compared with surface monitoring data, the model results reflected pollution concentrations accurately (correlation coefficients between simulated and measured PM2.5 were 0.7, 0.4, 0.5 and 0.6 in Beijing, Tianjin, Xianghe and Xinglong stations, respectively). Health impacts assessments show that the PM2.5 concentrations in January might cause 690 (95% confidence interval (CI): (490, 890)) premature deaths, 45,350 (95% CI: (21,640, 57,860)) acute bronchitis and 23,720 (95% CI: (17,090, 29,710)) asthma cases in Beijing area. Results of the economic losses assessments suggest that the haze in January 2013 might lead to 253.8 (95% CI: (170.2, 331.2)) million US$ losses, accounting for 0.08% (95% CI: (0.05%, 0.1%)) of the total 2013 annual gross domestic product (GDP) of Beijing.

Urban air and tobacco smoke as conditions that increase the risk of oxidative stress and respiratory response in youth

BACKGROUND

Air pollution and tobacco smoke can induce negative effects on the human health and often leads to the formation of oxidative stress.

OBJECTIVE

The purpose of this study was to clarify the role of the urbanization degree and of passive exposure to tobacco smoke in the formation of oxidative stress. Thus, a group of non-smoking adolescents was recruited among those who live and attend school in areas with three different population densities. To each subject a spot of urine was collected to quantify 15-F2t isoprostane as a marker of oxidative stress and cotinine as a marker of passive exposure to tobacco smoke. Furthermore, respiratory functionality was also measured.

RESULTS

Multiple linear regression analysis results showed a direct correlation (p<0.0001) of 15-F2t isoprostane with both the urbanization and passive smoke. Lung function parameters proved significantly lower for the subjects living in the most populous city of Torino.

CONCLUSION

This remarks the negative effect that urbanization has on the respiratory conditions. Lastly, lung functionality presented a low inverse correlation with 15-F2t isoprostane, suggesting an independent mechanism than that of the urban factor.

Custos da poluição atmosférica nas regiões metropolitanas brasileiras

O presente estudo avaliou o impacto econômico de eventos de saúde associados com a poluição do ar em regiões metropolitanas brasileiras. A partir de estimativa da mortalidade atribuível às concentrações de Material Particulado (MP) em 29 Regiões Metropolitanas, que totalizaram 20.050 óbitos, foram calculados os custos associados a essa mortalidade por meio da metodologia DALY (Disability Adjusted Life Years). O custo das mortes prematuras no Brasil resultou em US$ 1,7 bilhão anualmente. A tradução de perdas em saúde pública para valores econômicos serviu para comparar com o orçamento de gastos do Ministério da Saúde e evidenciar as prioridades na tomada de decisão de políticas públicas que minimizem a magnitude desses impactos.

Economic valuation of the mortality benefits of a regulation on SO2 in 20 European cities

BACKGROUND

Since the 1970s, legislation has led to progress in tackling several air pollutants. We quantify the annual monetary benefits resulting from reductions in mortality from the year 2000 onwards following the implementation of three European Commission regulations to reduce the sulphur content in liquid fuels for vehicles.

METHODS

We first compute premature deaths attributable to these implementations for 20 European cities in the Aphekom project by using a two-stage health impact assessment method. We then justify our choice to only consider mortality effects as short-term effects. We rely on European studies when selecting the central value of a life-year estimate (€ 2005 86 600) used to compute the monetary benefits for each of the cities. We also conduct an independent sensitivity analysis as well as an integrated uncertainty analysis that simultaneously accounts for uncertainties concerning epidemiology and economic valuation.

RESULTS

The implementation of these regulations is estimated to have postponed 2212 (95% confidence interval: 772-3663) deaths per year attributable to reductions in sulphur dioxide for the 20 European cities, from the year 2000 onwards. We obtained annual mortality benefits related to the implementation of the European regulation on sulphur dioxide of € 2005 191.6 million (95% confidence interval: € 2005 66.9-€ 2005 317.2).

CONCLUSION

Our approach is conservative in restricting to mortality effects and to short-term benefits only, thus only providing the lower-bound estimate. Our findings underline the health and monetary benefits to be obtained from implementing effective European policies on air pollution and ensuring compliance with them over time.

Air pollution and atherosclerosis: new evidence to support air quality policies

Nino Künzli discusses a large new cohort study that provides some of the first human evidence for the impact of air pollution on the development of atherosclerosis.