The Development, Progress, and Impact of National Suicide Prevention Strategies Worldwide.

National suicide prevention strategies have been identified as evidence-informed interventions that require multisectoral efforts by governments. This article reviews the rationale for national strategies, the need for a whole-of-government approach, and current progress on national strategies worldwide, including successes and challenges regarding implementation. We highlight the limitations of existing evidence and describe how future research may help to address knowledge gaps. We conclude that national strategies are an important tool for suicide prevention worldwide. However, a more robust evidence base evaluating the impact of strategies on suicide-related outcomes is needed.

Evaluating the Effectiveness of Components of National Suicide Prevention Strategies.

Background: National suicide prevention strategies support development of suicide prevention activities and their evaluation. Aims: To describe components included in national suicide prevention strategies and analyze the potential contribution of individual components to reduce suicide rates. Method: We conducted a narrative review and statistical analysis of national suicide prevention strategies. The narrative review was based on a framework of 12 components and included 29 countries (14 lower middle-income countries [LMICs] and 15 high-income countries [HICs]) with a national suicide prevention strategy. The statistical analyses covered suicide mortality data for 24 countries with a national strategy (9 LMICs and 15 HICs). Results: The number of components adopted in national strategies ranged from 4 to 11, and training and education were included in 96.5% of strategies. Estimated period effects for total suicide rates in individual countries ranged from a significant decrease in the yearly suicide rate (RR = 0.80; 95% CI 0.69-0.93) to a significant increase (RR = 1.12; 95% CI 1.05-1.19). There were no changes in suicide mortality associated with individual components of national strategies. Limitations: The limitations of existing suicide mortality data apply to our study. Conclusion: Further detailed evaluations will help identify the specific contribution of individual components to the impact national strategies. Until then, countries should be encouraged to implement and evaluate comprehensive national suicide prevention strategies.

A Volunteer-Run, Face-to-Face, Early Intervention Service for Reducing Suicidality.

Background: Befriending is one of many strategies with the potential to reduce suicidal ideation and decrease the risk of suicide. Aims: To measure change in suicidal ideation and behavior among visitors (service users) supported at The Listening Place (TLP), a charity which offers volunteer-run, face-to-face befriending to people who are suicidal. Method: This study was peer reviewed and preregistered on the Open Science Framework prior to data extraction. Anonymized data were extracted for visitors at the point of referral and after 3 months of receiving support. Paired-sample tests were used to test whether self-reported suicidal ideation and behaviors changed after 3 months of support from TLP. Multivariable regressions were used to test whether change in suicidal feelings was associated with demographic characteristics or baseline self-reported suicidality. Results: TLP received 13,938 referrals from July 2016 to February 2022. Self-reported suicidal ideation, suicidal behavior, and feelings of distress decreased after 3 months, while feelings of support increased. Only self-reported suicidal behavior prior to referral was associated with a lesser reduction in self-reported suicidality after 3 months. Limitations: In the absence of a control group, it cannot be concluded that TLP causes the reduction in self-reported suicidality. Conclusions: An empathetic, nonjudgmental, listening service for people who are feeling suicidal was well received by users, who experienced a reduction in suicidality.

Midlife suicide: A systematic review and meta-analysis of socioeconomic, psychiatric and physical health risk factors.

Suicide is an increasing contributing cause of mortality in middle-aged adults; however, knowledge to guide prevention is limited. This first systematic review and meta-analysis of studies on midlife suicide has provided an overview of published research on this issue and synthesized the evidence on socioeconomic and physical and mental health factors associated with this mortality. Using PRISMA guidelines MEDLINE, Embase, PsycINFO, Scopus and Web of Science were searched for English-language publications that involved persons aged 35 to 65, used individual-level data, and reported prevalence of exposure(s) or relative risks. The search identified 62 studies on midlife suicides and associated factors (28 for SES, 22 for psychiatric disorder and 23 for physical illness). All studies were from high income countries, and most (80.6%) used data from population registries. Meta-analyses showed that the pooled prevalence of exposure in suicide decedents was 57.8% for psychiatric disorder, 56.3% for low income, 43.2% for unemployment, and 27.3% for physical illness. The associated pooled risk ratio was 11.68 (95% confidence intervals: 5.82-23.47) for psychiatric illness of any type, 12.59 (8.29-19.12) for mood disorders, 3.91 (2.72-5.59) for unemployment, 3.18 (2.72-3.72) for being separated or divorced, 2.64 (2.26-3.10) for cancer, 2.50 (0.96-6.38) for central nervous system illness, and 2.26 (1.16-4.41) for low income. In conclusion, midlife suicide is strongly associated with socioeconomic difficulties and physical and psychiatric illnesses that are common in this age population. Future investigations should consider the interactions between risk factors, the intersectionality of sex and ethnicity, and include data from low- and middle-income countries.

European aerosol phenomenology - 8: Harmonised source apportionment of organic aerosol using 22 Year-long ACSM/AMS datasets.

Organic aerosol (OA) is a key component of total submicron particulate matter (PM1), and comprehensive knowledge of OA sources across Europe is crucial to mitigate PM1 levels. Europe has a well-established air quality research infrastructure from which yearlong datasets using 21 aerosol chemical speciation monitors (ACSMs) and 1 aerosol mass spectrometer (AMS) were gathered during 2013-2019. It includes 9 non-urban and 13 urban sites. This study developed a state-of-the-art source apportionment protocol to analyse long-term OA mass spectrum data by applying the most advanced source apportionment strategies (i.e., rolling PMF, ME-2, and bootstrap). This harmonised protocol was followed strictly for all 22 datasets, making the source apportionment results more comparable. In addition, it enables quantification of the most common OA components such as hydrocarbon-like OA (HOA), biomass burning OA (BBOA), cooking-like OA (COA), more oxidised-oxygenated OA (MO-OOA), and less oxidised-oxygenated OA (LO-OOA). Other components such as coal combustion OA (CCOA), solid fuel OA (SFOA: mainly mixture of coal and peat combustion), cigarette smoke OA (CSOA), sea salt (mostly inorganic but part of the OA mass spectrum), coffee OA, and ship industry OA could also be separated at a few specific sites. Oxygenated OA (OOA) components make up most of the submicron OA mass (average = 71.1%, range from 43.7 to 100%). Solid fuel combustion-related OA components (i.e., BBOA, CCOA, and SFOA) are still considerable with in total 16.0% yearly contribution to the OA, yet mainly during winter months (21.4%). Overall, this comprehensive protocol works effectively across all sites governed by different sources and generates robust and consistent source apportionment results. Our work presents a comprehensive overview of OA sources in Europe with a unique combination of high time resolution (30-240 min) and long-term data coverage (9-36 months), providing essential information to improve/validate air quality, health impact, and climate models.

Iran's National Suicide Prevention Program.

Background and Aims: Iran is one of the few countries in the Eastern Mediterranean Region (EMR) to have developed a national suicide prevention program (NSPP). This report introduces Iran's NSPP to policy planners and researchers working in suicide prevention, and is intended to encourage other low- and middle-income countries to develop, implement, and evaluate their own NSPPs. Method: This was a case study of a NSPP in one country, integrating quantitative and qualitative data. Bibliographic searches were conducted using both international and national databases, supplemented by other documents. The study benefited from the experiential evidence provided by the senior author. Results: While the national incidence of suicide is low, there are higher rates among young adults, particularly women, in western regions. In 2010, Iran's NSPP was integrated into primary health care. A rigorous evaluation of Iran's suicide prevention program concluded that Iran has the potential to take a leadership role in suicide prevention within the EMR, although several challenges were identified. Limitation: The findings of this case study cannot be generalized to other contexts. Conclusion: Given Iran's unstable situation, the NSPP needs to be monitored, evaluated, and adjusted according to evidence and ongoing changing national and local needs.

The Impact of Infectious Disease-Related Public Health Emergencies on Suicide, Suicidal Behavior, and Suicidal Thoughts.

Background: Infectious disease-related public health emergencies (epidemics) may increase suicide risk, and high-quality evidence is needed to guide an international response. Aims: We investigated the potential impacts of epidemics on suicide-related outcomes. Method: We searched MEDLINE, EMBASE, PsycInfo, CINAHL, Scopus, Web of Science, PsyArXiv, medRxiv, and bioRxiv from inception to May 13-16, 2020. Inclusion criteria: primary studies, reviews, and meta-analyses; reporting the impact of epidemics; with a primary outcome of suicide, suicidal behavior, suicidal ideation, and/or self-harm. Exclusion criteria: not concerned with suicide-related outcomes; not suitable for data extraction. PROSPERO registration: #CRD42020187013. Results: Eight primary papers were included, examining the effects of five epidemics on suicide-related outcomes. There was evidence of increased suicide rates among older adults during SARS and in the year following the epidemic (possibly motivated by social disconnectedness, fears of virus infection, and concern about burdening others) and associations between SARS/Ebola exposure and increased suicide attempts. A preprint study reported associations between COVID-19 distress and past-month suicidal ideation. Limitations: Few studies have investigated the topic; these are of relatively low methodological quality. Conclusion: Findings support an association between previous epidemics and increased risk of suicide-related outcomes. Research is needed to investigate the impact of COVID-19 on suicide outcomes.

Suicide Prevention Programs.

This chapter presents a narrative synthesis of the evidence relating to the effectiveness of 13 different approaches (interventions) that have been incorporated into national suicide prevention programs. These approaches are presented in an analytic framework that distinguishes between national and community-based multilevel programs, prevention, and treatment/maintenance. The primary source of evidence are six reviews of reviews published since 2005, supplemented by a small number of systematic reviews and primary studies. We report strongly supportive evidence concerning the effectiveness of structural interventions (restrictions on access to bridges, tall buildings, and railways) and restriction on access to pharmacological agents. Weakly supportive evidence of effectiveness is available for community-based multilevel programs; restrictions on access to firearms and ligature points in institutional settings; settings-based programs (in schools, communities, workplaces, prisons, and the armed forces); education and training targeted at primary care physicians; lithium; cognitive behavioral therapy and dialectical behavioral therapy; and brief contact. There is insufficient or conflicting evidence concerning the effectiveness of the remaining approaches. We conclude that the evidence base for effective suicide prevention is far from convincing. Major improvement in the extent and quality of collaboration between researchers, policymakers, and practitioners and a considerable increase in funding for evaluation studies in suicide prevention are required if the current knowledge gap about effective interventions is to be bridged.

Were the floods in the UK 2007 and Germany 2013 game-changers?

This paper examines recovery after major floods in the UK and Germany. It focuses on two areas that were badly hit by flooding: Catcliffe, near Sheffield in the UK, and Passau in Bavaria, Germany. It reports on surveys of residents and businesses in each place and on surveys of national flood experts in both countries. The two events were comparable in terms of impacts, levels of preparedness and government response and show similar patterns of speed and quality of recovery. In Germany, it took about 18 months for 90% or more of residents to get back to normal, while in the UK it took a year longer. This difference may be related to funding; in the UK, over 90% of funding came from household insurance while in Germany over 60% came from federal aid, which may have been quicker. In both countries, the economy had recovered to near normal within 12-18 months. The majority of people surveyed in both countries (74% in Germany and 67% in the UK) believe that their homes and businesses are as just as vulnerable now as they were before the respective floods. However, in the UK, half of the respondents thought their neighbourhood was safer and better prepared compared to only 11% in Germany. This may be because substantial progress has been made in improving protection in the UK in areas flooded in 2007. Both floods were considered to be 'game-changers' and resulted in a heightened awareness of flood risk, increased investment in flood defences and an increasing emphasis on citizens taking more responsibility for flood preparedness. However, the Environment Agency in the UK lacks powers to prevent development in flood-prone areas, in Germany there are issues of coordination across large catchments that cross state boundaries and the insurance sector could play a bigger role in 'building back better'. Many homes and businesses continue to be at risk from major floods and more progress needs to be made in making them more resilient. This article is part of the theme issue 'Urban flood resilience'.

Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions.

Secondary organic aerosol (SOA) is formed from the atmospheric oxidation of gas-phase organic compounds leading to the formation of particle mass. Gasoline- and diesel-powered motor vehicles, both on/off-road, are important sources of SOA precursors. They emit complex mixtures of gas-phase organic compounds that vary in volatility and molecular structure-factors that influence their contributions to urban SOA. However, the relative importance of each vehicle type with respect to SOA formation remains unclear due to conflicting evidence from recent laboratory, field, and modeling studies. Both are likely important, with evolving contributions that vary with location and over short time scales. This review summarizes evidence, research needs, and discrepancies between top-down and bottom-up approaches used to estimate SOA from motor vehicles, focusing on inconsistencies between molecular-level understanding and regional observations. The effect of emission controls (e.g., exhaust aftertreatment technologies, fuel formulation) on SOA precursor emissions needs comprehensive evaluation, especially with international perspective given heterogeneity in regulations and technology penetration. Novel studies are needed to identify and quantify "missing" emissions that appear to contribute substantially to SOA production, especially in gasoline vehicles with the most advanced aftertreatment. Initial evidence suggests catalyzed diesel particulate filters greatly reduce emissions of SOA precursors along with primary aerosol.

The Impact of Tobacco Control Policies on Smoking Among Socioeconomic Groups in Nine European Countries, 1990-2007.

BACKGROUND: It is uncertain whether tobacco control policies have contributed to a narrowing or widening of socioeconomic inequalities in smoking in European countries during the past two decades. This paper aims to investigate the impact of price and non-price related population-wide tobacco control policies on smoking by socioeconomic group in nine European countries between 1990 and 2007. METHODS: Individual-level education, occupation and smoking status were obtained from nationally representative surveys. Country-level price-related tobacco control policies were measured by the relative price of cheapest cigarettes and of cigarettes in the most popular price category. Country-level non-price policies were measured by a summary score covering four policy domains: smoking bans or restrictions in public places and workplaces, bans on advertising and promotion, health warning labels, and cessation services. The associations between policies and smoking were explored using logistic regressions, stratified by education and occupation, and adjusted for age, Gross Domestic Product, period and country fixed effects. RESULTS: The price of popular cigarettes and non-price policies were negatively associated with smoking among men. The price of the cheapest cigarettes was negatively associated with smoking among women. While these favorable effects were generally in the same direction for all socioeconomic groups, they were larger and statistically significant in lower socioeconomic groups only. CONCLUSIONS: Tobacco control policies as implemented in nine European countries, have probably helped to reduce the prevalence of smoking in the total population, particularly in lower socioeconomic groups. Widening inequalities in smoking may be explained by other factors. Policies with larger effects on lower socioeconomic groups are needed to reverse this trend. IMPLICATIONS: Socioeconomic inequalities in smoking widened between the 1990s and the 2000s in Europe. During the same period, there were intensified tobacco control policies in many European countries. It is uncertain whether tobacco control policies have contributed to a narrowing or widening of socioeconomic inequalities in smoking in European countries. This study shows that tobacco control policies as implemented in the available European countries have helped to reduce the prevalence of smoking in the total population, particularly in lower socioeconomic groups. Widening inequalities in smoking may be explained by other factors.

Speed or deliberation: a comparison of post-disaster recovery in Japan, Turkey, and Chile.

This paper compares recovery in the wake of three recent earthquakes: the Great East Japan Earthquake in March 2011; the Van earthquake in Turkey in October 2011; and the Maule earthquake in Chile in February 2010. The authors visited all three locations approximately 12-18 months after the incidents and interviewed earthquake specialists, disaster managers, urban planners, and local authorities. A key challenge to post-disaster recovery planning is balancing speed and deliberation. While affected communities must rebuild as quickly as possible, they must also seek to maximise the opportunities for improvement that disasters provide. The three case studies bring this dilemma into stark relief, as recovery was respectively slow, fast, and just right in the aftermath of the events: the Government of Japan adopted a deliberate approach to recovery and reconstruction; speed was of the essence in Turkey; and an effective balance between speed and deliberation was achieved in Chile.

Inorganic Salt Interference on CO2+ in Aerodyne AMS and ACSM Organic Aerosol Composition Studies.

Aerodyne aerosol mass spectrometer (AMS) and Aerodyne aerosol chemical speciation monitor (ACSM) mass spectra are widely used to quantify organic aerosol (OA) elemental composition, oxidation state, and major environmental sources. The OA CO2+ fragment is among the most important measurements for such analyses. Here, we show that a non-OA CO2+ signal can arise from reactions on the particle vaporizer, ion chamber, or both, induced by thermal decomposition products of inorganic salts. In our tests (eight instruments, n = 29), ammonium nitrate (NH4NO3) causes a median CO2+ interference signal of +3.4% relative to nitrate. This interference is highly variable between instruments and with measurement history (percentiles P10-90 = +0.4 to +10.2%). Other semi-refractory nitrate salts showed 2-10 times enhanced interference compared to that of NH4NO3, while the ammonium sulfate ((NH4)2SO4) induced interference was 3-10 times lower. Propagation of the CO2+ interference to other ions during standard AMS and ACSM data analysis affects the calculated OA mass, mass spectra, molecular oxygen-to-carbon ratio (O/C), and f44. The resulting bias may be trivial for most ambient data sets but can be significant for aerosol with higher inorganic fractions (>50%), e.g., for low ambient temperatures, or laboratory experiments. The large variation between instruments makes it imperative to regularly quantify this effect on individual AMS and ACSM systems.

Characterization of Gas-Phase Organics Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry: Cooking Emissions.

Cooking processes produce gaseous and particle emissions that are potentially deleterious to human health. Using a highly controlled experimental setup involving a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), we investigate the emission factors and the detailed chemical composition of gas phase emissions from a broad variety of cooking styles and techniques. A total of 95 experiments were conducted to characterize nonmethane organic gas (NMOG) emissions from boiling, charbroiling, shallow frying, and deep frying of various vegetables and meats, as well as emissions from vegetable oils heated to different temperatures. Emissions from boiling vegetables are dominated by methanol. Significant amounts of dimethyl sulfide are emitted from cruciferous vegetables. Emissions from shallow frying, deep frying and charbroiling are dominated by aldehydes of differing relative composition depending on the oil used. We show that the emission factors of some aldehydes are particularly large which may result in considerable negative impacts on human health in indoor environments. The suitability of some of the aldehydes as tracers for the identification of cooking emissions in ambient air is discussed.

General Practitioners' Accounts of Patients Who Have Self-Harmed: A Qualitative, Observational Study.

BACKGROUND: The relationship between self-harm and suicide is contested. Self-harm is simultaneously understood to be largely nonsuicidal but to increase risk of future suicide. Little is known about how self-harm is conceptualized by general practitioners (GPs) and particularly how they assess the suicide risk of patients who have self-harmed. AIMS: The study aimed to explore how GPs respond to patients who had self-harmed. In this paper we analyze GPs' accounts of the relationship between self-harm, suicide, and suicide risk assessment. METHOD: Thirty semi-structured interviews were held with GPs working in different areas of Scotland. Verbatim transcripts were analyzed thematically. RESULTS: GPs provided diverse accounts of the relationship between self-harm and suicide. Some maintained that self-harm and suicide were distinct and that risk assessment was a matter of asking the right questions. Others suggested a complex inter-relationship between self-harm and suicide; for these GPs, assessment was seen as more subjective. In part, these differences appeared to reflect the socioeconomic contexts in which the GPs worked. CONCLUSION: There are different conceptualizations of the relationship between self-harm, suicide, and the assessment of suicide risk among GPs. These need to be taken into account when planning training and service development.

Toxicity of aged gasoline exhaust particles to normal and diseased airway epithelia.

Particulate matter (PM) pollution is a leading cause of premature death, particularly in those with pre-existing lung disease. A causative link between particle properties and adverse health effects remains unestablished mainly due to complex and variable physico-chemical PM parameters. Controlled laboratory experiments are required. Generating atmospherically realistic aerosols and performing cell-exposure studies at relevant particle-doses are challenging. Here we examine gasoline-exhaust particle toxicity from a Euro-5 passenger car in a uniquely realistic exposure scenario, combining a smog chamber simulating atmospheric ageing, an aerosol enrichment system varying particle number concentration independent of particle chemistry, and an aerosol deposition chamber physiologically delivering particles on air-liquid interface (ALI) cultures reproducing normal and susceptible health status. Gasoline-exhaust is an important PM source with largely unknown health effects. We investigated acute responses of fully-differentiated normal, distressed (antibiotics-treated) normal, and cystic fibrosis human bronchial epithelia (HBE), and a proliferating, single-cell type bronchial epithelial cell-line (BEAS-2B). We show that a single, short-term exposure to realistic doses of atmospherically-aged gasoline-exhaust particles impairs epithelial key-defence mechanisms, rendering it more vulnerable to subsequent hazards. We establish dose-response curves at realistic particle-concentration levels. Significant differences between cell models suggest the use of fully-differentiated HBE is most appropriate in future toxicity studies.

Economic recession and suicidal behaviour: Possible mechanisms and ameliorating factors.

BACKGROUND: A growing body of research evidence from countries around the world indicates that economic recession is associated with increases in suicide, particularly in males of working age. AIMS: To explore contributory and ameliorating factors associated with economic recession and suicide and thereby stimulate further research in this area and encourage policy makers to consider how best to reduce the impact of recession on mental health and suicidal behaviour. METHOD: We conducted a selective review of the worldwide literature focusing on possible risk factors, mechanisms and preventative strategies for suicidal behaviour linked to economic recession. RESULTS: A model of how recession might affect suicide rates is presented. A major and often prolonged effect of recession is on unemployment and job insecurity. Other important effects include those exerted by financial loss, bankruptcy and home repossession. It is proposed these factors may lead directly or indirectly to mental health problems such as depression, anxiety and binge drinking and then to suicidal behaviour. Countries with active labour market programmes and sustained welfare spending during recessions have less marked increases in suicide rates than those that cut spending on welfare and job-search initiatives for the unemployed. Other measures likely to help include targeted interventions for unemployed people, membership of social organisations and responsible media reporting. Good primary care and mental health services are needed to cope with increased demand in times of economic recession but some governments have in fact reduced healthcare spending as an austerity measure. CONCLUSION: The research evidence linking recession, unemployment and suicide is substantial, but the evidence for the other mechanisms we have investigated is much more tentative. We describe the limitations of the existing body of research as well as make suggestions for future research into the effects of economic recession on suicidal behaviour.

PRINTQUAL - a measure for assessing the quality of newspaper reporting of suicide.

BACKGROUND: Many studies have demonstrated a relationship between newspaper reporting of actual or fictional suicides and subsequent suicidal behaviors. Previous measures of the quality of reporting lack consistency concerning which specific elements should be included and how they should be weighted. AIMS: To develop an instrument, PRINTQUAL, comprising two scales of the quality (poor and good) of newspaper reporting of suicide that can be used in future studies of reporting. METHOD: A first draft of the PRINTQUAL instrument was compiled, comprising items indicative of poor- and good-quality newspaper reporting based on guidelines and key sources of evidence. This was refined by team members and then circulated to a group of international experts in the field for further opinion and weighting of individual items. RESULTS: The final instrument comprised 19 items in the poor-quality scale and four in the good-quality scale. Following training, agreement between raters was acceptably high for most items (κ ≥ .75) except for three items for which agreement was still acceptable (κ ≥ .60). CONCLUSION: The PRINTQUAL instrument for assessing the quality of newspaper reporting of suicide appears appropriate for use in research and monitoring in future studies.

High secondary aerosol contribution to particulate pollution during haze events in China.

Rapid industrialization and urbanization in developing countries has led to an increase in air pollution, along a similar trajectory to that previously experienced by the developed nations. In China, particulate pollution is a serious environmental problem that is influencing air quality, regional and global climates, and human health. In response to the extremely severe and persistent haze pollution experienced by about 800 million people during the first quarter of 2013 (refs 4, 5), the Chinese State Council announced its aim to reduce concentrations of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 micrometres) by up to 25 per cent relative to 2012 levels by 2017 (ref. 6). Such efforts however require elucidation of the factors governing the abundance and composition of PM2.5, which remain poorly constrained in China. Here we combine a comprehensive set of novel and state-of-the-art offline analytical approaches and statistical techniques to investigate the chemical nature and sources of particulate matter at urban locations in Beijing, Shanghai, Guangzhou and Xi'an during January 2013. We find that the severe haze pollution event was driven to a large extent by secondary aerosol formation, which contributed 30-77 per cent and 44-71 per cent (average for all four cities) of PM2.5 and of organic aerosol, respectively. On average, the contribution of secondary organic aerosol (SOA) and secondary inorganic aerosol (SIA) are found to be of similar importance (SOA/SIA ratios range from 0.6 to 1.4). Our results suggest that, in addition to mitigating primary particulate emissions, reducing the emissions of secondary aerosol precursors from, for example, fossil fuel combustion and biomass burning is likely to be important for controlling China's PM2.5 levels and for reducing the environmental, economic and health impacts resulting from particulate pollution.