Effects of air pollution on health: A mapping review of systematic reviews and meta-analyses
Graphical abstract
Introduction
Air pollution is recognized as a leading problem for public health, and a major environmental health problem around the world, deserving growing interest from the scientific community (Brunekreef, Holgate, 2002; Landrigan, 2017). The ambient air pollution may be caused by many different contaminants, although the following are the most commonly studied; particulate matter (PM), ground-level ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen dioxide (NO2) (Brook et al., 2004; Sheehan et al., 2016). Regarding particulate matter, the most widely used descriptors are PM2.5 and PM10, defined as the mass, in a given air volume, of all the particles with an aerodynamic diameter below 2.5 μm and 10 μm, respectively.
There is much evidence that both acute and chronic exposure to air pollution, especially coarse and fine particulates, increases the morbidity and mortality of the population (Liu et al., 2019; Sanyal et al., 2018). The World Health Organization (WHO) estimates 4.2 million deaths every year as a result of exposure to ambient (outdoor) air pollution (WHO, 2018), which makes air pollution the fourth highest-ranking risk factor for death worldwide (Brauer, 2016). It is also worth mentioning that 91% of the world's population lives in places where air quality levels exceed WHO guideline limits (WHO, 2016). According to the Lancet Report, pollution costs the global economy $4.6 trillion per year, corresponding to 6.2% of global economic output (GAHP, 2020).
A notable increase in knowledge production on air pollution and human health has recently been observed (Sun, Zhu, 2019a), through numerous studies that reported both short- and long-term effects of air pollution exposure, including several investigated health outcomes and different pollutants (Sun, Zhu, 2019a). In particular, Sun, Zhu recently detected 799 original studies focused on health outcomes caused by outdoor air pollution (2019a).
According to Sheehan et al. (2016), the last decade was marked by the increase in the use of systematic reviews and meta-analyses (SRs and MAs) techniques in environmental health epidemiology with respect to the recent past. Considering the exponential increase in systematic reviews and meta-analyses, which may be related to the increase in scientific production of original studies, there is a need to analyze these publications, to identify gaps in the literature and guide future research. As the a priori hypothesis was that there are many systematic reviews and meta-analysis dealing with the topic, a mapping review could be a better way to analyze this vast literature, instead of an umbrella review. Mapping reviews are a research tool used to map out and categorize research with the aim of identifying gaps and commissioning further reviews (Craig et al., 2017).
To the best of the authors’ knowledge, there are few studies in this sense in the environmental sciences area. A similar study was conducted by Song et al. (2017) to investigate the impact of ambient temperature on morbidity and mortality; the authors included twenty-eight studies and concluded that heat exposure seemed to have an adverse effect on mortality. Alternatively, an overview of reviews on ambient air pollution was performed by Sheehan et al. (2016) who focused on reviewing the reporting and methods practices of 43 systematic reviews and meta-analyses published from 2009 to 2015.
Therefore, there is currently no up-to-date, complete, and comprehensive analysis through a systematic summary of systematic reviews and meta-analyses about the effects of air pollution on health, focused on human health outcomes. Thus, to better understand the research evolution in the field, considering the quantity of scientific evidence already published, it is important to analyze the characteristics of the studies and the main health outcomes investigated due to exposure to different pollutants. Thus, to assimilate the vast amount of research available regarding the relationship between air pollution and health, we performed a mapping review of existing systematic reviews and meta-analyses aiming to analyze the state of the art concerning the effects of air pollution on human health.
Section snippets
Guidelines
A systematic mapping review was performed to analyze and summarize the effects of air pollution on health. The work was based on the recommendations for mapping reviews in environmental sciences by James, Randall, and Haddaway (2016).
Three filters to gather (search procedure), select (inclusion and exclusion criteria), and extract (data extraction) relevant information from the literature were applied in this mapping review (Peters, Wood, 2017). The steps described in the Template for a Mapping
Literature search results
The literature search identified 3401 relevant articles and 2199 unique citations across all sources. Of these, 283 full papers were assessed for eligibility, and 240 SRs and MAs were selected for synthesis (see Fig. 1 PRISMA flowchart).
Here, the five previously detailed research questions will be answered based on the review synthesis.
RQ1. How many SRs and MAs have been published on the effects of air pollution on health? Is there any temporal trend? What is the geographical distribution of
Discussion
This is the first systematic mapping review carried out on the effects of air pollution on health, considering only systematic reviews and meta-analysis. The current mapping review includes relevant SRs and MAs to provide a more complete picture of the work performed thus far in one of the most important fields of research. Air pollution is a major environmental risk to health and a global health concern, being one of the main causes of morbidity and mortality of the population worldwide (WHO,
Funding
This work was supported by the Research Innovation Support Foundation of the State of Santa Catarina (FAPESC) under Grant [2019031000035 and Call number 04.2018]. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) – Finance Code 001.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
References (89)
- et al.
Acute effects of fine particulate matter constituents on mortality: a systematic review and meta-regression analysis
Environ. Int.
(2017) - et al.
Indoor air quality of environments used for physical exercise and sports practice: systematic review
J. Environ. Manag.
(2018) - et al.
Scientific production on indoor air quality of environments used for physical exercise and sports practice: bibliometric analysis
J. Environ. Manag.
(2017) - et al.
Air pollution and health
Lancet
(2002) - et al.
Towards sustainable, energy-efficient and healthy ventilation strategies in buildings: a review
Renew. Sustain. Energy Rev.
(2016) - et al.
Tuberculosis stigma as a social determinant of health: a systematic mapping review of research in low incidence countries
Int. J. Infect. Dis.
(2017) Early life exposure to ambient air pollution and childhood asthma in China
Environ. Res.
(2015)- et al.
The health effects of ambient PM2. 5 and potential mechanisms
Ecotoxicol. Environ. Saf.
(2016) - et al.
Outdoor air pollution and asthma
Lancet
(2014) - et al.
Short-term effect of air pollution on asthma patient visits in Shanghai area and assessment of economic costs
Ecotoxicol. Environ. Saf.
(2018)
Carbon monoxide poisoning in Iran during 1999–2016: a systematic review and meta-analysis
Journal of forensic and legal medicine
Air pollution exposure: a novel environmental risk factor for interstitial lung disease?
Chest
Health effects of particles in ambient air
Int. J. Hyg Environ. Health
Mortality and hospitalizations due to cardiovascular and respiratory diseases associated with air pollution in Iran: a systematic review and meta-analysis
Atmos. Environ.
Size, source and chemical composition as determinants of toxicity attributable to ambient particulate matter
Atmos. Environ.
Air pollution and health
The Lancet Public Health
Systematic review and meta-analysis of the adverse health effects of ambient PM2. 5 and PM10 pollution in the Chinese population
Environ. Res.
Airborne particles in indoor environment of homes, schools, offices and aged care facilities: the main routes of exposure
Environ. Int.
Assessing nitrogen dioxide (NO2) levels as a contributing factor to the coronavirus (COVID-19) fatality rate
Sci. Total Environ.
Daily submicron particle doses received by populations living in different low-and middle-income countries
Environ. Pollut.
Systematic review of Chinese studies of short-term exposure to air pollution and daily mortality
Environ. Int.
Non-linear increase of respiratory diseases and their costs under severe air pollution
Environ. Pollut.
Impact of ambient temperature on morbidity and mortality: an overview of reviews
Sci. Total Environ.
Possible environmental effects on the spread of COVID-19 in China
Meta-analysis of the Chinese studies of the association between ambient ozone and mortality
Chemosphere
Indirect effects of COVID-19 on the environment
Sci. Total Environ.
Effect of air pollution and hospital admission: a systematic review
Annals of global health
Ambient coarse particulate matter and human health: a systematic review and meta-analysis
Current environmental health reports
Growing evidence for the impact of air pollution on depression
Ochsner J. 2019 Spring
Infection risk in gyms during physical exercise
Environ. Sci. Pollut. Control Ser.
Fitness centers demonstrate CO2 concentration levels above recommended standards
Acta Sci. Health Sci.
Long-term exposure to ambient ozone and mortality: a quantitative systematic review and meta-analysis of evidence from cohort studies
BMJ open
Systematic review and meta-analysis of epidemiological time-series studies on outdoor air pollution and health in Asia
Air Quality, Atmosphere & Health
Epidemiological time series studies of PM2. 5 and daily mortality and hospital admissions: a systematic review and meta-analysis
Thorax
Fine particle components and health—a systematic review and meta-analysis of epidemiological time series studies of daily mortality and hospital admissions
J. Expo. Sci. Environ. Epidemiol.
Seventy-five trials and eleven systematic reviews a day: how will we ever keep up?
PLoS Med.
Who is sensitive to the effects of particulate air pollution on mortality? A case-crossover analysis of effect modifiers
Epidemiology
A meta-analysis of time-series studies of ozone and mortality with comparison to the national morbidity, mortality, and air pollution study
Epidemiology
Evidence on vulnerability and susceptibility to health risks associated with short-term exposure to particulate matter: a systematic review and meta-analysis
Am. J. Epidemiol.
Who is more affected by ozone pollution? A systematic review and meta-analysis
Am. J. Epidemiol.
Analysis of the time and workers needed to conduct systematic reviews of medical interventions using data from the PROSPERO registry
BMJ Open
Air pollution (particulate matter) exposure and associations with depression, anxiety, bipolar, psychosis and suicide risk: a systematic review and meta-analysis
Environ. Health Perspect.
The Global Burden of Disease from Air Pollution, 2016 AAAS Annual Meeting
Air pollution and cardiovascular disease: a statement for healthcare professionals from the expert panel on population and prevention science of the American heart association
Circulation
Cited by (108)
Long-term exposure to air pollution and risk of stroke by ecoregions: The REGARDS study
2024, Environmental PollutionOrganic Pollutant Exposure and CKD: A Chronic Renal Insufficiency Cohort Pilot Study
2024, Kidney Medicine