Systematic review and meta-analysis on the health effects of long-term exposure to ultrafine particles.

Background and aim: Studies have shown elevated concentrations of ultrafine particles (UFP) near airports. Little is known about the health effects of UFP, in particular from aviation (UFP-aviation). We evaluated the health effects of long-term exposure to UFP-aviation around Schiphol Airport, The Netherlands. Methods: We investigated a wide range of health outcomes, by linking modelled annual average residential concentrations of UFP-aviation to individual data from existing health registries and surveys. We conducted two longitudinal cohort studies, on mortality and incidence of medication use, and a cross-sectional study using survey data on self-reported health and lifestyle factors. The cohort studies included all residents of 31 municipalities in a 45x50 km area around Schiphol Airport (~1.3 million adults). Survey data was available for 90,880 adults. Effect estimates were adjusted for individual and neighborhood-level covariates and expressed per 3500 pts/cm3 (~p5-p95 increment across the three studies). We performed a number of sensitivity analyses to evaluate the robustness of the results, including adjustment for co-pollutants and noise. The combination of different databases and designs allowed us to evaluate consistency of the findings both within and across studies. Results: We found no clear or consistent associations between UFP-aviation and health outcomes related to general health, respiratory health, neurodegenerative disease, or mental health. For cardiovascular health, we found robust positive associations with incidence of medication use for heart disease [HR 1.03 (95%CI 1.00-1.05)] and mortality for arrhythmia [HR 1.08 (95%CI 0.98-1.02)], but not for incidence of medication use for hypertension or (total or other subclasses of) cardiovascular mortality. In the survey data, we found robust significant associations with prevalence of hypertension and self-reported heart attack and consistently elevated (non-significant) associations with self-reported stroke. Conclusions: Exposure to UFP from aviation around Schiphol Airport was associated with cardiovascular health outcomes. Keywords: ultrafine particles, aviation, air pollution, mortality, morbidity

BackgroundRecent studies reported elevated concentrations of ultrafine particles (UFP) near airports. Little is known about the health effects of UFP from aviation. Since UFP can deposit deep into the lungs and other organs, they may cause significant adverse health effects. ObjectiveWe investigated health effects of controlled short-term human exposure to UFP near a major airport. MethodsIn this study, 21 healthy non-smoking volunteers (age range: 18–35 years) were repeatedly (2–5 visits) exposed for 5 h to ambient air near Schiphol Airport, while performing intermittent moderate exercise (i.e. cycling). Pre- to post-exposure changes in cardiopulmonary outcomes (spirometry, forced exhaled nitric oxide, electrocardiography and blood pressure) were assessed and related to total- and size-specific particle number concentrations (PNC), using linear mixed effect models. ResultsThe PNC was on average 53,500 particles/cm3 (range 10,500–173,200). A 5–95th percentile increase in exposure to UFP (i.e. 125,400 particles/cm3) was associated with a decrease in FVC of −73.8 mL (95% CI −138.8 – −0.4) and a prolongation of the corrected QT (QTc) interval by 9.9 ms (95% CI 2.0 – 19.1). These effects were associated with particles < 20 nm (mainly UFP from aviation), but not with particles > 50 nm (mainly UFP from road traffic). DiscussionShort-term exposures to aviation-related UFP near a major airport, was associated with decreased lung function (mainly FVC) and a prolonged QTc interval in healthy volunteers. The effects were relatively small, however, they appeared after single exposures of 5 h in young healthy adults. As this study cannot make any inferences about long-term health impacts, appropriate studies investigating potential health effects of long-term exposure to airport-related UFP, are urgently needed.

Large number of studies provided convincing evidence for adverse effects of exposure to outdoor air pollution on human health, and served as basis for current USA and EU Air Quality Standards and limit values. Still, new knowledge is emerging, expanding our understanding of vast effects of exposure to air pollution on human health of this ubiquitous exposure affecting millions of people in urban setting. This paper focuses on the studies of health effects of long-term (chronic) exposures to air pollution, and includes major chronic and acute diseases in adults and especially elderly, which will present increasing public health burden, due to improving longevity and projected increasing numbers of elderly. The paper gives overview over the most relevant and latest literature presented by different health outcomes: chronic obstructive pulmonary disease, asthma, pneumonia, cardiovascular disease, and diabetes.

There is an unmet need for large-scale multicenter studies on health effects of long-term exposure to ultrafine particles (UFPs). Such studies have been hampered by the lack of high-resolution models covering large geographical areas. This study aims to develop and evaluate Europe-wide UFP models using mobile measurements. Between 2018 and 2024, we conducted UFP mobile measurement campaigns in nine European areas. We developed both Europe-wide pooled and area-specific models of UFP concentrations at a 25 m spatial scale, using supervised linear regression with a deconvolution approach. The performance of our pooled models, with and without deconvolution, was similar, exhibiting an overall R2 of 0.33-0.36, 0.34-0.35 in 5-fold cross-validation (CV), and 0.29 in leave-one-area-out CV. When evaluated against external independent, longer term off-road measurements collected from seven areas and countries, our deconvoluted model effectively captured UFP variability in both urban and rural settings, with R2 ranging from 0.25 to 0.70, modestly better than the non-deconvoluted model (R2 = 0.23-0.67) and superior to area-specific models (R2 = 0.15-0.42). These findings underscore the ability of our pooled deconvoluted Europe-wide UFP model to capture the variability of UFP across diverse environments. The UFP model estimates will facilitate large-scale multicenter studies to investigate the long-term health effects of UFP exposure.

Development of land-use regression models for exposure assessment to ultrafine particles in Rome, Italy

BackgroundLarge nation- and region-wide epidemiological studies have provided important insights into the health effects of long-term exposure to outdoor air pollution. Evidence from these studies for the long-term effects of ultrafine particles (UFP), however is lacking. Reason for this is the shortage of empirical UFP land use regression models spanning large geographical areas including cities with varying topographies, peri-urban and rural areas. The aim of this paper is to combine targeted mobile monitoring and long-term regional background monitoring to develop national UFP models. MethodWe used an electric car to monitor UFP concentrations in selected cities and towns across the Netherlands over a 14-month period in 2016–2017. Routes were monitored 3 times and concentrations were averaged per road segment. In addition, we used kriging maps based on regional background monitoring (20 sites; 3 × 2 weeks) over the same period to assess annual average regional background concentrations. All road segments were used to model spatial variation of UFP with three different land-use (regression) approaches: supervised stepwise regression, LASSO and random forest. For each approach, we also tested a deconvolution method, which segregates the average concentration at each road segment into a local and background signal. Model performance was evaluated with short-term (400 sites across the Netherlands; 3 × 30 minutes) and external longer-term measurements (42 sites in two major cities; 3 × 24 hours). We also compared predictions of all six models at 1000 random addresses spread over the country. ResultsWe found similar predictive performance for the six models, with validation R2 values from 0.25 to 0.35 for short-term measurements and 0.52 to 0.60 for longer-term external measurements. Models with and without deconvolution had similar predictive performance. All models based on the deconvolution method included a regional background kriging map as important predictor. Correlations between predictions at random addresses were high with Pearson correlations from 0.84 to 0.99. Models overestimated exposure at the short-term and long-term sites by about 20–30% in all cases, with small differences between regions and road types. ConclusionWe developed robust nation-wide models for long-term UFP exposure combining mobile monitoring with long-term regional background monitoring. Minor differences in predictive performance between different algorithms were found, but the deconvolution approach is considered more physically realistic. The models will be applied in Dutch nation-wide health studies.

Although concentrations of ambient air pollution continue to decline in high-income regions, epidemiological studies document adverse health effects at levels below current standards in many countries. The Health Effects Institute (HEI) recently completed a comprehensive research initiative to investigate the health effects of long-term exposure to low levels of air pollution in the United States (U.S.), Canada, and Europe. We provide an overview and synthesis of the results of this initiative along with other key research, the strengths and limitations of the research, and remaining research needs. The three studies funded through the HEI initiative estimated the effects of long-term ambient exposure to fine particulate matter (PM2.5), nitrogen dioxide, ozone, and other pollutants on a broad range of health outcomes, including cause-specific mortality and cardiovascular and respiratory morbidity. To ensure high quality research and comparability across studies, HEI worked actively with the study teams and engaged independent expert panels for project oversight and review. All three studies documented positive associations between mortality and exposure to PM2.5 below the U.S. National Ambient Air Quality Standards and current and proposed European Union limit values. Furthermore, the studies observed nonthreshold linear (U.S.), or supra-linear (Canada and Europe) exposure-response functions for PM2.5 and mortality. Heterogeneity was found in both the magnitude and shape of this association within and across studies. Strengths of the studies included the large populations (7-69 million), state-of-the-art exposure assessment methods, and thorough statistical analyses that applied novel methods. Future work is needed to better understand potential sources of heterogeneity in the findings across studies and regions. Other areas of future work include the changing and evolving nature of PM components and sources, including wildfires, and the role of indoor environments. This research initiative provided important new evidence of the adverse effects of long-term exposures to low levels of air pollution at and below current standards, suggesting that further reductions could yield larger benefits than previously anticipated.

Spatial and temporal variation of façade-level particle number concentrations using portable monitors in Copenhagen, Denmark

Effects of ultrafine carbon particle inhalation on allergic inflammation of the lung

Health effects of long-term exposure to ultrafine particles (UFP) have not been investigated in epidemiological studies because of the lack of spatially resolved UFP exposure data. Short-term monitoring campaigns used to develop land use regression (LUR) models for UFP typically had moderate performance. The aim of this study was to develop and evaluate spatial and spatiotemporal LUR models for UFP and Black Carbon (BC), including their ability to predict past spatial contrasts. We measured 30 min at each of 81 sites in Amsterdam and 80 in Rotterdam, The Netherlands in three different seasons. Models were developed using traffic, land use, reference site measurements, routinely measured pollutants and weather data. The percentage explained variation (R(2)) was 0.35-0.40 for BC and 0.33-0.42 for UFP spatial models. Traffic variables were present in every model. The coefficients for the spatial predictors were similar in spatial and spatiotemporal models. The BC LUR model explained 61% of the spatial variation in a previous campaign with longer sampling duration, better than the model R(2). The UFP LUR model explained 36% of UFP spatial variation measured 10 years earlier, similar to the model R(2). Short-term monitoring campaigns may be an efficient tool to develop LUR models.

Associations between ultrafine and fine particles and mortality in five central European cities — Results from the UFIREG study

Background: Studies have shown elevated concentrations of ultrafine particles (UFP) near airports. Little is known about the health effects of UFP, particularly from aviation. We evaluated the health effects of short-term exposure to UFP around Schiphol Airport, The Netherlands. Methods: We conducted three studies, with different designs: 1. Observational study with 191 schoolchildren in residential areas near Schiphol, including weekly lung function and exhaled NO measurements at school (161 children) and daily lung function and symptom recording at home (all 191 children). 2. Controlled exposure study with 21 healthy adults, including 2-5 repeated 5-hour exposures in a mobile laboratory directly next to Schiphol, with pre and post measurements of lung function, exhaled NO, electrocardiography and blood pressure. 3. Toxicological study with human bronchial epithelial cells (Calu-3), using UFP collected directly next to Schiphol as well as UFP collected from a turbine engine, and assessment of cell viability, cytotoxicity and inflammatory potential. Results: In children, we found statistically significant associations between exposure to UFP and an increase in daily respiratory symptoms and bronchodilator use. These associations were observed for UFP from aviation as well as UFP from road traffic, based on particle size distribution. In the adults study, exposure to UFP from aviation was associated with a decline in lung function (FVC) and a prolongation of the QTc interval (ECG). UFP from road traffic was associated with an increase in systolic blood pressure. In Calu-3 cells, exposure to UFP resulted in cell damage and release of pro-inflammatory markers, with no significant differences in reactivity between the different sources of UFP. Conclusions: Together these studies show that short-term increased exposure to UFP, as occurs around Schiphol, is associated with acute health effects. We found no indications that effects of UFP from aviation are substantially different from those of UFP from road traffic.

The health effects of traffic-related air pollution (TRAP) continue to be of important public health interest. Following its well-cited 2010 critical review, the Health Effects Institute (HEI) is conducting a systematic review of the epidemiological literature on the health effects of long-term exposure to TRAP, with a new expert Panel. The Panel consists of 14 experts in epidemiology, exposure assessment and biostatistics, and is chaired by Francesco Forastiere (King's College London) and Fred Lurmann (Sonoma Technology). Results are being combined quantitatively to evaluate the strength of evidence, where appropriate. The quantitative results of the review may be useful for future risk and health impact assessments of TRAP. The Panel is using a systematic approach to search the literature, assess study quality, summarize results, and reach conclusions about the body of evidence. To this end, a review protocol was developed and registered in Prospero. An extensive search was conducted of literature published between January 1980 and July 2019. Selected health outcomes include all-cause and cause-specific mortality, respiratory effects, cardiovascular effects, diabetes, and adverse birth outcomes. In addition, the Panel has developed an exposure framework to guide the selection and evaluation of epidemiological studies on TRAP. The review is now well underway, and preliminary results will be presented. After a broad search, the Panel has identified 1100 studies relevant for further screening; about 400 of which met the inclusion criteria and will be considered in the systematic review. Effect estimates were reported for all-cause mortality (40 papers), cardiovascular effects (70 papers), respiratory effects (180 papers), and birth outcomes (100 papers). The systematic review will undergo peer-review in 2020 and publication is aimed for 2021. The new review will be an authoritative update of HEI's most-cited report for use by researchers and policymakers.

With reductions in tailpipe emissions of particulate matter, there is an increasing interest in public health impacts of non-tailpipe emissions, specifically tire and brake wear and road dust. Following its well-cited 2010 critical review, a new Health Effects Institute (HEI) expert panel is conducting a systematic review of the epidemiological literature on the health effects of long-term exposure to TRAP, including non-tailpipe emissions. The Panel is using a systematic approach to search the literature, assess study quality, summarize results, and reach conclusions about the body of evidence. They developed a review protocol and registered it in Prospero. An extensive search was conducted of literature published between January 1980 and July 2019. Selected health outcomes include all-cause and cause-specific mortality, respiratory effects, cardiovascular effects, diabetes, and birth outcomes. In addition, the Panel has developed an exposure framework to guide the selection and evaluation of epidemiological studies on TRAP. The review is now well underway, and preliminary results will be presented. After a broad search identifying 1100 studies potentially relevant to the broader review, the panel included 14 studies reporting both relevant health outcomes and epidemiological results for non-tailpipe pollutants. Effect estimates were reported for all-cause mortality (3 papers), circulatory mortality (1 paper), cardiovascular effects (2 papers), respiratory effects (3 papers), and neurodevelopment in children (2 papers). Ten of the papers evaluated effects of copper (Cu) and iron (Fe); others evaluated only Cu (2 papers) or non-exhaust PM2.5 mass (2 papers). Further evaluation of these papers will inform future research questions related to health effects of non-tailpipe emissions from motor vehicles.

ISEE-0703 Background and Objective: Studies have suggested acute health effects related to short-term exposure to ultrafine particles (UFP). There are currently no epidemiological studies on health effects of long-term exposure to UFP, largely because of the lack of spatially resolved exposure data for UFP. The objective of this study was to develop a land use regression model for UFP in the city of Amsterdam. Methods: Total particle number was measured from October 2002 until March 2004 directly outside 50 homes spread over the city of Amsterdam, using condensation particle counters (TSI CPC3022a). Each home was measured during one week. Simultaneously measurements were made at one urban background site in the city center. The average difference of the home outdoor and the reference site measurements per home was used to develop the land use regression model. Predictor variables were obtained using geographic information systems. Results: Valid data were available for 48 sites, of which 22 were traffic sites. The mean difference with the reference site was 7644 cm−3 (interquartile range 2210–21081 cm−3). A linear regression model with indicator variables defining whether or not the site was a traffic site, in a street canyon, in the city center and the sampling height of the site explained 51% of the variance in concentrations. Traffic was the most important predictor. Conclusion: For the first time a land use regression model for UFP in Amsterdam has been developed, with similar validity as previously published models for more commonly measured pollutants such as NO2..