Current Air Quality Guidelines Research Articles

Low-level ambient ozone exposure associated with neutrophil extracellular traps and pro-atherothrombotic biomarkers in healthy adults

Background and aimsUncertainty of the causality determinations for ambient ozone (O3) on cardiovascular events is heightened by the limited understanding of the mechanisms involved in humans. We aimed to examine the pro-atherothrombotic impacts of O3 exposure and to explore the potential mediating roles of dysfunctional neutrophils, focusing on neutrophil extracellular traps (NETs). MethodsA longitudinal panel study of 152 healthy adults was conducted in the cool to cold months with relatively low levels of O3 between September 2019 and January 2020 in Beijing, China. Four repeated measurements of indicators reflecting atherothrombotic balance and NETs were performed for each participant. ResultsDaily average exposure levels of ambient O3 were 16.6 μg/m3 throughout the study period. Per interquartile range increase in average concentrations of O3 exposure at prior up to 7 days, we observed elevations of 200.1–276.3% in D-dimer, 27.2–36.8% in thrombin-antithrombin complex, 10.8–60.3% in plasminogen activator inhibitor 1, 13.9–21.8% in soluble P-selectin, 16.5–45.1% in matrix metalloproteinase-8, and 2.4–12.4% in lipoprotein-associated phospholipase A2. These pro-atherothrombotic changes were accompanied by endothelial activation, lung injury, and immune inflammation. O3 exposure was also positively associated with circulating NETs indicators, including citrullinated histone H3, neutrophil elastase, myeloperoxidase, and double-stranded DNA. Mediation analyses indicated that NETs could mediate O3-associated pro-atherothrombotic responses. The observational associations remained significant and robust after controlling for other pollutants, and were generally greater in participants with low levels of physical activity. ConclusionsAmbient O3 exposure was associated with significant increases in NETs and pro-atherothrombotic potential, even at exposure levels well below current air quality guidelines of the World Health Organization.

Increased HbA1c During Pregnancy is Associated with In-utero Exposure to PM2.5 at Levels below Current Air Quality Guidelines

Increased HbA1c During Pregnancy is Associated with In-utero Exposure to PM2.5 at Levels below Current Air Quality Guidelines

Low-level ambient sulfur dioxide exposure and genetic susceptibility associated with incidence of idiopathic pulmonary fibrosis: A national prospective cohort study

BackgroundThe association between long-term air pollution exposure and the development of idiopathic pulmonary fibrosis (IPF) has been established, but the evidence regarding the effect of low levels of air pollution, especially ambient sulfur dioxide (SO2), is limited. Besides, the combined effect and interaction between genetic susceptibility and ambient SO2 on IPF remain uncertain. MethodsThis study retrieved data from 402,042 participants who were free of IPF at baseline in the UK Biobank. The annual mean concentration of ambient SO2 was estimated for each participant based on their residential addresses using a bilinear interpolation method. Cox proportional hazard models were used to examine the relationship between ambient SO2 and incident IPF. We further generated a polygenic risk score (PRS) for IPF and estimated the combined effects of genetic susceptibility and ambient SO2 on incident IPF. ResultsAfter a median follow-up of 11.78 years, 2562 cases of IPF were identified. The results indicated that each 1 μg/m3 increase in ambient SO2 was associated with a hazard ratio (HR) (95% confidence interval [CI]) of 1.67 (1.58, 1.76) for incident IPF. The study found statistically significant synergistic additive interaction between genetic susceptibility and ambient SO2. Individuals with high genetic risk and high ambient SO2 exposure had a higher risk of developing IPF (HR = 7.48, 95% CI:5.66, 9.90). ConclusionThe study suggests that long-term exposure to ambient SO2, even at concentrations lower than current air quality guidelines set by the Word Health Organization and European Union, may be an important risk factor for IPF. This risk is more pronounced among people with a high genetic risk. Therefore, these findings emphasize the need to consider the potential health effects of SO2 exposure and the necessity for stricter air quality standards.

Different sized particles associated with all-cause and cause-specific emergency ambulance calls: A multicity time-series analysis in China

BackgroundCompared with mortality and hospital admission, emergency ambulance calls (EACs) could be a more accurate outcome indicator to reflect the health effects of short-term air pollution exposure. However, such studies have been scarce, especially on a multicity scale in China. MethodsWe estimated the associations of different diameter particles [i.e., inhalable particulate matter (PM10), coarse particulate matter (PMc), and fine particulate matter (PM2.5)] with EACs for all-cause, cardiovascular, and respiratory diseases in seven Chinese cities. We collected data on EACs and air pollution from 2014 to 2019. We used generalized additive models and random-effects meta-analysis to examine the city-specific and overall associations. Stratified analyses were conducted to examine the effect modifications of gender, age, and season. ResultsSignificant associations of PM10 and PM2.5 with EACs were observed, while the PMc associations were positive but not statistically significant in most analyses. Specifically, each 10 μg/m3 increase in 2-day moving average concentration of PM10 was associated with a 0.25% [95% confidence interval (CI): 0.04%, 0.47%] increase in all-cause EACs, 0.13% (95% CI: −0.01%, 0.26%) in cardiovascular EACs, and 0.35% (95% CI: 0.04%, 0.66%) in respiratory EACs. The corresponding increases in daily EACs for PM2.5 were 0.30% (95% CI, 0.03%, 0.57%), 0.13% (95% CI, −0.07%, 0.33%), and 0.46% (95% CI, 0.01%, 0.92%). Season of the year also modifies the association between particulate matter pollution and EACs. ConclusionsShort-term exposure to PM10 and PM2.5 were positively associated with daily all-cause and respiratory-related EACs. The associations were stronger during warm season than cold season. Our findings suggest that the most harmful fraction of particulate matter pollution is PM2.5, which has important implications for current air quality guidelines and regulations in China.

Ambient carbon monoxide and daily mortality: a global time-series study in 337 cities

Epidemiological evidence on short-term association between ambient carbon monoxide (CO) and mortality is inconclusive and limited to single cities, regions, or countries. Generalisation of results from previous studies is hindered by potential publication bias and different modelling approaches. We therefore assessed the association between short-term exposure to ambient CO and daily mortality in a multicity, multicountry setting. We collected daily data on air pollution, meteorology, and total mortality from 337 cities in 18 countries or regions, covering various periods from 1979 to 2016. All included cities had at least 2 years of both CO and mortality data. We estimated city-specific associations using confounder-adjusted generalised additive models with a quasi-Poisson distribution, and then pooled the estimates, accounting for their statistical uncertainty, using a random-effects multilevel meta-analytical model. We also assessed the overall shape of the exposure-response curve and evaluated the possibility of a threshold below which health is not affected. Overall, a 1 mg/m3 increase in the average CO concentration of the previous day was associated with a 0·91% (95% CI 0·32-1·50) increase in daily total mortality. The pooled exposure-response curve showed a continuously elevated mortality risk with increasing CO concentrations, suggesting no threshold. The exposure-response curve was steeper at daily CO levels lower than 1 mg/m3, indicating greater risk of mortality per increment in CO exposure, and persisted at daily concentrations as low as 0·6 mg/m3 or less. The association remained similar after adjustment for ozone but was attenuated after adjustment for particulate matter or sulphur dioxide, or even reduced to null after adjustment for nitrogen dioxide. This international study is by far the largest epidemiological investigation on short-term CO-related mortality. We found significant associations between ambient CO and daily mortality, even at levels well below current air quality guidelines. Further studies are warranted to disentangle its independent effect from other traffic-related pollutants. EU Horizon 2020, UK Medical Research Council, and Natural Environment Research Council.

Short-term PM2.5 exposure and emergency hospital admissions for mental disease

Epidemiologic studies regarding the relationship between short-term exposure to particulate matter with a median aerodynamic diameter < 2.5 µm (PM2.5) and mental disease are limited. This study examined the effects of short-term exposure to PM2.5 on emergency admissions to the hospital for mental disease in Seoul, Korea.Data regarding 80,634 emergency admissions for mental diseases were collected from a nationally centralized healthcare claims database in Seoul during 2003–2013. Generalized linear models with climate variables were used to examine associations between short-term PM2.5 exposure and mental disease admissions. To comprehensively assess PM2.5 effects, we used single- and two-pollutant models, which considered other pollutants in combination with PM2.5.The relative risk (RR) of emergency admissions for mental disease was 1.008 (95% confidence interval, 1.001–1.015) for each 10 μg/m3 increase in 2-day average PM2.5 concentration. This effect persisted or became slightly stronger in the two-pollutant models that included carbon monoxide, nitrogen dioxide, ozone, or sulfur dioxide (RR, 1.01–1.021), but association appeared to be limited to individuals < 65 years of age. Significant association was estimated only during the warm season (RR, 1.021–1.023) in the two-pollutant models. The exposure–response curve was steeper at lower concentrations, suggesting that the risk of mental disease at lower concentrations of pm2.5 (0–30 µg/m3). PM2.5 was associated with increased admissions even when it was below the World Health Organization's Air Quality Guidelines (25 μg/m3), but the association was not statistically significant.Thus, based on the data from a large database, exposure to PM2.5 was associated with increases in emergency admissions for mental diseases, and this association was significant during the warm season. PM2.5 may even affect mental disease at levels below the current air quality guidelines. These results provide substantial insight regarding the effects of air pollutants and have important implications for policy makers.

Long-term monitoring of trace metals in PM10 and total gaseous mercury in the atmosphere of Porto, Portugal

As part of a monitoring programme conducted by the Institute of Environment and Development (IDAD) and supported by the regional municipal solid waste (MSW) management authorities, an extensive database of trace metals (TMs) concentrations in ambient air was collected in two sites, Leça do Balio (LB) and Vila Nova da Telha (VNT), located in Porto's metropolitan area, north of Portugal. Since 2004, concentrations of As, Cd, Pb, Cu, Cr, Mn, Hg, Ni and Zn were measured in PM10. In addition, total gaseous mercury (TGM) was monitored since 2008. These measurements were used to assess long-term trends of concentrations. Statistical analysis was used to search for the possible origin of the TMs.During the monitoring period, the mean TMs concentrations followed the order: Zn > Cu > Pb > Mn > Cr > Ni > As ≈ Hg > Cd, and have not exceeded the current air quality guidelines values. Concentrations of As, Cd, Pb, Mn, and Hg have slightly decreased during the measurement period despite already being at historically low levels. The concentrations range of Zn, Cd, Pb and As suggests a seasonal variability for these elements in ambient air, for both sites. Average TGM levels were 1.93 and 1.35 ng m−3, for LB and VNT respectively. In terms of seasonality, a statistical difference was found in TGM concentrations between winter and summer for LB. A daily pattern was also observed in TGM with minimum concentrations during the night and early morning.

Impact of air quality guidelines on COPD sufferers

BackgroundCOPD 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.ObjectiveThis systematic review was to summarize the up-to-date literature on the impact of air pollution on the COPD sufferers.MethodsPubMed 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.ResultsBoth 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.ConclusionThere 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.

Gestational Diabetes and Preeclampsia in Association with Air Pollution at Levels below Current Air Quality Guidelines

Background: Several studies have estimated associations between air pollution and birth outcomes, but few have evaluated potential effects on pregnancy complications.Objective: We investigated whether low-level exposure to air pollution is associated with gestational diabetes and preeclampsia.Methods: High-quality registry information on 81,110 singleton pregnancy outcomes in southern Sweden during 1999–2005 was linked to individual-level exposure estimates with high spatial resolution. Modeled exposure to nitrogen oxides (NOx), expressed as mean concentrations per trimester, and proximity to roads of different traffic densities were used as proxy indicators of exposure to combustion-related air pollution. The data were analyzed by logistic regression, with and without adjusting for potential confounders.Results: The prevalence of gestational diabetes increased with each NOx quartile, with an adjusted odds ratio (OR) of 1.69 (95% CI: 1.41, 2.03) for the highest (> 22.7 µg/m3) compared with the lowest quartile (2.5–8.9 µg/m3) of exposure during the second trimester. The adjusted OR for acquiring preeclampsia after exposure during the third trimester was 1.51 (1.32, 1.73) in the highest quartile of NOx compared with the lowest. Both outcomes were associated with high traffic density, but ORs were significant for gestational diabetes only.Conclusion: NOx exposure during pregnancy was associated with gestational diabetes and preeclampsia in an area with air pollution levels below current air quality guidelines.

Broad Exposure Screening of Air Pollutants in the Occupational Environment of Swedish Soldiers Deployed in Afghanistan

The main objective of this study was to perform an initial characterization of Swedish soldiers' exposure to air pollutants in Afghanistan and screen for potential health hazards. Stationary monitoring was performed in two military camps, International Security Assistance Force Headquarters in Kabul and Camp Northern Lights in Mazar-e Sharif, at both outdoor and indoor locations. A broad screening including particulate matter (PM10 and PM2.5), polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs, n-alkanes, nitrogen dioxide (NO2), sulfur dioxide, toxic metals, and volatile organic compounds (VOCs) was performed over 2 weeks in the autumn of 2009. The results were compared to current air quality guidelines. Particulate matter was identified as the main potential health hazard since military exposure guidelines for marginal effects were exceeded outdoors. In addition, especially in Kabul, levels of particle-bound PAHs and oxy-PAHs were high, whereas levels of toxic metals were generally low. Among gaseous pollutants, elevated NO2 levels in Kabul supported combustion as a major contributor to the poor air quality. VOC levels were generally low, but levels of some pollutants exceeded current guidelines. Because of elevated concentrations of particles with a high content of toxic organics, further monitoring and characterization of the occupational environment are warranted.

Levels of selected metals in ambient air PM10 in an urban site of Zaragoza (Spain)

An assessment of the air quality of Zaragoza (Spain) was performed by determining the trace element content in airborne PM10 in a sampling campaign from July 2001 to July 2002. Samples were collected in a heavy traffic area with a high volume air sampler provided with a PM10 cutoff inlet. The levels of 16 elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were quantified after collecting the PM10 on Teflon-coated glass fiber filters (GFF). Regarding the PM10, 32% exceedance of the proposed PM10 daily limit was obtained, some of them corresponding to summer and autumn periods. The limit values of toxic trace elements from US-EPA, WHO, and EC were not exceeded, considering Zaragoza as a moderately polluted city under the current air quality guidelines. The contribution of anthropogenic sources to atmospheric elemental levels was reflected by the high values of enrichment factors for Zn, Pb, and Cu compared to the average crustal composition. Statistical analyses also determined the contribution of different sources to the PM10, finding that vehicle traffic and anthropogenic emissions related to combustion and industrial processes were the main pollutant sources as well as natural sources associated with transport of dust from Africa for specific dates. Regarding the influence of meteorological conditions on PM10 and trace elements concentrations, it was found that calm weather conditions with low wind speed favor the PM10 collection and the pollution for trace elements, suggesting the influence of local sources.

Air pollution and its health impacts: the changing panorama.

Urban air pollution levels are associated with increased mortality and cardiorespiratory morbidity. These health effects occur even at exposure levels below those stipulated in current air-quality guidelines, and it is unclear whether a safe threshold exists. Air pollution in Australia and New Zealand comes primarily from motor vehicle emissions, electricity generation from fossil fuels, heavy industry, and home heating using wood and coal. In individual patients a direct link between symptoms and air pollution exposure may be difficult to establish and may not change their clinical management. However, avoiding exposure during periods of peak pollution may be beneficial. Although there is some evidence that urban air pollution in Australia and New Zealand has been decreasing (through reduced car use, improved emission-control technology and use of more energy-efficient devices in the household and in industry), pollution levels are still unsatisfactory. Further reductions may prevent hundreds of cardiorespiratory hospital admissions and deaths each year.

Assessment of metal concentrations in atmospheric particles from Burnaby Lake, British Columbia, Canada

Trace metals were assessed in atmospheric particulates at Burnaby Lake, in the greater Vancouver area of British Columbia to assess concentrations, particle size distributions and deposition rates to an urban watershed. Week-long samples were collected over a period of 18 weeks in 1995 using a 13 stage low pressure impactor (LPI). Samples were analysed using inductively coupled plasma atomic emission spectroscopy (ICP). Aluminum, boron, calcium, iron, magnesium, manganese, sodium and strontium had a similar time series pattern and particle size distribution. For these metals, maximum concentrations occurred during weeks of low precipitation and exhibited a large peak in mid June. Their particle size distribution was mostly dominated by a large peak between 1.7–18.4 μm with a secondary peak at <0.08 μm. Metal concentrations were generally one to three orders of magnitude higher than those measured in a rural location 100 km away from Burnaby Lake but similar to those measured in urban Taipei, Taiwan. Concentrations of the highly toxic metals, arsenic, cadmium and lead were within current air quality guidelines, however boron exceeded the Ontario Ministry of Environment ambient air quality standard in two of the 16 samples. Deposition velocities ranged between 0.22 and 13 cm s −1 with the largest values corresponding to the coarse particle mode. Mean deposition rates ranged between 4.0 μg m −2 d −1 and 650 mg m −2 d −1. Depending on the metal, yearly loadings to the watershed ranged from 90 kg to several thousand tonnes. Calcium, aluminum, boron and magnesium had the highest metal loadings to the watershed. Manganese also had relatively high loadings, a reflection of the high traffic density in the area. The relatively high metal deposition rates indicate that metal contribution from atmospheric sources may represent a significant portion of the total metal load to the Burnaby Lake watershed.

Clara cell secretory protein (CC16): features as a peripheral lung biomarker.

Clara cell protein (CC16 or CC10) is a 15.8-kDa protein secreted all along the tracheobronchial tree and especially in the terminal bronchioles where Clara cells are localized. Even though the exact in vivo function of CC16 remains to be clarified, evidence is accumulating that CC16 plays an important protective role in the respiratory tract against oxidative stress and inflammatory response. CC16, however, presents also a major interest as a peripheral lung marker for assessing the cellular integrity or the permeability of the lung epithelium. The serum concentrations of CC16 are decreased in subjects with chronic lung damage caused by tobacco smoke and other air pollutants as a consequence of the destruction of Clara cells. By contrast, serum CC16 increases in acute or chronic lung disorders characterized by an increased airways permeability. The sensitivity of serum CC16 to an increased leakiness of the lung allows for the detection of defects of the epithelial barrier at ozone levels below current air-quality guidelines. Although the clinical significance of these early epithelial changes detected by serum CC16 remains to be determined, these results clearly show that the assay in serum of lung secretory proteins such as CC16 represents a new noninvasive approach to evaluate the integrity of the respiratory tract.