Trace Metal Exposure is Associated with Increased Exhaled Nitric Oxide in Asthmatic Children

Background Children with asthma experience increased susceptibility to airborne pollutants. Exposure to traffic and industrial activity have been positively associated with exacerbation of symptoms as well as emergency room visits and hospitalisations. The effect of trace metals contained in fine particulate matter (aerodynamic diameter 2.5 μm and lower, PM2.5) on acute health effects amongst asthmatic children has not been well investigated. The objective of this panel study in asthmatic children was to determine the association between personal daily exposure to ambient trace metals and airway inflammation, as measured by fractional exhaled nitric oxide (FeNO). Methods Daily concentrations of trace metals contained on PM2.5 were determined from personal samples (n = 217) collected from 70 asthmatic school aged children in Montreal, Canada, over ten consecutive days. FeNO was measured daily using standard techniques. Results A positive association was found between FeNO and children’s exposure to an indicator of vehicular non-tailpipe emissions (8.9 % increase for an increase in the interquartile range (IQR) in barium, 95 % confidence interval (CI): 2.8, 15.4) as well as exposure to an indicator of industrial emissions (7.6 % increase per IQR increase in vanadium, 95 % CI: 0.1, 15.8). Elevated FeNO was also suggested for other metals on the day after the exposure: 10.3 % increase per IQR increase in aluminium (95 % CI: 4.2, 16.6) and 7.5 % increase per IQR increase in iron (95 % CI: 1.5, 13.9) at a 1-day lag period. Conclusions Exposures to ambient PM2.5 containing trace metals that are markers of traffic and industrial-derived emissions were associated in asthmatic children with an enhanced FeNO response

Dataset associated with "Unequal airborne exposure burden to toxic metals is associated with race, ethnicity, and segregation"

This dataset contains annual and county-level mean concentrations and mass proportions of fine particulate metals (aggregated from the EPA's CSN/IMPROVE networks), associated minimum detectable limit for each monitor, as well as racial and ethnic demographic population data. This dataset is aggregated from publicly available air pollutant data from the EPA (http://views.cira.colostate.edu/fed/QueryWizard/Default.aspx) and the US Census Bureau (https://data.census.gov/cedsci/). This dataset is used to examine the association of racial residential segregation with fine particulate metal concentrations. The time period ranges from year 2009 to 2019.- Columns labeled "XX_concentration" report the annual and county-level mean concentration in ug m-3 - Columns labeled 'XX_content" report the mass proportion of fine particulate metals relative to PM2.5 mass - Columns labeled "XX_mdl" report the minimum detectable limit for that species at that monitor. In the case of more than one monitor in the county, this column reports the average. - Columns labeled "DI_XX" report the dissimilarity index for the racial/ethnic group using the non-Hispanic White population as the reference population (see associated manuscript for details), where "NHB" corresponds to non-Hispanic Black and "native_amer" to "Native American". - Columns labeled "XX_pop_county" report the county population of the respective racial/ethnic group. These groupings reflect the identification made by individuals in US Census Bureau data. "NHW" refers to "non-Hispanic White". - "CountyFIPS" refers to the county FIPS code. - "Latitude" and "Longitude" reflect the coordinates of the monitor in degrees. In the case of more than one monitor per county, these columns averages.Communities of color have been exposed to a disproportionate burden of air pollution across the United States for decades. Yet, the inequality in exposure to known toxic elements of air pollution is unclear. Here, we find that populations living in racially segregated communities are exposed to a form of fine particulate matter with over three times higher mass proportions of known toxic and carcinogenic metals. While concentrations of total fine particulate matter are two times higher in racially segregated communities, concentrations of metals from anthropogenic sources are nearly ten times higher. Populations living in racially segregated communities have been disproportionately exposed to these environmental stressors throughout the past decade. We find evidence, however, that these disproportionate exposures may be abated though targeted regulatory action. For example, recent regulations on marine fuel oil not only reduced vanadium concentrations in coastal cities, but also sharply lessened differences in vanadium exposure by segregation.This work was supported financially by grants from the Health Effects Institute under grant number 4953- RFA14-3/16-4 awarded to FD, National Institute of Health under grant numbers DP2MD012722 and P50MD010428 awarded to FD, National Institute of Health and National Institute of Environmental Health Sciences under grant number R01 ES028033 awarded to FD, National Institute of Health and Columbia University under grant number 1R01ES030616 awarded to FD, the National Institute On Minority Health And Health Disparities of the National Institutes of Health under award number R01MD012769 awarded to MLB and FD, the Environmental Protection Agency under grant number 83587201-0 awarded to FD and grant number RD83587101 awarded to MLB, The Climate Change Solutions Fund, and the Harvard Star Friedman Award. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Environmental Protection Agency

Particulate oxidative burden as a predictor of exhaled nitric oxide in children with asthma

Background: Epidemiological studies have provided strong evidence that fine particulate matter (PM2.5; aerodynamic diameter ≤ 2.5 μm) can exacerbate asthmatic symptoms in children. Pro-oxidant components of PM2.5 are capable of directly generating reactive oxygen species. Oxidative burden is used to describe the capacity of PM2.5 to generate reactive oxygen species in the lung. Objective: In this study we investigated the association between airway inflammation in asthmatic children and oxidative burden of PM2.5 personal exposure. Methods: Daily PM2.5 personal exposure samples (n = 249) of 62 asthmatic school-aged children in Montreal were collected over 10 consecutive days. The oxidative burden of PM2.5 samples was determined in vitro as the depletion of low-molecular-weight antioxidants (ascorbate and glutathione) from a synthetic model of the fluid lining the respiratory tract. Airway inflammation was measured daily as fractional exhaled nitric oxide (FeNO). Results: A positive association was identified between FeNO and glutathione-related oxidative burden exposure in the previous 24 hr (6.0% increase per interquartile range change in glutathione). Glutathione-related oxidative burden was further found to be positively associated with FeNO over 1-day lag and 2-day lag periods. Results further demonstrate that corticosteroid use may reduce the FeNO response to elevated glutathione-related oxidative burden exposure (no use, 15.8%; irregular use, 3.8%), whereas mold (22.1%), dust (10.6%), or fur (13.1%) allergies may increase FeNO in children with versus children without these allergies (11.5%). No association was found between PM2.5 mass or ascorbate-related oxidative burden and FeNO levels. Conclusions: Exposure to PM2.5 with elevated glutathione-related oxidative burden was associated with increased FeNO

Increased Oxidative Burden Associated with Traffic Component of Ambient Particulate Matter at Roadside and Urban Background Schools Sites in London

As the incidence of respiratory and allergic symptoms has been reported to be increased in children attending schools in close proximity to busy roads, it was hypothesised that PM from roadside schools would display enhanced oxidative potential (OP). Two consecutive one-week air quality monitoring campaigns were conducted at seven school sampling sites, reflecting roadside and urban background in London. Chemical characteristics of size fractionated particulate matter (PM) samples were related to the capacity to drive biological oxidation reactions in a synthetic respiratory tract lining fluid. Contrary to hypothesised contrasts in particulate OP between school site types, no robust size-fractionated differences in OP were identified due high temporal variability in concentrations of PM components over the one-week sampling campaigns. For OP assessed both by ascorbate (OPAA m−3) and glutathione (OPGSH m−3) depletion, the highest OP per cubic metre of air was in the largest size fraction, PM1.9–10.2. However, when expressed per unit mass of particles OPAA µg−1 showed no significant dependence upon particle size, while OPGSH µg−1 had a tendency to increase with increasing particle size, paralleling increased concentrations of Fe, Ba and Cu. The two OP metrics were not significantly correlated with one another, suggesting that the glutathione and ascorbate depletion assays respond to different components of the particles. Ascorbate depletion per unit mass did not show the same dependence as for GSH and it is possible that other trace metals (Zn, Ni, V) or organic components which are enriched in the finer particle fractions, or the greater surface area of smaller particles, counter-balance the redox activity of Fe, Ba and Cu in the coarse particles. Further work with longer-term sampling and a larger suite of analytes is advised in order to better elucidate the determinants of oxidative potential, and to fuller explore the contrasts between site types.\ud \u

Household air pollution and risk of pulmonary tuberculosis in HIV-Infected adults

Background: In low- and middle-income countries countries, millions of deaths occur annually from household air pollution (HAP), pulmonary tuberculosis (PTB), and HIV-infection. However, it is unknown whether HAP influences PTB risk among people living with HIV-infection. Methods: We conducted a case-control study among 1,277 HIV-infected adults in Bukavu, eastern Democratic Republic of Congo (February 2018 – March 2019). Cases had current or recent (<5y) PTB (positive sputum smear or Xpert MTB/RIF), controls had no PTB. Daily and lifetime HAP exposure were assessed by questionnaire and, in a random sub-sample (n=270), by 24-hour measurements of personal carbon monoxide (CO) at home. We used multivariable logistic regression to examine the associations between HAP and PTB. Results: We recruited 435 cases and 842 controls (median age 41 years, [IQR] 33-50; 76% female). Cases were more likely to be female than male (63% vs 37%). Participants reporting cooking for >3h/day and ≥2 times/day and ≥5 days/week were more likely to have PTB (aOR 1·36; 95%CI 1·06-1·75) than those spending less time in the kitchen. Time-weighted average 24h personal CO exposure was related dose-dependently with the likelihood of having PTB, with aOR 4·64 (95%CI 1·1-20·7) for the highest quintile [12·3-76·2 ppm] compared to the lowest quintile [0·1-1·9 ppm]. Conclusion: Time spent cooking and personal CO exposure were independently associated with increased risk of PTB among people living with HIV. Considering the high burden of TB-HIV coinfection in the region, effective interventions are required to decrease HAP exposure caused by cooking with biomass among people living with HIV, especially women

PM2.5, oxidant defence and cardiorespiratory health: a review

Abstract Airborne fine particle mass concentrations (PM2.5) are used for ambient air quality management worldwide based in part on known cardiorespiratory health effects. While oxidative stress is generally thought to be an important mechanism in determining these effects, relatively few studies have specifically examined how oxidant defence may impact susceptibility to particulate air pollution. Here we review studies that explore the impact of polymorphisms in anti-oxidant related genes or anti-oxidant supplementation on PM2.5-induced cardiorespiratory outcomes in an effort to summarize existing evidence related to oxidative stress defence and the health effects of PM2.5. Recent studies of PM-oxidative burden were also examined. In total, nine studies were identified and reviewed and existing evidence generally suggests that oxidant defence may modify the impact of PM2.5 exposure on various health outcomes, particularly heart rate variability (a measure of autonomic function) which was the most common outcome examined in the studies reviewed. Few studies examined interactions between PM2.5 and oxidant defence for respiratory outcomes, and in general studies focused primarily on acute health effects. Therefore, further evaluation of the potential modifying role of oxidant defence in PM2.5-induced health effects is required, particularly for chronic outcomes. Similarly, while an exposure metric that captures the ability of PM2.5 to cause oxidative stress may offer advantages over traditional mass concentration measurements, little epidemiological evidence is currently available to evaluate the potential benefits of such an approach. Therefore, further evaluation is required to determine how this metric may be incorporated in ambient air quality management

Transitioning to zero-emission bus fleets: state of practice of implementations in the United States

Several states and transit agencies have recently introduced zero-emission buses (ZEBs) to their fleets, including battery electric buses, fuel cell battery electric buses, and fuel cell plug-in hybrid electric buses in an effort to mitigate transportation-related impacts on air quality. The objective of this paper was to summarise information and insights from ZEB implementations across the United States (U.S.) to advance the state of practice and facilitate transit agencies’ transition to ZEBs. Information was obtained through a critical review of relevant literature from peer-reviewed journals and agency reports released by transit agencies and other relevant stakeholders, an online survey of several transit agencies that implemented or are planning to implement ZEBs, and interviews with transit agency representatives and other relevant stakeholders. This review focuses on ZEB in-service performance, cost, fuelling, and implementation strategies. In addition, challenges and lessons learned as reported by U.S. transit agencies are described. A comparison among the three technologies and conventional fuel buses (i.e. diesel and compressed natural gas) suggests that ZEBs outperform conventional buses in terms of fuel efficiency, but their procurement cost is higher. Battery electric buses present the highest fuel efficiency and lowest procurement, operation, and maintenance costs, and have been chosen by most transit agencies followed by fuel cell battery electric buses. While fuel cell hybrid plug-in buses have been implemented by several agencies over the past ten years, they have not gained popularity due to increased purchase and maintenance costs. Important factors for agencies to consider when implementing any of these ZEB technologies include: (1) fleet size: starting with a small fleet and gradually expanding; (2) technology type: understanding the technology and properly choosing the one that matches the needs and limitations of a service area (e.g. available space, existing schedule) as well as available resources and agency goals; (3) staff training: proper training for a suitable amount of time of drivers and maintenance personnel; and (4) stakeholder collaboration: having an effective level of collaboration, cooperation, and support between stakeholders. Overall, ZEBs are a viable and promising approach for reducing emissions from transit fleets. This review can assist in transit agencies’ transition to ZEB fleets by providing useful information and insights to ensure optimal technology choice and efficient implementations. It can also provide insights on ZEB implementation issues that warrant further research