Peak exposures to nitrogen dioxide and study design to detect their acute health effects

A study designed to detect the health effects of short term exposures to high levels of nitrogen dioxide (ranging from 0.1 μL/L to over 1.5 μL/L) on pulmonary function and respiratory symptoms in asthmatic and non-asthmatic subjects residing in inner-city apartments in New York City is described. The continuous exposure of nitrogen dioxide on the study subjects before, during, and after cooking a dinner on a gas stove is determined using a continuous nitrogen dioxide monitoring instrument. Lung function tests are performed and symptom questionnaires are administered throughout the study period to assess both health effects and changes in pulmonary function associated with the above exposures.In addition, peak levels of NO₂ at different heights above the floor, and at various distances from the stove, while the range and oven are in operation are reported for twenty four homes.     

Fuel from waste tyres and particulate matter emitted from the process

The interest in obtaining alternative fuels from waste sources and at the same time diminishing the impact of waste disposal has drawn attention to scrap tyres' carbon recovery. In order to thermally degrade used tyre rubber, a laboratory pyrolysis system was developed in this work. The installation devised focused on the production of liquid pyrolysates, where shredded rubber was supplied as the feedstock and nitrogen used as the carrier gas to provide an oxygen-free atmosphere. The variables affecting the performance of the process were investigated, including target temperature, heating rate and total residence time. Characterization of the volatile matter released was conducted by means of mass spectrometry to determine the composition of products, and particulate matter analysis to ascertain the aerosol content in the gas stream. The reproducibility of experiments, the influence of the temperature and time, and differences between the vapours before condensation and the exhaust gases are discussed. This work identified that the larger hydrocarbon fragments condense to constitute the oils, whereas the lighter molecules remain as non-condensable gases. This work also identified that the total number of nano-scale particles carried by the exhaust stream varies with temperature; significant changes in the composition of products and particle content were reported at approximately 400°C. The high number of nano-scale solid particulate matter present in the exhaust gases suggests that a thorough treatment for that stream would be required to avoid human health hazards.     

Environmentally compatible energy resource production—consumption pattern (case study: Iran)

Like all rapidly developing countries, the government of Iran (GOI) has to integrate environment priorities into its energy sector. In order to integrate environmental concerns into energy sector, an Energy-Environment Review (EER) may be considered as the mainstreaming tool capable of examining the interface between energy and the environment. The results of the EER should be interpreted, in the light of the objective of the 4th Five Year Development Plan in Iran, to achieve fast and sustainable growth and accelerate the transition to a market economy. In particular, the suggested actions will promote economic efficiency use of energy resources through a proper allocation of scarce resources, including environmental resources, so as to achieve economic efficiency and environmental and social protection. This paper comprises: (A) an analysis of the current situation with regards to energy production and consumption; (B) an evaluation of the growth prospects with regard to energy production and consumption; (C) the identification of environmental issues induced by the generation and use of energy and estimation of the associated costs of damages; (D) the evaluation of the extent of contribution to the climate-change phenomenon through emission of greenhouse gases; (E) the evaluation of the proposed mitigation measures for the previously identified environmental problems; and (F) conclusions and recommendations. The EER-Iran assessed the total health damage from air pollution in 2001 at about 56  ×  10¹² Rials (US $ seven billion); equivalent to 8.4% of nominal GDP. In the absence of the price reform and control policies, the EER-Iran estimated that the damage in Iran in the money of 2001, will grow to 155  ×  10¹² Rials (US $ nine billion) by 2019. This is equivalent to 10.9% of nominal GDP, i.e., a large percentage of a larger GDP. Of this total, 107  ×  10¹² Rials (US $ 8.4 billion) come from transport sector. The damage cost to the global environment from the flaring of natural gas, assessed on the basis of a carbon price of US $ 10/ton CO₂, is found to be approximately US $ 600 million per year. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Relationships among personal,indoor and outdoor NO2 measurements

Using integrating NO₂ diffusion dosimeters, personal, indoor and outdoor exposures were measured for nine families in Topeka, Kansas. NO₂ exposures in homes that used gas for cooking were clearly different from those in homes that used electricity. The gas-cooking homes had indoor levels three times the outdoor levels. Members of the gas-cooking households had levels twice those of electric-cooking families and twice the outdoor levels. A linear model that includes outdoor concentrations and stove types explains 77% of the variance in observed NO₂ exposure. The differential NO₂ exposures in homes with and without gas stoves should be considered in epidemiologic studies of the health effects of air pollution.     

An approach to comparative assessments of potential health risks from exposure to radionuclides and hazardous chemicals

The need to compare potential health risks to the public associated with different activities that can result in releases of hazardous substances to the environment is becoming increasingly important in decision-making. In making such comparisons, it is desirable to use equivalent indicators of potential health risks for radionuclides, chemical carcinogens, and noncarcinogenic hazardous chemicals. Current approaches to risk assessment that were developed for purposes of protecting human health do not provide equivalent indicators of potential risks from exposure to radionuclides and hazardous chemicals. Comparisons of environmental concentrations or calculated exposures or risks with standards for protection of public health also do not provide equivalent indicators of potential risks. We propose a simple approach to comparative risk assessments in which calculated exposures to any hazardous substances are expressed relative to no-observed-effect levels (NOELs) or, preferably, lower confidence limits of benchmark doses (BMDLs) in humans. This approach provides an equivalent, science-based indicator of the relative risks posed by different exposures to any hazardous substances.     

Sidestream tobacco smoke constituents in indoor air modelled in an experimental chamber— Polycyclic aromatic hydrocarbons

Exposure to sidestream tobacco smoke is concerned with constituents in suspension in the indoor atmosphere. The natural dissipation of sidestream tobacco smoke has been investigated in a static atmosphere in a 10 m³ experimental chamber, and the rate of dissipation is expressed as T_0.5, the half-life of residence in the air. Respective T_0.5 of smoke components are calculated from the various sample data points, assuming a kinetic equation of the first-order process. Sidestream smoke has been generated by a smoking machine according to the Coresta standard protocol and then left to age over an 8-hour period, with subsequent sampling at defined time intervals. The experiments have been repeated over five days, and eight data point samples are obtained for each experiment. Besides nicotine, CO, and smoke particulate matter, interest has been focused on polycyclic aromatic hydrocarbons (PAH). The initial concentrations, C₀ for smoke particulate matter and nicotine (gas and particulate phases) are found to be 13.8 mg and 92 μg per cigarette per cubic meter, with T_0.5 being 2.6 and 2.1 hours, respectively. Low molecular-weight PAH have T_0.5 up to 20 hours, explainable only by their high concentrations in the gas phase, while the 3- to 7-ring PAH have T_0.5 of about 2 hours. The contribution of CO to ambient concentration is 91 mg per cigarette per cubic meter. The data can be useful in mathematical modellization studies regarding ventilation or exposure to sidestream smoke.     

Experimental studies of the transfer of neptunium from sea water to sediments and organisms (annelids and molluscs)

This paper deals with the physico-chemical behaviour of neptunium in sea water and with its capacity for transfer to coastal or deep-sea sediments and for uptake by two benthic species, Arenicola marina (L.) and Cerastoderma edule (L.). We used the ²³⁹Np isotope with mass concentrations in sea water of about 2·5 × 10⁻¹⁰−5·4×10⁻¹² g litre⁻¹, which are close to the concentrations observed in the environment for ²³⁷Np. The experimental results show that Np occurs in solution mainly as the neptunyl ion NpO₂⁺, but soluble anionic and neutral complexes and particulate forms were also detected. The distribution coefficients for the sediments varied from 350 to 6500. The carbonate phase plays a decisive role in neptunium transfer but other fixation processes are also possible. Concentration factors after 13 days were found to have values of 40 and 14 for the shells and soft parts of cockles, respectively, while polychaetes had a concentration factor of 2. Thus Np has a smaller probability of transfer to sediments and organisms than have plutonium and americium.     

Health effects of oxidants

Oxidants of significance to human health include ozone, nitrogen dioxide, and peroxyacetylnitrate. All of these compounds are involved in complex photochemical reactions which makes quantification and prediction of their individual health effects difficult. Ozone causes trauma to lung tissues and interferes with enzyme systems in the lungs and other tissues causing a broad range of symptoms. Measurable health impacts can occur at concentrations as low as 390 μg/m³. Acute effects of ozone exposure are reversible at normal urban concentrations (80–120 μg/m³). A special problem of concern, however, is increased susceptibility to infectious diseases contracted through the lungs. Nitrogen dioxide also causes trauma to lung tissues and interferes with enzyme systems. Measurable impacts can occur at concentrations as low as 100 μg/m³, but recovery is rapid and it is not known whether repeated exposures at this level have cumulative effects or predispose the lungs to permanent damage. Chronic exposure of laboratory animals to higher nitrogen dioxide levels can cause emphysema-like conditions and reduction in resistance to respiratory infection. Epidemiological studies of children in houses with gas stoves confirm the finding of reduced resistance to respiratory infection. The U.S. EPA estimates that health effects may occur in young children exposed to concentrations in excess of 280 to 560 μg/m³ one-hour average. These concentrations occur routinely in houses having gas stoves. Peroxyacetylnitrate is a powerful eye irritant in photochemical smog. Other health effects are similar to those of ozone, but less important because of the relatively low concentrations of this pollutant compared to other oxidants.     

The formal electronic recycling industry: Challenges and opportunities in occupational and environmental health research

BackgroundE-waste includes electrical and electronic equipment discarded as waste without intent of reuse. Informal e-waste recycling, typically done in smaller, unorganized businesses, can expose workers and communities to serious chemical health hazards. It is unclear if formalization into larger, better-controlled electronics recycling (e-recycling) facilities solves environmental and occupational health problems.ObjectivesTo systematically review the literature on occupational and environmental health hazards of formal e-recycling facilities and discuss challenges and opportunities to strengthen research in this area.MethodsWe identified 37 publications from 4 electronic databases (PubMed, Web of Science, Environmental Index, NIOSHTIC-2) specific to chemical exposures in formal e-recycling facilities.DiscussionEnvironmental and occupational exposures depend on the degree of formalization of the facilities but further reduction is needed. Reported worker exposures to metals were often higher than recommended occupational guidelines. Levels of brominated flame-retardants in worker's inhaled air and biological samples were higher than those from reference groups. Air, dust, and soil concentrations of metals, brominated flame-retardants, dioxins, furans, polycyclic-aromatic hydrocarbons, or polychlorinated biphenyls found inside or near the facilities were generally higher than reference locations, suggesting transport into the environment. Children of a recycler had blood lead levels higher than public health recommended guidelines.ConclusionsWith mounting e-waste, more workers, their family members, and communities could experience unhealthful exposures to metals and other chemicals. We identified research needs to further assess exposures, health, and improve controls. The long-term solution is manufacturing of electronics without harmful substances and easy-to-disassemble components.     

Assessment of inhalation and ingestion population exposures from incinerated hazardous wastes

This assessment makes a preliminary determination of the relative importance of the air and food chain pathways of human exposure to hazardous materials released from hazardous waste incineration facilities. Identical 4400 kw (150 × 10⁶ Btu/h) rotary kiln incinerators burning pesticide-related wastes were assumed to be sited in three different U.S. locations. Individual exposures resulting from incineration of the 10 most prevalent pesticide-related chemicals currently being incinerated in the U.S. were estimated. Results indicate that the food chain pathway may be an important contributor to total human exposure from incineration of hazardous wastes.     

Greenhouse gas emissions from a semi-arid tropical reservoir in northeastern Brazil

We estimated carbon dioxide (CO₂) and methane (CH₄) emissions by diffusion, ebullition, and degassing in turbines from a semi-arid hydropower reservoir in northeastern Brazil. Sampling sites were allocated within the littoral and deeper waters of one embayment, the main-stream, and at turbines. Annual carbon emissions were estimated at 2.3?×?10⁵?±?7.45?×?10⁴ t C year^?1, or in CO₂-equivalents (CO₂-eq) at 1.33?×?10⁶?±?4.5?×?10⁵ t CO₂-eq year^?1. Diffusion across the water surface was the main pathway accounting for 96% of total carbon emissions. Ebullition was limited to littoral areas. A slight accumulation of CO₂, but not of CH₄, in bottom waters close to the turbines inlet led to degassing emissions about 8?×?10³ t C year^?1. Emissions in littoral areas were higher than in main-stream and contribute to 40% of the total carbon. Carbon (C) emissions per electricity generated, at 60% of installed capacity, is 0.05 t C-CO₂-eq MWh^?1. The ratio increases to 0.09 t C-CO₂ MWh^?1, equating 80% of the emissions from natural gas and 40% of diesel or coal power plants. Retention time and benthic metabolism were identified as main drivers for carbon emissions in littoral areas, while water column mixing and rapid water flow are important factors preventing CH₄ accumulation and loss by degassing. Our results indicate that Itaparica Reservoir, located in the semi-arid region of Northeastern Brazil, acts as a source of GHGs. Management measurements are needed to prevent emissions to raise in the future.     

GRADE: Assessing the quality of evidence in environmental and occupational health

There is high demand in environmental health for adoption of a structured process that evaluates and integrates evidence while making decisions and recommendations transparent. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework holds promise to address this demand. For over a decade, GRADE has been applied successfully to areas of clinical medicine, public health, and health policy, but experience with GRADE in environmental and occupational health is just beginning. Environmental and occupational health questions focus on understanding whether an exposure is a potential health hazard or risk, assessing the exposure to understand the extent and magnitude of risk, and exploring interventions to mitigate exposure or risk. Although GRADE offers many advantages, including its flexibility and methodological rigor, there are features of the different sources of evidence used in environmental and occupational health that will require further consideration to assess the need for method refinement. An issue that requires particular attention is the evaluation and integration of evidence from human, animal, in vitro, and in silico (computer modeling) studies when determining whether an environmental factor represents a potential health hazard or risk. Assessment of the hazard of exposures can produce analyses for use in the GRADE evidence-to-decision (EtD) framework to inform risk-management decisions about removing harmful exposures or mitigating risks. The EtD framework allows for grading the strength of the recommendations based on judgments of the certainty in the evidence (also known as quality of the evidence), as well as other factors that inform recommendations such as social values and preferences, resource implications, and benefits. GRADE represents an untapped opportunity for environmental and occupational health to make evidence-based recommendations in a systematic and transparent manner. The objectives of this article are to provide an overview of GRADE, discuss GRADE's applicability to environmental health, and identify priority areas for method assessment and development.     

Modeling human exposures to air pollution control (APC) residues released from landfills in England and Wales

Human exposures to air pollution control (APC) residues released from 6 landfills were modeled and assessed. Following a qualitative risk characterisation, direct and indirect exposures were quantified. Site-specific air dispersion modeling was conducted for PM(10), PCDDs/PCDFs, Pb, Cd, As and Cr(VI) concentrations at the closest residential points of exposure for 4 landfill sites accepting, in total, 75% w/w of the APC residues disposed of in 2000-2001 (UK). Inhalation risks, assessed by reference to air quality standards at residential exposure points, were assessed as insignificant. Preliminary modeling suggested that indirect exposures from PCDDs/PCDFs at the 95th percentile level for the site where APC deposition rates were highest could potentially exceed the tolerable daily soil intake (TDSI) but this warrants further study given the model limitations. These results offer an initial screen of the significance of potential risks from APC disposal, which is of value in addressing concerns about the uncertainty of potential risks to human health from bulk APC disposal at strategic locations.     

Health effects of indoor air pollution: Synergistic effects of nitrogen dioxide and a respirable aerosol

Comparative studies of the effects of various air pollutants on lung collagen biosynthesis have been performed. A hitherto unexpected synergism between the oxidant air pollutants ozone or nitrogen dioxide and a respirable-sized aerosol of ammonium sulfate was observed during controlled exposures of rats to these substances. In an assay system, measuring collagen biosynthesis by lung minces prepared from rats exposed for 1 week to either filtered air or to these pollutants gases, dose-response curves to either O₃ or NO₂ are altered in the presence of 5 mg/m³ of (NH₄)₂SO₄ aerosol. These observations may have broad implications for the appropriate evaluation of laboratory data in the setting of ambient air quality standards and/or the setting of threshold limit values for maintenance of occupational health and safety.     

A quantitative risk assessment method based on population and exposure distributions using Australian air quality data

This paper develops a practical probabilistic method for assessing aggregate population health risks from different types of population exposures. The method consists of calculating the product of two functions: a population-weighted distribution of concentrations and a concentration-response distribution. This operation yields the corresponding aggregated health-risk distribution function. The method can use alternative exposure-response distributions and populations-specific exposure patterns, depending on the context of the assessment. A deterministic sensitivity analysis is included in the methodological aspects of this research. The distributions of concentrations are generated by combining area-specific population densities with atmospheric concentrations for each of the areas where exposure to air pollutants occurs. The exposure-response functions are developed from the literature. The method is exemplified using alternative exposure probabilities to carbon monoxide, nitrogen dioxide, particulate matter (PM₁₀), and exposure-response models developed specifically for these pollutants for assessing health risks, and applied to data from a number of Australian cities. The results, which hold when the functions are monotonic, show single maximum per pollutant, regardless of the choice of exposure and exposure-response distribution. Although those maxima are often below the Australian Air Pollution Standards, there are instances when this is not the case.     

UO22+-humate interactions in soft,acid, humate-rich waters

Few analytical techniques are sensitive enough to detect environmental concentrations of uranium in waters where humic acids are present. One objective of this study was to devise a technique for measuring humic-complexed and uncomplexed uranium at these concentrations. Three techniques were combined to determine the binding capacity and conditional stability constant of uranium with Aldrich^® humic acid. Free UO₂²⁺ was separated from bound by chelating resin; the CC bonds were destroyed by photo-oxidation and UO₂²⁺ was quantified by laser fluorometry. The binding capacity (BC) of 3·5 mg C liter⁻¹ Aldrich humic acid solution was estimated to be 1·14 × 10⁻⁶MUO₂²⁺ with an asymptotic standard error of 5·0 × 10⁻⁸MUO₂²⁺. UO₂²⁺ was bound to humic acid by a continuum of sites with different strengths. The frequency distribution of these sites was log-normal. A Gaussian-Scatchard model was used to estimate the overall conditional stability constant for uranium concentrations of 5·25 × 10⁻⁸Mto 2·1 × 10⁻⁷M in the presence of 3·5 mg liter⁻¹ humate (1·14 × 10⁻⁶M = φ). The estimates of the mean and standard deviation for the log of the stability constants were 6·5 and 0·8, respectively. When these mean and standard deviations were used to determine the mole-average number of binding sites at three points on the Gaussian distribution, the estimators of log-stability constants were found to be: K₁ = 5·2, K₂ = 6·5 andK₃ = 7·7 with mole fractions of the total number of binding sites associated with each region of 0·21, 0·55 and 0·21, respectively. The thermodynamic, geochemical simulation model GEOCHEM and the three-component Gaussian-Scatchard estimates allowed accurate prediction of the relative proportion of UO₂²⁺ bound to humates for a soft water pond across the entire range of metal-ligand ratios studied. Approximately 22% of the UO₂²⁺ was predicted to be associated with dissolved organic carbon.     

Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids,toxic isocyanic acid and carbon monoxide

In the north west Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October–November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r ≥ 0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62 ± 0.18 ppb), benzene (2.51 ± 0.28 ppb), toluene (3.72 ± 0.41 ppb), C8-aromatics (2.88 ± 0.30 ppb), C9-aromatics (1.55 ± 0.19 ppb) and CO (552 ± 113 ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97 ± 0.17 ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6 ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of benzene and ensure compliance with the NAAQS. Calculations of excessive lifetime cancer risk due to benzene amount to 25 and 10 per million inhabitants for children and adults, respectively, exceeding the USEPA threshold of 1 per million inhabitants. Annual exposure to isocyanic acid was close to 1 ppb, the concentration considered to be sufficient to enhance risks for cardiovascular diseases and cataracts. This study makes a case for urgent mitigation of post-harvest paddy residue fires as the unknown synergistic effect of multi-pollutant exposure due to emissions from this anthropogenic source may be posing grave health risks to the population of the N.W. IGP.     

Traffic-related fine and ultrafine particle exposures of professional drivers and illness: An opportunity to better link exposure science and epidemiology to address an occupational hazard?

Exposures to traffic-related air pollution (TRAP) can be particularly high in transport microenvironments (i.e. in and around vehicles) despite the short durations typically spent there. There is a mounting body of evidence that suggests that this is especially true for fine (< 2.5 µm) and ultrafine (< 100 nm, UF) particles. Professional drivers, who spend extended periods of time in transport microenvironments due to their job, may incur exposures markedly higher than already elevated non-occupational exposures. Numerous epidemiological studies have shown a raised incidence of adverse health outcomes among professional drivers, and exposure to TRAP has been suggested as one of the possible causal factors. Despite this, data describing the range and determinants of occupational exposures to fine and UF particles are largely conspicuous in their absence. Such information could strengthen attempts to define the aetiology of professional drivers' illnesses as it relates to traffic combustion-derived particles.In this article, we suggest that the drivers' occupational fine and UF particle exposures are an exemplar case where opportunities exist to better link exposure science and epidemiology in addressing questions of causality. The nature of the hazard is first introduced, followed by an overview of the health effects attributable to exposures typical of transport microenvironments. Basic determinants of exposure and reduction strategies are also described, and finally the state of knowledge is briefly summarised along with an outline of the main unanswered questions in the topic area.     

Greenhouse gases emissions from a closed old landfill cultivated with biomass crops

Closed landfills need after-closure rehabilitation. The chosen option should ensure greenhouse gases release, from the landfill, is not promoted once settled. The objective of this study was to estimate and confront, during different seasons, CH₄, CO₂ and N₂O emissions under three vegetation covers in a closed landfill in Buenos Aires, Argentina. CH₄ (methane), CO₂ (carbon dioxide) and N₂O (nitrous oxide) emissions from landfill’s technosol under spontaneous vegetation (control), Pennisetum purpureum and Miscanthus giganteus (biomass crops), were quantified with non-steady-state non-flow-through chambers, in July 2014 and from February to July 2015. A linear regression analysis was performed to relate the variables “flux of a gas” and “concentration of that gas” from the 3 treatments and 6 dates, separating the 5 sampling times. A high correlation between concentrations and fluxes of CO₂ and N₂O was found, but no correlation was established for CH₄. Mean emissions (2014–2015) varied from: ?2.3 to 639.41 mgCH₄ m^?2 day^?1, 3884 to 46,365 mgCO₂ m^?2 day^?1 and 0.40 to 14.59 mgN₂O m^?2 day^?1. Vegetation covers had no significant effect on CH₄ and N₂O concentration in time, but they had on CO₂ concentration. Season of the year had a significant effect on concentration of the three gases. This is the first study on CH₄, CO₂ and N₂O emissions from a landfill closed 27 years ago covered with biomass crops.