Hazardous Air Pollutants Research Articles

Health Risk-Oriented Source Apportionment of Hazardous Volatile Organic Compounds in Eight Canadian Cities and Implications for Prioritizing Mitigation Strategies.

Traditionally, environmental authorities make regulatory policies for controlling volatile organic compound (VOC) pollution based on the mitigation of dominant VOC sources. However, the emission from each VOC source has a unique combination of VOC species of different toxicities. Without quantitatively assessing the health risk associated with each source, the effectiveness of the mitigation policy could be undermined. To address this shortcoming, we developed a new health risk-oriented source apportionment method that can provide quantitative health risk assessment and source-specific mitigation strategies for hazardous VOCs. We estimated that the integrated inhalation cancer risk (ICR) of hazardous VOCs was 7.7 × 10-5 in Western Canada, indicating a 100% likelihood of exceeding Health Canada's acceptable risk level (1.0 × 10-5). Anthropogenic sources were responsible for 56.3-73.8% of cancer risks across eight Canadian cities except for the regional background island, where natural sources contributed over 77% to the integrated ICR. Thus, substantial environmental and health cobenefits could be achieved via reducing the ambient levels of benzene and 1,3-butadiene by 39.3-75.7 and 14-69.3%, respectively, and mitigating emissions from fuel combustion (by 31.3-54.1%), traffic source (3.0-36.8%), and other anthropogenic sources (5.3-20.1%) in Western Canada. Our study has significant implications for prioritizing air pollution mitigation policies, especially for quantitative reduction of hazardous air pollutants.

Emissions of organic compounds from western US wildfires and their near-fire transformations

Abstract. The size and frequency of wildfires in the western United States have been increasing, and this trend is projected to continue, with increasing adverse consequences for human health. Gas- and particle-phase organic compounds are the main components of wildfire emissions. Some of the directly emitted compounds are hazardous air pollutants, while others can react with oxidants to form secondary air pollutants such as ozone and secondary organic aerosol (SOA). Further, compounds emitted in the particle phase can volatize during smoke transport and can then serve as precursors for SOA. The extent of pollutant formation from wildfire emissions is dependent in part on the speciation of organic compounds. The most detailed speciation of organic compounds has been achieved in laboratory studies, though recent field campaigns are leading to an increase in such measurements in the field. In this study, we identified and quantified hundreds of gas- and particle-phase organic compounds emitted from conifer-dominated wildfires in the western US, using two two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC ToF-MS) instruments. Observed emission factors (EFs) and emission ratios are reported for four wildfires. As has been demonstrated previously, modified combustion efficiency (MCE) was a good predictor of particle-phase EFs (e.g., R2=0.78 and 0.84 for sugars and terpenoids, respectively), except for elemental carbon. Higher emissions of diterpenoids, resin acids, and monoterpenes were observed in the field relative to laboratory studies, likely due to distillation from unburned heated vegetation, which may be underrepresented in laboratory studies. These diterpenoids and resin acids accounted for up to 45 % of total quantified organic aerosol, higher than the contribution from sugar and sugar derivatives. The low volatility of resin acids makes them ideal markers for conifer fire smoke. The speciated measurements also show that evaporation of semi-volatile organic compounds took place in smoke plumes, which suggests that the evaporated primary organic aerosol can be a precursor of SOAs in wildfire smoke plumes.

Changing trends in the air pollution-related disease burden from 1990 to 2019 and its predicted level in 25years.

In the twenty-first century, exposure to air pollution has become a threat to human health worldwide due to industrial development. Timely, comprehensive, and reliable assessment and prediction of disease burden can help mitigate the health hazards of air pollution. This study conducted a two-stage analysis. First, we reported the air pollution–related disease burden globally and for different subgroups like socio-demographic index (SDI), sex, and age. We analyzed the trend of the disease burden from 1990 to 2019. In addition, we explored whether and how some national indicators modified the disease burden. Second, we predicted the number and the age-standardized rates of death and disability-adjusted life years (DALYs) attributable to air pollution from 2020 to 2044 by the autoregressive integrated moving average (ARIMA) model and exponential smoothing model. The age-period-cohort (APC) model in the maximum likelihood framework and the Bayesian APC model integrated nested Laplace approximations (INLAs) were further applied to perform sensitivity analysis. In 2019, air pollution accounted for 11.62% of death and 0.84% of DALY worldwide. The corresponding age-standardized rate was 85.62 (95% uncertainty interval (UI): 75.71, 96.07) and 2791.08 (95% UI: 2468.81, 3141.39) per 100,000 population. From 1990 to 2019, the number of death attributable to air pollution remained stable, and the number of DALY exhibited a downward trend. The corresponding age-standardized rates both declined. In some countries with larger population densities, higher proportions of elders, and lower proportions of females, the disease burden attributable to air pollution was lower. The predicted results showed that the number of air pollution-related death and DALY would increase. This study comprehensively assessed and predicted the air pollution–related disease burden worldwide. The results indicated that the disease burden would remain very serious in the future. Hence, some relevant policies should be developed to prevent and manage air pollution.Supplementary informationThe online version contains supplementary material available at 10.1007/s11356-022-22318-z.

Biorefinery upgrading of herbaceous biomass to renewable hydrocarbon fuels, Part 2: Air pollutant emissions and permitting implications

The development of advanced biofuel production facilities is still at a nascent stage, and the biorefineries could face challenges in obtaining air permits required for their construction and operation because they are novel emission sources. To fill gaps in knowledge regarding potential emissions, we perform a detailed federal regulatory analysis and estimate air pollutant emissions for an advanced biorefinery that produces renewable diesel blendstock (RDB) from lignocellulosic biomass via aerobic respiration documented in Part 1 of the paper. We evaluate 12 design permutations that include two feedstocks, a uniform format blend (UFB) and corn stover; three biorefinery scales, 2,000, 5,200, and 9,100 dry metric tons per day (dmtd) of lignocellulosic biomass feed; and two lignin uses, as either a boiler fuel or for pellet production. We also evaluate 6 additional design permutations by incorporating non-emitting renewable power, which could reduce up to 63% carbon monoxide (CO) and nitrogen oxides (NO x ) each, 21% volatile organic compounds (VOC), and 43% hazardous air pollutants (HAP) as opposed to on-site power production, for biorefineries that produce pellets, using either UFB or corn stover. Our results indicate that all 18 design permutations would be classified as a major source under the Clean Air Act's New Source Review program without additional emission controls. Compared to using lignin as a boiler fuel, diverting lignin for pellet production reduces the emissions of CO up to 88%, NO x up to 73%, sulfur dioxide (SO 2 ) up to 99%, VOCs up to 72%, and HAPs up to 66%. Additionally, we explore control options that could further reduce emissions and assess whether reductions are enough to achieve minor source classification. Insights from our analysis can help biorefinery developers and regulators develop permitting strategies to mitigate investment risks. • Air emissions from 12 biorefinery process design variations are quantified. • Biorefineries would be classified as major sources without additional controls. • Control options are available for compliance with applicable federal regulations. • Diverting lignin for pellet production could reduce air emissions by at least 66%. • Integrating non-emitting renewable power could help achieve minor source.

Air pollution exposure assessment at schools and playgrounds in Williamsburg Brooklyn NYC, with a view to developing a set of policy solutions.

Community science offers unique opportunities for non-professional involvement of volunteers in the scientific process, not just during the data acquisition, but also in other phases, like problem definition, quality assurance, data analysis and interpretation, and the dissemination of results. Moreover, community science can be a powerful tool for public engagement and empowerment during policy formulation. This paper aims to present a pilot study on personal exposure to fine particulate matter (PM2.5) and raises awareness of the hazards of air pollution. As part of data acquisition conducted in 2019, high school students gathered data at their schools, schoolyards, and playgrounds using low-cost monitors AirBeam2. The data was automatically uploaded every second onto the AirCasting mobile app. Besides, a stationary network of air monitors (fixed stations) was deployed in the neighborhood to collect real-time ambient air concentrations of PM2.5. Students involved in the project attended workshops, training sessions, and researched to better understand air pollution, as part of their science class curriculum and portfolio. This air quality monitoring was incorporated into the “Our Air/Nuestro Aire” — El Puente grassroots campaign. The main goals of this campaign included sharing the data collected with the community, engaging academic partners to develop a set of policy and urban design solutions, and to be considered into a 5-point policy platform.

Household energy stacking and structures in Pakistan – Results from a multiple-energy study in Azad Kashmir and Punjab

Solid fuel use (SFU) is common in most developing countries and would release many hazardous air pollutants posing high risks on human health. The Global Burden of Disease (GBD) study highlighted risks associated with household SFU in Pakistan, however, high uncertainties prevail because of scanty data on SFU and unaccounted energy stacking. This study conducted a field campaign aiming at collecting first-hand data on household energy mix in Pakistan. The first survey was in Punjab and Azad Kashmir, and revealed that stacked energy use was pervasive, especially for cooking. The stacking was found to be much more obvious in SFU households (defined as those using SFU dominantly) compared to those non-SFU. There were significantly substantial differences between Azad Kashmir and Punjab because of distinct resources available and economic conditions. Woody materials comprised up to nearly 70% in Azad Kashmir, but in Punjab, gas was frequently used for cooking. Only investigating primary household energy would probably overestimate main energy types that being used for a longer time but underestimated other supplements, suggesting the preference of multiple-energy surveys in household energy studies.

Literature review on health benefits due to good quality of air during lockdown

The epidemic caused by COVID-19 triggered a terrible situation that spread over the whole world. Since the third week of March 2020, all forms of industrialization, including hospitality, education, the corporate world, and entertainment, are subject to restrictions as a result of this. Please provide research analyzing the effect of the lockout on habitats throughout the whole country of India or beyond. The findings not only show a reduction in potentially hazardous air pollutants such as SO2, NO2, PM10, and PM2.5, but they also show an increase in levels of O3, which in turn leads to the repair of our ozone layer, which is essential for maintaining human health. These studies demonstrate the significant consequences of air quality affects across 46 cities located across the whole country of India.

Urban Particulate Matter Hazard Mapping and Monitoring Site Selection in Nablus, Palestine

Few air pollution studies have been applied in the State of Palestine and all showed an increase in particulate matter concentrations above WHO guidelines. However, there is no clear methodology for selecting monitoring locations. In this study, a methodology based on GIS and locally calibrated low-cost sensors was tested. A GIS-based weighted overlay summation process for the potential sources of air pollution (factories, quarries, and traffic), taking into account the influence of altitude and climate, was used to obtain an air pollution hazard map for Nablus, Palestine. To test the methodology, eight locally calibrated PM sensors (AirUs) were deployed to measure PM2.5 concentrations for 55 days from 7 January to 2 March 2022. The results of the hazard map showed that 82% of Nablus is exposed to a high and medium risk of PM pollution. Sensors’ readings showed a good match between the hazard intensity and PM concentrations. It also shows an elevated PM2.5 concentrations above WHO guidelines in all areas. In summary, the overall average for PM2.5 in the Nablus was 48 µg/m3. This may indicate the effectiveness of mapping methodology and the use of low-cost, locally calibrated sensors in characterizing air quality status to identify the potential remediation options.

Cross-sectional and longitudinal associations of styrene and ethylbenzene exposure with heart rate variability alternation among urban adult population in China

Styrene and ethylbenzene (S/EB) are the monomers of polystyrene (PS) and polyethylene (PE), respectively, and have been identified as significant hazardous air pollutants by the U.S. Environmental Protection Agency. However, the adverse effects of S/EB on human health, especially cardiovascular health, have not been well established. Urinary biomarker of S/EB exposure and heart rate variability (HRV) were measured in urban adults from the Wuhan-Zhuhai cohort and were repeated after 3-year and 6-year follow-ups. Linear mixed models were used to estimate associations of S/EB exposure biomarker with HRV and longitudinal additional annual change of HRV. The mediating role of transforming growth factor (TGF)-β1 was tested by using mediation analysis. A total of 2842 general adults were included at baseline analysis, and 4748 observations were included in the repeated measurement study. In the cross-sectional analysis, each 1% increment in urinary S/EB exposure biomarker was significantly associated with a 0.106 % (95 % CI: −0.160, −0.052), 0.109 % (−0.169, −0.049), 0.099 % (−0.145, −0.053), 0.040 % (−0.060, −0.020), and 0.031 % (−0.054, −0.007) decrement in low frequency (LF), high frequency (HF), total power (TP), standard deviation of all normal-to-normal intervals (SDNN), and square root of the mean squared difference between adjacent normal-to-normal interval, respectively. Smoking status modified the relationships of urinary S/EB exposure biomarker with TP and SDNN. TGF-β1 mediated 3.09–5.16 % of the association between urinary S/EB biomarker and lower HRV. The follow-up analyses detected a negative association between urinary S/EB exposure biomarker and the additional annual change of LF (β: −0.016; 95 % CI: −0.028, −0.004), HF (−0.014; −0.026, −0.001), and TP (−0.011; −0.021, −0.001). Our findings demonstrated that S/EB exposure was associated with HRV reduction among the general urban adults and the TGF-β pathway may play a part of the mediating role in this association.

Air Pollution Monitoring in Remote Areas using Smart UAV based System

Real time monitoring of air pollution and measurement of pollutant gases is very challenging task and needs more numbers of sensors and lots of observation. In this paper, Unmanned Aerial Vehicle (UAV) based system equipped with different micro sensor, is introduced for monitoring of air quality. It will offer a new approach in environmental pollution assessment instead of ground based monitoring system. Air pollution concentration data is collected by different sensors present in UAV, are effectively monitored in personal computer or mobile devices. The main objective of this paper is to elaborate the performance capability of UAV for effective monitoring of air pollution and measure health hazard air pollutants with high sensitivities in a particular area where human cannot reach. As it is quite recent field, a fruitful effort has dedicated to develop an integrated sensing system and optimization of its crucial features as dimension, weight and energy autonomy. The effectiveness of the developed system is evaluated by performing some field experiments using a hardware prototype UAV model.

Exploring socio-environmental effects on community health in Edmonton, Canada to understand older adult and immigrant risk in a changing climate

We investigated health risks associated with climate and air pollution hazards and community covariates to generate insights into the resilience of older adults and immigrants at the community level in a northern urban center in the Canadian prairies. Communities with higher proportions of older adults were associated with increased cardiovascular, injury, mental, and respiratory health event rates. Notably, heat effects on injury rates impacted communities with higher percentages of older adults (Prevalence Rate Ratio (PRR) [95%CI] 1.110 [1.011, 1.219] at 25% ≥65 years). Ozone effects on cardiovascular event rates exhibited similar trends. Areas with higher percentages of immigrants generally had lower rates of hxealth events. However, increasing diurnal temperature range became a risk factor for respiratory health rates where there were higher percentages of refugees (PRR 1.205 [1.004, 1.447] at 20%). Industrial emission effects on injury and respiratory health rates also amplified in areas with higher percentages of refugees (PRR 1.127 [1.058, 1.200]; 1.130 [1.050, 1.216] at 20%). Similar effects were observed for mental health event rates and total immigrants. Greater neighborhood material and social deprivation were significant risk factors for increased health event rates across outcomes. Future work should focus on disproportionately affected vulnerable populations to address community-level resilience.

Home is Where the Pipeline Ends: Characterization of Volatile Organic Compounds Present in Natural Gas at the Point of the Residential End User.

The presence of volatile organic compounds (VOCs) in unprocessed natural gas (NG) is well documented; however, the degree to which VOCs are present in NG at the point of end use is largely uncharacterized. We collected 234 whole NG samples across 69 unique residential locations across the Greater Boston metropolitan area, Massachusetts. NG samples were measured for methane (CH4), ethane (C2H6), and nonmethane VOC (NMVOC) content (including tentatively identified compounds) using commercially available USEPA analytical methods. Results revealed 296 unique NMVOC constituents in end use NG, of which 21 (or approximately 7%) were designated as hazardous air pollutants. Benzene (bootstrapped mean = 164 ppbv; SD = 16; 95% CI: 134–196) was detected in 95% of samples along with hexane (98% detection), toluene (94%), heptane (94%), and cyclohexane (89%), contributing to a mean total concentration of NMVOCs in distribution-grade NG of 6.0 ppmv (95% CI: 5.5–6.6). While total VOCs exhibited significant spatial variability, over twice as much temporal variability was observed, with a wintertime NG benzene concentration nearly eight-fold greater than summertime. By using previous NG leakage data, we estimated that 120–356 kg/yr of annual NG benzene emissions throughout Greater Boston are not currently accounted for in emissions inventories, along with an unaccounted-for indoor portion. NG-odorant content (tert-butyl mercaptan and isopropyl mercaptan) was used to estimate that a mean NG-CH4 concentration of 21.3 ppmv (95% CI: 16.7–25.9) could persist undetected in ambient air given known odor detection thresholds. This implies that indoor NG leakage may be an underappreciated source of both CH4 and associated VOCs.

α−Fe2O3 nanoparticles and hazardous air pollutants release during cooking using cast iron wok in a commercial Chinese restaurant

Long-term exposure to fine particles (PM2.5), ultrafine particles (UFPs), and volatile organic compounds (VOCs) emissions from cooking has been linked to adverse human health effects. Here, we measured the real-time number size distribution of particles emitted when cooking two served food in Chinese restaurants and estimated the emission rate of UFPs and PM2.5. Experiments were conducted under a control hood, and both online measurement and offline analysis of PM2.5 were carried out. The measured emission rates of PM2.5 generated from deep-frying and grilling were 0.68 ± 0.11 mg/min and 1.58 ± 0.25 mg/min, respectively. Moreover, the UFPs emission rate of deep-frying (4.3 × 109 #/min) is three times higher than that of grilling (1.4 × 109 #/min). Additionally, the PM2.5 emission of deep-frying was comprised of a considerable amount of α−Fe2O3 (5.7% of PM2.5 total mass), which is more toxic than other iron oxide species. A total of six carcinogenic HAPs were detected, among which formaldehyde, acrolein, and acetaldehyde were found to exceed the inhalation reference concentration (RfC) for both cooking methods. These findings can contribute to future evaluation of single particle and HAPs emission from cooking to better support toxicity assessment.

Supercritical Carbon Dioxide Extraction of Vegetable Oils: Retrospective and Prospects

AbstractSupercritical carbon dioxide (SC‐CO2) extraction is projected as one of the most viable alternatives to conventional hexane extraction due to its density‐dependent solvent power, low viscosity, moderately high diffusion coefficient, and low‐temperature operative conditions. Demands for retention of bioactive compounds in oils like wheat germ oil, rice bran oil, almond oil, etc., are increasing and that can be easily met up by this alternative solvent. Solvent extraction of oils rich in polyunsaturated fatty acid, like flaxseed oil, microbial oil, etc., is highly sensitive. Prolonged heating during removal of solvent often leads to degradation of essential fatty acids. As the phase change is done by changing the pressure, the use of SC‐CO2 overcomes such issues. It is quite evident that degumming, one of the processing steps in refining of vegetable oils, will not be required if SC‐CO2 is used for extraction. Moreover, in some other cases, bioactive compounds will be retained in the de‐fatted meal and can be recovered with better purity. All these factors will add to the overall economy. A detailed review of the application of SC‐CO2 for the extraction of vegetable oils—the initial reports, current status, and future prospectsis presented in this paper.Practical applications: In recent years, the oils and fats industry has gone through several technological advancements and the most important of them was shifting to physical refining process from highly polluting chemical process. The industry may see another major change in the extraction process in the near future. Hexane has been enlisted as a hazardous air pollutant as per the Clean Air Act, 1990. Recent reports show that hexane may have some role even in ozone layer depletion. Scientists are looking forward to alternatives. SC‐CO2 has emerged as one of the most suitable alternatives. The large capital investment required for the installation of SC‐CO2‐based extraction plants was a major drawback. However, ready availability of critical machineries and advancements in terms of automation has brought down the capital expenditure significantly. The utilization of superior quality by‐products generated by the process of SC‐CO2 extraction may be an added advantage for the overall economy of the process.

Risk assessment for public health from air pollution in the industrial regions of Ukraine

The main purpose of the research is to improve the efficiency of management decisions in the field of environmental protection through using the methods for assessing the public health risk at the current level of air pollution. Methodology. The article presents a hierarchical methodological approach for determination of the level of air pollution hazard at the state, regional and local levels. The state of atmospheric air is greatly affected by emergencies associated with accidents at chemically hazardous facilities, which result in burst releases of hazardous chemicals into the environment. When determining the environmental risk of deterioration in the state of atmospheric air, the chemical hazard indicator was taken into account. Results. On the territory of the East of Ukraine there is the largest number of potentially dangerous enterprises. A new methodology of determination of the hazard level of air pollution is presented at the existing trends of anthropogenic load and the possible occurrence of technogenic emergencies. Assessment of public health risk due to air pollution in the Mariupol city showed an extremely high level of danger. The determination of the risk as a macroecological indicator according to the new method shows a high level of hazard of air pollution in the industrial developed regions of Ukraine. The shortcomings of the methodical approach of the United States Environmental Protection Agency (EPA US), widely used in many countries of the world, are shown. An analysis of methodological approaches to assessing the public health risk has shown the promise of using the methodology for assessing potential risk in determining the level of environmental hazard of industrial enterprises. The assessment of the public health risk in the current quality state of air is given by two different methods for the regions of Ukraine with a high level of ecological and chemical hazard. The improvement of the methodology for assessing the risk to public health due to air pollution is proposed, which is presented as a scientific novelty. Currently when Ukraine has been affected by hostilities and the economic crisis, the issue of priority funding for environmental protection is very important. The implementation of the proposed methodological approach will make it possible to scientifically determine regions with an increased level of hazard to public health and minimize financial resources for improving the air quality, which has actual practical significance.

The toxicity emissions and spatialized health risks of heavy metals in PM2.5 from biomass fuels burning

The widespread and high use of biomass fuels (BF) by farmers contribute to air pollution-associated health impacts. However, the toxicity and spatial health risks of heavy metals in PM2.5 from BF burning, especially for elements (Cr, As, Cd, Hg, and Pb) listed as hazardous air pollutants (HAPs) in China, remain unknown on the national scale. This study tested the emission factors (EFs) of 18 heavy metals in PM2.5 for 23 BF sources throughout China. Then, complete emission results for heavy metals in PM2.5 from BF burning in China were estimated using the measured EFs and a field survey. Finally, the GEOS-Chem and Risk Quotients models were utilized to calculate the spatialized health risks from heavy metals in PM2.5 for the first time, including the gridded hazard index (HI) and carcinogenic risk (CR). Overall, the measured total EFs of 18 heavy metals in PM2.5 for 23 BF sources ranged from 5.13 mg kg−1 to 24.14 mg kg−1, and the sum EFs of hazardous elements (Cr, As, Cd, Hg, and Pb) varied from 0.45 mg kg−1 to 7.26 mg kg−1. The results indicated that the emissions of Fe, Zn, Pb, Cd, and Cu in PM2.5 from BF burning were the highest, with emissions of 1440.4, 801.8, 434.8, 399.5, and 397.4 Mg, respectively, in 2014. The emissions of other hazardous elements (Cr, As and Hg) in PM2.5 from BF burning were 203.7, 68.67, and 6.36 Mg, respectively. Compared with other anthropogenic sources, the emissions of As (66.7 Mg) from domestic coal burning were similar to those from BF burning, while the emissions of Cr (98.7 Mg) and Cd (102.7 Mg) were much lower for coal. Former studies might have underestimated the toxicity of Cr, As, and Cd by ignoring the emissions from BF burning. Spatially, the hazardous elements exhibited higher emission intensities in the Sichuan Basin, Northeast China Plain, and North China Plain, which exceeded 200, 55, 350, 5 and 350 g yr−1 for Cr, As, Cd, Hg, and Pb, respectively. The monthly emissions of hazardous elements were the highest in winter (January, February, and December), accounting for 41% of the total emissions. On the national scale, the gridded health risk of hazardous elements attributable to BF burning exhibited a relatively high level and spatial heterogeneity. The national HI for children (≤2.8 × 10−2) and adults (≤1.5 × 10−2) were all far lower than the acceptable level (HI ≤ 1). However, the CR in rural areas of Shanxi, Hebei, Beijing, and Henan (1 × 10−6 to 2.7 × 10−6) reached 2.7 times higher than the acceptable level (CR ≤ 1 × 10−6). These results highlighted that when aiming to mitigate the heavy metals exposure risk in the general population, BF burning emissions should be carefully considered. The governments should improve the awareness of the toxicity and health risks from BF burning. which may reduce the willingness of farmers to use BF sources and further promote the rural energy transition and utilization systematically.

Environmental and human health risks of plastic composites can be reduced by optimizing manufacturing conditions

New plastic composites are being manufactured outdoors, inside buried water and sewer pipes. This cured-in-place-pipe (CIPP) practice has been less expensive than other infrastructure repair options, but pollutants discharged during and after plastic manufacture pose environmental and human health problems. The study goal was to better understand how composite manufacturing conditions could be altered to reduce the amount of pollution released. Initiator loading, curing time, and curing pressure were modified for CIPP styrene and non-styrene ("HAP and VOC free") resin based composites. The styrene resin contained 39 wt% volatile organic compounds (VOC) whereas the non-styrene resin contained 4 wt% VOCs. Both resins contained hazardous air pollutants (HAP), endocrine disruptor, and carcinogenic compounds not listed on their safety data sheets. Vacuum pressure prompted greater VOC loss from the resins compared to ambient pressure manufacture. During both pressure manufacturing conditions, less than 1 wt% VOC was released from non-styrene composites into air compared to 8.8 to 26.4 wt% VOC released from styrene composites. VOCs including acetophenone, dibutyl maleate, p,α-dimethylstyrene, ethylbenzene, isopropylbenzene, methacrylic acid, 2-phenyl-2-propanol, styrene, toluene, and m-xylene were present in the non-styrene composite after manufacture. By doubling the styrene composite's initiator loading, styrene and styrene oxide residuals were reduced by 42 and 33 wt%, respectively. Manufacturer recommended conditions for the non-styrene composite resulted in <1 wt% initiator usage. The life cycle environmental impact assessment, which considered only composite VOC residual, predicted that styrene dominantly influenced ecotoxicity and human carcinogenic levels. Modifications to CIPP resin composition and the curing process can reduce environmental and human health impacts.

Carcinogenic air pollution along the United States’ southern border: Neighborhood inequities in risk

Air pollution poses serious and socially inequitable risks to public health. Social disparities are marked along the US-Mexico border, yet prior research has not assessed inequities in air pollution exposure across the entire US-side of the border region. We apply an intersectional approach to examine contextually relevant sociodemographic variables, including (1) Hispanic/Latinx ethnicity by race and (2) nativity (US vs. Foreign) by citizenship, and cancer risks attributable to air pollution exposures. We pair data from the 2012–2016 American Community Survey with 2014 National Air Toxics Assessment estimates of carcinogenic risks from all sources of hazardous air pollutants at the census tract level (n = 1448) and use a series of generalized estimating equations to assess inequities in risk. Increased concentrations of renter-occupants, Hispanics, mid-to-high socioeconomic status households, and foreign-born citizens were associated with elevated risks. Hispanic ethnicity intersected with non-White racial identification to amplify risks. In contrast, increased concentrations of non-Hispanic Black people and foreign-born non-citizens were not associated with disparate risks. To ameliorate environmental health inequities in this context, research and policy actions must be tailored to the US-Mexico border and consider intersectional positions within the Hispanic population.

Removal of a mixture of formaldehyde and methanol vapors in biotrickling filters under mesophilic and thermophilic conditions: Potential application in ethanol production

ABSTRACT Ethanol is a significant source of energy as a biofuel; however, its production using corn involves the generation of harmful emissions from both fermentation tanks and dryers. Scrubbers control the emissions from fermentation tanks, while the emissions from the dryers are controlled by regenerative thermal oxidizers. Potential alternatives to these energy- and water-intensive technologies are biotrickling filters (BTFs). In this study, two BTFs were operated in parallel to treat formaldehyde and methanol emissions in a volumetric ratio of 4:1, one at 25°C (mesophilic), and the other at 60°C (thermophilic). The mesophilic BTF simulated emissions from fermentation tanks, while the thermophilic BTF simulated emissions from dryers. Both beds were operated at an empty bed residence time of ~30 s and influent formaldehyde concentrations of 20, 50, and 100 parts per million per volume (ppmv). Formaldehyde polymerization was reduced in this study by adding NaOH to pH levels of 7.0–7.4 and heating the solution to a temperature of 60°C. BTFs have successfully removed formaldehyde at typical ethanol plants emissions ~21 ppmv. The BTF technology have the potential in replacing the conventional air treatment methods used at ethanol plants. Implications: Currently, ethanol plants remove and treat hazardous air pollutants (HAPs) using wet scrubbers from the fermenter off-gasses and using thermal oxidizers to combust off-gasses. The utilization of biotrickling filters (BTFs) for HAP removal generally and formaldehyde particularly has wide implication in the field of renewable energy. Utilizing BTFs in the 200+ ethanol plants in USA will save cost and reduce water and energy needs significantly. BTFs can reduce an ethanol plant’s carbon intensity (CI) by 1 to 3 g CO2/MJ. This can result in roughly $50 million per year in additional revenue in Nebraska for instance.

The P value plot does not provide evidence against air pollution hazards.

Background:A number of papers by Young and collaborators have criticized epidemiological studies and meta-analyses of air pollution hazards using a graphical method that the authors call a P value plot, claiming to find zero effects, heterogeneity, and P hacking. However, the P value plot method has not been validated in a peer-reviewed publication. The aim of this study was to investigate the statistical and evidentiary properties of this method.Methods:A simulation was developed to create studies and meta-analyses with known real effects , integrating two quantifiable conceptions of evidence from the philosophy of science literature. The simulation and analysis is publicly available and automatically reproduced.Results:In this simulation, the plot did not provide evidence for heterogeneity or P hacking with respect to any condition. Under the right conditions, the plot can provide evidence of zero effects; but these conditions are not satisfied in any actual use by Young and collaborators.Conclusion:The P value plot does not provide evidence to support the skeptical claims about air pollution hazards made by Young and collaborators.