Air NOx Research Articles

Vehicle emission models alone are not sufficient to understand full impact of change in traffic signal timings

Few studies have considered the real-world impact of changes in traffic signal timings on air pollution and pedestrian exposure with most only drawing their conclusion from vehicle emission models alone. Here, we consider two distinct cycle timings at a junction in London, UK, model the impact using a traffic microsimulation and a NOx emissions model, and compare these results with NOx and other air pollution measurements collected during a two-week field study at the junction.Our models predict that extending the cycle time leads to a 23% decrease in NOx emissions within a 15 m radius of the junction itself. When the wind direction was such that our sensors were downwind of the junction a 21% decrease in traffic and background-adjusted NOx concentrations were seen, suggesting that the intervention was successful. However, when the sensors were upwind of the junction, we observed an increase of 23% in adjusted NOx concentrations. Similar patterns were found for the other pollutants NO2, lung deposited surface area, black carbon and CO2 we measured. This indicates that meteorology was by far the greatest determinant of roadside concentrations during our two-week study period.Looking at pedestrian exposure for pedestrians waiting to cross the road, we found that their NOx exposure increased by 46% as waiting times to cross the road increased and that potential small reductions in air pollution were offset by increases in waiting times on the main road.The study demonstrates the need to go beyond assessing the impact of hyper-local traffic interventions on vehicle emissions. Real-world trials over extended periods are required to evaluate the impact of meteorology and changes to air pollution concentrations and pedestrian exposures.

A method for identifying exceedances of permissible NOX air pollutants by car traffic in a polish city

A method for identifying exceedances of permissible NOX air pollutants by car traffic in a polish city

Soil Moisture, Soil NOx and Regional Air Quality in the Agricultural Central United States

AbstractAgricultural soils containing nitrogen‐rich fertilizers are a substantial source of reactive nitrogen to the atmosphere with potential to impact air quality. One form of reactive nitrogen, nitrogen oxides (NOx = NO + NO2), are a harmful air pollutant and form secondary pollutants, including particulate matter (PM) and ozone (O3). Soil nitrogen oxide emissions (SNOx) are heavily influenced by environmental conditions, however the understanding of the influence of environmental drivers on the behavior of SNOx is limited. Here, we implement a modified soil moisture‐dependent SNOx parameterization into the Weather Research and Forecasting model coupled with Chemistry (WRF‐Chem) and investigate the impact on regional air quality in the central U.S. Evaluating against TROPOspheric Monitoring Instrument (TROPOMI) column NO2 observations, WRF‐Chem columns better capture the TROPOMI column magnitudes earlier in the growing season when using the updated SNOx parametrization, with modeled column bias improved to −1.1% over the most heavily fertilized regions. Evaluating against Environmental Protection Agency (EPA) surface NO2 observations, the relationship between surface NO2 and soil moisture is better represented in agriculturally‐dominant regions when using the updated parameterization, with greatest surface NO2 concentrations at moderate soil moisture and lower concentrations at wetter or drier soil conditions. In simulations, these SNOx lead to increased O3 in select urban regions, with more than double the occurrences of O3 exceeding the EPA 8‐hr O3 standard of 70 ppb.

Establishing Z-scheme Bi2WO6/g-C3N4 interfaces toward efficient photocatalytic performance of NOx under visible light

NOx gas is released from automobile emissions and fossil fuel combustion. The photocatalytic method was applied to address environmental issues, notably NOx air pollution because of environmentally friendly, low cost, and utilized solar light irradiation. In this work, a Z-scheme Bi2WO6/g-C3N4 heterojunction photocatalyst was successfully synthesized by a hydrothermal method at 180 °C for 12 h. Combining g-C3N4 with Bi2WO6 promoted two oxidation (over Bi2WO6) and reduction (over g-C3N4) sites, enhancing the photocatalytic activity of the g-C3N4 single-component system. The sample contains 20 wt% of Bi2WO6, becoming the best excellent photocatalytic activity at approximately 43.45% in 30 minutes of visible light irradiation. In addition, the photogenerated electron (e−) and hole (h+) were determined as primary agents. The high stability of Bi2WO6/g-C3N4 photocatalysts was demonstrated by little change in photocatalytic performance over five cycles of photocatalytic measurements. The NOx removal mechanism and the intermediate generation were proposed to understand the reaction process better.

Effect of silica addition on the photocatalytic activity of MO2@SiO2 (M=Ti, Zr, Sn, Ce) nanocomposites prepared by sol-gel

AbstractPhotocatalysis uses wide band gap ceramic semiconductors (anatase, zirconia, ceria, cassiterite…) that have the ability to promote electron-hole pairs by UV light irradiation producing both reducing and oxidants ions and radicals. In general, oxidizing species are more efficient, using photocatalysis as an advanced oxidation process (AOP) for the biodegradation of organic substances refractory to conventional treatments, such as azo dyes, or atmospheric pollutants as NOx. In this communication, the photocatalytic activity of xSiO2@(1-x)MO2 (M = TiO2, ZrO2, SnO2, CeO2, x = 0, 0.1, 0.3 and 0.5) composites on the Orange II azo dye in solution, as well as on NOx in air, was analysed. The composites were obtained by Sol-Gel methods based on the hydrolysis-condensation of alcoholic solutions of silicon tetraethoxide (TEOS) and titanium n-butoxide, zirconium iso-propoxide, SnCl2.2H2O and Ce(NO3)3.6H2O as precursors of MO2 oxides. The resulting xerogels were studied by XRD, bandgap measurements from UV-Vis-NIR diffuse reflectance spectroscopy, photocatalytic activity against Orange II in dissolution and NOx in air (efficiency in nitrate abatement), and SEM-EDX microstructural analysis. In the case of non-stabilized samples, charring samples at 300 °C/1 h and fired samples at 500 °C/1 h were also studied. The cassiterite-silica composite stands out for its photocatalytic activity against Orange II in solution and the cerianite-silica composite against NOx in air. Silica increases the photocatalytic activity on NOx in zirconia, tin oxide and ceria composites and also on Orange II in zirconia and tin oxide. Graphical Abstract

Bismuth oxyhalide as efficient photocatalyst for water, air treatment and bacteria inactivation under UV and visible light

Fifteen bismuth oxyhalides were synthetized, including BiOX, BiOX/BixOyXz, heterostructures and BiOXxY1−x (X, Y = Cl, Br, I) solid solutions. The photocatalytic activity and intermediates formation of as-prepared bismuth-based semiconductors (BBS) were compared with the benchmark TiO2 P25 photocatalyst for NOx air purification, phenol decomposition, and E.Coli bacteria inactivation. TiO2 P25 possessed the highest photocatalytic oxidation rate of phenol (K = 0.003 min−1) and NO degradation efficiency (η = 38 %) when exposed to UV light, but also the lowest performance under visible light on both photocatalytic process (K = 0.0007 min−1 and η = 14 %). Under visible light, BiOI/Bi4O5I2 or solid solutions (BiOI0.5Cl0.5 and BiOI0.5Br0.5) enhanced the photocatalyic for phenol degradation (K = 0.01–0.026 min−1) and NO (35–37 %). BBS samples generated more NO2 during NOx oxidation, but less typical intermediates (benzoquinone, hydroquinone and catechol) during phenol decomposition were detected. BiOCl0.5I0.5 and BiOBr0.5I0.5 composites exhibited the most outstanding antibacterial performance under both irradiation conditions resulting in E. coli 102-3 cfu/mL after 60 min irradiation. The differences can be mainly linked to a different ROS-mediated mechanism of TiO2 and BBS. The BBS photocatalytic results is closely related to the balance between effective light absorption and adequate redox potentials.

Sterilization effect and mechanism exploration of a mode‐combination method on Staphylococcus aureus in thick ice layers in a large sealed freezer

AbstractCold‐chain transport is a crucial cross‐regional transmission pathway for severe acute respiratory syndrome coronavirus 2 and other microorganisms. In this study, the mode‐combination method is adopted for sterilization in a 1.138 m3 freezer by mixing effluent gases of NOx and O3 mode air discharges. The mixed gas can effectively inactivate Staphylococcus aureus in 10 mm ice within 3 h, which significantly surpasses O3 gas. Moreover, the inactivation effect of the mixed gas can penetrate deep into ice, contrasting with the surface effect of O3 gas. This disparity is linked to the difference in penetration depth of strong oxidizing long‐lived reactive species. This study validates the sterilization efficacy of cold atmospheric plasma in practical cold‐chain environment, critical for curbing infectious disease transmission.

Quantifying effects of long-range transport of NO2 over Delhi using back trajectories and satellite data

Abstract. Exposure to air pollution is a leading public health risk factor in India, especially over densely populated Delhi and the surrounding Indo-Gangetic Plain. During the post-monsoon seasons, the prevailing north-westerly winds are known to influence aerosol pollution events in Delhi by advecting pollutants from agricultural fires as well as from local sources. Here we investigate the year-round impact of meteorology on gaseous nitrogen oxides (NOx=NO+NO2). We use bottom-up NOx emission inventories (anthropogenic and fire) and high-resolution satellite measurement based tropospheric column NO2 (TCNO2) data, from S5P aboard TROPOMI, alongside a back-trajectory model (ROTRAJ) to investigate the balance of local and external sources influencing air pollution changes in Delhi, with a focus on different emissions sectors. Our analysis shows that accumulated emissions (i.e. integrated along the trajectory path, allowing for chemical loss) are highest under westerly, north-westerly and northerly flow during pre-monsoon (February–May) and post-monsoon (October–February) seasons. According to this analysis, during the pre-monsoon season, the highest accumulated satellite TCNO2 trajectories come from the east and north-west of Delhi. TCNO2 is elevated within Delhi and the Indo-Gangetic Plain (IGP) to the east of city. The accumulated NOx emission trajectories indicate that the transport and industry sectors together account for more than 80 % of the total accumulated emissions, which are dominated by local sources (>70 %) under easterly winds and north-westerly winds. The high accumulated emissions estimated during the pre-monsoon season under north-westerly wind directions are likely to be driven by high NOx emissions locally and in nearby regions (since NOx lifetime is reduced and the boundary layer is relatively deeper in this season). During the post-monsoon season the highest accumulated satellite TCNO2 trajectories are advected from Punjab and Haryana, where satellite TCNO2 is elevated, indicating the potential for the long-range transport of agricultural burning emissions to Delhi. However, accumulated NOx emissions indicate local (70 %) emissions from the transport sector are the largest contributor to the total accumulated emissions. High local emissions, coupled with a relatively long NOx atmospheric lifetime and shallow boundary layer, aid the build-up of emissions locally and along the trajectory path. This indicates the possibility that fire emissions datasets may not capture emissions from agricultural waste burning in the north-west sufficiently to accurately quantify their influence on Delhi air quality (AQ). Analysis of daily ground-based NO2 observations indicates that high-pollution episodes (>90th percentile) occur predominantly in the post-monsoon season, and more than 75 % of high-pollution events are primarily caused by local sources. But there is also a considerable influence from non-local (30 %) emissions from the transport sector during the post-monsoon season. Overall, we find that in the post-monsoon season, there is substantial accumulation of high local NOx emissions from the transport sector (70 % of total emissions, 70 % local), alongside the import of NOx pollution into Delhi (30 % non-local). This work indicates that both high local NOx emissions from the transport sector and the advection of highly polluted air originating from outside Delhi are of concern for the population. As a result, air quality mitigation strategies need to be adopted not only in Delhi but in the surrounding regions to successfully control this issue. In addition, our analysis suggests that the largest benefits to Delhi NOx air quality would be seen with targeted reductions in emissions from the transport and agricultural waste burning sectors, particularly during the post-monsoon season.

Ambient air quality monitoring of Chandrapur District, Central India

Declining air quality is highly ignored and very common form of degradation of the environment in nations that are both developed and developing. There are several contaminants in the air that have been identified in various studies on air pollution. The crucial parameters of all air pollutants are gaseous and particle pollution. The present study was undertaken to estimate the quality of ambient air in Chandrapur district, Maharashtra state of India. In this paper, an effort has been made to study the standing and trend of Sulphur dioxide (SO2), Oxides of Nitrogen (NOx), Carbon Monoxide (CO), Ozone (O3), Ammonia (NH3), Respirable Suspended Particulate Matter i.e.; PM10, PM2.5, toxic pollutants i.e.; lead, arsenic, nickel, benzo [a] pyarene and benzene and hydrocarbons. The results clearly show that, all parameters of ambient air quality monitoring values were some shown slightly below permissible limit. The ambient air quality monitoring data show that the Chandrapur district has substantial air pollution concerns in terms of SO2, NOx, PM, and other air pollutants. However, after comparing these values with NAAQS levels, the yearly averages of these air pollutants have been found to be below than the NAAQS levels. However, without effective mitigation measures, the concentrations of these pollutants will rise at quite alarming rate.

Dual function of ultra-laminated hydrotalcite in environmental remediation: Adsorption of water contaminant BP-4 and reutilization of the adsorption product for photocatalytic NOx air decontamination

UV filters are a class of emerging water pollutants used in cosmetics to protect the skin from ultraviolet radiation. This work appraises the uptake of benzophenone-4 (BP-4), widely used and highly soluble sunscreen agent, by its adsorption on hydrotalcite based compounds. The studied adsorbents were hydrotalcite Mg3Al-CO3 (HT), ultra-laminated hydrotalcite (UHT) prepared by “Aqueous Miscible Organic Solvent Treatment” and their calcined products (HT500 and UHT500, respectively). Adsorbents were characterised by different techniques such as XRD, TEM, FT-IR, BET, XRF and TGA. The most remarkable feature was the enhancement in the specific surface area (SSA) of the ultra-laminated hydrotalcite samples, UHT and UHT500 with values of 212 m2·g─1 and 247 m2·g─1, respectively. Adsorption capacities decreased from very high for UHT500 to low values for HT in order UHT500 > HT500 > UHT > HT. The results showed that not only the SSA values were relevant for adsorbing BP-4, but also other factors such as anionic exchange capacity (AEC) and surface charge. In addition, the adsorption product (UHT-BP4) was evaluated as a photocatalyst for air purification, exhibiting good efficiency for the removal of atmospheric pollutants such as NOx gases.

Inferring the diurnal variability of OH radical concentrations over the Amazon from BVOC measurements

The atmospheric oxidation of biogenic volatile organic compounds (BVOC) by OH radicals over tropical rainforests impacts local particle production and the lifetime of globally distributed chemically and radiatively active gases. For the pristine Amazon rainforest during the dry season, we empirically determined the diurnal OH radical variability at the forest-atmosphere interface region between 80 and 325 m from 07:00 to 15:00 LT using BVOC measurements. A dynamic time warping approach was applied showing that median averaged mixing times between 80 to 325 m decrease from 105 to 15 min over this time period. The inferred OH concentrations show evidence for an early morning OH peak (07:00–08:00 LT) and an OH maximum (14:00 LT) reaching 2.2 (0.2, 3.8) × 106 molecules cm−3 controlled by the coupling between BVOC emission fluxes, nocturnal NOx accumulation, convective turbulence, air chemistry and photolysis rates. The results were evaluated with a turbulence resolving transport (DALES), a regional scale (WRF-Chem) and a global (EMAC) atmospheric chemistry model.

Extreme Value Analysis of NOx Air Pollution in the Winter Seaport of Varna

The work studies extreme pollution events and their return period in the winter seaport of Varna, providing information for decision-makers, government agencies and civil society on how the intensity of shipping traffic may impact the air pollution in the vicinity of the port. Extreme value analysis employing the Weibull distribution is applied to investigate air pollution and the probability of higher concentrations of oxides of nitrogen (NOx) generated by ships while queuing in the winter seaport. Potential cleaning of the air pollution generated by the anchored ships is introduced to meet the acceptable level of air pollution concentrations in coastal zones. The employed ship pollution cleaning and overall ship service costs are minimised to satisfy cleaner environmental conditions. The developed approach is adopted to analyse the air pollution of a port without a monitoring system to control and prevent pollution and with limited information on ship traffic and air pollution.

Impact of AIS Data Thinning on Ship Air Pollutant Emissions Inventories

This article examines the impact of automatic identification system (AIS) data thinning on ship emissions inventory results. AIS data thinning is theoretically proven to lead to a smaller result for a ship’s air pollutant emissions inventory. The AIS dynamic data of six sampled ships for 1 day and for 1 year were thinned at 1 min, 3 min, 10 min, 30 min, and 1 h time intervals, and then CO2, NOX, CH, PM, SO2, and other air pollutant emissions were estimated both with and without AIS data thinning in the different time intervals. The results show that AIS data thinning affects the air pollutant emissions inventory results of the ships, and the impact is greater as the thinning interval increases. When the thinning interval is less than 10 min, the impact is less than 10%, but the impact increases to about 10–15% at a 30 min interval and about 15–20% at a 60 min interval. The impacts of thinning on the emissions of ships with acutely fluctuating speeds are more significant because the constantly changing speed is the main reason why data thinning affects the ship emissions inventory. Therefore, these data suggest that the AIS data can be thinned at intervals of 5 or 10 min when establishing a coastal or national ship air pollutant emissions inventory, the AIS data should be thinned at intervals of less than 3 min when establishing the air pollutant emissions inventory of inland river ships, and data thinning is not recommended when establishing a port or smaller-scale ship air pollutant emissions inventory.

An Exploratory Investigation of Government Air Monitoring Data after Hurricane Harvey.

Southeast Texas is home to some of the largest refineries in the United States. During Hurricane Harvey, emergency shutdowns took place. In this exploratory investigation, we examine how government air monitors performed in measuring air quality in Beaumont, Texas during and in the months following Hurricane Harvey. Texas Commission on Environmental Quality (TCEQ) data from two active air monitors in Beaumont, Texas were analyzed during the year 2017–2018. Concentrations of sulfur dioxide (SO2), nitric oxide (NO), oxides of nitrogen (NOx), ozone, benzene, and hydrogen sulfide (H2S) were investigated. The number of hours and days no data were reported by air monitors were also investigated. Yearly maximum values (MAX, all in parts per billion (ppb)) in 2017 for SO2, NO, and NOx (53.7, 113.4, 134, respectively) and their respective standard deviations (SD: 1.3, 3.4, and 14) were higher as compared to 2018 (MAX, all in ppb and (SD) = 40.9, (1.4); 103.9, (3.3); 123.8, (14), respectively). The data capture rate for these chemicals were between 88 and 97% in both years. During the months following Hurricane Harvey (August–December 2017) there was an increase in most maximum values. The yearly averages for H2S were 0.68 ppb (SD 1.02) in 2017 and 0.53 ppb (SD 1.07) in 2018. Missing days were observed for both the H2S and NOx air monitors, with the highest number observed in 2017 (213 missing days) for the air monitor measuring H2S. We identified that residents of Beaumont, Texas are exposed daily to low-level concentrations of air pollutants. H2S is released each day at a level high enough to be smelled. Data capture rates for air monitors are not always above 90%. Improved air quality data and disaster preparations are needed in Beaumont, Texas.

Response of atmospheric deposition and surface water chemistry to the COVID-19 lockdown in an alpine area

The effects of the COVID-19 lockdown on deposition and surface water chemistry were investigated in an area south of the Alps. Long-term data provided by the monitoring networks revealed that the deposition of sulfur and nitrogen compounds in this area has stabilized since around 2010; in 2020, however, both concentrations and deposition were significantly below the average values of the previous decade for SO4 and NO3. Less evident changes were observed for NH4 and base cation. The estimated decrease of deposition in 2020 with respect to the previous decade was on average − 54% and − 46% for SO4 and NO3, respectively. The lower deposition of SO4 and NO3 recorded in 2020 was caused by the sharp decrease of SO2 and particularly of NOx air concentrations mainly due to the mobility restrictions consequent to the COVID-19 lockdown. The limited effects on NH4 deposition can be explained by the fact that NH3 emission was not affected by the lockdown, being mainly related to agricultural activities. A widespread response to the decreased deposition of S and N compounds was observed in a group of pristine freshwater sites, with NO3 concentrations in 2020 clearly below the long-term average. The rapid chemical recovery observed at freshwater sites in response to the sharp decrease of deposition put in evidence the high resilience potential of freshwater ecosystems in pristine regions and demonstrated the great potential of emission reduction policy in producing further substantial ameliorations of the water quality at sensitive sites.

Digital Colorimetry: Raspberry Pi-Based Sensors for Ar and Water Quality Monitoring

In this paper, we report Raspberry Pi-based, portable sensors for rapid and in situ determination of analytes relevant for bio-environmental analysis (PiSENS). We exploit the principle of digital colorimetry and the use of Red-Green-Blue (RGB) color system for quantitative assessment of color. The PiSENS was largely built using materials that can be found in a DIY shop while utilizing a Raspberry Pi and its imaging camera for data acquisition and processing. To automate the analysis and simplify the usage, we have written a python script which utilizes the principles outlined above. We will herein demonstrate two modes of PiSENS.PiSENS-A is developed for continuous monitoring of NOx in air and is based on color development as a consequence of the interaction of the gas with an absorbing solution. We utilize the traditional Saltzman reaction for capturing NO2 from the air that results in color development upon contact with a suitable absorbing solution. The PiSENS-A allowed data acquisition with a high temporal resolution, while low construction and operation costs open the possibility for the production and installation of a number of devices in order to increase spatial resolution.PiSENS-O is developed for the detection of analytes in water. The analysis is based on the utilization of polymer membrane-based optodes. We demonstrate the utility of PiSENS-O by the determination of Na+ and NO3 - in water. The results show that the precision expressed as relative standard deviation (%RSD) is in the range of 2.0-12.5% and 5-27% for Na+ and NO3 - respectively, while the accuracy expressed as the relative error (RE%) was 2.9% for both ions.The low construction and operational cost, and portability are very exciting as it shows potential to significantly improve the spatio-temporal frequency of analysis especially in rural and/or remote communities where access to expensive and complex instrumentation is limited. Furthermore, WiFi and/or Bluetooth capability of Raspberry Pi can be exploited for instantaneous data transmission, mapping, and the development of large-scale networks assisting in the development of high precision models.

The relationship of polluted air and drinking water sources with the prevalence of systemic lupus erythematosus: a provincial population-based study

Environmental exposures interact with genetic factors has been thought to influence susceptibility of systemic lupus erythematosus (SLE) development. To evaluate the effects of environmental exposures on SLE, we conducted a population-based cohort study across Jiangsu Province, China, to examine the associations between the living environment including air and water pollution, population density, economic income level, etc. and the prevalence and mortality of hospitalized SLE (h-SLE) patients. A total of 2231 h-SLE patients were retrieved from a longitudinal SLE database collected by the Jiangsu Lupus Collaborative Group from 1999 to 2009. The results showed that: It existed regional differences on the prevalence of h-SLE patients in 96 administrative districts; The distribution of NO2 air concentration monitored by atmospheric remote sensors showed that three of the ultra-high-prevalence districts were located in the concentrated chemical industry emission area; h-SLE patient prevalence was positively correlated with the excessive levels of nitrogen in drinking water; The positive ratio of pericarditis and proteinuria was positively correlated with the prevalence of h-SLE patients and pollution not only induced a high h-SLE patient prevalence but also a higher mortality rate, which might be attributed to NOx pollution in the air and drinking water. In summary, our data suggested that NOx in air and drinking water may be one of the important predispositions of SLE, especially for patients with renal involvement.

Characterization of ground-based atmospheric pollution and meteorology sampling stations during the Lake Michigan Ozone Study 2017

ABSTRACT The Lake Michigan Ozone Study 2017 (LMOS 2017) in May and June 2017 enabled study of transport, emissions, and chemical evolution related to ozone air pollution in the Lake Michigan airshed. Two highly instrumented ground sampling sites were part of a wider sampling strategy of aircraft, shipborne, and ground-based mobile sampling. The Zion, Illinois site (on the coast of Lake Michigan, 67 km north of Chicago) was selected to sample higher NOx air parcels having undergone less photochemical processing. The Sheboygan, Wisconsin site (on the coast of Lake Michigan, 211 km north of Chicago) was selected due to its favorable location for the observation of photochemically aged plumes during ozone episodes involving southerly winds with lake breeze. The study encountered elevated ozone during three multiday periods. Daytime ozone episode concentrations at Zion were 60 ppb for ozone, 3.8 ppb for NOx, 1.2 ppb for nitric acid, and 8.2 μg m-3 for fine particulate matter. At Sheboygan daytime, ozone episode concentrations were 60 ppb for ozone, 2.6 ppb for NOx, and 3.0 ppb for NOy. To facilitate informed use of the LMOS 2017 data repository, we here present comprehensive site description, including airmass influences during high ozone periods of the campaign, overview of meteorological and pollutant measurements, analysis of continuous emission monitor data from nearby large point sources, and characterization of local source impacts from vehicle traffic, large point sources, and rail. Consistent with previous field campaigns and the conceptual model of ozone episodes in the area, trajectories from the southwest, south, and lake breeze trajectories (south or southeast) were overrepresented during pollution episodes. Local source impacts from vehicle traffic, large point sources, and rail were assessed and found to represent less than about 15% of typical concentrations measured. Implications for model-observation comparison and design of future field campaigns are discussed. Implications: The Lake Michigan Ozone Study 2017 (LMOS 2017) was conducted along the western shore of Lake Michigan, and involved two well-instrumented coastal ground sites (Zion, IL, and Sheboygan, WI). LMOS 2017 data are publicly available, and this paper provides detailed site characterization and measurement summary to enable informed use of repository data. Minor local source impacts were detected but were largely confined to nighttime conditions of less interest for ozone episode analysis and modeling. The role of these sites in the wider field campaign and their detailed description facilitates future campaign planning, informed data repository use, and model-observation comparison.

Efficient destruction of sodium cyanide by thermal decomposition with addition of ferric oxide

Abstract Efficient destruction of cyanide by thermal decomposition with ferric oxide addition was proposed. The mechanism of destruction of sodium cyanide with or without ferric oxide addition under various conditions was examined by XRD, DSC−TG, and chemical analysis technologies. In the absence of ferric oxide, sodium cyanide decomposes at 587.4 °C in air and 879.2 °C in argon atmosphere. In the presence of ferric oxide, about 60% of sodium cyanide decomposes at 350 °C for 30 min in argon, while almost all sodium cyanide decomposes within 30 min in air or O2 with mass ratio of ferric oxide to sodium cyanide of 1:1. The increase of ferric oxide addition, temperature, and heating time facilitates the destruction of sodium cyanide. It is believed that with ferric oxide addition, NaCN reacts with Fe2O3 to form Na4Fe(CN)6, Na2CO3, NaNO2 and Fe3O4 in argon. NaCN decomposes into NaCNO, Na4Fe(CN)6, minor NaNO2, and the formed NaCNO and Na4Fe(CN)6 further decompose into Na2CO3, CO2, N2, FeOx, and minor NOx in air or O2.

Chimney Filter Model Wet Scrubber to Reduce Air Pollutant Emissions on the Incinerator

In general, inpatient health care facilities produce infectious and non-infectious waste 0.3 mᶟ / day. Non-infectious waste that is burned in an incinerator without a chimney filter, can cause particles, CO, SO2, NOx (air pollutants) and cause environmental pollution. This study aims to make a chimney filter design with a Scrubber model on an incinerator at the Public Health Center, Maospati District, Magetan Regency to reduce the amount of air pollutants emitted. This type of research is experimental research. This research designed a particle trapping device, gas by spraying water into the scrubber. The independent variable of this research was the variation of the water flow sprayed in the scrubber (3.2 liters / minute, 4 liters / minute, 5.6 liters / minute). The dependent variables of this study were particles, SO2, NOx, CO. Data collection using a digital gas detector method in the form of a UV spectrophotometer. Data were analyzed descriptively, in the form of frequency distribution, and percentage, presentation of data in a table based on air emission quality standards from thermal waste processing. The results illustrate that the use of a chimney scrubber filter with water spraying 3.2 liters / minute, 4 liters / minute, 5.6 liters / minute can reduce air pollutants, emission of SO2, CO to below the air quality standard. In addition, this tool can also reduce NOx gas and particles, but not yet below the quality standard. The conclusion from the results of this study is particulate emission air pollutants, gas SO2, CO, NOx. the incinerator can be lowered by modifying variations by spraying water 3.2 liters / minute, 4 liters / minute, 5.6 liters / minute on the chimney scrubber filter on the incinerator.
 
 Keywords: incinerator; scrubber; water discharge variations; particle; gas