Ambient NOx Research Articles

Ambient air pollutants and breast cancer stage in Tehran, Iran

This study aimed to examine the impacts of single and multiple air pollutants (AP) on the severity of breast cancer (BC). Data of 1148 diagnosed BC cases (2008–2016) were obtained from the Cancer Research Center and private oncologist offices in Tehran, Iran. Ambient PM10, SO2, NO, NO2, NOX, benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, and BTEX data were obtained from previously developed land use regression models. Associations between pollutants and stage of BC were assessed by multinomial logistic regression models. An increase of 10 μg/m3 in ethylbenzene, o-xylene, m-xylene, and 10 ppb of NO corresponded to 10.41 (95% CI 1.32–82.41), 4.07 (1.46–11.33), 2.89 (1.08–7.73) and 1.08 (1.00–1.15) increase in the odds of stage I versus non-invasive BC, respectively. Benzene (OR, odds ratio = 1.16, 95% CI 1.01–1.33) and o-xylene (OR = 1.18, 1.02–1.38) were associated with increased odds of incidence of BC stages III & IV versus non-invasive stages. BC stage I and stage III&IV in women living in low SES areas was associated with significantly higher levels of benzene, ethylbenzene, o-xylene, and m-xylene. The highest multiple-air-pollutants quartile was associated with a higher odds of stage I BC (OR = 3.16) in patients under 50 years old. This study provides evidence that exposure to AP is associated with increased BC stage at diagnosis, especially under premenopause age.

Oxidation capacity changes in the atmosphere of large urban areas in Europe: Modelling and experimental campaigns in atmospheric simulation chambers

Air pollution is a major concern for human health and the environment. Consequently, environmental standards have become stricter to improve air quality. Thanks to this, the ambient levels of O3 precursors such as VOCs and NOX have decreased. However, O3 levels in Europe, especially during winter, have increased, potentially impacting on atmospheric oxidation capacity and the associated chemistry of tropospheric oxidants. In this work, we focus on recent changes in the oxidation capacity of urban atmospheres. The study is conducted with the results of the CMAQ modelling system with a regional resolution with 12 × 12 km2 across the entire European continent for the winter (January) and summer (July) of 2007 and 2015. The 2015 meteorological data is used for both years to emphasise emission changes during the studied period. We scrutinise the changes in ambient concentration levels of the main tropospheric oxidants (O3 and HOX radicals) in five representative cities, Valencia, Madrid, Milan, Berlin, and The Hague. The enhanced O3 formation in winter seems to be due to the low VOC/NOX ratio, while the opposite trend in summer may be related to a relatively high ratio. Additionally, photooxidation experiments are carried out in the EUPHORE chambers to study the effect of changes in NOX concentration and NO/NO2 ratio on the variation of the given oxidants at constant VOCs concentrations. For the baseline experiments, two scenarios are selected based on the model results of 2015: two representative winter and summer days of low and high pollution in Berlin and Madrid, respectively. The role of VOC/NOX and NO/NO2 ratios on atmospheric reactivity is discussed. As a result, it is first suggested that further decreases in ambient NOX levels are required to reduce ambient O3 levels. Moreover, additional factors should be considered when designing local-specific emission abatement strategies.

Exposure to various ambient air pollutants and 9 cardiovascular conditions among individuals with diabetes: A prospective analysis of the UK Biobank

Background and aimsThe adverse effects of air pollutants on the risk of most cardiovascular diseases (CVDs) are well-established, but the risk of CVDs such as deep vein thrombosis, pulmonary embolism, or aortic valve stenosis have been underappreciated, especially in the diabetic population. This study aimed to evaluate associations between long-term air pollutants exposure and the risk of incident CVDs among participants with diabetes. MethodsThis study included 27,827 participants with baseline diabetes from the UK Biobank. We then estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for CVDs associated with chronic air pollutant exposure in the diabetic population by fitting the Cox proportional hazards model. Moreover, we investigated the cardiovascular effects of air pollutants at concentrations below WHO guideline limits. ResultsAfter multivariable adjustment, long-term NO2 and NOx exposures were positively associated with the development of 8 and 6 types of CVDs in participants with diabetes, respectively. In term of particulate matters, the effect estimates ranged from 1.51 (1.13, 2.03) (coronary artery disease) to 4.65 (2.73, 7.92) (peripheral arterial disease) per 10 μg/m3 increase in PM2.5. Whereas, the effect estimates ranged from 1.15 (1.04, 1.27) (arterial hypertension) to 2.28 (1.40, 3.69) (pulmonary embolism) per 10 μg/m3 increase in PM10. In addition, our study discovered that for most of the cardiovascular events (8 of 9), the deleterious effects of air pollutants persisted even when participants were exposed to air pollutants concentrations below WHO guideline limits. ConclusionsLong-term exposure to ambient NO2, NOx, PM2.5, and PM10, either at normal or low level, increased risk of various cardiovascular outcomes in the diabetic population.

Assessing the Impact of Lightning NOx Emissions in CMAQ Using Lightning Flash Data from WWLLN over the Contiguous United States

Comparison of lightning flash data from the National Lightning Detection Network (NLDN) and from the World Wide Lightning Location Network (WWLLN) over the contiguous United States (CONUS) for the 2016–2018 period reveals temporally and spatially varying flash rates that would influence lightning NOx (LNOx) production due to known detection efficiency differences especially during summer months over land (versus over ocean). However, the lightning flash density differences between the two networks show persistent seasonal patterns over geographical regions (e.g., land versus ocean). Since the NLDN data are considered to have higher accuracy (lightning detection with >95% efficiency), we developed scaling factors for the WWLLN flash data based on the ratios of WWLLN to NLDN flash data over time (months of year) and space. In this study, sensitivity simulations using the Community Multiscale Air Quality (CMAQ) model are performed utilizing the original data sets (both NLDN and WWLLN) and the scaled WWLLN flash data for LNOx production over the CONUS. The model performance of using the different lightning flash datasets for ambient O3 and NOx mixing ratios that are directly impacted by LNOx emissions and the wet and dry deposition of oxidized nitrogen species that are indirectly impacted by LNOx emissions is assessed based on comparisons with ground-based observations, vertical profile measurements, and satellite products. During summer months, the original WWLLN data produced less LNOx emissions (due to its lower lightning detection efficiency) compared to the NLDN data, which resulted in less improvement in model performance than the simulation using NLDN data as compared to the simulation without any LNOx emissions. However, the scaled WWLLN data produced LNOx estimates and model performance comparable with the NLDN data, suggesting that scaled WWLLN may be used as a substitute for the NLDN data to provide LNOx estimates in air quality models when the NLDN data are not available (e.g., due to prohibitive cost or lack of spatial coverage).

Ambient and indoor air pollution exposure and adverse birth outcomes in Adama, Ethiopia.

Air pollution poses a threat to human health, with pregnant women and their developing fetuses being particularly vulnerable. A high dual burden of ambient and indoor air pollution exposure has been identified in Ethiopia, but studies investigating their effects on adverse birth outcomes are currently lacking. This study explores the association between ambient air pollution (NOX and NO2) and indoor air pollution (cooking fuel type) and fetal and neonatal death in Adama, Ethiopia. A prospective cohort of mothers and their babies was used, into which pregnant women were recruited at their first antenatal visit (n=2085) from November 2015 to February 2018. Previously developed land-use regression models were utilized to assess ambient concentrations of NOX and NO2 at the residential address, whereas data on cooking fuel type was derived from questionnaires. Birth outcome data was obtained from self-reported questionnaire responses during the participant's postnatal visit or by phone if an in-person meeting was not possible. Binary logistic regression was employed to assess associations within the final study population (n = 1616) using both univariate and multivariate models; the latter of which adjusted for age, education, parity, and HIV status. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were reported. Within the cohort, 69 instances of fetal death (n=16 miscarriages; n=53 stillbirths) and 16 cases of neonatal death were identified. The findings suggest a tendency towards an association between ambient NOX and NO2 exposure during pregnancy and an increased risk of fetal death overall as well as stillbirth, specifically. However, statistical significance was not observed. Results for indoor air pollution and neonatal death were inconclusive. As limited evidence on the effects of exposure to ambient air pollution on adverse birth outcomes exists in Sub-Saharan Africa and Ethiopia, additional studies with larger study populations should be conducted.

Source emission and attribution of a large airport in Central China

Large airport operation release harmful air pollutants and have adverse impact on local air quality. As one of the world's top 30 busiest airports, Xinzheng International Airport (CGO) located in Zhengzhou City, China, its emission impacts needs particular attention. To identify the possible impacts and quantify the contribution of CGO airport to air pollution, a comprehensive approach including emission inventory, continuous monitoring, coupled with statistical modelling was adopted in this study. We estimated a more detailed emissions inventory for CGO, including hourly and annual emissions from engines and auxiliary power units of aircrafts during landing and take-off flight, and airside ground support equipment (GSE) in 2019. The results indicate that almost all the CGO specific parameters including operating hours, fuel consumption and unit LTO emissions at different modes were lower than ICAO reference values. The annual total emissions of NOx, CO, HC, SO2 and PM from CGO from aircrafts and GSE were 1207.7, 921.3, 123.7, 268.3 and 36.2 tons, respectively. In addition to SO2, the main engines of the aircraft accounted for 80.3%, 62.6%, 45.5% and 74.3% of the total emissions, respectively. Meanwhile, a continuous monitoring campaign was conducted for one year in the vicinity of CGO airport. The monitoring data were analyzed using generalized additive model (GAM) to quantify the impact of NOx emissions from airport activities on air quality at CGO. The results showed that even the influence of environmental and meteorological variables was greater, nearly 13% of the ambient NOx concentrations were explained by emissions from airport activities, indicating the importance of airport-related emissions as the major source affecting local air quality.

Sampling Low Air Pollution Concentrations at a Neighborhood Scale in a Desert U.S. Metropolis with Volatile Weather Patterns.

Background: Neighborhood-scale air pollution sampling methods have been used in a range of settings but not in low air pollution airsheds with extreme weather events such as volatile precipitation patterns and extreme summer heat and aridity—all of which will become increasingly common with climate change. The desert U.S. metropolis of Tucson, AZ, has historically low air pollution and a climate marked by volatile weather, presenting a unique opportunity. Methods: We adapted neighborhood-scale air pollution sampling methods to measure ambient NO2, NOx, and PM2.5 and PM10 in Tucson, AZ. Results: The air pollution concentrations in this location were well below regulatory guidelines and those of other locations using the same methods. While NO2 and NOx were reliably measured, PM2.5 measurements were moderately correlated with those from a collocated reference monitor (r = 0.41, p = 0.13), potentially because of a combination of differences in inlet heights, oversampling of acutely high PM2.5 events, and/or pump operation beyond temperature specifications. Conclusion: As the climate changes, sampling methods should be reevaluated for accuracy and precision, especially those that do not operate continuously. This is even more critical for low-pollution airsheds, as studies on low air pollution concentrations will help determine how such ambient exposures relate to health outcomes.

Short-term exposure to traffic-related air pollution and STEMI events: Insights into STEMI onset and related cardiac impairment

AimsEvidence on the impacts of traffic-related air pollution (TRAP) on ST-segment elevation myocardial infarction (STEMI) events is limited. We aimed to assess the acute effects of TRAP exposure on the clinical onset of STEMI and related cardiac impairments. Methods and resultsWe recruited patients who were admitted for STEMI and underwent primary percutaneous coronary intervention at Peking University Third Hospital between 2014 and 2020. Indicators relevant to cardiac impairments were measured. Concomitantly, hourly concentrations of traffic pollutants were monitored throughout the study period, including fine particulate matter, black carbon (BC), particles in size ranges of 5–560 nm, oxides of nitrogen (NOX), nitrogen dioxide, and carbon monoxide. The mean (SD) age of participants was 62.4 (12.5) years. Daily average (range) concentrations of ambient BC and NOX were 3.9 (0.1–25.0) μg/m3 and 90.8 (16.6–371.7) μg/m3. Significant increases in STEMI risks of 5.9% (95% CI: 0.1, 12.0) to 21.9% (95% CI: 6.0, 40.2) were associated with interquartile range increases in exposure to TRAP within a few hours. These changes were accompanied by significant elevations in cardiac troponin T levels of 6.9% (95% CI: 0.2, 14.1) to 41.7% (95% CI: 21.2, 65.6), as well as reductions in left ventricular ejection fraction of 1.5% (95% CI: 0.1, 2.9) to 3.7% (95% CI: 0.8, 6.4). Furthermore, the associations were attenuated in participants living in areas with higher residential greenness levels. ConclusionsOur findings extend current understanding that short-term exposure to higher levels of traffic pollution was associated with increased STEMI risks and exacerbated cardiac impairments, and provide evidence on traffic pollution control priority for protecting vulnerable populations who are at greater risks of cardiovascular events.

Non-linearity of secondary pollutant formation estimated from emissions data and measured precursor-secondary pollutant relationships

In order to predict the impacts of reductions in air pollutant emissions, it is important to know whether secondary pollutant concentrations will decline in direct proportion to the reduction in their precursor, referred to as linearity. Trends in airborne concentrations of nitrate, sulfate, and SOC at sites in southern England are compared with emissions and concentration trends for sulfur dioxide (SO2), oxides of nitrogen (NOx), and non-methane VOC, and show some increased ratios of concentrations to emissions, strongly suggestive of non-linearity in the primary-secondary pollutant relationships for nitrate, but not the other pollutants. Analysis of a further 20-year dataset from the AGANET network shows a decline of nitrate concentrations significantly lower than that of NOx emissions and ambient NOx concentrations. For sulfate, the decline lies between that of emissions and airborne concentrations of SO2. Back trajectory analysis and Potential Source Contribution Function mapping for 2014–2018 show that the highest concentrations of secondary constituents in southern England are associated with air masses originating in mainland Europe, with 42% of sulfate, 55% of nitrate, and 35% of SOC estimated to be associated with air masses entering the UK from the European mainland.

COVID-19 lockdown closures of emissions sources in India: Lessons for air quality and climate policy

Reduced anthropogenic activities during the COVID-19 pandemic caused significant reductions in ambient fine particulate matter (PM2.5), SO2 and NOx concentrations across India. However, tropospheric O3 concentrations spiked over many urban regions. Moreover, reductions in SO2 and NOx (atmospheric cooling agents) emissions unmask heating exerted by warming forcers. Basing governmental guidelines, we model daily emissions reductions in CO2 and short-lived climate forcers (SLCFs) during different lockdown periods using bottom-up regional emission inventory. The transport sector, with maximum level of closure, followed by power plants and industry reduced nearly −50% to −75% emissions of CO2, primary PM2.5, SO2 and NOx, while warming SLCFs (black carbon, CH4, CO and non-methane VOCs) showed insignificant reduction from continuing activity in residential and agricultural sectors. Consequently, the analysis indicates that reduction in the emission ratio of NOx to NMVOC coincided spatially with observed increases in O3, consistent with reduced uptake of O3 from night-time NOx reactions. Also, similar reductions, occurring for longer timescales (say, a year), can potentially increase the annual warming rate over India from the positive regional temperature response, estimated using climate metric. Further, by linking ongoing policies to sectoral reductions during lockdown, this study shows that the relative pacing of implementation among policies is crucial to avoid counter-productive results. A key policy recommendation is introduction and improving efficacy of programs targeting reduction of NMVOC and warming SLCF emissions (shifts away from biomass cooking technologies, household electrification and curbing open burning of crop residues), must precede the strengthening of policies targeting NOx and SO2 dominated sectors.

Seasonal Variation in Nitrate Removal Mechanisms in Coastal Stormwater Ponds

AbstractStormwater wet ponds (SWPs) are engineered structures used to collect and retain stormwater runoff from developed areas. SWPs are generally regarded as important nitrogen (N) sinks, but seasonal variation in SWP N cycling that influences pond nitrogen removal has not been characterized. To inform SWP function across seasons, we sampled the sediments and water columns of three stormwater ponds in the southeastern US coastal plain and measured gas and nutrient fluxes from the sediment‐water interface during ambient conditions and nitrate (NO3)‐enriched “simulated storm” conditions. Dissolved organic nitrogen (DON) was the dominant form of dissolved N in the water column, while nitrate + nitrite (NOx) was typically below detection. SWP sediment organic matter properties varied by study site but had minimal impact on sediment N processes or estimated NO3 fate. SWP sediments generally functioned as TN sinks during NO3‐enriched conditions, but the estimated fate of NO3 varied based on water temperature, DON concentrations, and sediment O2 uptake. These results suggest that permanent N removal (denitrification) by SWPs varies seasonally, with retention of NOx becoming more important during hotter conditions when NOx uptake is largest. Low ambient NOx concentrations and rapid NO3 uptake suggest that coastal stormwater ponds can host reduced conditions that may promote NO3 retention over denitrification. Additional research is needed to determine the fate of retained NO3 in SWP sediments and how variation in NO3 fate might impact downstream water quality.

Switching to electric vehicles can lead to significant reductions of PM2.5 and NO2 across China

Switching to electric vehicles can lead to significant reductions of PM2.5 and NO2 across China

Association of Prenatal Ambient Air Pollution Exposure With Placental Mitochondrial DNA Copy Number, Telomere Length and Preeclampsia.

Background: Studies have shown that ambient air pollution is linked to preeclampsia (PE), possibly via generation of oxidative stress in the placenta. Telomere length and mitochondrial DNA copy number (mtDNAcn) are sensitive to oxidative stress damage.Objective: To study the association between prenatal exposure to ambient nitrogen oxides (NOx, a marker for traffic-related air pollution), and PE, as well as potential mediation effects by placental telomere length and mtDNAcn.Methods: This is a cross-sectional study of 42 preeclamptic and 95 arbitrarily selected normotensive pregnant women with gestational ambient NOx exposure assessment in southern Scania, Sweden. Hourly concentrations of NOx were estimated at the residential addresses by a Gaussian-plume dispersion model with 100 × 100 m spatial resolutions and aggregated into trimester-specific mean concentrations. Placental relative mtDNAcn and telomere length were measured using qPCR. Linear and logistic regression models were used to investigate associations, adjusted for perinatal and seasonal characteristics.Results: Exposure was categorized into low and high exposures by median cut-offs during first [11.9 μg/m3; interquartile range (IQR) 7.9, 17.9], second (11.6 μg/m3; IQR: 7.1, 21.1), third trimesters (11.9 μg/m3; IQR: 7.7, 19.5) and entire pregnancy (12.0 μg/m3; IQR: 7.6, 20.1). Increased risk of PE was found for high prenatal NOx exposure during the first trimester (OR 4.0; 95% CI: 1.4, 11.1; p = 0.008), and entire pregnancy (OR 3.7; 95% CI: 1.3, 10.4; p = 0.012). High exposed group during the first trimester had lower placental relative mtDNAcn compared with low exposed group (−0.20; 95% CI: −0.36, −0.04; p = 0.01). Changes in relative mtDNAcn did not mediate the association between prenatal NOx exposure and PE. No statistically significant association was found between placental relative telomere length, prenatal NOx exposure and PE.Conclusion: In this region with relatively low levels of air pollution, ambient NOx exposure during the first trimester was associated with reduced placental relative mtDNAcn and an increased risk of PE. However, we did not find any evidence that mtDNAcn or TL mediated the association between air pollution and PE. Future research should further investigate the role of mtDNAcn for pregnancy complications in relation to exposure to ambient air pollution during pregnancy.

Ambient air quality data reported at Sasol Secunda monitoring stations during COVID-19 lockdown – Mpumalanga, South Africa

Various local and international research has been published on the effects of COVID-19 lockdown on ambient air quality. In most cases, a reduction in ambient NOx and PM concentrations have been observed with varying changes in ambient SO2 levels. Secunda, located in the Highveld Priority Area in Mpumalanga, South Africa is known for its large industrial facilities utilising coal as primary feedstock. The towns of Secunda and eMbalenhle provide the majority of the workforce to Sasol and has therefore been the focus of this study. The ambient air quality in the Secunda region was assessed due to the changes in human behaviour during lockdown, familiarity with the Sasol facility and the strategic locations of ambient air quality stations.Results show a clear decrease in ambient CO, NO2 and PM concentrations, especially during the first two weeks of lockdown. Only subtle changes were observed for ambient H2S and SO2 pollutant concentrations at the ambient monitoring stations. An increasing trend in all ambient species was observed towards the end and post lockdown, in contrast to declining ambient temperatures with the onset of winter. This is also contrary to the reduction in emissions from the factory that conducted annual maintenance in the month following lockdown (phase shutdown). This article concludes that human behaviour has a material local ambient impact on CO, NO2 and PM pollutant species, while H2S concentration profiles are more directly related to the industrial complex’s levels of activity. Ambient SO2 trends did not show a similar correlation with the facility’s activities (as H2S), but a stronger correlation was observed with the diverse local and regional sources in close proximity to Secunda and eMbalenhle. The influence of better dispersion especially on a local scale, brought about by more effective emission heights, is considered material. Moreover, meteorological factors, on local air quality, has been shown to be a material contributor to observed ambient air quality levels in the study domain

Analisis pengaruh V/C ratio lalu lintas kendaraan terhadap tingkat polusi udara berdasarkan volume lalu lintas kendaraan (studi di kawasan persimpangan Mall SKA Kota Pekanbaru)

Completion of the transportation problems in the city of Pekanbaru currently only looked at in terms of congestion, but not touching insights from environmental aspects such as performance air pollution and noise levels. This research was conducted at the observation point road ahead Repair Tambusai lord Eastern Daihatshu, road Tuanku Tambusai West Side Mall SKA, North Soekarno Hatta street front retail outlets, street front Soekarno Hatta South Hotel Ibis Pekanbaru. V / C Ratio highest in the afternoon rush hour on the road ahead Tambusai lord Stations Daihatsu ie 0.86 pelyanan road performance E. Quality Standard ambient NOx emissions do not exceed the threshold of ambient quality standards, the NOx emission = 281.76 mg/m3. Quality Standard ambient CO emissions do not exceed the threshold of ambient quality standards, namely emission = 7456.79 mg/m3, the noise level over the limit of noise that is 71.41 dB (A). To balance the load reduction in pollutant emissions and noise levels at the flyover plan with the plan of special bus lane traffic volume assumptions have to move 25% of the transfer of the road users of private vehicles and motorbikes switch to using mass public transport vehicles ie Trans Metro bus Pekanbaru.

Oxidation and sources of atmospheric NOx during winter in Beijing based on δ18O-δ15N space of particulate nitrate.

The determination of both stable nitrogen (δ15N-NO3-) and stable oxygen (δ18O-NO3-) isotopic signatures of nitrate in PM2.5 has shown potential for an approach of assessing the sources and oxidation pathways of atmospheric NOx (NO+NO2). In the present study, daily PM2.5 samples were collected in the megacity of Beijing, China during the winter of 2017-2018, and this new approach was used to reveal the origin and oxidation pathways of atmospheric NOx. Specifically, the potential of field δ15N-NO3- signatures for determining the NOx oxidation chemistry was explored. Positive correlations between δ18O-NO3- and δ15N-NO3- were observed (with R2 between 0.51 and 0.66, p<0.01), and the underlying environmental significance was discussed. The results showed that the pathway-specific contributions to NO3- formation were approximately 45.3% from the OH pathway, 46.5% from N2O5 hydrolysis, and 8.2% from the NO3+HC channel based on the δ18O-δ15N space of NO3-. The overall nitrogen isotopic fractionation factor (εN) from NOx to NO3- on a daily scale, under winter conditions, was approximately+16.1‰±1.8‰ (consistent with previous reports). Two independent approaches were used to simulate the daily and monthly ambient NOx mixtures (δ15N-NOx), respectively. Results indicated that the monthly mean values of δ15N-NOx compared well based on the two approaches, with values of-5.5‰ ± 2.6‰,-2.7‰ ± 1.9‰, and-3.2‰ ± 2.2‰ for November, December, and January (2017-2018), respectively. The uncertainty was in the order of 5%, 5‰ and 5.2‰ for the pathway-specific contributions, the εN, and δ15N-NOx, respectively. Results also indicated that vehicular exhaust was the key contributor to the wintertime atmospheric NOx in Beijing (2017-2018). Our advanced isotopic perspective will support the future assessment of the origin and oxidation of urban atmospheric NOx.

Plasma-Treated Flammulina velutipes-Derived Extract Showed Anticancer Potential in Human Breast Cancer Cells

Natural products with medicinal properties are among alternative therapies of interest due to their high body tolerance. We aimed to determine whether nonthermal gas plasma could enhance the medicinal value of Flammulina velutipes mushrooms. Generated gas plasma was characterized by its emission spectrum in ambient air, pH, temperature, and H2O2 and NOx concentrations after exposure for various periods. Phenolic and flavonoid contents in the extracts were measured using antioxidant assays and Fourier transform infrared and ultraviolet-visible spectroscopy. We analyzed the effects of the plasma-treated mushroom-derived extracts against breast carcinoma using the MCF7 and MDA-MB231 cell lines. The extracts significantly and concentration dependently inhibited the growth of breast cancer cells without inducing toxicity in normal MCF10A cells, and induced apoptosis via oxidative stress, evidenced by DNA damage (γ-H2AX foci formation), and increased the population of MCF7 breast cancer cells arrested in the G2/M phase of the cell cycle. The extracts also induced mitochondrion-mediated apoptosis of MCF7 cells through cytochrome c release and caspase cleavage activity. The plasma improved the biological activity of mushrooms by increasing their phenolic compounds that prevented the growth of breast cancer cells in vitro.

Interference from alkenes in chemiluminescent NO&amp;lt;sub&amp;gt;&amp;lt;i&amp;gt;x&amp;lt;/i&amp;gt;&amp;lt;/sub&amp;gt; measurements

Abstract. Nitrogen oxides (NOx=NO+NO2) are critical intermediates in atmospheric chemistry and air pollution. NOx levels control the cycling and hence abundance of the primary atmospheric oxidants OH and NO3 and regulate the ozone production which results from the degradation of volatile organic compounds (VOCs) in the presence of sunlight. They are also atmospheric pollutants, and NO2 is commonly included in air quality objectives and regulations. NOx levels also affect the production of the nitrate component of secondary aerosol particles and other pollutants, such as the lachrymator peroxyacetyl nitrate (PAN). The accurate measurement of NO and NO2 is therefore crucial for air quality monitoring and understanding atmospheric composition. The most commonly used approach for the measurement of NO is the chemiluminescent detection of electronically excited NO2 (NO2∗) formed from the NO + O3 reaction within the NOx analyser. Alkenes, ubiquitous in the atmosphere from biogenic and anthropogenic sources, also react with ozone to produce chemiluminescence and thus may contribute to the measured NOx signal. Their ozonolysis reaction may also be sufficiently rapid that their abundance in conventional instrument background cycles, which also utilises the reaction with ozone, differs from that in the measurement cycle such that the background subtraction is incomplete, and an interference effect results. This interference has been noted previously, and indeed, the effect has been used to measure both alkenes and ozone in the atmosphere. Here we report the results of a systematic investigation of the response of a selection of commercial NOx monitors to a series of alkenes. These NOx monitors range from systems used for routine air quality monitoring to atmospheric research instrumentation. The species-investigated range was from short-chain alkenes, such as ethene, to the biogenic monoterpenes. Experiments were performed in the European PHOtoREactor (EUPHORE) to ensure common calibration and samples for the monitors and to unequivocally confirm the alkene levels present (via Fourier transform infrared spectroscopy – FTIR). The instrument interference responses ranged from negligible levels up to 11 %, depending upon the alkene present and conditions used (e.g. the presence of co-reactants and differing humidity). Such interferences may be of substantial importance for the interpretation of ambient NOx data, particularly for high VOC, low NOx environments such as forests or indoor environments where alkene abundance from personal care and cleaning products may be significant.

Spatial-temporal levels, variations and sources of NO2/NOx in the sub-Saharan African city of Accra, Ghana

Background. As the world’s fastest urbanizing region, rapid economic growth in Sub-Saharan Africa (SSA) is raising levels of urban air pollution from diverse local and regional sources. While measurement data are now emerging from SSA on particulate matter pollution, there is limited information on major combustion related gaseous pollutants. We examined the levels, spatial, seasonal, and socioeconomic patterns as well as sources of oxides of nitrogen (NOx: NO2/NO) in Accra, Ghana’s capital and one of SSA’s largest metropolitan cities.Methods. We collected weekly integrated ambient NO2 and NOx samples using OGAWA passive samplers at 150 sites, consisting of a year-long (n=10) and week-long (n=140) averages which included a range of land-uses and emissions sources (traffic, biomass).Results. Annual mean NO2 across all sites was 52 µg/m3. Both NO2 and NOx concentrations were highest between November and February, the ‘Harmattan’ period when local and regional meteorology is altered, with means of 73 and 218 µg/m3, respectively, comparing to 47 and 116 µg/m3 during non-Harmattan period. The mean NO2 and NOx levels were highest at roadside sites (82 and 285 µg/m3), followed by residential (46 and 102 µg/m3) and sub-urban background sites (27 and 67 µg/m3). There was no difference between high-density (i.e. low-income and high biomass use) and low-density (i.e. high-income and low biomass use) residential sites. The overall sample mean NO2/NOx ratio was 0.53, varying from 0.35 at roadside sites to 0.63 at residential sites.Conclusions. Traffic is the most important contribution for NOx in Accra, while contribution from biomass burning shows no difference at high- and low-income neighborhoods. NO2/NOx ratios are significantly lower than in North American, European and East Asian cities, indicating a less oxidative atmospheric condition in Accra, especially among traffic sites. “Harmattan” increases local pollution level significantly, possibly by altering local and regional meteorology conditions.

Mapping spatial distribution of traffic induced criteria pollutants and associated health risks using kriging interpolation tool in Delhi

The present study undertakes to understand the spatial influence of traffic-induced criteria air pollutants and associated health risks assessment at major transport corridors in Delhi. The study includes the classification of vehicular pollutants parameters into five different distribution categories, i.e., low, moderately low, moderate, moderately high, and high. Spatial distribution maps were developed using Geographic Information System (GIS) environment for eleven districts covering 36 transport corridors of the city. The study demonstrated the concentration of three out of the five ambient air pollutants, namely, NOx, PM10 and PM2.5, with highest values in the range of 294.10–362.57, 203.99–422.42 and 333.71–541.72 μg/m3, respectively. Corresponding National Ambient Air Quality Standards (NAAQS) values were found to be grossly violated as reflected by NOx, PM2.5 and PM10 concentrations with 2–5 times higher values. Remaining two (CO and SOx) were found to be under permissible limits, and most of them exhibited low levels of observed concentrations. The ambient air quality in south, central, east, and New Delhi areas were found to be in high and moderately high categories and necessitating adequate control measures. The study reported a total of 281107, 20791, 31636 expected cases of human exposure to respiratory mortality, cardiovascular mortality and total mortality, respectively whereas, 281107 and 71608 number of cases were reported in relation to respiratory morbidity in terms of COPD hospital admission and cardiovascular morbidity along the transport corridors. The outcome of the study may provide a basis for decision makers to formulate the policy as per the scale of impact of traffic induced air pollution in critical areas around the major transport corridors.