Average Concentrations Of SO2 Research Articles

Long-term ambient SO2 concentration and its exposure risk across China inferred from OMI observations from 2005 to 2018

Long-term trends in the ambient SO2 concentrations across China from 2005 to 2018 were estimated using Ozone Monitoring Instrument (OMI) SO2 columns and an atmospheric SO2 profile simulated by the Model for Ozone And Related Chemical Tracers (MOZART)-4. The estimated ground-level SO2 concentrations were in strong agreement with the ground observations (R = 0.86, root-mean-square error = 10.49 μg/m3, relative prediction error = 19%). From 2005 to 2018, the average ground-level SO2 concentration ranged from 0.97 to 106.41 μg/m3 across China, with higher values in eastern China than in western China. Considering the uneven distribution of SO2 concentration and population across China, the population-weighted SO2 concentration was estimated to be 20.30 μg/m3 on a national scale. The population-weighted SO2 levels showed decreasing trends, and the absolute values of the decreasing trend peaked in winter (1.41 μg/m3 per year), followed by those in autumn (0.92 μg/m3 per year), spring (0.74 μg/m3 per year) and summer (0.75 μg/m3 per year) from 2005 to 2018. Although the SO2 exposure risk in 2018 decreased significantly from 2005 on a national scale, 80% and 17% of people still faced a high SO2 exposure risk (higher than 20 μg/m3) in the North China Plain and Northwest China, respectively.

Understanding the knowledge gaps between air pollution controls and health impacts including pathogen epidemic

Sustainable development calls for a blue sky with quality air. Encouragingly, the current mass reduction-oriented pollution control is making substantial achievements, as the data from Chinese Environmental Monitoring Stations show a significant drop in the annual average concentrations of particulate matters (i.e., PM10 and PM2.5) and SO2. But many challenges and knowledge gaps are still confronted nowadays. On one hand, long-term health impacts of fine air particles have to be closely probed through both epidemiological and laboratory studies, and the toxic effects owing to the interactions between particles and associated chemical pollutants should be differentially teased out. On the other hand, due to sole mass control, there are significant changes of overall pollutant fingerprint, such as the increase of ground-level ozone concentration, which should be taken into account for altered health effects relative to the past. Moreover, the interplays with air pollutants and air-borne pathogens should be scrutinized in more details. In other words, it is worth investigating likely spread of pathogens (even for SARS-CoV-2) with aid of aerosols. Here, we recapitulate the current knowledge gaps between air pollution controls and health impacts including pathogen epidemic, and we also propose future research directions to support policy making in balance mass control and health impacts.

Spatial distribution characteristics of gaseous pollutants and particulate matter inside a city in the heating season of Northeast China

The aim of this paper is to analyze the distribution characteristics of gaseous pollutants (SO2 and NO2) and particulate matter (PM1.0, PM2.5 and PM10) and to explore the main factors affecting the distribution pattern of air pollutants inside Shenyang urban areas in the heating season of Northeast China. To achieve this goal, the concentration of five air pollutants on two main roads in the Shenyang four-ring area was measured by a vehicle-borne air pollutant monitor. Through analysis of the spatial distribution pattern of these air pollutants, it can be found that the average concentrations of SO2 for the three monitoring events are similar (43.1, 40.6 and 40.3 μg/m3), and the concentrations of NO2, PM1.0, PM2.5 and PM10 are the highest for the 20190304 event, followed by the 20190107 and 20181213 events. Pearson correlation was used to analyze the relationships of the gaseous pollutants and particulate matter based on the data from the three monitoring events. The results indicated that SO2 is negatively correlated with the other pollutants, while there are positive correlations among the other four pollutants. In particular, there is a strong positive correlation among the three classes of particulate matter (correlation coefficients > 0.97, p < 0.01). The relative contributions of environmental factors and landscape pattern factors to the air pollutants were analyzed by the BRT model. It is revealed that the environmental factors have a significant influence (relative contributions> 10 %) on air pollution, and temperature was the main influencing factor (relative contributions > 20 %). The findings obtained through this study can increase the understanding of the distribution pattern of air pollutants and their main influencing factors in the heating season of Northeast China and provide decision makers and urban planners with a scientific basis for the amelioration of air pollution via urban planning and management.

Quantification of mortality and morbidity attributed to the ambient air criteria pollutants in Shiraz city, Iran

According to the epidemiological surveys, ambient air pollution has directly related to mortality and different diseases such as cardiovascular and respiratory defects. Among the atmospheric contaminants, criteria air ones (NO2, O3, PM2.5/10, SO2) demonstrated that have particular importance in the community disease. The overall goal of this paper was to study the impact of criteria air contaminants on the health of the inhabitants of Shiraz city, Iran. To accomplish this, the AirQ2.2.3 software was applied. The results of the study revealed that the annual average NO2, SO2, PM2.5, PM10, and O3 concentrations are 39.98, 27.6, 14.35, 46.16, and 120.03 μg/m3 in 2016 and 30.27, 23.97, 16.45, 51.65, and 52.58 μg/m3 in 2017. The total International Classification of Diseases (ICD), cardiovascular, and respiratory mortalities caused by air contaminants in Shiraz was predicted as 911, 628, and 182 cases in 2016, and 346, 370, and 82 cases in 2017, respectively. Sulfur dioxide (SO2) had the greatest rate of total mortality with the attributable equivalent of 4.3% in 2016, but this value has been decreased to 0.42% in 2017. The findings of this research revealed that air contamination has caused problems in Shiraz city according to the predicted results. The findings of this work provide useful data for regional and national health policymakers, who should take decisions to develop strategies for control air contaminants and estimate the cost-effectiveness of interventions.

Analysis of roadside air pollutant concentrations and potential health risk of exposure in Hanoi, Vietnam

The large number of vehicles plying in roads is the main cause of traffic jam and air pollution in Hanoi. In this study, the vehicle density and shares of different vehicle types, the traffic flow velocity and roadside air pollutants concentrations were monitored in Chua Boc street, a typical arterial road in the city. The shares of the motorcycle, car and bus fleets in the total on-road traffic in the street were 78.4-87.3, 12.3-20.2 and 0.4-1.4%, respectively. The high density of vehicles caused traffic jam during rush hours and considerably reduced the vehicle speed. The traffic flow velocity during non-rush and rush hours was found to vary from 26.4-34.5 and 10.3-12.1 km/h, respectively. The average concentrations of PM10, PM2.5, SO2, NO2, CO and NMVOC during the rush hours were the following: 117.1 ± 8.5, 65.2 ± 10.6, 113.5 ± 10.9, 138.5 ± 16.0, 6792 ± 998 and 451 ± 71 µg/m3, respectively, which were about 1.9-2.6 times above the levels during non-rush hours. The decrease in vehicle speed during rush hours were strongly correlated with the increase in concentration of PM10 (R2 = 0.732), PM2.5 (R2 = 0.685), SO2 (R2 = 0.578), NO2 (R2 = 0.738), CO (R2 = 0.689) and NMVOC (R2 = 0.747). High levels of these toxic air pollutants in Hanoi city posed a high health risk to humans. Facemask use was more popular among the motorcycle commuters and pedestrians, especially during rush hours, than among the people working for extended time period alongside of the street.

Study on the Emission Characteristics of PCDD/Fs and Other Multiple Pollutants in Flue Gas from Sintering Plant in China

In China, sintering flue gas has become the most important source of air pollution rather than burning coal-fired flue gas.The emission characteristics and removal efficiencies of various gaseous pollutants were studiedon a 180 m2 sintering equipped with a semi-dry oxidative desulfurization and denitrification system in Tangshang, Hebei province. The emission concentrations of particulate matter, fluoride,NOX and SO2were measured in the flue gas whilepolychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) were tested in both flue gas and dust ash at 100% and 60% loadconditions. The collections and analyses ofpollutantswere used by smoke sampler, TESTO350 and dioxin sampleraccording to national standards of China. The results shown that the average emission concentration of particulate matter, fluoride, NOX and SO2 in the inlet of the flue gas purification system were 47.4 mg/m3, 0.12 mg/m3, 150 mg/m3 and 521 mg/m3 while the emission concentrations in the outlet were 1.2 mg/m3, 0.07 mg/m3, 24 mg/m3 and 20 mg/m3,respectively. Through the flue gas purification system, the PCDD/Fs concentrations were reduced from 23.12 ng/m3to 1.14 ng/m3at100% load and from 12.25 ng/m3 to 0.84 ng/m3at60% load. The PCDD/Fs concentrations in the dust ash were about 178.56~197.21 ng/kg. Thedesulfurization and denitrification system significant reduced effect on the emission of particulate matter, fluoride, NOX, SO2 and PCDD/Fs with the value 97.5%, 41.7%, 84.0%, 96.2% and 95.1% at 100% load, respectively.The removal affects increases along the chlorination degree of PCDD/Fs. Meanwhile,the different load influenced the emission concentrations and removal rates of PCDD/Fs in the flue gas, the removal effects increases as the load increases. Although the desulfurization and denitrification system has good removal effects on various pollutants, the dioxins were enriched in the dust ashso as to cause secondary pollution.

Relationship between the number of hospitalized cardiovascular and respiratory disease and the average concentration of criteria air pollutants (CAP) in Ahvaz.

This study aims to investigate the relationship between the number of hospitalized cardiovascular and respiratory patients and the average concentration of criteria air pollutants, including NO2, SO2, CO, O3 and PM10 in Ahvaz in the period of 10years (2007-2017). Data on referrals and the number of hospitalized cardiovascular and respiratory patients and also on air pollutants are obtained through Hospital Information System and air quality monitoring stations including Department of Environment Protection Station, Naderi Square Station, University Square Station and the Meteorological Organization Station. The data were analyzed by SPSS version 4 and Poisson distribution regression model to evaluate the effects of each pollutant and the rate of hospitalization. In this study, confidence interval and the significance level are considered at 95% and 5%, respectively. Changes in air pollution indices and number of patients with cardiovascular diseases were evaluated using Excel, Stata and ARIMA models. Based on the results of Poisson regression analysis, there was a significant relationship between the average concentration of NO2, O3, CO and SO2 and hospitalization of patients with cardiovascular disease, with a confidence level of less than 5%. This was the case with NO2 more than other pollutants. Furthermore, there was a significant relationship between the average concentrations of NO2, CO and O3 and the hospitalization rate of patients with respiratory problems and a confidence level of 5%. The effect of NO2 was also higher here. Due to the results, NO2, CO, and O3 had a significant direct correlation with cardiovascular and respiratory rates. The effect of NO2 has been higher than other pollutants. In the study of time intervals of patients with cardiovascular, the results of time-interval analysis indicate the relationship between cardiovascular clients with the "t" time of 7days earlier and NO2 as a pollutant. The results of this analysis also revealed the relationship between respiratory patients at the time "t" up to 7days before and O3.

Characterization of atmospheric trace gases and water soluble inorganic chemical ions of PM1 and PM2.5 at Indira Gandhi International Airport, New Delhi during 2017–18 winter

Water soluble inorganic chemical ions of PM1 and PM2.5 and atmospheric trace gases were monitored simultaneously on hourly resolution at Indira Gandhi International Airport (IGIA), Delhi during 8 December 2017–10 February 2018. Monitoring was made by MARGA (Monitoring AeRosol and Gases in ambient Air) under winter fog experiment (WIFEX) program of the Ministry of Earth Sciences (MoES), Government of India. The result based on the analysis of the data so generated reveals that Cl−, NH4+, NO3− and SO42− were dominant ions in order which collectively constituted 96.8 and 97.3% of the of the total measured ionic mass in PM1 and PM2.5 respectively. Their overall average concentrations in PM1 were 19.5 ± 19.7, 18.4 ± 10.5, 16.6 ± 8.7 and 10.3 ± 5.7 μg/m3 and in PM2.5 were 36.0 ± 33.9, 32.7 ± 17.2, 28.5 ± 13.6 and 19.9 ± 13.9 μg/m3. Average concentrations of HCl, HNO3, HNO2, SO2 and NH3 trace gases were 0.7 ± 0.3, 2.7 ± 1.1, 6.6 ± 4.7, 22.0 ± 12.3 and 25.7 ± 9.1 μg/m3 respectively. Weather parameters along with low mixing height played significant role in the occurrence of high concentration of these chemical species.NH4+ was the prime neutralizer of the acidic components and mostly occurred in (NH4)2SO4/NH4HSO4, NH4NO3 and NH4Cl molecular forms. Major sources of these chemical species were fossil fuel combustion in aviation activity and transportation, coal burning in thermal power plants, industrial processes and emissions from biomass burning and agro-based activity.The quality of air with respect to PM2.5 always remained deteriorated. It became alarming during low visibility period mainly due to high concentration of Cl−, NO3−, SO42− and NH4+. Both meteorological and chemical processes interactively fed each other which occasionally resulted in fog development and visibility degradation. The knowledge gained by this study will help in simulation of atmospheric processes which lead to fog development and dispersal in the Delhi region.

Gaseous Pollutants and Particulate Matter (PM) in Ambient Air and the Number of New Cases of Type 1 Diabetes in Children and Adolescents in the Pomeranian Voivodeship, Poland.

The increase in type 1 diabetes mellitus (T1DM) incidence in children is worrying and not yet fully explored. It is suggested that probably air pollution exposure could contribute to the development of T1DM. The aim of the study was to investigate the relationship between the concentration of gaseous pollutants including, nitrogen dioxide (NO2), nitric oxides (NOx), sulphur dioxide (SO2), carbon monoxide (CO), and particulate matter (PM) in the air, and the number of new cases of T1DM in children. The number of new cases of T1DM was obtained from the Clinic of Paediatrics, Diabetology, and Endocrinology, Medical University of Gdańsk. The number of children of 0–18 years old in Pomeranian Voivodeship was acquired from the Statistical Yearbook. The concentrations of PM10 absorbance, NO2, NOx, SO2, and CO were measured at 41 measuring posts, between 1 January 2015 and 31 December 2016. It was detected that the average annual concentration of PM10 was higher than the value acceptable to the WHO. Furthermore, the average 24-hour concentration of PM10 was 92 μg/m3 and was higher compared to the acceptable value of 50 μg/m3 (acc. to EU and WHO). Moreover, the number of new cases of T1DM showed a correlation with the annual average concentration of PM10 (β = 2.396, p < 0.001), SO2 (β = 2.294, p < 0.001), and CO (β = 2.452, p < 0.001). High exposure to gaseous pollutants and particulate matter in ambient air may be one of the factors contributing to the risk of developing T1DM in children. Therefore, it is important to take action to decrease air pollutant emissions in Poland. It is crucial to gradually but consistently eliminate the use of solid fuels, such as coal and wood in households, in favour of natural gas and electricity. The development of new technologies to improve air quality, such as “best available techniques” (BAT) or renewable energy sources (water, wind, and solar generation) is of critical importance as well.

Monitoring history and change trends of ambient air quality in China during the past four decades

This study summarized the history of ambient air quality monitoring and air pollution prevention and control, and it analyzed the spatiotemporal patterns of ambient air pollutants during 1981–2017 in China. The results showed that monitoring of ambient air quality has changed dramatically in terms of determinants, sampling methods, monitoring extent, and evaluation basis during the previous four decades. Annual average concentrations of total suspended particulates, PM10 and SO2 have shown obvious decreasing trends during the studied period. These improvements have been closely related to the considerable efforts and various approaches undertaken to prevent and control air pollution. However, although policy implementation has been decisive and, at least in part, it has been enforced effectively, significant challenges remain. Air pollution control cannot be accomplished without a long-term strategy designed to achieve clean air in all parts of China.

The characteristics of inorganic gases and volatile organic compounds at a remote site in the Tibetan Plateau

Abstract In order to study the characteristics of pollutants in the remote background site of Tibetan Plateau, volatile organic compounds (VOCs), NO, NO2, SO2, CO, O3 and meteorological parameters (temperature, relative humidity, rainfall, horizontal wind speed and direction) were measured in the autumn of 2013 at Menyuan station (37.59°N, 101.29°E, 3250 m a.s.l.), which is a newly established background site located in the Tibetan Plateau. The significantly lower average concentrations of NO, NO2, SO2 and CO were observed, indicating the distinct background characteristics at Menyuan. The O3 diurnal variation pattern and correlation analyses revealed the influence of in situ photochemical reactions and vertical mixing during the daytime and the long-range and vertically downslope transport from the upper troposphere or lower stratosphere during the nighttime. A total of 30 VOCs samples were collected and 66 VOCs species were analyzed. The oxygenated VOCs (OVOCs) were the most abundant components and high levels of acetone, acetaldehyde, nonanal, hexachloro-1,3-butadiene, 1,2-dichloroethane and CCl4 were observed. The LOH and OFP analysis confirmed that OVOCs and aromatics were the most active substances, and the VOCs had relatively stable chemical compositions and low photochemical potential. The long-range transport air masses from the southeast of Menyuan station passed by some polluted areas, such as Xining, and could result in the elevated NOx, CO and SO2 concentrations at Menyuan. Therefore, this work enriches the understanding of O3 cycles and transport influence in the Tibetan Plateau.

Relationship between atmospheric pollutants and risk of death caused by cardiovascular and respiratory diseases and malignant tumors in Shenyang, China, from 2013 to 2016: an ecological research.

Background:Air pollutants and their pathogenic effects differ among regions and seasons. We aimed to explore the relationship between fine particulate matter (PM2.5), sulfur dioxide (SO2), and ozone-8 hours (O3-8h) concentrations in heating and non-heating seasons and the associated death risk due to cardiovascular diseases (CDs), respiratory diseases (RDs), and malignant tumors.Methods:Data were collected in Shenyang, China, from April 2013 to March 2016. We analyzed the correlation or lagged effect of atmospheric pollutant concentration, meteorological conditions, and death risk due to disorders of the circulatory system, respiratory system, and malignant tumor in heating and non-heating seasons. We also used multivariate models to analyze the association of air pollutants during holidays with the death risk due to the evaluated diseases while considering the presence or absence of meteorological factors.Results:An increase in the daily average SO2 concentration by 10 μg/m3 increased the death risk by CDs, which reached a maximum of 2.0% (95% confidence interval [CI]: 1.3%–2.7%) on lagging day 4 during the non-heating season and 0.2% (95% CI: 0.1%–0.4%) on lagging day 3 during the heating season. The risk of death caused by RDs peaked on lagging day 1 by 0.8% (95% CI: 0.4%–1.2%) during the heating season. An increase in O3-8h concentration by 10 μg/m3 increased the risk of RD-related death on lagging day 2 by 1.0% (95% CI: 0.4%–1.7%) during the non-heating season, which was significantly higher than the 0.1% (95% CI: 0–0.9%) increase during the heating season. Further, an increase in the daily average PM2.5 concentration by 10 μg/m3 increased the risk of death caused by RDs by 0.3% and 0.8% during heating and non-heating seasons, respectively, which peaked on lagging day 0. However, air pollution was not significantly associated with the risk of death caused by malignant tumors.Conclusion:Short-term exposure to PM2.5, SO2, and O3 during the non-heating season resulted in higher risks of CD-related death, followed by RD-related death.

Characterizing Spatial Patterns of NO2 and SO2 in Xi’an by Passive Sampling

Nitrogen dioxide (NO2) and sulfur dioxide (SO2) are important air pollutants that affect air quality, human health, and climate. The concentrations of NO2 and SO2 were measured in Xi’an, China with passive samplers deployed at 70 sites in summer and winter. The average concentrations of NO2 and SO2 were 19.82 μg m−3 and 2.24 μg m−3, respectively, in summer and 21.09 μg m−3 and 7.99 μg m−3 in winter. Statistical analyses showed that the seasonal differences in SO2 were significant but those for NO2 were not. The concentrations of NO2 and SO2 in the Beilin district were higher than other districts, while those in Baqiao were relatively low. The concentrations of NO2 in commercial mixed areas were higher compared with other functional areas, and SO2 in the residential/educational areas during winter was high. Spatial distributions of NO2 and SO2 were obtained by ordinary kriging interpolation, and the results showed high summertime NO2 concentrations in the central urban and northwestern parts of the sampling grid and high wintertime NO2 in the central part of the grid. Summer SO2 concentrations were higher in the northern and lower in the southern parts of the grid, while SO2 was in winter high in the mid-west and low in the east.

Evaluation of different control measures in 2014 to mitigate the impact of ship emissions on air quality in the Pearl River Delta, China

Various control measures have been proposed to reduce ship emissions. However, improvements in air quality after its implementation have rarely been evaluated on a regional scale. To fill this gap, this study employed the Weather Research and Forecast model coupled with Chemistry (WRF/Chem) model to investigate the improvement in air quality under scenarios separately implementing different control measures. The domestic emission control area (DECA) in the Pearl River Delta (PRD) region of China was selected as the target area for the study. The results suggest that the use of cleaner fuels is a promising way to improve air quality. For vessels sailing in the DECA, using 0.5% sulfur-content fuel could reduce SO2 and PM2.5 by 0.52 μg/m3 and 1.43 μg/m3, respectively, in the target cities of PRD, while 0.1% sulfur-content fuel could increase these figures to 0.59 μg/m3 and 1.62 μg/m3, respectively. The use of liquefied natural gas (LNG) fuel was predicted to be the most effective method for air quality improvement. LNG fuel could reduce the annual average concentrations of SO2, NO2 and PM2.5 by 0.63 μg/m3, 2.80 μg/m3 and 2.14 μg/m3, respectively, in the target cities of PRD. The application of shore side electricity (SSE) would reduce the ship-contributed SO2 and PM2.5 by 0.33 μg/m3 and 1.06 μg/m3, respectively. For the NOX control, the retrofit of the selective catalytic reduction (SCR) system could reduce the ambient concentrations of NO2 and PM2.5 by 2.09 μg/m3 and 0.15 μg/m3, respectively. These results suggest that the use of cleaner fuels and the retrofit SCR system all have positive effects on lowering the impact of ship emissions, while the application of SSE could be a useful supplement.

Prospective cohort study on association between peri-conceptional air pollution exposure and gestational diabetes mellitus

Objective: To explore the association between the exposure to major air pollutants in pre-pregnancy and early pregnancy (peri-conceptional period) and gestational diabetes mellitus (GDM). Methods: From March 2015 to April 2018, 4 817 pregnancies were recruited at three prenatal check-ups hospital in Hefei (Hefei First People's Hospital, Hefei. Maternal and Child Care Hospital and the First Affiliated Hospital of Anhui Medical University), China. Questionnaire was used to collect the demographic data, the health status and lifestyle of pregnant women. GDM was diagnosed according to the Chinese Guidelines for the Prevention and Treatment of Type 2 Diabetes (2017 Edition). Logistic regression was used to investigate the association of exposure to major air pollutants (PM(2.5), PM(10), SO(2), CO and NO(2)) during different periods of pre-pregnancy (12 weeks before pregnancy) and first trimester (12 weeks after last menstruation) and duration of exposure to high levels of pollutants with GDM. Results: The mean±SD of the age of subjects was (29.14±4.19) years old and the prevalence of GDM was 21.4% (n=1 030). The results of multivariate logistic regression analysis showed that after adjusting for confounding factors, the risk of GDM increased gradually with the prolonged exposure time of high-concentration pollutants compared with pregnant women who were not exposed to high pollution during the pre-pregnancy (χ(2)=61.28, P(trend)<0.001) with the OR (95%CI) values for exposure time of 1, 2, and 3 months about 1.42 (1.10-1.84), 1.73 (1.29-2.33), and 2.51 (1.75-3.59), respectively. In the pre-pregnancy period, in every 10 μg/m(3) increase of PM(2.5) and PM(10), the OR (95%CI) values of GDM were 1.14 (1.08-1.20) and 1.13 (1.08-1.19), respectively; for each increase of 1 μg/m(3) and 0.10 mg/m(3) of SO(2) and CO, the OR (95% CI) values of GDM were 1.03 (1.01-1.05) and 1.07 (1.01-1.13), respectively. For every 1 μg/m(3) increase in the average concentration of SO(2) in the first trimester, the OR (95%CI) value of GDM was 1.02 (1.01-1.05). Conclusion: PM(2.5), PM(10), SO(2) and CO exposure during the pre-pregnancy and SO(2) exposure in first trimester were positively correlated with the risk of GDM.

NO and SO2 emissions in palm kernel shell catalytic steam gasification with in-situ CO2 adsorption for hydrogen production in a pilot-scale fluidized bed gasification system

The NO and SO2 emissions in enhanced hydrogen production from palm kernel shell (PKS) steam gasification with integrated catalytic adsorption steam gasification is investigated. The influence of steam and adsorbent to biomass ratios (1.5–2.5, 1.0–1.5), temperature (600–750 °C), biomass particle size (0.355–2.0 mm) and fluidization velocity (0.15–26 m/s) was reported. The results inferred that lower temperature (600 °C) contributed to emissions of NO (30 ppm) and SO2 (110 ppm) whereas high steam to biomass ratio (2.5 wt/wt) produced emissions of <30 ppm and <110 ppm, respectively, at experimental conditions of 675 °C, adsorbent to biomass ratio of 1.0 (wt/wt) and catalyst to biomass ratio of 0.1 (wt/wt). The lowest average minimum NO and SO2 concentration of 16 ppm and 46 ppm, respectively, was observed at 675 °C, steam to biomass ratio of 2.0 (wt/wt), adsorbent to biomass ratio of 1.5 (wt/wt) and catalyst to biomass ratio of 0.1(wt/wt). Nevertheless, emissions were prorportional to fluidization velocities and small particle size (0.3–0.5 mm) contributed to high NO and SO2. The comparative studies found that the present study produced similar emission of NO (30 ppm) when compared with commercial indirect heated fluidized bed gasifier using steam as an oxidizing agent. Besides, some other studies operated at high temperature reported high NO and SO2 concentration which might be due to the temperature being the most influential variable in the context.

Investigation of gaseous pollutants in residential-industrial area: Ambient levels, temporal variation and health risk assessment

Introduction: The purpose of the current study was to investigate the ambient concentration levels of ground-level ozone (GLO), nitrogen dioxide, and sulfur dioxide with temporal variations and to determine the risk of exposure to their pollutant on public people living in this area. Materials and methods: In the present study, GLO, NOx and SO2 concentrations were monitored using an ambient analyzer during the period of April to September 2018. Results: The obtained results demonstrated that the average concentrations of SO2, NO2 and GLO in the INZ station was significantly greater than the two other evaluated stations (i.e. SHV and CMC). The corresponding values for the measured parameters in INZ station was almost 8.9, 7.2 and 11.9 times higher than those in SHV station, however, 4.8, 5.3 and 2.9 times greater than of ones in CMC station, respectively. The average values of SO2 and NO2 concentrations in the INZ varied from 97.2 to 128.1 μg/m3 in the evening hours and from 50.2 to 62.3 μg/m3 in the morning hours respectively. Also, the lowest concentration of NO2 was observed during afternoon hours when GLO showed a peak. The maximum pikes of GLO concentration were observed at 13:00 PM with 249.3 μg/m3. Results of human health risk assessment indicated acceptable risk (hazard quotient (HQ) values˂ 1) for non-carcinogenic adverse health effect. Conclusion: The findings in the present study can be useful in developing control-based strategies for primary pollutant emissions, and also GLO formation, improve air quality and reducing possible risks on human health. Policymakers should enforce the limits on the release of pollutants into the atmosphere in the study area by strengthening existing legislation.

Phosphogypsum pyrolysis with mineralization agent under weak reducing atmosphere

Batch experiments of phosphogypsum (PG) pyrolysis were carried out under weak reducing atmosphere, adding coke as reductant and CaF2 as mineralization agent. As 3 wt% CaF2 was added to the mixture, the optimal parameters of PG decomposition were mole ratio (C: CaSO4) 0.7, reaction temperature 950 °C, pyrolysis time 60 min, and 1.9-2.2% oxygen content of inlet gas. Under this condition, the decomposition ratio of CaSO4 was up to 90.6%, the SO2 conversion was 70.4%, and the average volume concentration of SO2 was 11.9%. With the aid of CaF2, the pyrolysis temperature of CaSO4 decreased significantly. The surface structure and morphology analysis revealed that CaF2 was beneficial to the pyrolysis efficiency of CaSO4. TG curve, XRD analysis and kinetic process have proved that the generation of intermediate substance CaS is the first stage for thermal decomposition of CaSO4, and CaO is the end product of CaSO4 pyrolysis under weak reducing atmosphere.

Association between ambient air pollution and hyperuricemia in traffic police officers in China: a cohort study

ABSTRACT To evaluate the association between ambient air pollution and hyperuricemia, we prospectively followed 1748 traffic police officers without hyperuricemia at baseline (2009–2014) from 11 districts in Guangzhou, China. We calculated six-year average PM10, SO2 and NO2 concentrations using data collected from air monitoring stations. The hazard ratios for hyperuricemia per 10 µg/m3 increase in air pollutants were 1.46 (95% CI: 1.28–1.68) for PM10, 1.23 (95% CI: 1.00–1.51) for SO2, and 1.43 (95% CI: 1.26–1.61) for NO2. We also identified changes in the ratio of serum uric acid to serum creatinine concentrations (ua/cre) per 10 µg/m3 increase in air pollutants as 11.54% (95% CI: 8.14%-14.93%) higher for PM10, 5.09% (95% CI: 2.76%-7.42%) higher for SO2, and 5.13% (95% CI: 2.35%-7.92%) higher for NO2, respectively. Long-term exposure to ambient air pollution was associated with a higher incidence of hyperuricemia and an increase in ua/cre among traffic police officers.

Short-term effects of air pollution on lung function of school-age children in Hangzhou

A total of 1 685 school-age children selected from Hangzhou received lung function testing to evaluate the short-term effects of air pollution on their lung function. The results showed that in every 10 μg/m(3) increase of average concentration of PM(2.5) and PM(10) on the day of the test and the day before the test,peak expiratory flow (PEF) decreased 0.039 (95%CI: 0.012-0.067) L/s and 0.031 (95% CI:0.011-0.051) L/s,respectively. When the average concentration of SO(2) increased 10 μg/m(3) on the day of test and the day prior to the test, PEF and 75% of the forced vital capacity that has not been exhaled (MEF(75)) decreased 0.437 (95%CI: 0.217-0.658) L/s and 0.396 (95%CI: 0.180-0.613) L/s. After being adjusted for NO(2),with every 10 μg/m(3) increase of average concentration of PM(2.5) and PM(10) on the day of the test and the day before the test,PEF and MEF(75) decreased 0.056 (95%CI: 0.028-0.085), 0.053(95%CI: 0.027-0.081) and 0.047 (95%CI: 0.026-0.068) L/s,0.044 (95%CI: 0.023-0.065) L/s on the day before the test, respectively. The results indicate that air pollution have short-term and lag effects on lung function of school-age children in Hangzhou.