Ambient black carbon particulate matter in the coal region of Dhanbad, India

Assessment of carbonaceous aerosols at Mukteshwar: A high-altitude (~2200 m amsl) background site in the foothills of the Central Himalayas

The present study examined the equivalent black carbon (eBC) mass concentrations measured over 10.5 years (September 2005-March 2016) using a 7-wavelength Aethalometer (AE-31) at Mukteshwar, a high-altitude and regional background site in the foothills of Indian central Himalayas. The total spectral absorption coefficient (b_abs) was divided into three categories: black carbon (BC) and brown carbon (BrC); fossil fuels (FF) and wood/biomass burning (WB/BB); and primary and secondary sources. At the wavelength of 370 nm, a significant BrC contribution (25 %) to the total b_abs is identified, characterized by a pronounced seasonal variation with winter (December-January-February) maxima (31 %) and post-monsoon (October and November) minima (20 %); whereas, at 660 nm, the contribution of BrC is dramatically less (9 %). Climatologically, the estimated BC_FF at 880 nm ranges from 0.25 ± 0.19 μg m^-3 in July to 1.17 ± 0.80 μg m^-3 in May with the annual average of 0.67 ± 0.63 μg m^-3, accounting for 79 % of the BC mass. The maximum BC_FF/BC fraction reaches its peak value during the monsoon (July and August, 85 %), indicating the dominance of local traffic emissions due to tourism activities. Further, the highest BC_WB concentration observed during pre-monsoon (March-May) suggests the influence of local forest fires along with long-range transported aerosols from the low-altitude plains. The increased contribution of BrC (26 % at 370 nm) and WB absorption (61 % at 370 nm) to the total absorption at the shorter wavelengths suggests that wood burning is one of the major sources of BrC emissions. Secondary BrC absorption accounts for 24 % [91 %] of the total absorption [BrC absorption] at 370 nm, implying the dominance of secondary sources in BrC formation. A trend analysis for the measured BC concentration shows a statistically significant increasing trend with a slope of 0.02 μgm^-3/year with a total increase of about 22 % over the study period. A back trajectory-based receptor model, potential source contribution function (PSCF), was used to identify the potential regional source region of BC. The main source regions of BC are the northwest states of India in the IGP region and the northeast Pakistan region.

A cross sectional study exploring determinants for vaccine awareness, belief and hesitancy among health care professionals regarding Covid-19 vaccine, findings from a teaching hospital based in coal capital of India

Background:

India intends to start its 1^st dose of vaccination against Covid-19 on January 16^th, 2021 prioritizing its frontline health care professionals with either of the two vaccines—Covaxin or Covishield. Whenever a new vaccine is launched, it is marred with controversy and myths. To understand the doubts and concerns better, this study was conducted on health care professionals working in a tertiary care hospital.

Materials and Methods:

Willing respondents, who are working in the institute, were administered the questionnaire asking their views on knowledge, beliefs, and reasons for hesitancy regarding Covid-19 immunization. A Likert scale was used to quantify the responses regarding participants’ knowledge, beliefs, and hesitancies regarding immunization with the available vaccines. Data were analyzed using MS office Excel sheets and JASP software was used to analyze the data thus obtained.

Results:

Out of 122 complete responses, we had 73 (60%) doctors, while 30 (24%) were nursing staff, the rest comprised of other health care workers, such as housekeeping staff, janitorial, etc., 66 (54%) respondents were unaware, while 25 (20%) respondents had hesitancy and 23 (18%) were having extremely negative views regarding vaccination. Some of the variables, such as age, role, marital status, gender, etc., were found to be possibly associated with these scores.

Conclusion:

Issues like concerns over vaccine safety, efficacy, reliability, etc., are deterrents for individuals and whole programme and vaccination drive across the nation. Time and again it has been seen that despite the vaccines’ contribution in breaking the transmission, concerns are making people either hesitant or unmotivated to get the vaccines. More dialogues from the authorities regarding the issues of concern may pave the way for more motivation to accept vaccination and increase the vaccination coverage.

Tree responses to foliar dust deposition and gradient of air pollution around opencast coal mines of Jharia coalfield, India: gas exchange, antioxidative potential and tolerance level

Atmospheric pollution by opencast mining activities affects tree species around the mining area. The present study evaluated the responses of five native tree species to air pollution in Jharia coalfield. Sites were selected as closest to farthest from the mining area. Foliar dust deposition and foliar sulphate content affected stomatal conductance, superoxide dismutase activity and ascorbic acid and, thus, increased the susceptibility of sensitive species. Ficus benghalensis and Butea monosperma showed maximum dust deposition, while Adina cordifolia showed minimum deposition. Maximum dust deposition in Ficus benghalensis lowered stomatal conductance and, thus, checked the flux of other acidic gaseous pollutants which led to minimum variation in leaf extract pH. Higher stomatal conductance in Adina cordifolia and Aegle marmelos, on the other hand, facilitated the entry of acidic pollutants and disrupted many biological functions by altering photosynthesis and inducing membrane damage. Low variations in Ficus religiosa, Ficus benghalensis and Butea monosperma with sites and seasons suggest better physiological and morphological adaptations towards pollution load near coal mining areas. Tree species with better adaptation resisted variation in leaf extract pH by effectively metabolising sulphate and, thus, had higher chlorophyll content and relative water content.

Source Apportionment of Ambient Black Carbon During the COVID-19 Lockdown

Black carbon (BC) particles being emitted from mobile and stationary emission sources as a result of combustion activities have significant impacts on human health and climate change. A lot of social activities have been halted during the COVID-19 lockdowns, which has evidently enhanced the ambient and indoor air quality. This paper investigates the possible emission sources and evaluates the meteorological conditions that may affect the dispersion and transport of BC locally and regionally. Ground-level equivalent BC (eBC) measurements were performed between January 2020 and July 2020 at a university campus located in Dammam city of the Kingdom of Saudi Arabia (KSA). The fossil fuel (eBCff) and biomass burning (eBCbb) fractions of total eBC (eBCt) concentrations were estimated as 84% and 16%, respectively, during the entire study period. The mean eBCbb, eBCff, and eBCt concentrations during the lockdown reduced by 14%, 24%, and 23%, respectively. The results of statistical analyses indicated that local fossil fuel burning emissions and atmospheric conditions apparently affected the observed eBC levels. Long-range potential source locations, including Iraq, Kuwait, Iran, distributed zones in the Arabian Gulf, and United Arab Emirates and regional source areas, such as the Arabian Gulf coastline of the KSA, Bahrain, and Qatar, were associated with moderate to high concentrations observed at the receptor site as a result of cluster analysis and concentration-weighted trajectory analysis methods.

[Evaluation of cyclists exposure to air pollution: a literature review]

OBJECTIVES

To describe and interpret the methodologies and results of the main studies related to the monitoring of exposure of cyclists to air pollution.

METHODS

Research and analysis of national and international research of the last ten years in the Cochrane, Scopus, Embase, Science Direct and Pubmed databases. The search was conducted in August and September 2017 using the following search descriptors for MeSH: air pollution, bicycle riding, environmental exposure, environmental health, exposure by inhalation, environmental pollutants, transportation, public health and toxicology. For DeCS: air Pollution, cycling, exposure to environmental risks, environmental pollutants, inhalation, transportation, public health and toxicology.

RESULTS

Nineteen eligible published articles were identified. Most studies were conducted in Europe and the United States. Four studies have been reported in South America. Other studies seek comparisons on different bicycle routes, compare exposure during variations of the same route, and others determine the distance-exposure relationship. In the same way, variables such as vehicular traffic, distance to the emission sources and the type of bike path, play a fundamental role in the exposure to pollutants in cyclists.

CONCLUSIONS

Several variables were found that influence, directly or indirectly, the cyclists exposure to air pollution, as well as some factors that can reduce this exposure.

Multichannel characteristics of absorbing aerosols in Xuzhou and implication of black carbon

Black carbon (BC) is an important component of atmospheric aerosols; BC aerosols are produced mainly by the incomplete combustion of carbon-containing substances, and they have important effects on climate change, the atmospheric environment, and public health. Most of the existing research has focused on the single-band measurement results of BC aerosols. However, each band offers different information regarding the optical absorption properties of aerosols, such as enhanced light absorption by brown carbon in the 370 nm band. To bridge this research gap, the present study used BC concentration data measured by an AE42 aethalometer to analyze the multiband pollution characteristics of BC aerosols in Xuzhou city in China. An aethalometer model was established to quantitatively describe the concentrations of BC produced by solid and liquid fuels, and a concentration-weighted trajectory analysis was used to analyze the potential sources of BC aerosols in Xuzhou and their contributions to the total BC. The following results were obtained. (1) The BC concentration was high in spring and winter and low in summer and autumn, and the diurnal variation showed bimodal characteristics. (2) The difference among the aerosol concentrations in the seven bands was larger in autumn and winter than in spring and summer, and the contribution of brown carbon in autumn and winter was greater than that in spring and summer. (3) In winter, the solid source (coal and biomass combustion) of BC accounted for a large proportion of the total BC. (4) A source analysis of BC pollution days and BC clean days indicated different sources of BC pollution in different seasons. The results of this study provide a theoretical basis and realistic guide for the prevention and control of atmospheric pollution in Xuzhou and are anticipated to be of great significance for improving the regional and global atmospheric environment.

Aerosol light absorption in a coastal city in Southeast China: Temporal variations and implications for brown carbon

Light-absorbing carbonaceous aerosols including black carbon (BC) and brown carbon (BrC) play significant roles in atmospheric radiative properties. One-year measurements of aerosol light absorption at multi-wavelength were continuously conducted in Xiamen, southeast of China in 2014 to determine the light absorption properties including absorption coefficients (σ_abs) and absorption Ångström exponent (AAE) in the coastal city. Light absorptions of BC and BrC with their contributions to total light absorption were further quantified. Mean σ_abs at 370 nm and 880 nm were 56.6 ± 34.3 and 16.5 ± 11.2 Mm^-1, respectively. σ_abs presented a double-peaks diurnal pattern with the maximum in the morning and the minimum in the afternoon. σ_abs was low in warm seasons and high in cold seasons. AAE ranged from 0.26 to 2.58 with the annual mean of 1.46, implying that both fossil fuel combustion and biomass burning influenced aerosol optical properties. σ_abs of BrC at 370 nm was 24.0 ± 5.7 Mm^-1, contributing 42% to the total absorption. The highest AAE (1.52 ± 0.02) and largest BrC contributions (47% ± 4%) in winter suggested the significant influence of biomass burning on aerosol light absorption. Long-distance air masses passing through North China Plain and the Yangtze River Delta led to high AAE and BrC contributions. High AAE value of 1.46 in July indicated that long-range transport of the air pollutants from intense biomass burning in Southeast Asia would affect aerosol light absorption in Southeast China. The study will improve the understanding of light absorption properties of aerosols and the optical impacts of BrC in China.

Dependence of urban air pollutants on morning/evening peak hours and seasons

Traffic emission is a major source of air pollution in urban cities of developing world. This paper shows dependence of traffic-related air pollutants in urban cities on morning/evening peak hours and winter/summer seasons. This research also shows the meteorological impact, such as temperature (T), relative humidity (RH), and wind speed (WS), on traffic-related air pollutants in urban cites. Based on the research output, the elevated level of PM concentration was observed between 1.8 and 6.7 times at all nearby roadway locations compared with background (IIT [ISM] campus). We have found 2.3, 2.4, 2.6 (morning) and 2.0, 2.1, and 2.1 (evening) times higher average PM₁₀, PM_2.5, and PM₁ concentrations, respectively, in the winter than summer monitoring periods across all locations, due to the stable boundary layer, lower mixing height, and lower friction velocity. It is indicated that urban meteorology plays a crucial role in increasing or decreasing exposed pollutant concentrations in various microenvironments. The analysis of PM_2.5/PM₁₀ ratios was lower during whole campaign due to higher contribution of coarser particles generated by vehicles. During winter and summer seasons, 0.57 and 0.33 was observed, respectively. It is indicated that 57% and 33% of PM₁₀ makes up PM_2.5 particle, respectively. PM concentrations have showed a negative linear relationship with T and WS and positive relationship with RH in winter/summer seasons. Therefore, traffic and meteorology play a big role to increase or decrease in traffic-related air pollutants in urban air quality.