Dataset Information

Validation of Low-Cost Sensors in Measuring Real-Time PM10 Concentrations at Two Sites in Delhi National Capital Region.

ABSTRACT: In the present study, we assessed for the first time the performance of our custom-designed low-cost Particulate Matter (PM) monitoring devices (Atmos) in measuring PM10 concentrations. We examined the ambient PM10 levels during an intense measurement campaign at two sites in the Delhi National Capital Region (NCR), India. In this study, we validated the un-calibrated Atmos for measuring ambient PM10 concentrations at highly polluted monitoring sites. PM10 concentration from Atmos, containing laser scattering-based Plantower PM sensor, was comparable with that measured from research-grade scanning mobility particle sizers (SMPS) in combination with optical particle sizers (OPS) and aerodynamic particle sizers (APS). The un-calibrated sensors often provided accurate PM10 measurements, particularly in capturing real-time hourly concentrations variations. Quantile-Quantile plots (QQ-plots) for data collected during the selected deployment period showed positively skewed PM10 datasets. Strong Spearman's rank-order correlations (rs = 0.64-0.83) between the studied instruments indicated the utility of low-cost Plantower PM sensors in measuring PM10 in the real-world context. Additionally, the heat map for weekly datasets demonstrated high R2 values, establishing the efficacy of PM sensor in PM10 measurement in highly polluted environmental conditions.

SUBMITTER: Sahu R

PROVIDER: S-EPMC7085545 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Validation of Low-Cost Sensors in Measuring Real-Time PM10 Concentrations at Two Sites in Delhi National Capital Region.

Sahu Ravi R Dixit Kuldeep Kumar KK Mishra Suneeti S Kumar Purushottam P Shukla Ashutosh Kumar AK Sutaria Ronak R Tiwari Shashi S Tripathi Sachchida Nand SN

Sensors (Basel, Switzerland) 20200229 5

In the present study, we assessed for the first time the performance of our custom-designed low-cost Particulate Matter (PM) monitoring devices (Atmos) in measuring PM10 concentrations. We examined the ambient PM10 levels during an intense measurement campaign at two sites in the Delhi National Capital Region (NCR), India. In this study, we validated the un-calibrated Atmos for measuring ambient PM10 concentrations at highly polluted monitoring sites. PM10</ ...[more]

PMID: 32121462

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Project description:BackgroundFood policies and environment (availability, accessibility, affordability, marketing) in and around educational institutes can influence food choices and behaviours of children and adolescents.MethodsCross-sectional, mixed-methods study was implemented in schools (n = 9; Private = 6, Public = 3) and colleges (n = 4) from Delhi and National Capital Region (India). The data was collected from students of schools (n = 253) and colleges (n = 57), parents of school students (n = 190), teachers (n = 12, schools = 9, colleges = 3) and canteen operators of Private schools and colleges (n = 10; schools = 6, and colleges = 4). The primary and secondary data was collected to: 1) identify the strengths and weaknesses of the existing guidelines and directives (desk review); 2) examine food environment, existing policies and its implementation (structured observations, in-depth interviews, surveys, focus group discussions), and; 3) assess food choices, behaviours of students (focus group discussions). The thematic analysis was used for qualitative data and descriptive analysis for quantitative data.ResultsThe available food and beverage options, in and around the participating educational institutes were either high in fat, salt and sugar (HFSS), despite government and educational institute guidelines on restricting the availability and accessibility of HFSS foods. The healthy food and beverage options were expensive compared to HFSS foods both inside and outside educational institutes. In total, 37 vendors (Private = 27; Public:10) were observed outside schools at dispersal and twelve at lunchtime. Around colleges, vendors (n = 14) were seen throughout the day. Students from all Private schools (n = 6) and colleges (n = 2) were exposed to food and beverage advertisements either HFSS (Private schools = 1-3 and colleges = 0-2 advertisements), whereas no advertisements were observed around Public schools.ConclusionIt is imperative to implement food policies to improve the food environment in and around educational institutes to ensure the availability of healthy foods to establish and sustain healthy eating behaviours among students. Thus, the study findings emphasise stringent implementation, regular monitoring and surveillance of recently introduced Food Safety and Standards (Safe food and balanced diets for children in school) Regulation 2020, ensuring its compliance through effective enforcement strategies.

Project description:Typical low-cost electrochemical sensors for ozone (O3) are also highly responsive to nitrogen dioxide (NO2). Consequently, a single sensor's response to O3 is indistinguishable from its response to NO2. Recently, a method for quantifying O3 concentrations became commercially available (Alphasense Ltd., Essex, UK): collocating a pair of sensors, a typical oxidative gas sensor that responds to both O3 and NO2 (model OX-B431) and a second similar sensor that filters O3 and responds only to NO2 (model NO2-B43F). By pairing the two sensors, O3 concentrations can be calculated. We calibrated samples of three NO2-B43F sensors and three OX-B431 sensors with NO2 and O3 exclusively and conducted mixture experiments over a range of 0-1.0 ppm NO2 and 0-125 ppb O3 to evaluate the ability of the paired sensors to quantify NO2 and O3 concentrations in mixture. Although the slopes of the response among our samples of three sensors of each type varied by as much as 37%, the individual response of the NO2-B43F sensors to NO2 and OX-B431 sensors to NO2 and O3 were highly linear over the concentrations studied (R2 ≥ 0.99). The NO2-B43F sensors responded minimally to O3 gas with statistically non-significant slopes of response. In mixtures of NO2 and O3, quantification of NO2 was generally accurate with overestimates up to 29%, compared to O3, which was generally underestimated by as much as 187%. We observed changes in sensor baseline over 4 days of experiments equivalent to 34 ppb O3, prompting an alternate method of calculating concentrations by baseline-correcting sensor signal. The baseline-correction method resulted in underestimates of NO2 up to 44% and decreases in the underestimation of O3 up to 107% for O3. Both methods for calculating gas concentrations progressively underestimated O3 concentrations as the ratio of NO2 signal to O3 signal increased. Our results suggest that paired NO2-B43F and OX-B431 sensors permit quantification of NO2 and O3 in mixture, but that O3 concentration estimates are less accurate and precise than those for NO2.

Project description:Globally, since the end of December 2019, coronavirus disease (COVID-19) has been recognized as a severe infectious disease. Therefore, this study has been attempted to examine the linkage between climatic variables and COVID-19 particularly in National Capital Territory of Delhi (NCT of Delhi), India. For this, daily data of COVID-19 has been used for the period March 14 to June 11, 2020, (90 days). Eight climatic variables such as maximum, minimum and mean temperature (°C), relative humidity (%), bright sunshine hours, wind speed (km/h), evaporation (mm), and rainfall (mm) have been analyzed in relation to COVID-19. To study the relationship among different climatic variables and COVID-19 spread, Karl Pearson’s correlation analysis has been performed. The Mann–Kendall method and Sen’s slope estimator have been used to detect the direction and magnitude of COVID-19 trends, respectively. The results have shown that out of eight selected climatic variables, six variables, viz. maximum temperature, minimum temperature, mean temperature, relative humidity, evaporation, and wind speed are positively associated with coronavirus disease cases (statistically significant at 95 and 99% confidence levels). No association of coronavirus disease has been found with bright sunshine hours and rainfall. Besides, COVID-19 cases and deaths have shown increasing trends, significant at 99% confidence level. The results of this study suggest that climatic conditions in NCT of Delhi are favorable for COVID-19 and the disease may spread further with the increasing temperature, relative humidity, evaporation and wind speed. This is the only study which has presented the analysis of COVID-19 spread in relation to several climatic variables for the most densely populated and rapidly growing city of India. Thus, considering the results obtained, effective policies and actions are necessary especially by identifying the areas where the spread rate is increasing rapidly in this megacity. The prevention and protection measures should be adopted aiming at to reduce the further transmission of disease in the city.

Dataset Information

Validation of Low-Cost Sensors in Measuring Real-Time PM10 Concentrations at Two Sites in Delhi National Capital Region.

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Validation of Low-Cost Sensors in Measuring Real-Time PM<sub>10</sub> Concentrations at Two Sites in Delhi National Capital Region.

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