Article
Engineering, Environmental
Priyanka deSouza, An Wang, Yuki Machida, Tiffany Duhl, Simone Mora, Prashant Kumar, Ralph Kahn, Carlo Ratti, John L. Durant, Neelakshi Hudda
Summary: This study investigates the correction of low-cost sensor data and the factors affecting the differences between mobile low-cost sensor data and higher-quality instrument data. The results show that more complex correction models and minute-level aggregated data perform better in the mobile setting. The speed of the mobile laboratory, sensor orientation, date, hour-of-the-day, and road class contribute to the variation between corrected low-cost sensor measurements and higher-quality instrument measurements. The study also finds that low-cost sensor data can be used to identify hotspots and generate PM2.5 concentration maps.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Environmental Sciences
Vanessa Schwarstzhaupt Gamboa, Eder Julio Kinast, Marcal Pires
Summary: The increasing emissions of air pollutants have raised concerns over health and the environment. Low-cost atmospheric sensors are emerging as an alternative to traditional air quality monitoring stations. However, the reliability of data obtained by these sensors is still questionable. This study aimed to calibrate and evaluate the performance of low-cost sensors, comparing their results to reference analyzers. Satisfactory accuracy and minimal bias were achieved after calibration.
ATMOSPHERIC POLLUTION RESEARCH
(2023)
Article
Engineering, Chemical
Michael R. Giordano, Carl Malings, Spyros N. Pandis, Albert A. Presto, V. F. McNeill, Daniel M. Westervelt, Matthias Beekmann, R. Subramanian
Summary: Low-cost sensors for particulate matter mass (PM) provide spatially dense, high temporal resolution measurements of air quality, especially beneficial in low and middle-income countries with limited reference grade measurements. However, these sensors also face challenges that must be addressed to ensure data quality.
JOURNAL OF AEROSOL SCIENCE
(2021)
Article
Environmental Sciences
Louise Boge Frederickson, Hugo Savill Russell, Dafni Fessa, Jibran Khan, Johan Albrecht Schmidt, Matthew Stanley Johnson, Ole Hertel
Summary: This study examined the performance of low-cost sensor devices for monitoring air pollution levels in urban areas. The results showed significant variations in air pollution levels over short distances, with higher concentrations of NO2 near busy roads. The study demonstrated that low-cost sensors can accurately measure air pollution exposure with high spatiotemporal resolution.
Article
Environmental Sciences
Haneen Khreis, Jeremy Johnson, Katherine Jack, Bahar Dadashova, Eun Sug Park
Summary: The emergence of low-cost air quality sensors has the potential to improve our ability to monitor urban air pollution. However, there are still gaps in our understanding of their performance compared to high-cost regulatory monitors. In this study, the authors evaluated the performance of 12 commercial low-cost sensors over 18 months, finding variations in sensor responses and the impact of meteorological factors. Calibration improved accuracy to some extent, but regular calibration is still necessary. The authors suggest minimizing the distance between sensors and regulatory monitors for better accuracy.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2022)
Review
Chemistry, Analytical
Janani Venkatraman Jagatha, Andre Klausnitzer, Miriam Chacon-Mateos, Bernd Laquai, Evert Nieuwkoop, Peter van der Mark, Ulrich Vogt, Christoph Schneider
Summary: Cost-effective sensors have become popular for measuring ambient and indoor particulate matter concentration, but their data reliability is hindered by sensitivities to temperature and relative humidity, especially in mobile measurement setups. Quantile mapping is identified as a useful calibration methodology for mobile measurements, retaining spatial characteristics of the data, albeit without a common correction factor. A well-elaborated measurement plan is crucial for successful application of quantile mapping in mobile measurements.
Article
Chemistry, Analytical
Marian-Emanuel Ionascu, Nuria Castell, Oana Boncalo, Philipp Schneider, Marius Darie, Marius Marcu
Summary: This study investigates the calibration methods for low-cost sensor platforms, which successfully improved the accuracy of CO and O-3 gases and achieved similar accuracy for NO2 gas. Despite the low price level, the platform's performance met the DQO criteria after the calibration algorithms were applied.
Article
Meteorology & Atmospheric Sciences
Misti Levy Zamora, Colby Buehler, Abhirup Datta, Drew R. Gentner, Kirsten Koehler
Summary: Low-cost sensors are commonly used with reference instruments for calibration, but little attention has been given to optimizing the calibration period. This study investigated the optimal duration of co-location calibration for sensors measuring various pollutants. The results showed that the required calibration period varied for different sensor types and factors such as sensor response to environmental factors and cross-sensitivities to other pollutants influenced the duration.
ATMOSPHERIC MEASUREMENT TECHNIQUES
(2023)
Article
Environmental Sciences
Georgios C. Spyropoulos, Panagiotis T. Nastos, Konstantinos P. Moustris
Summary: A significant portion of European cities' population is exposed to harmful levels of air pollution, leading to the installation of low-cost electrochemical sensor monitoring systems. The market is developing new air quality monitoring systems to provide forecasting services based on advanced technologies, protocols, and characteristics. This study compares data quality and Air Quality Index between low-cost sensors and fixed monitoring stations, revealing the need for flexible and affordable alternatives for monitoring low-cost gas sensors.
Article
Environmental Sciences
Andrew Patton, Abhirup Datta, Misti Levy Zamora, Colby Buehler, Fulizi Xiong, Drew R. Gentner, Kirsten Koehler
Summary: This study presents a framework for direct field-calibration of low-cost air pollution sensors using probabilistic gradient boosted decision trees (GBDT). The results show that the probabilistic GBDT model improves point and distribution accuracies compared to linear regression models, particularly at high concentrations and on monitors not included in the training set. The study also demonstrates the use of the GBDT model in conducting probabilistic spatial assessments of human exposure on a neighborhood level.
JOURNAL OF EXPOSURE SCIENCE AND ENVIRONMENTAL EPIDEMIOLOGY
(2022)
Article
Engineering, Multidisciplinary
Sylvain Poupry, Kamal Medjaher, Cedrick Beler
Summary: Air pollution is a significant environmental and societal issue. This paper introduces a new method for monitoring air quality using low-cost sensor networks, addressing the drawbacks of conventional monitoring methods. The proposed approach ensures reliable data collection and generates diagnostic results through three indicators. The initial implementation of this method demonstrates its adaptability for future implementations and long-term monitoring of air quality.
Article
Environmental Sciences
Luca Shindler
Summary: Air pollution in urban areas is a complex issue with variability of pollutants concentrations. Fixed monitoring stations have limitations, and low-cost sensors could be a potential solution to improve spatial resolution in urban air quality monitoring.
ENVIRONMENTAL TECHNOLOGY
(2021)
Article
Environmental Sciences
Marie-Laure Aix, Sean Schmitz, Dominique J. Bicout
Summary: Low-cost sensors (LCS) of particulate matter (PM) are increasingly used worldwide to accurately assess individual exposure to pollutants. However, a standardized methodology for calibrating PM sensors is still lacking. In this study, a calibration method combining an adaptation of an approach for gas-phase pollutants and a dust event preprocessing is developed for PM LCS commonly used in urban environments.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Engineering, Environmental
Emilio Molina Rueda, Ellison Carter, Christian L'Orange, Casey Quinn, John Volckens
Summary: Particulate matter (PM) air pollution is a major health hazard, with health effects closely related to particle size. Low-cost particle sensors have become popular but their accuracy across different particle size fractions is limited. We evaluated three low-cost sensor models in an urban setting and found that they were only accurate for the smallest particle size fraction (PM1), with significant biases and uncertainties for the larger size fractions. We recommend that crowdsourced air quality monitoring networks should not report coarse and PM10 mass concentrations using these sensors.
ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Xhensilda Allka, Pau Ferrer-Cid, Jose M. M. Barcelo-Ordinas, Jorge Garcia-Vidal
Summary: In this article, two algorithms are proposed to denoise and calibrate low-cost sensors used in IoT monitoring platforms. The first method, TPB-D, achieves signal denoising by projecting the daily signals of the sensor onto a subspace generated by reference instruments. The second method, TPB-C, corrects and calibrates the daily sensor signals by linear mapping with regularization based on the subspace produced by the reference database.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Environmental Sciences
Pamela A. Dominutti, James R. Hopkins, Marvin Shaw, Graham P. Mills, Hoang Anh Le, Duong Huu Huy, Grant L. Forster, Sekou Keita, To Thi Hien, David E. Oram
Summary: Volatile organic compounds (VOCs) are significant contributors to urban air pollution, both as primary pollutants and in the formation of secondary pollutants. This study monitored over 30 VOC species in the two most populous cities in Vietnam and compared emission ratios with cities worldwide. Road transport was found to be the main source of VOC concentrations in Vietnamese cities. The study also revealed significant discrepancies between observed VOC emissions and those estimated by a global emission inventory, highlighting the need for improved air quality models and pollution reduction strategies.
ENVIRONMENTAL POLLUTION
(2023)
Article
Multidisciplinary Sciences
Simone T. Andersen, Lucy J. Carpenter, Chris Reed, James D. Lee, Rosie Chance, Tomas Sherwen, Adam R. Vaughan, Jordan Stewart, Pete M. Edwards, William J. Bloss, Roberto Sommariva, Leigh R. Crilley, Graeme J. Nott, Luis Neves, Katie Read, Dwayne E. Heard, Paul W. Seakins, Lisa K. Whalley, Graham A. Boustead, Lauren T. Fleming, Daniel Stone, Khanneh Wadinga Fomba
Summary: Particulate nitrate (pNO(3)(-)) has traditionally been considered a sink for NOx, but recent evidence shows that it can be recycled back to the gas phase through photolysis, with implications for tropospheric ozone and OH budgets. This study provides evidence of renoxification occurring on marine aerosols in the remote Atlantic troposphere, reconciling discrepancies in renoxification rate constants found in previous studies. The active release of HONO from aerosols has important implications for atmospheric oxidants in both polluted and clean environments.
Article
Engineering, Environmental
Samuel J. J. Cliff, Alastair C. C. Lewis, Marvin D. D. Shaw, James D. D. Lee, Michael Flynn, Stephen J. J. Andrews, James R. R. Hopkins, Ruth M. M. Purvis, Amber M. M. Yeoman
Summary: Measurements reveal that screenwash application is the main source of vehicular VOC emissions, which is not included in road transport inventories. The assumption that phasing out gasoline and diesel engines will reduce VOC emissions from road transport is undermined by real-world emissions measurements showing a significant underestimation of alcohol-based species. This discrepancy is attributed to the use of ancillary solvent products like screenwash and deicer, which are not included in internationally applied vehicle emission methodologies.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Geosciences, Multidisciplinary
R. J. Pound, D. P. Durcan, M. J. Evans, L. J. Carpenter
Summary: The GEOS-Chem model was used to compare the impacts of isoprene and iodine emissions on present-day tropospheric composition. Removing isoprene emissions leads to a 3.4% decrease in tropospheric O-3 burden, while removing iodine emissions leads to a 5.9% increase. Isoprene has a substantial impact on global mean OH concentrations and methane lifetime, while iodine has a negligible impact. It is suggested that iodine should receive greater attention in model development and experimental research to improve predictions of tropospheric O-3.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Editorial Material
Multidisciplinary Sciences
Alastair C. Lewis, Deborah Jenkins, Christopher J. M. Whitty
Summary: While dirty outdoor air gets more attention, understanding how pollutants form, accumulate, and affect our health indoors is equally important.
Article
Environmental Sciences
Adedayo R. Adedeji, Stephen J. Andrews, Matthew J. Rowlinson, Mathew J. Evans, Alastair C. Lewis, Shigeru Hashimoto, Hitoshi Mukai, Hiroshi Tanimoto, Yasunori Tohjima, Takuya Saito
Summary: This study used the GEOS-Chem atmospheric chemistry transport model to analyze the gas observations and simulations on Hateruma Island in 2018. The simulation results showed good agreement with the measurements, but the simulated mixing ratios of ethane and propane were lower than the observations, especially in winter. In addition, the influence of biomass burning emissions on the compounds was found to be small in winter and significant in summer, and increasing anthropogenic emissions improved the accuracy of the simulations in winter.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Environmental Sciences
Joanna E. Dyson, Lisa K. Whalley, Eloise J. Slater, Robert Woodward-Massey, Chunxiang Ye, James D. Lee, Freya Squires, James R. Hopkins, Rachel E. Dunmore, Marvin Shaw, Jacqueline F. Hamilton, Alastair C. Lewis, Stephen D. Worrall, Asan Bacak, Archit Mehra, Thomas J. Bannan, Hugh Coe, Carl J. Percival, Bin Ouyang, C. Nicholas Hewitt, Roderic L. Jones, Leigh R. Crilley, Louisa J. Kramer, W. Joe F. Acton, William J. Bloss, Supattarachai Saksakulkrai, Jingsha Xu, Zongbo Shi, Roy M. Harrison, Simone Kotthaus, Sue Grimmond, Yele Sun, Weiqi Xu, Siyao Yue, Lianfang Wei, Pingqing Fu, Xinming Wang, Stephen R. Arnold, Dwayne E. Heard
Summary: The impact of heterogeneous uptake of HO2 on aerosol surfaces on radical concentrations and the O-3 production regime in Beijing in summertime was investigated. The average uptake coefficient of HO2 was calculated as 0.070 +/- 0.035, significantly lower than commonly used values. The result suggests that under most conditions, HO2 uptake onto aerosol surfaces is not important, but at low NO concentrations, it can contribute significantly to the loss of HO2.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Analytical
Thomas Warburton, Stuart K. Grange, James R. Hopkins, Stephen J. Andrews, Alastair C. Lewis, Neil Owen, Caroline Jordan, Greg Adamson, Bin Xia
Summary: Plug-in fragrance diffusers, commonly found in homes, were evaluated for their effects on indoor air quality. Air samples were taken from 60 homes in Ashford, UK, with the diffuser on or off. The concentrations of volatile organic compounds (VOCs) were measured using gas chromatography. The study found that homes with low air exchange rates and using the diffuser had higher concentrations of fragrance VOCs.
ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS
(2023)
Article
Environmental Sciences
Samuel J. Cliff, Will Drysdale, James D. Lee, Carole Helfter, Eiko Nemitz, Stefan Metzger, Janet F. Barlow
Summary: Fluxes of nitrogen oxides (NOx=NO+NO2) and carbon dioxide (CO2) at the British Telecommunications (BT) Tower in central London were measured during the coronavirus pandemic using eddy covariance. Comparing the fluxes to pre-pandemic measurements from 2017 showed a 73% reduction in NOx emissions, a 20% reduction in CO2 emissions, and a 32% reduction in traffic load. Transport and heat and power generation were identified as the main sources of NOx and CO2, but with different relative contributions. The reduction in transport NOx emissions was attributed to both air quality policies and reduced congestion during the pandemic.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Environmental Sciences
Jacob T. Shaw, Amy Foulds, Shona Wilde, Patrick Barker, Freya A. Squires, James Lee, Ruth Purvis, Ralph Burton, Ioana Colfescu, Stephen Mobbs, Samuel Cliff, Stephane J. -B. Bauguitte, Stuart Young, Stefan Schwietzke, Grant Allen
Summary: Gas flaring is a significant contributor to global carbon emissions and is seen as a way to reduce the carbon footprint of the oil and gas industry. However, quantifying flaring emissions is resource-intensive and offshore regions have not been studied yet. This study presents data on CO2, CH4, C2H6, and NOx emissions from gas flaring in the North Sea, with higher combustion efficiencies observed in the Norwegian sector compared to the UK sector. The measurements were used to estimate total annual emissions from gas flaring in the North Sea.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Environmental Sciences
Viral Shah, Daniel J. Jacob, Ruijun Dang, Lok N. Lamsal, Sarah A. Strode, Stephen D. Steenrod, K. Folkert Boersma, Sebastian D. Eastham, Thibaud M. Fritz, Chelsea Thompson, Jeff Peischl, Ilann Bourgeois, Ilana B. Pollack, Benjamin A. Nault, Ronald C. Cohen, Pedro Campuzano-Jost, Jose L. Jimenez, Simone T. Andersen, Lucy J. Carpenter, Tomas Sherwen, Mat J. Evans
Summary: Satellite-based retrievals of tropospheric NO2 columns are widely used to infer NOx emissions. These retrievals rely on model information for the vertical distribution of NO2. Free tropospheric background above 2 km is important for these retrievals and has a significant impact on tropospheric OH and ozone concentrations.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Environmental Sciences
Xuewei Hou, Yifan Zhang, Xin Lv, James Lee
Summary: Based on OMI/MLS data and CESM2 simulated results, this study explores the annual variation trends of tropospheric column ozone (TCO) in the past two decades and quantifies the separate impacts of meteorological conditions and emissions on TCO. The findings indicate increasing TCO over East Asia and Southeast Asia regions primarily due to changes in ozone precursors, while changes in meteorological conditions weaken the increase in TCO. In the southern hemisphere, TCO is decreasing mainly due to changes in meteorological conditions. The study also highlights the contribution of stratospheric ozone to TCO and explains the variability in TCO trends.
Article
Environmental Sciences
Simone T. Andersen, Beth S. Nelson, Katie A. Read, Shalini Punjabi, Luis Neves, Matthew J. Rowlinson, James Hopkins, Tomas Sherwen, Lisa K. Whalley, James D. Lee, Lucy J. Carpenter
Summary: This study investigates the relationship between PSS-derived NO2 and observed NO2 under different air conditions, and finds higher levels of observed NO2 compared to PSS predictions in clean air containing small amounts of aged pollution.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Environmental Sciences
Alfred W. Mayhew, Ben H. Lee, Joel A. Thornton, Thomas J. Bannan, James Brean, James R. Hopkins, James D. Lee, Beth S. Nelson, Carl Percival, Andrew R. Rickard, Marvin D. Shaw, Peter M. Edwards, Jaqueline F. Hamilton
Summary: This study evaluated the ability of three chemically detailed mechanisms to predict the diurnal profiles of isoprene nitrates in Beijing using a 0-D chemical box model. It found that non-isoprene hydroperoxy nitrate (IPN) species significantly contributed to the measurement of C(5)H(9)NO(5), and emphasized the importance of up-to-date alkoxy radical chemistry for accurate predictions of isoprene carbonyl nitrate (ICN) formation.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)