Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using Variograms

This study aims to determine the optimal frequency for monitoring airborne pollutants in densely populated urban areas to effectively capture their temporal variations. While environmental organizations worldwide typically update air quality data hourly, there is no global consensus on the ideal mon...

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Main Authors: Gokul Balagopal, Lakitha Wijeratne, John Waczak, Prabuddha Hathurusinghe, Mazhar Iqbal, Rittik Patra, Adam Aker, Seth Lee, Vardhan Agnihotri, Christopher Simmons, David J. Lary
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Air
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Online Access:https://www.mdpi.com/2813-4168/3/1/7
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author Gokul Balagopal
Lakitha Wijeratne
John Waczak
Prabuddha Hathurusinghe
Mazhar Iqbal
Rittik Patra
Adam Aker
Seth Lee
Vardhan Agnihotri
Christopher Simmons
David J. Lary
author_facet Gokul Balagopal
Lakitha Wijeratne
John Waczak
Prabuddha Hathurusinghe
Mazhar Iqbal
Rittik Patra
Adam Aker
Seth Lee
Vardhan Agnihotri
Christopher Simmons
David J. Lary
author_sort Gokul Balagopal
collection DOAJ
description This study aims to determine the optimal frequency for monitoring airborne pollutants in densely populated urban areas to effectively capture their temporal variations. While environmental organizations worldwide typically update air quality data hourly, there is no global consensus on the ideal monitoring frequency to adequately resolve pollutant (particulate matter) time series. By applying temporal variogram analysis to particulate matter (PM) data over time, we identified specific measurement intervals that accurately reflect fluctuations in pollution levels. Using January 2023 air quality data from the Joppa neighborhood of Dallas, Texas, USA, temporal variogram analysis was conducted on three distinct days with varying <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>PM</mi><mrow><mn>2.5</mn></mrow></msub></mrow></semantics></math></inline-formula> (particulate matter of size ≤ <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.5</mn><mo> </mo><mi mathvariant="sans-serif">μ</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> in diameter) pollution levels. For the most polluted day, the optimal sampling interval for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>PM</mi><mrow><mn>2.5</mn></mrow></msub></mrow></semantics></math></inline-formula> was determined to be 12.25 s. This analysis shows that highly polluted days are associated with shorter sampling intervals, highlighting the need for highly granular observations to accurately capture variations in PM levels. Using the variogram analysis results from the most polluted day, we trained machine learning models that can predict the sampling time using meteorological parameters. Feature importance analysis revealed that humidity, temperature, and wind speed could significantly impact the measurement time for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>PM</mi><mrow><mn>2.5</mn></mrow></msub></mrow></semantics></math></inline-formula>. The study also extends to the other size fractions measured by the air quality monitor. Our findings highlight how local conditions influence the frequency required to reliably track changes in air quality.
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spelling doaj-art-134dd719749c4155aa3cd3ebef9567082025-08-20T02:33:07ZengMDPI AGAir2813-41682025-03-0131710.3390/air3010007Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using VariogramsGokul Balagopal0Lakitha Wijeratne1John Waczak2Prabuddha Hathurusinghe3Mazhar Iqbal4Rittik Patra5Adam Aker6Seth Lee7Vardhan Agnihotri8Christopher Simmons9David J. Lary10Hanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAHanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX 75080, USAThis study aims to determine the optimal frequency for monitoring airborne pollutants in densely populated urban areas to effectively capture their temporal variations. While environmental organizations worldwide typically update air quality data hourly, there is no global consensus on the ideal monitoring frequency to adequately resolve pollutant (particulate matter) time series. By applying temporal variogram analysis to particulate matter (PM) data over time, we identified specific measurement intervals that accurately reflect fluctuations in pollution levels. Using January 2023 air quality data from the Joppa neighborhood of Dallas, Texas, USA, temporal variogram analysis was conducted on three distinct days with varying <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>PM</mi><mrow><mn>2.5</mn></mrow></msub></mrow></semantics></math></inline-formula> (particulate matter of size ≤ <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.5</mn><mo> </mo><mi mathvariant="sans-serif">μ</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> in diameter) pollution levels. For the most polluted day, the optimal sampling interval for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>PM</mi><mrow><mn>2.5</mn></mrow></msub></mrow></semantics></math></inline-formula> was determined to be 12.25 s. This analysis shows that highly polluted days are associated with shorter sampling intervals, highlighting the need for highly granular observations to accurately capture variations in PM levels. Using the variogram analysis results from the most polluted day, we trained machine learning models that can predict the sampling time using meteorological parameters. Feature importance analysis revealed that humidity, temperature, and wind speed could significantly impact the measurement time for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>PM</mi><mrow><mn>2.5</mn></mrow></msub></mrow></semantics></math></inline-formula>. The study also extends to the other size fractions measured by the air quality monitor. Our findings highlight how local conditions influence the frequency required to reliably track changes in air quality.https://www.mdpi.com/2813-4168/3/1/7environmental researchparticulate matterair qualitystatisticsIOTvariogram
spellingShingle Gokul Balagopal
Lakitha Wijeratne
John Waczak
Prabuddha Hathurusinghe
Mazhar Iqbal
Rittik Patra
Adam Aker
Seth Lee
Vardhan Agnihotri
Christopher Simmons
David J. Lary
Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using Variograms
Air
environmental research
particulate matter
air quality
statistics
IOT
variogram
title Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using Variograms
title_full Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using Variograms
title_fullStr Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using Variograms
title_full_unstemmed Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using Variograms
title_short Characterizing the Temporal Variation of Airborne Particulate Matter in an Urban Area Using Variograms
title_sort characterizing the temporal variation of airborne particulate matter in an urban area using variograms
topic environmental research
particulate matter
air quality
statistics
IOT
variogram
url https://www.mdpi.com/2813-4168/3/1/7
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