Daily Average Concentrations of Criteria Air Pollutants measured by the MoCaALTAMA Network

Description

This dataset contains daily average concentrations of six criteria air pollutants — PM₁₀, PM₂.₅, SO₂, NO₂, O₃, and CO — measured at four air quality monitoring stations within the MoCaALTAMA Network, located in key locations such as the Madero Refinery (AQS-MR), the Altamira Industrial Corridor (AQS-ACI), Puente Tampico (AQS-PT), and Tampico Airport (AQS-TA) in Tamaulipas, Mexico. The performance, accuracy, and data reliability of the factory- calibrated air quality stations (AQS) were assessed by co-locating one AQS with a reference station from the Mexico City Air Quality Office, at the Institute of Atmospheric Sciences and Climate Change (Universidad Nacional Autonoma de Mexico, UNAM) and comparing the data correlation to be at least R2=0.75. Data coverage periods are from October 2023 to June 2025 for stations AQS-ACI, AQS-MR, and AQS-TA, and from October 2023 to August 2024 for station AQS-PT. Pollutant concentrations are reported as daily averages in two units, micrograms per cubic meter (µg/m³) for particulate matter (PM₁₀ and PM₂.₅) and micrograms per cubic meter (µg/m³) and parts per million (ppm) for gaseous pollutants (SO₂, NO₂, O₃, and CO), following official Mexican environmental standards for unit conversions. Daily averaging of concentrations was carried out in accordance with the guidelines established by the Mexican Official Standard NOM-172-SEMARNAT-2019, which defines the procedures for calculating and communicating the Air Quality Index and associated health risks. Although this dataset includes only 24-hour averages, the original measurements (collected at one-minute intervals using Libelium-based IoT sensors) are available at higher temporal resolutions, such as minute or hourly, upon request. To access this high-resolution data, please contact Dr. Felipe Caballero at fcaballero@ipn.mx or M.I.A. Mireya del Socorro Ovando Rocha at movando@utaltamira.edu.mx. This dataset supports air quality assessments, temporal trend analyses, and environmental modeling in the conurbated area of southern Tamaulipas, including Tampico, Madero, and Altamira. The data were collected using Libelium-based air quality sensors and quality-controlled to ensure consistency.

Steps to reproduce

Measurement data for six air pollutants (PM₁₀, PM₂.₅, SO₂, NO₂, O₃, and CO) were collected using Libelium-based air quality monitoring stations equipped with the following sensors: PM₁₀ and PM₂.₅: OPC-N3 optical particle counter (µg/m³) NO₂: Alphasense NO2-B43F electrochemical sensor SO₂: Alphasense SO2-B4 electrochemical sensor O₃: Alphasense OX-B431 sensor CO: Alphasense CO-B4 electrochemical sensor All stations recorded pollutant concentrations at one-minute intervals using the Libelium IoT platform. Due to the large volume of data, the minute-level records were aggregated to daily averages using Microsoft Excel by calculating the arithmetic mean for each pollutant per day. A quality control process was applied, which included: Removal of null, negative, or clearly erroneous values, application of threshold filters based on expected ambient ranges, standardization of data formats (date, units, station codes) and for gaseous pollutants (SO₂, NO₂, O₃, and CO), values originally recorded in µg/m³ were converted to parts per million (ppm) using the ideal gas law under standard conditions of 25 °C and 1 atmosphere. Molar masses used for conversion were: CO: 28.01 g/mol NO₂: 46.01 g/mol SO₂: 64.07 g/mol O₃: 48.00 g/mol These unit conversions were performed following internationally accepted atmospheric chemistry principles, aligned with monitoring procedures and health protection criteria described in the following Mexican Official Standards: NOM-020-SSA1-2021 — Ozone (O₃) NOM-022-SSA1-2019 — Sulfur dioxide (SO₂) NOM-023-SSA1-2021 — Nitrogen dioxide (NO₂) NOM-021-SSA1-2023 — Carbon monoxide (CO) The resulting dataset includes daily average concentrations in µg/m³ for all pollutants, and ppm values for gaseous pollutants, along with date and station identifiers. These data support air quality assessment, environmental modeling, and long-term trend analysis for the conurbated area of southern Tamaulipas (Tampico, Madero, and Altamira). Although this dataset contains only 24-hour averages, original high-resolution data (minute-level) are available upon request. Please contact Dr. Felipe Caballero (fcaballero@ipn.mx) or Mtra. Mireya del Socorro Ovando Rocha (movando@utaltamira.edu.mx) for access to these detailed datasets.

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