RESUMEN

Within the scope of the Aveiro STEAM City project, an air quality monitoring network was installed in the city of Aveiro (Portugal), to evaluate the potential of sensors to characterize spatial and temporal patterns of air quality in the city. The network consists of nine sensors stations with air quality sensors (PM10, PM2.5, NO2, O3 and CO) and two meteorological stations, distributed within selected locations in the city of Aveiro. The analysis of the data was done for a one-year measurement period, from June 2020 to May 2021, using temporal profiles, statistical comparisons with reference stations and Air Quality Indexes (AQI). The analysis of sensors data indicated that air quality variability exists for all pollutants and stations. The majority of the study area is characterized by good air quality, but specific areas-associated with hotspot traffic zones-exhibit medium, poor and bad air quality more frequently. The daily patterns registered are significantly different between the affected and non-affected road traffic sites, mainly for PM and NO2 pollutants. The weekly profile, significative deltas are found between week and weekend: NO2 is reduced on the weekends at traffic sites, but PM10 is higher in specific areas during winter weekends, which is explained by residential combustion sources.

RESUMEN

People spend most of their time in indoor environments without knowing about the air quality in these spaces. In this study, indoor low-cost sensors were used (for 5 months) to assess the comfort and air quality patterns in two indoor households. To strengthen the robustness of the considered approach and build confidence in the obtained comfort and indoor air quality (IAQ) levels, the sensor measurements were also compared against information from reference monitoring equipment; in which, high correlation coefficients were obtained (> 0.85) and also low errors (on average 22%). The IAQ results were strongly influenced by the residents' activity and behaviour, the outdoor weather conditions, and indoor/outdoor air pollution sources. Overall, the recommended values of temperature and relative humidity for the occupant's comfort in indoor environments were not fulfilled. The highest particulate matter (PM) levels were recorded at the weekend (on average +14% higher), while maximum CO2 and CO levels were obtained on the weekdays (on average +9% higher). PM daily profiles followed the outdoor concentrations with the maximum levels at the end of the night and the lowest values in the early morning/mid-afternoon. The highest and lowest CO2 concentrations were registered in the early morning (< 1536 ppm) and mid-afternoon (< 627 ppm), respectively, while the CO daily profiles showed a high impact of outdoor emissions, with the minimum concentrations up to 0.81 mg m-3 (at 10 a.m. or 6 p.m.), and a maximum concentration of 1.87 mg m-3 (at 10 p.m.). Real-time comfort conditions and IAQ levels are a powerful approach to providing fast decisions to minimise human exposure and prevent negative health impacts.

Asunto(s)

Contaminantes Atmosféricos , Contaminación del Aire Interior , Contaminación del Aire , Humanos , Dióxido de Carbono/análisis , Monitoreo del Ambiente/métodos , Contaminación del Aire/análisis , Contaminación del Aire Interior/análisis , Material Particulado/análisis , Contaminantes Atmosféricos/análisis

RESUMEN

Conventional NO2 monitoring devices are relatively cumbersome, expensive, and have a relatively high-power consumption that limits their use to fixed sites. On the other hand, they offer high-quality measurements. In contrast, the low-cost NO2 sensors offer greater flexibility, are smaller, and allow greater coverage of the area with the measuring devices. However, their disadvantage is much lower accuracy. The main goal of this study was to investigate the measurement data quality of NO2-B43F Alphasense sensors. The measurement performance analysis of Alphasense NO2-B43F sensors was conducted in two research areas in Poland. Sensors were placed near fixed, professional air quality monitoring stations, carrying out measurements based on reference methods, in the following periods: July-November, and December-May. Results of the study show that without using sophisticated correction methods, the range of measured air pollution concentrations may be greater than their actual values in ambient air-measured in the field by fixed stations. In the case of summer months (with air temperature over 30 °C), the long-term mean absolute percentage error was over 150% and the sensors, using the methods recommended by the manufacturer, in the case of high temperatures could even show negative values. After applying the mathematical correction functions proposed in this article, it was possible to significantly reduce long-term errors (to 40-70% per month, regardless of the location of the measurements) and eliminate negative measurement values. The proposed method is based on the recalculation of the raw measurement, air temperature, and air RH and does not require the use of extensive analytical tools.

Asunto(s)

Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Monitoreo del Ambiente/métodos , Dióxido de Nitrógeno/análisis , Estaciones del Año

RESUMEN

Maritime Spatial Planning (MSP) is bringing new challenges to planning and management in the marine realm, namely on the environmental assessment of the new plans and projects. Portugal is developing its first MSP instrument, PSOEM (Plano de Situação do Ordenamento do Espaço Marítimo), since 2015 and published it on December 2019. This paper focuses on a particular stage of the Strategic Environmental Assessment (SEA) of PSOEM regarding the assessment of the activities/uses that may significantly affect Natura 2000 marine network during the Plan's implementation in the Mainland subdivision. Over the years, progress has been made in researching and assessing the environmental impacts of maritime activities/uses. However, its application to practice raised several challenges and limitations. The methodological approach presented in this paper was developed to overcome knowledge, data and time constraints. Some of the limitations are a consequence of the MSP approach itself adopted in Portugal, namely the low technical detail on future uses and activities, which is required and desirable at this level of planning. Others relate with the lack of spatially explicit data on marine habitats and species distribution preserved under Natura 2000 network, which is not fully established in the marine environment. The adopted methodology started with the characterization and mapping of the conservation values and the pressures arising from the potential activities/uses. It followed with the assessment of their impacts and finally with the identification of mitigation measures, which were then adopted by the PSOEM as good practices. As new knowledge is generated and more information is collected, this tailor-made approach can be easily adapted and improved to keep supporting decision-making throughout PSOEM's implementation. The method can be easily adapted and transferred to other contexts, not only within the Portuguese maritime area, and could be made available to stakeholders that wish to invest in blue growth.