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The measurement of the CO2 concentration has a wide range of applications. Traditionally, it has been used to assess air quality, with other applications linked to the experimental assessment of occupancy patterns and air renewal rates. More recently, the worldwide dissemination of COVID-19 establishing a relationship between infection risk and the mean CO2 level has abruptly led to the measurement of the CO2 concentration in order to limit the spread of this respiratory disease in the indoor environment. Therefore, the extensive application of this measurement outside of traditional air quality assessment requires an in-depth analysis of the suitability of these sensors for such modern applications. This paper discusses the performance of an array of commercial wall-mounted CO2 sensors, focusing on their application to obtain occupancy patterns and air renovation rates. This study is supported by several long-term test campaigns conducted in an in-use office building located in south-eastern Spain. The results show a spread of 19–101 ppm, with a drift of 28 ppm over 5 years, an offset of 2–301 ppm and fluctuations up to 80 ppm in instantaneous measurements not related to concentration changes. It is proposed that values averaged over 30 min, using a suitable reference value, be used to avoid erroneous results when calibration is not feasible. [ABSTRACT FROM AUTHOR]

Very unhealthy air quality is consistently connected with numerous diseases. Appropriate extreme analysis and accurate predictions are in rising demand for exploring potential linked causes and for providing suggestions for the environmental agency in public policy strategy. This paper aims to model the spatial and temporal pattern of both moderate and extremely poor PM 10 concentrations (of daily mean) collected from 342 representative monitors distributed throughout mainland Spain from 2017 to 2021. We first propose and compare a series of Bayesian hierarchical generalized extreme models of annual maxima PM 10 concentrations, including both the fixed effect of altitude, temperature, precipitation, vapour pressure and population density, as well as the spatio-temporal random effect with the Stochastic Partial Differential Equation (SPDE) approach and a lag-one dynamic auto-regressive component (AR(1)). Under WAIC, DIC and other criteria, the best model is selected with good predictive ability based on the first four-year data (2017–2020) for training and the last-year data (2021) for testing. We bring the structure of the best model to establish the joint Bayesian model of annual mean and annual maxima PM 10 concentrations and provide evidence that certain predictors (precipitation, vapour pressure and population density) influence comparably while the other predictors (altitude and temperature) impact reversely in the different scaled PM 10 concentrations. The findings are applied to identify the hot-spot regions with poor air quality using excursion functions specified at the grid level. It suggests that the community of Madrid and some sites in northwestern and southern Spain are likely to be exposed to severe air pollution, simultaneously exceeding the warning risk threshold. [ABSTRACT FROM AUTHOR]

Air pollution and obesity are two of the main challenges that need to be addressed in developed countries. This paper analyses the relationship between obesity/overweight rates and outdoor (ambient) air quality in Spain. The results confirm, through logistic regressions, that the typical profile of an obese/overweight person is that of an older man. Air pollution does not have a clear negative effect on obesity/overweight for our sample selection (OR: 0.99; N = 23,089, men and women aged 15 and over). Similarly, there does not appear to be an urban pollution/obesity pattern. However, we find a detrimental effect for the group of elderly people, perhaps linked to a negative exposure duration effect (OR: 1.11; for those aged ≥55 years, N = 10,932). In our study we argue that public policies should address lifestyles and at the same time reduce specific air pollutants to enhance population health and wellbeing. [ABSTRACT FROM AUTHOR]

This paper explores the relationship between air pollution, climate and reported subjective well-being (or happiness) in Spanish regions. The results show that, after controlling for most of the socio-economic variables affecting happiness, there are still significant regional differences in subjective well-being. Evidence also suggests that climate and air pollution variables play a significant role in explaining these regional differences in happiness. The analysis also allows us to calculate the monetary value of air quality and climate, deriving the average marginal rate of substitution between income and air quality and climate for the Spanish regions. [ABSTRACT FROM AUTHOR]

Highlights • The paper describes a methodology to obtain an Urban Energy Sustainability Index (UESI). • This methodology can evaluate the global energy performance for any city. • UESI works through the measurement of 12 clearly-defined indicators and targets. • UESI is also a tool for designing effective actions towards energy-sustainable cities. • The index has been applied successfully to two Spanish cities (Malaga and Barcelona). Abstract The aim of the paper is to propose a methodology for evaluating the energy sustainability of a city based on the characterization of the energy end-use, energy systems and flows, as well as other intrinsically related concepts, such as the quality of air and the energy efficiency in transport and buildings. As a result, an Urban Energy Sustainability Index (UESI) has been proposed to measure the energy sustainability of the cities. Several indicators have been proposed to be used to build the index. These indicators have been grouped into three types depending on their influence on energy urban sustainability: basic, instrumental and complementary. For each indicator, an analysis has been done and as a result an expression for estimating it has been proposed. The value of the index is obtained from the combination of these indicators using the weighted average method. The proposed index can be used as an operational tool to improve the sustainability of cities. It also aims to have an international application as it is related to the global sustainability objectives defined by internationally recognized organizations. The proposed methodology has been used for two different Spanish cities, Barcelona and Malaga. The results show that it covers most of the issues related to the use of energy and sustainability in the cities and that it can also be applied to others cities. [ABSTRACT FROM AUTHOR]

The design of emission abatement measures to effectively reduce high ground-level ozone (O3) concentrations in urban areas is very complex. In addition to the strongly non-linear chemistry of this secondary pollutant, precursors can be released by a variety of sources in different regions, and locally produced O3 is mixed with that transported from the regional or continental scales. All of these processes depend also on the specific meteorological conditions and topography of the study area. Consequently, high-resolution comprehensive modeling tools are needed to understand the drivers of photochemical pollution and to assess the potential of local strategies to reduce adverse impacts from high tropospheric O3 levels. In this study, we apply the Integrated Source Apportionment Method (ISAM) implemented in the Community Multiscale Air Quality (CMAQ v5.3.2) model to investigate the origin of summertime O3 in the Madrid region (Spain). Consistent with previous studies, our results confirm that O3 levels are dominated by non-local contributions, representing around 70 % of mean values across the region. Nonetheless, precursors emitted by local sources, mainly road traffic, play a more important role during O3 peaks, with contributions as high as 25 ppb. The potential impact of local measures is higher under unfavorable meteorological conditions associated with regional accumulation patterns. These findings suggest that this modeling system may be used in the future to simulate the potential outcomes of specific emission abatement measures to prevent high- O3 episodes in the Madrid metropolitan area. [ABSTRACT FROM AUTHOR]

The spiraling growth of the world's population and unregulated urbanization have resulted in many environmental problems, including poor quality of air, which is associated with a wide range of health issues. Machine learning approaches have been extensively employed to predict air quality, attracting the attention of the scientific community worldwide. Bibliometric studies provide a useful means by which to visualize and analyze published works, helping researchers to make novel scientific contributions by filling existing knowledge gaps in the research. To acquire an in-depth understanding of the topic, this paper presents a bibliometric analysis of all published articles on the use of machine learning networks to predict air quality found in the Web of Science (WoS) search engine from 1992 to 2021. S-curve analysis and social network analysis were used to identify the temporal distribution of articles, productivity by countries/continents, research institutions, and scientific metrics of journal productivity. This study indicated that maximum expansion of the literature witnessed during 2017–2021 (second phase) which represents an expansion or growth stage of machine learning and air quality prediction research. The number of published works increased significantly with 1432 articles accounting for 68.51% of all publications. As a result of the increased interest in machine learning-based prediction tools, the number of articles grew 2.17-fold compared to the 1992–2016 (first phase). In terms of international collaboration impact, Italy emerged as the most successful country (43.44), followed by Greece (31.22) and Spain (23.29). Author keywords analysis was employed to explore and evaluate the emerging research trends on the subject of air quality using machine learning models. Keywords that appear most frequently in this study are 'air pollution', 'air quality', 'machine learning', and 'forecasting'. Citation burst analysis, research productivity analysis, highly influential and highly cited works were also employed to examine various research themes and questions. In this study we also discussed how conventional methods were transformed into machine learning approaches. It is expected that this paper will provide technical guidelines, research priorities, and future opportunities for the precise prediction of air quality and emergency management of air pollution globally. • Interest in air quality prediction through machine learning model is expanding. • China and US were found productive countries in terms of countries collaboration. • Big data, Internet of Things, and Smart city are emerging topic for future research. • Significant difference between citations, funded and non-funded research. • Ensemble modeling is popular in air quality prediction research. [ABSTRACT FROM AUTHOR]

• The main goal is to identify key factors determining modal shift caused by a LEZ. • "Madrid Central" LEZ triggered a notable modal shift towards sustainable modes. • The highest modal shift rates are observed among car users. • Modal shift is mainly explained by mobility habits and socio-demographic variables. • Environmental awareness and political ideology do not play a key role. Although Low Emission Zones (LEZs) have been adopted to address the environmental challenge of improving air quality in urban contexts worldwide, limited attention has been paid to studying their effects on promoting a shift to greener modes. This paper aims to gain insight into that issue by studying the case of "Madrid Central", a LEZ recently implemented in Spain. A survey campaign was conducted to explore changes in modal shift declared by respondents due to the LEZ implementation. Based on that, a discrete choice analysis was conducted to identify key factors determining changes in the modal share after implementing the LEZ. The results show the high impact of the LEZ on decreasing car use and promoting cleaner modes thereby contributing to reduce air pollution. The paper concludes that modal shift is mainly associated with socio-demographic variables, individual perceptions towards LEZs and mobility habits. By contrast, attitudinal variables were not found relevant for explaining modal shift. The effectiveness of "Madrid Central" in reducing car use provides policy-makers with lessons and a guidelines for implementing LEZs. Given the scarcity of research about that specific topic, the results are scalable to other experiences in the international context. [ABSTRACT FROM AUTHOR]

Much work has been done in the context of the hedonic price theory to estimate the impact of air quality on housing prices. Research has employed objective measures of air quality, but only slightly confirms the hedonic theory in the best of cases: the implicit price function relating housing prices to air pollution will, ceteris paribus, be negatively sloped. This paper compares the performance of a spatial Durbin model when using both objective and subjective measures of pollution. On the one hand, we design an Air Pollution Indicator based on measured pollution as the objective measure of pollution. On the other hand, the subjective measure of pollution employed to characterize neighborhoods is the percentage of residents who declare that the neighborhood has serious pollution problems, the percentage being referred to as residents' perception of pollution. For comparison purposes, the empirical part of this research focuses on Madrid (Spain). The study employs a proprietary database containing information about the price and 27 characteristics of 11,796 owner-occupied single family homes. As far as the authors are aware, it is the largest database ever used to analyze the Madrid housing market. The results of the study clearly favor the use of subjective air quality measures. [ABSTRACT FROM AUTHOR]

During the central months of the year, southwestern Spain is under strong insolation and weak synoptic forcing, promoting the development of sea breezes and mountain-induced winds and creating recirculations of pollutants. The complex topography of the Southwestern Iberia Peninsula induces the formation of vertical layers, into which the pollutants are injected and subjected to long-distance transport and compensatory subsidence. The characteristics of these highly complex flows have important effects on the pollutant dispersion. Air pollution studies in very complex terrains require high-resolution modelling for resolving the flow dynamics. This paper shows the results obtained from using the MM5-CAMx multiscale-nested air quality model to relate the sensitivity regimes for ozone, nitrogen oxides and volatile organic compounds in an area of high geographical complexity. The article assesses the impact on the hourly and eight-hourly maximum daily ozone concentrations of four reduction strategies during two ozone pollution episodes. This analysis of the ozone response has led to a preliminary evaluation of the effectiveness of the most common control strategies: traffic, industry, mixed traffic and industry, and closure of some of the largest industries (oil and petrochemical refineries). Photochemical indicators show that ozone chemistry in southwestern Spain is strongly sensitive to NO. However, volatile organic compound-sensitive points are found in areas with anthropogenic influence (highways, cities and industrial parks). Our results indicate that reductions in road traffic lead to ozone reductions over large areas, whereas reductions in industrial emissions, despite sometimes showing greater decreases in the maximum hourly and eight-hourly ground-level ozone levels, lead to ozone reductions in a local area only. In the control study case, with the oil refinery and the petrochemical plants closed, decreases in ozone hourly concentrations are up to 40% higher than in the other emission control scenarios studied. This analysis provides an assessment of the effectiveness of different policies for controlling precursor emissions by comparing the modelled results for different scenarios. [ABSTRACT FROM AUTHOR]

This paper describes a method to design air quality monitoring networks for nitrogen dioxide and ozone and its application in Granada, a city located in Andalusia, southern Spain. The city has a population of 236,988 inhabitants, and traffic is its main source of air pollution. Sampling campaigns with passive diffusion samplers at 88 sites were carried out to obtain information on the pollution distribution in Granada. The average concentrations found for NO2 and O3 were 36.5 μg/m3 and 51.6 μg/m3, respectively. Maximum values of up to 57.1 μg/m3 NO2 were found in Granada city center and O3 reached 77.2 μg/m3 downwind from the emission source. After spatial interpolation of the obtained values with Geographical Information Systems, a selection of the best locations for the monitoring stations was made, in line with the macro- and microscale siting requirements of the European Directive 2008/50/EC on ambient air quality and cleaner air for Europe. Another sampling campaign with diffusive samplers was carried out in 2007 to determine if the locations of the air quality assessment stations were still representative for their zone. A correction was made in the control network following results of this verification campaign. [ABSTRACT FROM AUTHOR]

The aim of this paper was to analyse the effect of particulate matter PM2.5, a recent air quality guideline value for the protection of health, on hospital admissions in Madrid, Spain. This dependent variable was used as a measure against the daily number of emergency hospital admissions from 2003-2005. The causes analysed were: all causes, respiratory and circulatory. The independent variables were daily records of PM2.5, PM10, NO2, NOx, SO2 and O3. Seasonalities, trend, flu epidemics, noise and pollen were used as control variables. Poisson Regression Models were performed to calculate the Relative Risk (RR) and the Attributable Risk (AR). The function relationship with hospital admissions was linear and without threshold. The RR for an increase of 25 μg/m3 in PM2.5 concentrations was 1.07 IC 95% (1.05 1.09) for all causes; for circulatory was 1.08 IC 95%: (1.03 1.13) and for respiratory was 1.07 IC 95% (1.02 1.11). PM2.5 concentrations were the only primary pollutant that showed a statistical association with hospital admissions in Madrid. [ABSTRACT FROM AUTHOR]

Abstract: This paper discusses the performance of Radial Basis Function networks (RBF) in a problem of spatial regression of pollutants in Madrid. Specifically, the spatial regression of NO x and O3 is considered, in such a way that, starting from a set of measuring points provided by the air quality monitoring network of Madrid, the complete surface of the pollutants in the city is obtained. This pollutant surface can be used as an initial step for modeling intra-urban pollution using land-use regression techniques for example. Also, different works has used a pollutant surface to study the patterns of pollution in different cities in the world and also to establish their air monitoring networks under mathematical criteria. The paper is focussed in analyzing the performance of RBF networks to obtain this first pollutant surface, so different RBF training algorithms are tested in this paper. Specifically, evolutionary-based RBF training algorithms are described, and compared with classical training algorithms for RBF networks with Gaussian kernels. The inclusion of meteorological variables in the RBF networks are also discussed in the paper. The experimental part of the article studies real results of the application of RBF networks to obtain a first pollutant surface of NO x and O3, using the data of the air pollution monitoring network of Madrid and the meteorological network of the city. [Copyright &y& Elsevier]

In many cases, a substantial proportion of large industrial emissions are located in the surrounding areas of cities and are the cause of an important part of air concentrations over the city and surrounding areas. The need to have a tool to analyze and manage these concentrations is the main objective of this contribution. In this paper, we show the implementation of an adapted version of the MM5-CMAQ (Byun et al. , Description of the Models-3 Community Multiscale Air Quality (CMAQ) model. Proceedings of the American Meteorological Society 78th Annual Meeting Phoenix, AZ, Jan. 11–16, 264–268, 1998)—PSU/NCAR and EPA (US) models—modeling system for a large combined cycle power plant located near Madrid city (Spain). The system called TEAP (EUREKA project)—a Tool to Evaluate the Air Quality Impact of Industrial Plants—allows the assessment of the impact of each individual power group (400 MW) in real-time and forecasting mode. As a consequence, the industrial plant and authorities are having a period of time (≈16 h) to decide to switch off one power group or several, to minimize or avoid the possible exceedance of European Union (EU) limits—as declared in the EU directives. The quantification of the impact of these possible exceedances of EU Directives due to emissions produced by the power plant is essential for decision making according to the daily forecasts. We will show the implementation of the TEAP system and operation in two real applications which are operating since summer 2005 and January, 2007 in the surrounding area of Madrid (Spain). [ABSTRACT FROM AUTHOR]

This paper assesses the health impact, in terms of the reduction of premature deaths associated with changes in air pollutant exposure, resulting from double-aim strategies for reducing emissions of greenhouse gases and air pollutants from the transport sector for the year 2030 in Spain. The impact on air quality of selected measures for reducing emissions from the transport sector (increased penetration of biofuel and electric car use) was assessed by air quality modeling. The estimation of population exposure to NO2, particulate matter (PM) and O3 allows for estimation of associated mortality and external costs in comparison with the baseline scenario with no measures. The results show that the penetration of the electric vehicle provided the largest benefits, even when the emissions due to the additional electricity demand were considered. [ABSTRACT FROM AUTHOR]

Source apportionment analysis was used to identify the factors contributing to atmospheric pollution at a monitoring location in the Southeast of Spain, a well documented area with an arid climate and high insolation favouring two sources of particulate matter: secondary transformation in the atmosphere and resuspension of crustal dry soils to the air. These conditions are further complicated by numerous industrial facilities in the area of the historical city of Cartagena. This paper describes the air quality of an area which includes a zinc metallurgical industry, a petrochemical factory, an oil power station, a shipyard and natural phenomena including African dust transport and resuspension of regional and/or local crustal materials. Major and trace element concentrations in PM10 and PM2.5 were determined at two monitoring stations in Cartagena (one PM10 sampler located at a traffic hotspot and the PM2.5 sampler at a suburban station), during 2004 and 2005. Results showed that in the PM10 fraction, the zinc metallurgical activity was linked to high levels of Cd, Zn and Pb; shipyard emission was associated with high levels of Cr and Ni; and high Ni and V levels were associated with the secondary aerosol indicating the contribution from oil combustion (oil-fired power station or petrochemical facilities). In the PM2.5 size fraction, the zinc source is defined by Zn and Pb; V, Ni and As appear with the oil combustion emissions. In contrast to PM10, shipyard activity is not consistently defined. Consistent sources found in both size fractions include crustal materials and traffic emissions. [ABSTRACT FROM AUTHOR]

This paper presents the main experimental results of surface ozone concentrations measured at a rural area in Northern Spain from February 2000 to December 2005. Daily and seasonal variation of ozone has been analysed. The peak concentration levels are obtained in the afternoon, mean value around 88 µg m−3, with extreme average values of 59 µg m−3 in January and 113 µg m−3 in July. Small differences are found in the mean and median of the ozone levels from April to August, when spring and summer maxima are observed. Despite the great inter-annual ozone variability obtained, most air quality indicators showed a positive trend. Further analysis of the monthly mean ozone concentrations of the main percentiles have also been performed using a harmonic model. The upward trend was 6.2 ± 1.7 µg m−3 for the 98th percentile. To interpret the main features of the annual cycle and describe the ozone peaks, the influence of meteorological factors is studied. In summer, ozone production is governed by local processes, air temperature being the major controlling factor. However, the origin of the spring maximum is not so well identified. [ABSTRACT FROM AUTHOR]

Abstract??Twenty first century epidemiological publications on urban air pollution are confirming that inhalation of fine, airborne particulate matter (PM) has serious chronic human health effects and is a major cause of premature death worldwide. Recently updated recommendations by WHO identify three ?Interim Targets? for the stepped reduction in PM levels within world cities in the quest to achieve an annual mean Air Quality Guideline (AQG) concentration of 20??g/m3for particles less than 10?microns in size (PM10). In this paper we offer a perspective from Spain, a country with the longest record of reporting pollution data from large numbers of urban traffic sites to a central European database (AIRBASE). We can demonstrate that average annual PM concentrations at urban traffic monitoring stations in many European cities continue to be 50?100% above the WHO AQG, a situation exacerbated by high urban PM2.5/10ratios which indicate a dominance of finer, more deeply inhalable particles potentially more detrimental to health. Given that WHO has estimated in 2000 there were well over 250,000 premature deaths in Europe attributable to PM inhalation, such continuing high urban pollution levels are placing a huge burden on European medical resources. [ABSTRACT FROM AUTHOR]

This work aims to quantify potential pollution level changes in an urban environment (Madrid city, Spain) located in South Europe due to the lockdown measures for preventing the SARS-CoV-2 transmission. Polluting 11 species commonly monitored in urban zones were attended. Except for O3, a prompt target pollutant levels abatement was reached, intensely when implanted stricter measures and moderately along those measures' relaxing period. In the case of TH and CH4, it is evidenced a progressive diminution over the lockdown period. While the highest decreasing average changes relapsed on NOx (NO2: − 40.0% and NO: − 33.3%) and VOCs (C7H8: − 36.3% and C6H6: − 32.8%), followed by SO2 (− 27.0%), PM10 (− 19.7%), CO (− 16.6%), CH4 (− 14.7%), TH (− 11.6%) and PM2.5 (− 10.1%), the O3 level slightly raised 0.4%. These changes were consistently dependent on the measurement station location, emphasizing urban background zones for SO2, CO, C6H6, C7H8, TH and CH4, suburban zones for PM2.5 and O3, urban traffic sites for NO and PM10, and keeping variations reasonably similar at all the stations in the case of NO2. Those pollution changes were not translated in variations on geospatial pattern, except for NO, O3 and SO2. Although the researched urban atmosphere improvement was not attributable to meteorological conditions' variations, it was in line with the decline in traffic intensity. The evidenced outcomes might offer valuable clues to air quality managers in urban environments regarding decision-making in favor of applying punctual severe measures for quickly and considerably relieving polluting high load occurred in urban environments. [ABSTRACT FROM AUTHOR]

This paper provides scientific results from a European LIFE project carried out in the Valencian region of Spain during the 2017 to 2018 time frame. In 2018, more than 60,000 tons of pesticides were commercialized in Spain, with approximately 15% destined for Valencian crops. In order to improve the air quality in the agricultural areas of this region, an innovative cropping system based on irrigation was developed and compared to conventional treatments based on hand-spray and turbo application. After applying conventional treatments to five types of crops (citrus, persimmon, nectarine, watermelon, and other stone fruits), a total of 13 active substances were detected in the air. The same active substances were applied to crops using the novel irrigation system, and no pesticide was detected in the air. Moreover, applicator and bystander populations in the region were assessed for their risk of inhalation exposure to pesticides, and no risk was found when either of the techniques, the innovative and the conventional agricultural one, were applied. [ABSTRACT FROM AUTHOR]

Due to the exponential growth of the SARS-CoV-2 pandemic in Spain (2020), the Spanish Government adopted lockdown measures as mitigating strategies to reduce the spread of the pandemic from 14 March. In this paper, we report the results of the change in air quality at two Atlantic Coastal European cities (Northwest Spain) during five lockdown weeks. The temporal evolution of gaseous (nitrogen oxides, comprising NOx, NO, and NO2; sulfur dioxide, SO2; carbon monoxide, CO; and ozone, O3) and particulate matter (PM10; PM2.5; and equivalent black carbon, eBC) pollutants were recorded before (7 February to 13 March 2020) and during the first five lockdown weeks (14 March to 20 April 2020) at seven air quality monitoring stations (urban background, traffic, and industrial) in the cities of A Coruña and Vigo. The influences of the backward trajectories and meteorological parameters on air pollutant concentrations were considered during the studied period. The temporal trends indicate that the concentrations of almost all species steadily decreased during the lockdown period with statistical significance, with respect to the pre-lockdown period. In this context, great reductions were observed for pollutants related mainly to fossil fuel combustion, road traffic, and shipping emissions (−38 to −78% for NO, −22 to −69% for NO2, −26 to −75% for NOx, −3 to −77% for SO2, −21% for CO, −25 to −49% for PM10, −10 to −38% for PM2.5, and −29 to −51% for eBC). Conversely, O3 concentrations increased from +5 to +16%. Finally, pollutant concentration data for 14 March to 20 April of 2020 were compared with those of the previous two years. The results show that the overall air pollutants levels were higher during 2018–2019 than during the lockdown period. [ABSTRACT FROM AUTHOR]

Air pollution affects human health and is one of the main problems in the world, including in coastal cities with industrial seaports. In this sense, the city of Gijón (northern Spain) stands out as one of the 20 Spanish cities with the worst air quality. The study aims to identify outliers in air quality observations near the El Musel seaport, resulting from the emissions of six pollutants over an eight-year period (2014–2021). It compares methods based on the functional data analysis (FDA) approach and vector methods to determine the optimal approach for detecting outliers and supporting air quality control. Our approach involves analyzing air pollutant observations as a set of curves rather than vectors. Therefore, in the FDA approach, curves are constructed to provide the best fit to isolated data points, resulting in a collection of continuous functions. These functions capture the behavior of the data in a continuous domain. Two FDA approach methodologies were used here: the functional bagplot and the high-density region (HDR) boxplot. Finally, outlier detection using the FDA approach was found to be more powerful than the vector methods and the functional bagplot method detected more outliers than the HDR boxplot. [ABSTRACT FROM AUTHOR]

Air quality management is underpinned by continuous measurements of concentrations of target air pollutants in monitoring stations. Although many approaches for optimizing the number and location of air quality monitoring stations are described in the literature, these are usually focused on dense networks. However, there are small and medium-size urban areas that only require one monitoring station but also suffer from severe air pollution. Given that target pollutants are usually measured at the same sampling points; it is necessary to develop a methodology to determine the optimal location of the single station. In this paper, such a methodology is proposed based on maximizing an objective function, that balances between different pollutants measured in the network. The methodology is applied to a set of data available for the city of Cartagena, in southeast Spain. A sensitivity analysis reveals that 2 small areas of the studied city account for 80% of the optimal potential locations, which makes them ideal candidates for setting up the monitoring station. The methodology is easy to implement, robust and supports the decision-making process regarding the siting of fixed sampling sites. Image 1 • Small and medium-size urban areas require one fixed sampling point of air pollutants. • Few studies explore methodologies to locate a sole air quality monitoring station. • A multi-pollutant methodology to select the best location of the station is shown. • The methodology is proven to be robust and underpins air quality management. This paper describes an easy-to-use methodology to find out the optimum location for setting up a single air quality monitoring station, especially useful for small and medium-size urban areas. [ABSTRACT FROM AUTHOR]

The paper shows the results of measurements of carbon dioxide concentrations conducted in the school buildings located in two different climates: Białystok (Poland) and Belmez/Córdoba (Spain). CO 2 concentration in first 45 min met requirements of regulations, but with medium occupation of places in classrooms, then the recommended values were excided. We developed a model for CO 2 level estimation. This model allowed us to simulated the CO 2 concentration for full occupation of classrooms in both countries. In these cases CO 2 concentration would exceed maximum value (1000 ppm) during the first hour. Furthermore required air change rates were calculated: for actual occupation they should be in a range 2.5–5 h −1 to maintain IDA2 and carbon dioxide concentration below 1000 ppm, while in case of full occupation even 6–9 h −1 . Finally, surveys of student satisfaction were performed in situ during the measurements of CO 2 level to obtain the dependence of student comfort perception on this concentration. [ABSTRACT FROM AUTHOR]

The present study intends to explore the relationship between tourism growth and air pollution at a regional level for five important tourism European destinations: France, Spain, Greece, Portugal, and Italy. Most of the studies found in the literature examine this relationship on a national scale and focus only on the CO2 pollutant, which is a greenhouse gas but not a critical pollutant in terms of air quality and human exposure. This research focuses on a regional basis (NUTS 2 classification) and takes into account the main critical pollutants in terms of urban air pollution (namely: NOx, PM10, and PM2.5), and considers 10 years, from 2009 until 2018. This work aims to investigate evidence of a tourism-induced Environmental Kuznets Curve (EKC) for the countries through the construction of five panels, one for each country, including different variables: the Gross Domestic Product, the energy consumption, and the number of nights spent at tourist accommodation establishments from both domestic and foreign tourists. The Levin-Lin-Chu unit root test proves the variables to be stationary, while the Pedroni cointegration test shows that they are integrated. The pooled OLS estimator is employed throughout the countries to check the relationship among the variables. Results reveal that the tourism-induced EKC hypothesis is not validated for any of the countries. The findings also show that in Portugal, Italy, and Greece, there is a negative relationship between economic growth and environmental pollution, while mixed evidence is found for France and Spain. Moreover, differences in the impacts of international and domestic tourists on air pollution are found: foreign tourists negatively impact emissions, while domestic ones increase them. This result is clear for Spain, Greece, and Italy. The Granger panel causality test is then conducted to see the causality among the variables. [ABSTRACT FROM AUTHOR]

The management of the COVID-19 pandemic, which required global lockdowns and mobility restrictions, positively impacted air quality (especially the concentrations of primary pollutants). With the progressive return to normal activity during the last few months of 2020 and 2021, air pollutant concentrations were expected to rise again. In this work, together with meteorological conditions and traffic intensity, the concentrations of NO, NO 2 , O 3 , PM 10 , and SO 2 measured at three different locations (urban, industrial, and rural) in southeast Spain, from January 2016 to December 2021, were analyzed. For the three locations, PM 10 concentrations did not change significantly in 2020 or 2021. SO 2 concentrations did not experience changes at the industrial site in 2020 or 2021, but SO 2 concentrations did slightly increase in five months of 2021 in the urban location (with a maximum monthly average concentration of 11 μ g·m − 3 ). In 2020, NO and NO 2 concentrations were, in general, lower than those measured in previous years (2016–2019). Interestingly, at the urban site (San Basilio), the levels of NO and NO 2 were significantly lower in 2021 than in 2020 despite the higher traffic intensity in 2021. While the concentrations of NO and NO 2 decreased, in VOC-limited areas, O 3 concentrations increased. This was clearly observed at the industrial and the urban sites. Despite the increase, O 3 concentrations were still below the European O 3 target value for the protection of human health. An analysis of new registrations of EVs and HEVs in the latter years and their impact on the vehicle fleet of Murcia and, subsequently, on road emissions was carried out. Regardless of the steep increase in environmentally friendly vehicles in 2021, their share of the vehicle fleet is still negligible; thus, the lower concentrations of NO and NO 2 are likely due to more favorable weather conditions in 2021 than in 2020. [ABSTRACT FROM AUTHOR]

Air pollution is one of the big concerns for smart cities. The problem of applying big data analytics to sampling bias in the context of urban air quality is studied in this paper. A nonparametric estimator that incorporates kernel density estimation is used. When ignoring the biasing weight function, a small-sized simple random sample of the real population is assumed to be additionally observed. The general parameter considered is the mean of a transformation of the random variable of interest. A new bootstrap algorithm is used to approximate the mean squared error of the new estimator. Its minimization leads to an automatic bandwidth selector. The method is applied to a real data set concerning the levels of different pollutants in the urban air of the city of A Coruña (Galicia, NW Spain). Estimations for the mean and the cumulative distribution function of the level of ozone and nitrogen dioxide when the temperature is greater than or equal to 30 ∘ C based on 15 years of biased data are obtained. [ABSTRACT FROM AUTHOR]

This paper analyses the effects of policy making for air pollution abatement in Spain between 2000 and 2020 under an integrated assessment approach with the AERIS model for number of pollutants (NO x /NO 2 , PM 10 /PM 2.5 , O 3 , SO 2 , NH 3 and VOC). The analysis of the effects of air pollution focused on different aspects: compliance with the European limit values of Directive 2008/50/EC for NO 2 and PM 10 for the Spanish air quality management areas; the evaluation of impacts caused by the deposition of atmospheric sulphur and nitrogen on ecosystems; the exceedance of critical levels of NO 2 and SO 2 in forest areas; the analysis of O 3 -induced crop damage for grapes, maize, potato, rice, tobacco, tomato, watermelon and wheat; health impacts caused by human exposure to O 3 and PM 2.5 ; and costs on society due to crop losses (O 3 ), disability-related absence of work staff and damage to buildings and public property due to soot-related soiling (PM 2.5 ). In general, air quality policy making has delivered improvements in air quality levels throughout Spain and has mitigated the severity of the impacts on ecosystems, health and vegetation in 2020 as target year. The findings of this work constitute an appropriate diagnosis for identifying improvement potentials for further mitigation for policy makers and stakeholders in Spain. [ABSTRACT FROM AUTHOR]

Since the airborne transmission of SARS-CoV-2 is the key in the spread of COVID-19, the interest in the quality of the air in enclosed spaces has become utmost importance. Natural ventilation is the first obvious option to improve epidemiological security, and general rules have been widely disseminated. Nevertheless, the changes in weather conditions greatly limit the validity of such rules. Here we present a system that, upon the introduction of basic parameters of a given space, its volume, location, orientation, architectural environment and average occupancy, yields optimized ventilation times on the basis of wind meteorological forecasts. It has been successfully implemented in the educative system of the Autonomous Community of Galicia (northwest Spain) and it is currently operative. [ABSTRACT FROM AUTHOR]

Abstract: Benzo(a)pyrene (BaP) is one of the most dangerous PAH due to its high carcinogenic and mutagenic character. Because of this reason, the Directive 2004/107/CE of the European Union establishes a target value of 1 ng/m3 of BaP in the atmosphere. In this paper, the main aim is to estimate the BaP concentrations in the atmosphere by using last generation of air quality dispersion models with the inclusion of the transport, scavenging and deposition processes for the BaP. The degradation of the particulated BaP by the ozone has been considered. The aerosol–gas partitioning phenomenon in the atmosphere is modelled taking into a count that the concentrations in the gas and the aerosol phases. If the pre-existing organic aerosol concentrations are zero gas/particle equilibrium is established. The model has been validated at local scale with data from a sampling campaign carried out in the area of Zaragoza (Spain) during 12 weeks. [Copyright &y& Elsevier]

Abstract: The objectives of this paper are the application of uncertainty and sensitivity analysis methods in atmospheric dispersion modeling to study the prediction of the dispersion of pollutants in the atmosphere. The Gaussian Plume Model is used to study the impact of meteorology on the dispersion of the emissions from an industrial source complex. The determination of ground-level concentration and maximum ground-level concentration is useful for the prediction of violations of air quality regulations. The Industrial Source Complex Short-Term (ISCST-3) air pollution model was adopted to predict the ground-level concentration of sulfur dioxide (SO2) emitted by a power plant located in an industrial region site in Spain. Quantitative uncertainty analysis has become a common component of risk assessments. Uncertainties were defined a priori for each of the following variables: wind speed, wind direction, and pollutant emission rate. In order to obtain information about the uncertainty of computer code results, a number of code runs was performed using the nonparametric tolerance limits method. The Monte Carlo method was used to propagate uncertainty across codes. The Spearman rank correlation coefficient was used as a sensitivity measure. [Copyright &y& Elsevier]

Abstract: The CALIOPE high-resolution air quality modeling system (4 km × 4 km, 1 h) estimates particulate matter from two aerosol models, CMAQv4.5 (AERO4) and BSC-DREAM8b. While CMAQv4.5 calculates biogenic, anthropogenic and sea-salt aerosols; BSC-DREAM8b provides hourly estimates of the natural mineral dust contribution from North Africa deserts. This paper presents an evaluation of the CALIOPE system to reproduce the spatial and temporal variability levels of PM2.5, PM10 and chemical composition (nitrate, non-marine sulfate, ammonium, organic and elemental carbon, sea-salt, and desert dust) across Spain. The evaluation is performed against ground-based observations for the year 2004, when a number of time series of chemically speciated compounds were available. A new data set of Saharan dust PM10 concentration is used to evaluate the PM10 contribution modeled by BSC-DREAM8b. The results indicate that both natural aerosol sea-salt and desert dust accomplish the model performance criteria (MFE ≤ 75% and MFB ± 60%). Modeled PM10 sea-salt is highly dependent on wind speed and presents high correlation with experimental data in coastal areas (r = 0.67). The BSC-DREAM8b is able to reproduce the daily variability of the observed levels of desert dust and most of the outbreaks affecting southern Spain. Species in the equilibrium (e.g. sulfate/nitrate/ammonium) are highly correlated each other and show high dependency on ammonia emissions. Non-marine sulfate and ammonium are underestimated by a factor of 3. An underestimation of nitrate was also seen (factor of 2). Fine carbonaceous aerosols present the highest underestimations (factor of 4) in part related to the state-of-the-science concerning secondary organic aerosol formation pathways. Spatial and seasonal variability of PM2.5, PM10 and their chemical compounds increase the correlation with observations when multiplicative bias-correction factors for the aforementioned underestimated species are taking into account. Furthermore, simulated spatial and seasonal patterns of aerosol agree with those described in related studies based on experimental values. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: This paper quantifies the very short-term variability of the total solar irradiance and the ultraviolet erythemal irradiance (UVER) averaged over 1-min intervals at Granada (Southeastern Spain). A statistical analysis for a four-year period (January 2006–December 2009) under different cloudiness and characterized by the amount of cloud cover (oktas) retrieved from an All-Sky Imager located next to the radiometers is presented. Very short-term variability of the total solar irradiance was larger than UVER fluctuations under cloudy conditions (above three oktas), in accordance with previous works found in the literature. Nevertheless, for cloud cover bellow three oktas the opposite was true; the median relative 1-min fluctuation was larger for UVER than for total solar irradiance. Moreover, while the coefficient of variation (CV) for UVER presented a clear dependence on the solar zenith angle (SZA) under completely cloud-free conditions (from 1.5% for SZA = 20° to 9.5% for SZA = 65°), the CV of the total solar irradiance was under 1.3% with a more stable behaviour for the entire range of SZA. Large differences were found for cloud cover of seven oktas, where the median diurnal 1-min variability for total solar irradiance was 3.9% min−1 compared to 2.5% min−1 for UVER data. Additionally, an episode with surface total solar irradiance higher than its corresponding extraterrestrial value is analyzed. [Copyright &y& Elsevier]

Abstract: This paper presents a summary of the results obtained from the particulate matter (PM) data collected over the 1999–2008 period from representative sites of the Madrid air basin (an urban traffic site, an urban background site and a rural site) which is located in the centre of Spain. A number of PM10 and PM2.5 filters were obtained with high volume samplers and cut-off inlets and chemically analyzed. Pollutants recorded in this area at the Air Quality monitoring stations were also analyzed. The influence of the atmospheric transport scenarios on the levels of PM was investigated by means of atmospheric back-trajectories, satellite imagery and meteorological synoptic charts. Source apportionment studies were performed to characterize the main PM sources whenever was possible. Their contributions to bulk PM levels showed clear spatial patterns, linked to characteristic meteorological scenarios. [Copyright &y& Elsevier]

Abstract: Damage caused to objects of cultural heritage is one of the most serious detrimental effects of air pollutants. Within the 6th Framework Programme of the EU, the CULT-STRAT project is an inter-agency, multi-disciplinary project that has integrated research and monitoring information to provide answers to policy and management questions, which relate the effects of air pollutants on heritage and the management options available to mitigate them. The overall aim of the project has been to assess and predict the effects of different pollutants on materials and objects of cultural heritage in a multipollutant scenario and to identify indicators and thresholds levels of pollutants. These have been used for development of management strategies for sustainable maintenance and preventive conservation of European Cultural Heritage and air quality policy from continental to local scale. The present paper reports one of the studies carried out in the CULT-STRAT project at city level and focused on the town of Madrid (Spain). Different maps are shown for the present and possible future scenarios (2010 and 2020): inventory of stock of cultural heritage for each selected material, concentration of selected pollutants (SO2, NO2, O3 and PM10), corrosion (cast bronze) and recession (Portland limestone), exceedance of tolerable degradation thresholds for each material and corrosion-cultural heritage overlapped maps. [Copyright &y& Elsevier]

Abstract: The assessment of air quality is necessary in order to control and reduce pollution to levels which minimise harmful effects on human health and the environment. This paper describes a method to design air quality monitoring networks for nitrogen dioxide and ozone and its application in Jaen (southern Spain). A fibre-glass filter impregnated with triethanolamine was used in diffusive sampling badges for NO2 determination. For O3 analysis, sodium nitrite was selected and nitrate, a product of the reaction of ozone and nitrite, was used to assess the ozone concentrations. Sampling campaigns with passive diffusion samplers at 62 sites were then carried out to obtain information on the pollution emissions in Jaen. The sampling campaigns in 2001–2002 revealed an average concentration of 10.4μg/m3 NO2 with maximum values up to 22.5μg/m3 in Jaen City centre. The average ozone concentrations were recorded downwind from the emission source, reaching 96.2μg/m3; the average ozone value in Jaen was 72.0μg/m3. After spatial interpolation of the obtained values with Geographical Information Systems, a selection of the best locations for the monitoring stations was made, in line with the macro- and microscale siting requirements of the European Directive 2008/50/EC on ambient air quality and cleaner air for Europe. A second sampling campaign with diffusive samplers was carried out in 2005–2006 to control if the locations of the air quality assessment stations were still representative for their zone. [Copyright &y& Elsevier]

This paper suggests new strategies of HVAC system design and operative parameters based on simulation, real sampled data, tests, questionnaires and climatic conditions. This investigation is based on real data measured in different kinds of typical Spanish buildings like a set of flats, office buildings, museums and schools located in the area of A Coruña, Spain. The purpose of these investigations was to determine the relationship between indoor comfort, energy saving, health effects, materials conservation and work risk prevention as a consequence of parameters like HVAC adjusting, wall materials, indoor air changes and occupants' habits. The general conclusion obtained in flats was that ventilation procedures, under the current levels of occupation, should be modified to keep the relative humidity lower than the maximum recommended of 60%. In spite of this, natural ventilation could be effectively used in keeping both the indoor temperature and humidity, as well as the microbiological load, within acceptable limits. In office buildings, wall coverings showed a clear effect on indoor air conditions as a passive climate control method during the unoccupied period. Buildings with permeable coverings present better indoor comfort conditions and acceptability. Furthermore, this effect improves the energy saving especially during the first hours of occupation. Old schools and museums, with higher thermal inertia, showed better indoor temperature conditions on store zone than new buildings. This effect is a consequence of the clear thermal inertia in old museums, despite the fact that these now incorporate modern air conditioning systems. [ABSTRACT FROM AUTHOR]

Abstract: Air monitoring networks are necessary to assess air quality in order to reduce pollution to levels which minimise harmful effects on human health and the environment. This paper describes a method to design air quality monitoring networks for nitrogen dioxide and ozone and its application in Cordova, Andalusia, southern Spain. The city has a population of 325,453 inhabitants and traffic is its main source of air pollution. The first step of this method made it possible to determine from historical data that two control stations for NO2 and one control stations for O3 are necessary according to the legislation. Sampling campaigns with passive diffusion samplers at 81 sites were then carried out to obtain information on the pollution distribution in Cordova. The sampling campaigns in 2001–2002 revealed an average concentration of 19.5μg/m3 for NO2 with maximum values up to 28.6μg/m3 in Cordova city centre. The average ozone concentrations were recorded downwind from the emission source, reaching 91.8μg/m3; the average ozone value in Cordova was 65.3μg/m3. After spatial interpolation of the obtained values with Geographical Information Systems, a selection of the best locations for the monitoring stations was made, in line with the macro- and microscale siting requirements of the European Directive 2008/50/EC on ambient air quality and cleaner air for Europe. A second sampling campaign with diffusive samplers was carried out in 2007 to control if the locations of the air quality assessment stations were still representative for their zone. [Copyright &y& Elsevier]

Global warming and air quality are headline environmental issues of our time and policy must preempt negative international effects with forward-looking strategies. As part of the revision of the European National Emission Ceilings Directive, atmospheric emission projections for European Union countries are being calculated. These projections are useful to drive European air quality analyses and to support wide-scale decision-making. However, when evaluating specific policies and measures at sectoral level, a more detailed approach is needed. This paper presents an original methodology to evaluate emission projections. Emission projections are calculated for each emitting activity that has emissions under three scenarios: without measures (business as usual), with measures (baseline) and with additional measures (target). The methodology developed allows the estimation of highly disaggregated multi-pollutant, consistent emissions for a whole country or region. In order to assure consistency with past emissions included in atmospheric emission inventories and coherence among the individual activities, the consistent emission projection (CEP) model incorporates harmonization and integration criteria as well as quality assurance/quality check (QA/QC) procedures. This study includes a sensitivity analysis as a first approach to uncertainty evaluation. The aim of the model presented in this contribution is to support decision-making process through the assessment of future emission scenarios taking into account the effect of different detailed technical and non-technical measures and it may also constitute the basis for air quality modelling. The system is designed to produce the information and formats related to international reporting requirements and it allows performing a comparison of national results with lower resolution models such as RAINS/GAINS. The methodology has been successfully applied and tested to evaluate Spanish emission projections up to 2020 for 26 pollutants but the methodology could be adopted for any particular region for different purposes, especially for European countries. [Copyright &y& Elsevier]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper shows how PM speciation studies allow the evaluation of the strategies to be followed to diminish PM pollution in highly industrialized areas with a large number of potential pollution sources. Evolution of levels and speciation of PM10 in the ceramic producing area of Castelló (East Spain) was studied from April 2002 until December 2005. PM10 levels were measured at one rural (Borriana-rural), two suburban (Almassora and Onda) and three urban (Borriana-urban, L''Alcora and Vila-real) sites, all influenced by the ceramics industry. Average PM10 levels varied between 27 and 36 μg/m3 for the study period. Evaluation of 1996–2005 PM data from Onda shows a clear decrease of PM levels since the beginning of 2002. Summer peak levels and winter minima occurred at both rural and suburban sites, whereas urban sites had no clear seasonal trend, with high PM10 episodes being due variously to local, regional, and African dust intrusion events. PM10 chemical analysis at four of the sites showed the dominant constituent to be mineral matter, exceeding by 5–12 μg/m3 the usual ranges of annual mineral loadings in PM10 at comparable Spanish urban or regional background sites with no industrial influence. Given current PM10 loadings, we recommend a lowering target of 3–5 μg/m3 of the annual mean at the urban sites, which should be achievable given available emission abatement techniques. [Copyright &y& Elsevier]

Air pollution in large cities produces numerous diseases and even millions of deaths annually according to the World Health Organization. Pollen exposure is related to allergic diseases, which makes its prediction a valuable tool to assess the risk level to aeroallergens. However, airborne pollen concentrations are difficult to predict due to the inherent complexity of the relationships among both biotic and environmental variables. In this work, a stochastic approach based on supervised machine learning algorithms was performed to forecast the daily Olea pollen concentrations in the Community of Madrid, central Spain, from 1993 to 2018. Firstly, individual Light Gradient Boosting Machine (LightGBM) and artificial neural network (ANN) models were applied to predict the day of the year (DOY) when the peak of the pollen season occurs, resulting the estimated average peak date 149.1 ± 9.3 and 150.1 ± 10.8 DOY for LightGBM and ANN, respectively, close to the observed value (148.8 ± 9.8). Secondly, the daily pollen concentrations during the entire pollen season have been calculated using an ensemble of two-step GAM followed by LightGBM and ANN. The results of the prediction of daily pollen concentrations showed a coefficient of determination (r2) above 0.75 (goodness of the model following cross-validation). The predictors included in the ensemble models were meteorological variables, phenological metrics, specific site-characteristics, and preceding pollen concentrations. The models are state-of-the-art in machine learning and their potential has been shown to be used and deployed to understand and to predict the pollen risk levels during the main olive pollen season. [ABSTRACT FROM AUTHOR]

This paper provides insights into the potential of cold-ironing for the reduction of externalities. External cost derived from the emissions of CO 2 , NO x , SO x , and PM from berthed ships in the Spanish port system during 2016 are estimated providing a Spain-wide empirical evidence into where the highest externalities exist and where, on a port by port level, the introduction of cold ironing could yield the highest potential on reducing said externalities. The combined overall external costs from both local and global effects of shipping emissions from berthed vessels were between 326 and 440 million Euro. Eco-efficiency parameters are also obtained. It is found that the population in the port city as well as the composition of traffic are key factors when the external costs are determined, and they should be considered when the investment decision about where cold ironing should be placed is taken. • Local and global external costs of 46 Spanish ports are estimated to be 439.700.000€. • Population and traffic mix are key factors for external costs of berthed vessels. • Eco-efficiency indicators can support new policy measures in ports. • The potential of cold-ironing for the reduction of externalities are provided. [ABSTRACT FROM AUTHOR]

Indoor air quality plays an important role in children's wellbeing and performance. The primary attention of previous research is focused on the air quality in school environments, but time at school only represent 27% of the daily schedule. This paper analyses a broad spectrum of volatile organic compounds and aldehydes in different indoor microenvironments, according to typical children's daily routines, aiming at identifying potential indoor air pollutants and obtain valuable information about the contribution of each indoor microenvironment to the global daily exposure and the inhaled dose of air pollutants in children. High priority pollutants were monitored through passive techniques in 18 indoor microenvironments associated with 3–12-year-old schools, 12-18-year-old schools, and private homes located in Southern Spain. Air pollutant concentrations are compared with the recommended indoor air guideline values (IAGVs) reported by different standards and health organisations. The results show adequate indoor air quality values, within the ranges recommended by guidelines, and highlight the importance of monitoring benzene and formaldehyde to minimise adverse health effects, especially in homes, whose microenvironments are responsible for 88% of the inhaled dose of measured VOCs and aldehydes. Moreover, special attention should be taken of bedrooms, whose air pollutant concentrations are responsible for approximately 60% of the total inhaled dose of VOCs and aldehydes in children. Specific measures should be considered by public health authorities and other policymakers on how to develop and strengthen indoor air quality policy to protect and promote health in the housing stock. • Contribution of indoor spaces to the daily inhaled dose of air pollutants in children. • Passive IAQ monitoring in 18 indoor microenvironments: schools and homes. • Bedrooms are responsible for 60% of the daily inhaled dose of air pollutants. • Importance of monitoring benzene and formaldehyde to minimise adverse health effects. • Tremendous need to bring this research target into more attention. [ABSTRACT FROM AUTHOR]

The human effect on air quality in cities and the evolution of air pollution is obvious, due to economic activity, vehicle traffic, etc. The situation created indirectly by COVID-19, has caused many countries to impose during certain periods restriction of movement and stoppage of economic activities, which has allowed us to observe the instant effect that occurs on the air quality in cities. This article discusses what the observed effect has been, focusing on the early moments of the pandemic (January 2020 to March 2020), with an analysis of the situation from its origin in China to its arrival in Europe and more specifically the situation created in Spain. After the analysis of the situation, it can be seen the large reduction of pollutants in the air of different cities, and in particular in Spain, which came to reduce about 80%. All this leads us to the observation of how human activity can greatly influence air pollution. [ABSTRACT FROM AUTHOR]

The coronavirus (COVID-19) pandemic is infecting the human population, killing people, and destroying livelihoods. This research sought to explore the associations of daily average temperature (AT) and air quality (PM2.5) with the daily new cases of COVID-19 in the top four regions of Spain (Castilla y Leon, Castilla-La Mancha, Catalonia, and Madrid). To this end, the authors employ Pearson correlation, Spearman correlation, and robust panel regressions to quantify the overall co-movement between temperature, air quality, and daily cases of COVID-19 from 29 February to 17 July 2020. Overall empirical results show that temperature may not be a determinant to induce COVID-19 spread in Spain, while the rising temperature may reduce the virus transmission. However, the correlation and regression findings illustrate that air quality may speed up the transmission rate of COVID-19. Our findings are contrary to the earlier studies, which show a significant impact of temperature in raising the COVID-19 spread. The conclusions of this work can serve as an input to mitigate the rapid spread of COVID-19 in Spain and reform policies accordingly. [ABSTRACT FROM AUTHOR]

• Temperature and stagnation increased and precipitation less frequent, mainly in warmer months. • Strong variability of weather effects for different regions, seasons and pollutants. • Regional weather penalties up to 0.883 μg⋅m−3⋅yr−1 (95% CI: 0.834, 1.000) for PM 10. • 3220 deaths (CI: 626, 5813) due to weather penalties on PM 10 in 25 years. • 10% greater air quality-related health benefits if weather had remained constant. Climate change is a major public health concern. In addition to its direct impacts on temperature patterns and extreme weather events, climate change affects public health indirectly through its influence on air quality. Pollution trends are not only affected by emissions changes but also by weather changes. In this paper we analyze air quality trends in Spain of important air pollutants (C 6 H 6 , CO, NO 2 , NO x , O 3 , PM 10 , PM 2.5 , and SO 2) recorded during the last 25 years, from 1993 to 2017. We found substantial reductions in ambient concentration levels for all the pollutants studied except for O 3. To assess the influence of recent weather changes on air quality trends we applied generalized additive models (GAMs) using nonparametric smoothing; with and without adjusting for weather parameters including temperature, wind speed, humidity and precipitation frequency. The difference of annual slopes estimated by the models without and with adjusting for these meteorological variables represents the impact of weather changes on pollutant trends, i.e. the 'weather penalty'. The analyses were seasonally and geographically stratified to account for temporal and regional differences across Spain. The results were meta-analyzed to estimate weather penalties on ambient concentration trends at a national level as well as the impact on mortality for the most relevant pollutants. We found significant penalties for most pollutants, implying that air quality would have improved even more during our study period if weather conditions had remained constant. The largest weather influences were found for PM 10 , with seasonal penalties up to 22 μg⋅m−3 accumulated over the 25-year period in some regions. The national meta-analysis shows penalties of 0.060 μg⋅m−3 per year (95% Confidence Interval, CI: 0.004, 0.116) in cold months and 0.127 μg⋅m−3 per year (95% CI: 0.089, 0.164) in warm months. Penalties of this magnitude would correspond to 129 annual deaths (95% CI: 25, 233), i.e. approximately 3200 deaths over the 25-year period in Spain. According to our results, the health benefits of recent emission abatements for this pollutant in Spain would have been up to 10% greater if weather conditions had remained constant during the last 25 years. [ABSTRACT FROM AUTHOR]

It is well established that in Europe, high O3 concentrations are most pronounced in southern/Mediterranean countries due to the more favourable climatological conditions for its formation. However, the contribution of the different sources of precursors to O3 formation within each country relative to the imported (regional and hemispheric) O3 is poorly quantified. This lack of quantitative knowledge prevents local authorities from effectively designing plans that reduce the exceedances of the O3 target value set by the European air quality directive. O3 source attribution is a challenge because the concentration at each location and time results not only from local biogenic and anthropogenic precursors, but also from the transport of O3 and precursors from neighbouring regions, O3 regional and hemispheric transport and stratospheric O3 injections. The main goal of this study is to provide a first quantitative estimation of the contribution of the main anthropogenic activity sectors to peak O3 events in Spain relative to the contribution of imported (regional and hemispheric) O3. We also assess the potential of our source apportionment method to improve O3 modelling. Our study applies and thoroughly evaluates a countrywide O3 source apportionment method implemented in the CALIOPE air quality forecast system for Spain at high resolution (4 × 4 km 2) over a 10-day period characterized by typical summer conditions in the Iberian Peninsula (IP). The method tags both O3 and its gas precursor emissions from source sectors within one simulation, and each tagged species is subject to the typical physico-chemical processes (advection, vertical mixing, deposition, emission and chemistry) as the actual conditions remain unperturbed. We quantify the individual contributions of the largest NOx local sources to high O3 concentrations compared with the contribution of imported O3. We show, for the first time, that imported O3 is the largest input to the ground-level O3 concentration in the IP, accounting for 46 %–68 % of the daily mean O3 concentration during exceedances of the European target value. The hourly imported O3 increases during typical northwestern advections (70 %–90 %, 60–80 µ g m -3), and decreases during typical stagnant conditions (30 %–40 %, 30–60 µ g m -3) due to the local NO titration. During stagnant conditions, the local anthropogenic precursors control the O3 peaks in areas downwind of the main urban and industrial regions (up to 40 % in hourly peaks). We also show that ground-level O3 concentrations are strongly affected by vertical mixing of O3 -rich layers present in the free troposphere, which result from local/regional layering and accumulation, and continental/hemispheric transport. Indeed, vertical mixing largely explains the presence of imported O3 at ground level in the IP. Our results demonstrate the need for detailed quantification of the local and remote contributions to high O3 concentrations for local O3 management, and show O3 source apportionment to be an essential analysis prior to the design of O3 mitigation plans in any non-attainment area. Achieving the European O3 objectives in southern Europe requires not only ad hoc local actions but also decided national and European-wide strategies. [ABSTRACT FROM AUTHOR]

In Madrid, as in many European cities, air pollution is known about and made accountable through techno-scientific monitoring processes based on data, and the toxicity of the air is defined through epidemiological studies and made political through policy. In 2009, Madrid's City Council changed the location of its air quality monitoring stations without notice, reducing the average pollution of the city and therefore provoking a public scandal. This scandal challenged the monitoring process, as the data that used to be the evidence of pollution could not be relied on anymore. To identify the characteristics of some of the diverse forms of public's participation that emerged, I route theories of environmental sensing from STS and feminist theory through the notion of attuned sensing. Reading environmental sensing through processes of attunement expands the ways in which toxicity can be sensed outside of quantitative data. This mode of sensing recognizes how the different spontaneous attunements to and with air pollution and the scandal acknowledged Madrid's chemical infrastructure, rendering visible qualitative conditions of toxicity. This mode of sensing politicized the toxicity of the air not through management or policy making, nor only through established forms environmental activism, but through contagion and accumulation of the different forms of public participation. All together, they made air pollution a matter of public concern. They also redistributed the actors, practices and objects that make the toxicity not only knowable, but also accountable, and most importantly, they opened up spaces for citizen intervention. [ABSTRACT FROM AUTHOR]