Alfonso Aranda

Indoor air quality (IAQ) in archival environments represents a critical but underexplored interface between occupational health and cultural heritage conservation. This study provides a multidisciplinary assessment of IAQ in the Historical Archive of the Nobility (Toledo, Spain), integrating physical, chemical, and microbiological parameters across five functional spaces under real working conditions, and evaluating the performance of portable air purification strategies. Results show that IAQ is strongly influenced by specific occupational activities and limited ventilation. Document handling and unpacking act as dominant emission sources, leading to extreme particulate peaks that exceed guideline values by an order of magnitude. Chemical exposure remained generally low; however, recurrent exceedances of formaldehyde thresholds and elevated solvent-related VOCs in restoration areas revealed localized risks. Radon concentrations in semi-basement workspaces exceeded the recommendations of the World Health Organization (WHO), indicating a potential chronic exposure pathway. Microbiological analyses revealed consistently high fungal loads above recommended limits and the presence of both human-associated and outdoor-derived taxa. The detection of cellulolytic genes in airborne microbiota indicates a dual risk, affecting both occupational exposure and material biodeterioration. Air purification significantly reduced particulate matter and bioaerosols, with size-dependent efficiencies, but showed limited effectiveness for gaseous pollutants. Overall, IAQ in this heritage facility is governed by the interaction between building characteristics, conservation practices, and human activity, generating transient but intense exposure scenarios. These findings display the need for integrated mitigation strategies combining ventilation, source control, and targeted filtration to protect both worker health and archival collections.

This work presents a year-long integral study of air quality parameters in Ciudad Real, a small city in the center of Spain, and its influence on the nearby national park, Las Tablas de Daimiel. The study covers meteorological parameters and criteria pollutants such as O₃, NO, NO₂, SO₂, and PM₁₀. Additionally, for each month, a 1-week campaign was performed sampling air in sorbent tubes with 8-h time resolution to analyze anthropogenic volatile organic compounds and the effects of seasons, daytime, and working-weekend days. During these campaigns, 24-h PM_2.5 samples were also collected to measure the load of bacteria and fungi, as well as the trace concentrations of elements. The city and the national park NOx profiles showed that emissions from the town had a non-perceivable effect on the protected area. PM₁₀ levels in Ciudad Real were influenced by Saharan intrusions, as was the national park; however, Ciudad Real had a higher contribution from anthropogenic sources. Ozone levels were lower in the city during the cold season due to the higher concentration of NOx and have not changed significantly in the last decade. The VOCs with higher average concentrations were toluene, m,p-xylene, benzene, methylene chloride, and o-xylene, with traffic being the main source of these pollutants in the city. For benzene and carbon tetrachloride levels, weak carcinogenic risks were estimated. In PM_2.5, the most abundant metals were Na, Zn, Mg, Ca, Al, Fe, and K. The carcinogenic and non-carcinogenic risks estimated from the levels of the studied metals were negligible. Bacterial and fungal counts positively correlated with the concentration of PM_2.5. Microbial community composition showed seasonal variability, with the dominance of human pathogenic bacteria which correlated with certain pollutants such as SO₂. Bacillus and Cutibacterium were the most abundant genera.

Biomass is a significant renewable energy source and is expected to grow in importance in the transition away from fossil energy sources at a relatively low cost. Lignocellulosic biomass, which is the most abundant biomass, has critical importance as sustainable production of chemicals and fuels. Catalytic production methods of converting lignocellulosic biomass into furan derivatives have been improved significantly. One of these furan derivatives, 2,5-dimethylfuran (2,5-DMF), has attracted interest as a potential biofuel due to its physicochemical properties, in some aspects better than gasoline and ethanol, such as the low pollutant emissions in its combustion. However, before 2,5-DMF can be accepted as an alternative transport fuel, some outstanding problems, as its atmospheric fate, must be resolved.2,5-DMF can be degraded by the main tropospheric oxidants, resulting in furan derivatives such as furanones which are efficient precursors of SOA. To this end, the present study had the aim of analyzing the OH radical photooxidation and ozonolysis of 2,5-DMF, characterizing the conditions that lead to the formation and growth of new particles. Factors such as relative humidity (RH), NOx and SO2 level and pre-existing inorganic seed particles, which could influence in SOA formation, has been assessed. The study was carried out in two different chambers at (296±1) K and atmospheric pressure. Results for OH-photooxidation indicate that SOA yields decrease (from 6.2 to 0.4%) with the rise of 2,5-DMF concentration (from10 to 1000 ppb). In the absence of NOx and under high relative humidity (RH) conditions (60%), higher aerosol yields are favored. SOA formation is dependent on the initial seed surface for two kinds of inorganic seed particles ((NH4)2SO4 and CaCl2), being the effect slightly greater for CaCl2. The ozonolysis only generates particles in the presence of SO2 and the increase of relative humidity from 0 to 15% lowers the particle number and particle mass concentrations. The water-to-SO2 rate constant ratio of the Criegee intermediate was derived from the SOA yield in experiments with different relative humidity values.The obtained results provide detailed daytime chemistry about SOA formation from 2,5-DMF oxidation and improves our understanding of the chemical evolution of biomass burning plumes. Moreover, these results could be integrated into air quality simulation models, especially in developing countries which are suffering severe fine particulate matter pollution.

SO₂-Criegee intermediate reactions enhance the formation and growth of new particles in the atmosphere.