Indoor air quality is a significant aspect of public health, yet it remains less studied than outdoor air pollution. Understudied indoor pollutants include volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). This review focuses on these two groups of compounds known for their health effects, including respiratory issues, neurological disorders, and carcinogenicity. We systematically compiled and analyzed data from studies reporting measured concentrations of VOCs and PAHs in European indoor environments—homes, schools, and offices—published in the past two decades. Concentration levels vary substantially across studies, influenced by regional differences, climate, building type, ventilation systems, and indoor activities. Identified sources include tobacco smoke, cooking, heating (e.g., biomass burning), and off‐gassing from construction and furnishing materials. Our analysis reveals clear geographic patterns: lower concentrations of VOCs and PAHs are consistently reported in Northern and Western European countries, likely due to stricter air quality regulations, cleaner outdoor air, greater use of electric heating, and more advanced ventilation systems. Conversely, higher concentrations are more commonly observed in Southern and Eastern Europe, where biomass heating and poorer ventilation remain more prevalent. Seasonal variation also has a significant role, with higher indoor levels typically measured during colder months due to increased heating and reduced air exchange. This highlights the need for improved indoor air quality management practices and regulatory standards to minimize the health risks associated with VOCs and PAHs. This review of 46 scientific publications is aimed at informing future studies and guiding future field measurements and risk assessments in epidemiological studies.

Due to widespread use of silver nanoparticles (AgNPs), the assessment of their potential harm to microalgal photosynthesis is crucial, as microalgae, together with cyanobacteria, contribute to approximately 50% of global oxygen production. This study investigated photosynthetic pigments, photosynthetic rate, chlorophyll a fluorescence, and the expression of photosynthesis-related genes and proteins in green alga Chlorella vulgaris after 72 h exposure to citrate- and cetyltrimethylammonium bromide (CTAB)-stabilized AgNPs, as well as silver ions (AgNO₃), at concentrations allowing 75% cell survival (EC₂₅). All treatments impaired photosynthetic performance. The most pronounced decreases in chlorophyll fluorescence parameters and photosynthetic rate, alongside elevated energy dissipation, were observed after exposure to AgNP-CTAB and AgNO₃. AgNP-citrate had milder effects and induced compensatory responses, reflected in an increased performance index and upregulation of photosynthesis-related proteins. AgNP-CTAB induced the strongest downregulation of gene and protein expression, likely due to its higher EC₂₅ concentration and cationic surface promoting interaction with photosynthetic structures. Although AgNO₃ caused fewer molecular changes, it significantly disrupted photosynthetic function, suggesting a direct effect of Ag⁺ ions on photosynthesis-related proteins. Overall, the results highlight the role of AgNPs’ surface coatings and dosage in determining their phytotoxicity, with photosystem disruption and oxidative stress emerging as key mechanisms of action.

Plant responses to heat stress include complex transcriptional networks and protein regulations in which BTB/POZ-MATH (BPM) proteins participate as a part of ubiquitin-mediated protein degradation. Arabidopsis thaliana contains six BPM genes involved in responses to environmental changes, including heat. Seedlings overexpressing BPM1 (oeBPM1), seedlings with downregulation of BPM1, 4, 5, and 6 (amiR-bpm) and wild type were exposed to 37 °C for 6 h. Treatment caused stronger decline of photosynthesis in oeBPM1 than in amiR-bpm and wild type, although all seedlings recovered after 24 h at 24 °C. The activity of the antioxidant enzymes catalase, guaiacol peroxidase, and ascorbate peroxidase remained unchanged in oeBPM1, but increased in amiR-bpm and wild type. Heat stress induced HSP70 and HSP90 in all seedlings but expression remained notably higher in amiR-bpm after recovery. DREB2A and HSFA3 expression increased in all seedlings immediately after stress, with the strongest induction in amiR-bpm. In amiR-bpm and wild type, BPM2 expression was induced immediately after exposure, while BPM1, BPM3, BPM4, and BPM6 were upregulated in wild type after recovery. In oeBPM1 seedlings, BPM4 expression decreased and BPM6 expression increased immediately after treatment at 37 °C for 6 h. The results suggest that BPM proteins modulate heat stress response by influencing photosynthesis, activation of antioxidant enzymes, accumulation of HSPs, and expression of heat-responsive genes, thus contributing to the different physiological strategies observed in A. thaliana lines with altered expression of BPM genes.