Urban air pollutants are a major public health concern and include biological matters which composes about 25% of the atmospheric aerosol particles. Airborne microorganisms were traditionally characterized by culture-based methods recognizing just 1.5–15.3% of the total bacterial diversity that was evaluable by genome signature in the air environment (aerobiome). Despite the large number of exposed people, urban aerobiomes are still weakly described even if recently advanced literature has been published. This paper aims to systematically review the state of knowledge on the urban aerobiome and human health effects. A total of 24 papers that used next generation sequencing (NGS) techniques for characterization and comprised a seasonal analysis have been included. A core of Proteobacteria, Actinobacteria, Firmicutes, and Bacteroides and various factors that influenced the community structure were detected. Heterogenic methods and results were reported, for both sampling and aerobiome diversity analysis, highlighting the necessity of in-depth and homogenized assessment thus reducing the risk of bias. The aerobiome can include threats for human health, such as pathogens and resistome spreading; however, its diversity seems to be protective for human health and reduced by high levels of air pollution. Evidence of the urban aerobiome effects on human health need to be filled up quickly for urban public health purposes.

Purpose: The anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) is a treatment biologically optimizable. The analysis of the microbial balance within the digester allows not only to describe and improve the efficiency of the system but also to foresee potential variations after biochemical interventions. This work aims to highlight methanogenic population variations in two similar parallel digesters to identify bio-indicators for digestion performance after the inclusion of an additive. Methods: The analysed industrial case study involved the two parallel, pilot-scale, bio-digesters of ACEA Pinerolese Industriale. They had analogous design and fed by the same OFMSW except for an additive inclusion. The analyses by qRT-PCR, on both bio-digesters, have been performed to determine an impact of the additive on the growth and metabolic activity of total methanogens, Methanosarcina spp., Methanocorpuscolum spp., and Methanospirillus spp. Results: Collected data showed that the addition of biopolymers extracted from compost produced both total methanogens and Methanosarcina decrease (7.67 vs. 7.48 and 6.05 vs. 5.69 Log gene copies/mL sludge respectively, T-test p < 0.01) affecting slightly the methane yield (-8%). Methanosarcina was the highest expressed methanogen; however, the results suggested the involvement of a highly complex and heterogeneous methanogen community. Conclusions: Total methanogens and active Methanosarcina modulations are able to highlight major bio-methane production even if their shift is slight. Globally only 3–4% of the present and 12–13% of the active methanogens were described. However, biological approach can supply a proxy of production performance of the digester also concerning the feeding peculiarities. Graphical

Environmentally sustainable methods of waste disposal are a strategic priority. For organic waste management and innovative biological treatments present advantageous opportunities, although organic waste treatment also includes environmental drawbacks, such as bioaerosol production. This study aims to evaluate bioaerosol spread during an innovative experimental treatment. The process consists of two anaerobic steps: acidogenesis, which includes polyhydroxyalkanoate accumulation, followed by methanogenesis. Bioaerosol, PM10, and endotoxin concentrations were measured at three sampling points during different campaigns to evaluate: (1) the background levels, (2) the contamination produced in the pre-treatment stage, and (3) the residual contamination of the outgoing digested sludge. Environmental PM10 seemed to be generally quite contained, while the endotoxin determination was close to 90 EU/m³. Significant microbial concentrations were detected during the loading of the organic fraction of municipal solid waste (fungi > 1300 CFU/m³, Bacillus genus (≈10³ CFU/m³), higher Clostridium spp. and opportunistic human pathogens such as Pseudomonas aeruginosa and Klebsiella pneumoniae), suggesting a significant contamination level. Such results are useful for hazard identification in the risk assessment of innovative processes, as they reveal contaminants potentially harmful to both workers’ health and the environment.

Background: Urban air pollution is recognized as a critical problem for public health and is classified as a carcinogen for humans. A great number of studies have focused on the monitoring of urban air mutagenicity. One of the best-known and applied methods for assessing mutagenicity is the Ames test, a bacterial reverse mutation test. The classic protocol for assessing air mutagenicity involves the concentration of particulate matter (PM) on filters and subsequent extraction using organic solvents. This work aimed to develop a method for the evaluation of air mutagenicity directly impacted by air on microbial plates already containing an Ames’ microbial sensor. Methods: A specific six-month sampling campaign was carried out in Turin in a period with high air pollution. Samples were tested for mutagenicity on Salmonella typhimurium strains TA98, TA100, and YG1024 with the traditional method and with the new direct method. Results: The new protocol is able to evaluate the mutagenicity of the sampled air and obtain repeatable results. The final sensitivity is similar to the traditional method (≈10 net revertants/m³); however, the mutagenic response is due to the complete air pollution mixture, including volatile and semivolatile pollutants avoiding the concentration of filters and the following laborious extraction procedures. Conclusions. Despite some critical issues in contamination control, the method is easier, faster, and less expensive than traditional methods.