Nontuberculous Mycobacteria Prevalence in Aerosol and Spiders’ Webs in Karst Caves: Low Risk for Speleotherapy

A total of 152 aerosol and spider web samples were collected: 96 spider’s webs in karst areas in 4 European countries (Czech Republic, France, Italy, and Slovakia), specifically from the surface environment (n = 44), photic zones of caves (n = 26), and inside (aphotic zones) of caves (n = 26), 56 Particulate Matter (PM) samples from the Sloupsko-Sosuvsky Cave System (speleotherapy facility; n = 21) and from aerosol collected from the nearby city of Brno (n = 35) in the Czech Republic. Nontuberculous mycobacteria (NTM) were isolated from 13 (13.5%) spider’s webs: 5 isolates of saprophytic NTM (Mycobacterium gordonae, M. kumamotonense, M. terrae, and M. terrae complex) and 6 isolates of potentially pathogenic NTM (M. avium ssp. hominissuis, M. fortuitum, M. intracellulare, M. peregrinum and M. triplex). NTM were not isolated from PM collected from cave with the speleotherapy facility although mycobacterial DNA was detected in 8 (14.3%) samples. Temperature (8.2 °C, range 8.0–8.4 °C) and relative humidity (94.7%, range 93.6–96.6%) of air in this cave were relatively constant. The average PM2.5 and PM10 mass concentration was 5.49 µg m−3 and 11.1 µg m−3. Analysed anions (i.e., F−, Cl−, NO2−, SO42−, PO43− and NO3−) originating largely from the burning of wood and coal for residential heating in nearby villages in the surrounding area. The air in the caves with speleotherapy facilities should be monitored with respect to NTM, PM and anions to ensure a safe environment.

Estimation of the PM2.5 and PM10 Mass Concentration over Land from FY-4A Aerosol Optical Depth Data

The purpose of this study is to estimate the particulate matter (PM2.5 and PM10) in China using the improved geographically and temporally weighted regression (IGTWR) model and Fengyun (FY-4A) aerosol optical depth (AOD) data. Based on the IGTWR model, the boundary layer height (BLH), relative humidity (RH), AOD, time, space, and normalized difference vegetation index (NDVI) data are employed to estimate the PM2.5 and PM10. The main processes of this study are as follows: firstly, the feasibility of the AOD data from FY-4A in estimating PM2.5 and PM10 mass concentrations were analysed and confirmed by randomly selecting 5–6 and 9–10 June 2020 as an example. Secondly, hourly concentrations of PM2.5 and PM10 are estimated between 00:00 and 09:00 (UTC) each day. Specifically, the model estimates that the correlation coefficient R2 of PM2.5 is 0.909 and the root mean squared error (RMSE) is 5.802 μg/m3, while the estimated R2 of PM10 is 0.915, and the RMSE is 12.939 μg/m3. Our high temporal resolution results reveal the spatial and temporal characteristics of hourly PM2.5 and PM10 concentrations on the day. The results indicate that the use of data from the FY-4A satellite and an improved time–geographically weighted regression model for estimating PM2.5 and PM10 is feasible, and replacing land use classification data with NDVI facilitates model improvement.

Water-Soluble Anions in PM10 Samples Collected in the Metropolitan Area of Costa Rica: Temporal and Spatial Variations

The concentrations of water-soluble anions present in PM10 collected from ambient air in four sites of Costa Rica’s greater metropolitan area (GAM) were analyzed. Samples were collected over a 24-h period for three days during the 2011–2018 period, using high-volume air samplers with mass flow controller. The PM10 samples were collected using quartz fiber filters, which were analyzed using ion chromatography to identify organic and inorganic ions. The annual averages for PM10, F−, Cl−, and SO42− showed significant differences between the sampling sites, with Uruca (UR) consistently registering annual averages above the maximum concentration established by Costa Rica’s air quality regulations (30 µgm−3). The ions analyzed contributed 33%, 34%, 35%, and 37% of the PM10 mass for sampling sites UR, HA, AL, and CA, respectively. Using Spearman correlations and principal component analysis (PCA), the following contributions were identified: biomass burning, secondary particle formation processes from mobile and stationary emissions, and biogenic emissions. For each variable, seasonal patterns and trends were analyzed using time series with additive decomposition.

Morphology, Mineralogy, and Chemistry of Atmospheric Aerosols Nearby an Active Mining Area: Aljustrel Mine (SW Portugal)

Mining activities increase contaminant levels in the environment, so it is crucial to study the particulate matter in these areas to understand the impacts on nearby urban areas and populations. This work was conducted close to the active mine of Aljustrel (Portugal), where black dust deposition is evident. PM10 samples were collected in two periods: 10–17 July and 1–10 November of 2018. Two different techniques were used: SEM-EDX for the individual characterization of the aerosols and ICP-MS to quantify the elemental concentration of 11 elements (Ca, Na, Fe, Mn, As, Cd, Cu, Sb, Pb, and Zn). In this region, the observed PM10 mass concentration was 20 to 47 µg m −3 (July) and 4 to 23 µg m−3 (November), which is lower than the limit of 50 μg m−3 established in the European Directive. The individual characterization of 2006 particles by SEM-EDX shows oxides (17%) and sulfides (10%), while Na, Si, Fe, S, Al, and Cu are the elements with the most representativeness in all the analyzed particles. The ICP-MS results indicate that the daily elemental concentration in the samples collected in July is higher than November, and only As exceeds the limit established for European legislation.

PM10-Bound Sugars: Chemical Composition, Sources and Seasonal Variations

The presence of anhydrosugars and sugar alcohols in airborne articulate matter <10 µm (PM10) samples collected between December 2018 and June 2019 was studied for two urban environments in Coimbra. Anhydrosugars were used to estimate the biomass burning contribution, and sugar alcohols were investigated regarding biological sources. Anhydrosugars contributed more than sugar alcohols to the total sugars, mainly levoglucosan. Higher levoglucosan concentrations were linked with the use of biomass-fueled heating appliances, mainly during cold periods. A significant contribution from biomass burning smoke was registered, accounting for 20% to 23% of the PM10 mass in the colder period. Xylitol presented higher concentrations in the colder period and was well correlated with levoglucosan, indicating a common origin. Mannitol and arabitol were well correlated with each other but did not present any kind of correlation with anhydrosugars or xylitol, suggesting a natural source. A quantitative estimation based on the concentration of ambient tracers (mannitol) was evaluated, and the results reveal that, for the two sites, the fungal spore relative contribution to PM10 (roadside site: 2.7% to 2.8%; urban background: 1.9% to 2.7%) and OC mass (roadside site: 6.2% to 8.1%; urban background: 3.9% to 7.5%) was significant and always higher in the warmer period.

Pilot study on assessment of trace metals in PM10 at road sites in Bac Giang province, Vietnam

In this study, characterization of PM10 mass and its trace metals concentration at road sites in Bac Giang province located in the North of Vietnam during two different seasons has been performed. PM10 samples at 11 road sites using the high volume SIBATA HV-500R (Japan) at the flow rate of 400 L/min were collected during 10 hours (from 7:00 to 17:00) at flat low-lying plain, midland, mountain and highland areas. Data on PM10 mass and metals were used to estimate the pollution level of PM10 and trace elements bounded with PM10. The results showed that 10-hour mean PM10 concentrations at road sites in Bac Giang ranged from 103.4 µg/m3 to 577.9 µg/m3 with the average value of 292.6 µg/m3. Generally, the level of trace metals appeared to be higher in autumn than that in summer period. Additionally, concentrations of trace metals were higher at the sites with high traffic density than those with low traffic density. While the concentrations of Cd, Mn and Cr exceeded the guideline values of WHO, arsenic concentration was larger than the concentration limit of EU Directives. The degree of contamination values suggested that level of metal was high contamination at flat low-lying plain, while those values were from low to considerable contamination at the mountain and highland areas. The pollution load index values at most of sampling sites were larger than 1, which indicated the existence of dust pollution at road sides in Bac Giang province. Keywords: PM10; trace metals; degree of contamination; pollution load index, roadsides.

Simultaneous Roadside and Urban Background Measurements of Submicron Aerosol Number Concentration and Size Distribution (in the Range 20–800 nm), along with Chemical Composition in Strasbourg, France

The adverse health impact of particles and ultrafine particles (UFP) is proven, highlighting the need of measuring the particle number concentration (PNC) dominated by UFP. So far, PNC had never been measured in the Strasbourg urban area (France). The present study on particle size distribution and PNC measurements by an UFP-3031 analyzer was conducted during winter 2019 on a background and a roadside multi-instrumented sites (Black Carbon, chemical speciation, particulate matter 10 μm or less in diameter—PM10 mass). This paper shows significantly higher particle number concentrations of particles below 100 nm at the traffic site compared to the background site. The presence of a road axis thus mainly influences UFP, contrary to larger particles whose levels are more homogeneous over the agglomeration. During the measurement period, the nature of the particles (particle size contribution and chemical composition) was different between periods of high PM10 mass concentrations and periods of high PNC. High PM10 mass concentrations were associated with a high contribution of particles larger than 100 nm but they did not show specific chemical signature. On the other hand, during the periods with high PNC, the chemical composition was modified with an increase of the primary carbonaceous fraction compared to the periods with low PNC, but there was then no clear change in size distribution. Overall, this study illustrates that PM10 mass concentrations were barely representative of UFP and PNC variations, confirming that the monitoring of the latter metrics is necessary to better evaluate the particles toxicity, knowing that this toxicity also depends on the particle’s chemical composition.