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Air samples were collected using polyurethane foam passive samplers from 26 air-monitoring stations located in the Pearl River Delta, China and two in Shaoguan City in Guangdong Province in 2015 to investigate the occurrence and distribution of priority polycyclic aromatic hydrocarbons (PAHs). Sixteen PAHs were identified and 15 of them (except for naphthalene) were quantified at a total concentration (∑15PAHs) that varied from 3.56 ng/m³ to 37.2 ng/m³ (average value 19.8 ± 9.69 ng/m³). The results indicated that PAHs with 3–4 benzene rings accounted for approximately 80% of all PAH compounds, among which phenanthrene and fluoranthene were the predominant components. Diagnostic parameters suggested that the possible sources of PAHs in the Delta region were mixed of petrogenic and pyrogenic sources from fuel/biomass/coal combustion. Based on the measured PAHs concentrations, the Carcinogenic Potency Risk (BaPeq) and Inhalation Cancer Risk (ICR) were assessed, and indicated that two air samples from Guangzhou and one from Foshan exceeded the BaPeq limit (1 ng/m³), whereas all samples from the 28 sampling locations exceeded the health-based guideline concentration for ICR. The results of this research suggest that a potential human health risk exists from PAHs in the study area via the respiration and inhalation pathway.

In this paper, we present the development and evaluation of a new designed light emitting diodes (LEDs) based optical fiber coupling long-path differential optical absorption spectroscopy (LP-DOAS) instrument for atmospheric SO2, O3 and NO2 detections. The strongest absorption structures of these trace gases scattered along a wide spectral range which could not be covered by a single LED. Therefore, a new fiber optic coupling telescope was developed to combine multiple LEDs with different spectral emission ranges as broad band light source for atmospheric trace gas detections. Details of the experimental setup, measurement and retrieval procedure, error analysis and the atmospheric measurement results are presented. The new LED LP-DOAS measurement results show perfect agreements with a co-located Xenon Lamp coaxial LP-DOAS observations with Pearson correlation coefficient (R) larger than 0.9 for SO2, O3 and NO2 observations. The estimated background light contributes about 3–10% of the total measurement error during daytime, which is improved by a factor of 3–10 compared to previous study. Diurnal analysis of the measurement results shows a similar diurnal pattern of NO2 and SO2 which implies that they are probably originated from similar emission sources. Satellite observation and backward trajectories analysis indicated local and regional transports of pollutants have significant impacts on the air quality in Hefei. Analysis of the wind speed and wind direction show that elevated NO2 and SO2 levels were related to the emissions of the power plant and factories located at the east and northeast of the measurement site.

The first continuous measurements of the hourly surface ozone (O3), nitric oxide (NO) and nitrogen dioxide (NO2) concentrations at 7 rural and 15 urban sites in Marmara Region of Turkey during the period from March 2013 to April 2016. The results indicate that surface O3 is an extensive problem throughout the Marmara Region. O3 levels have similar seasonal pattern in rural and urban sites by following the order of summer, spring, fall, and winter. The seasonal results showed an opposite behaviour among O3 and NOx (NO + NO2) in both rural and urban sites, marked by maximums (minimum NOx) of O3 in summer and minimums (maximum NOx) in fall and winter. The summer concentrations vary between 91.5 and 123.6 μg/m³ and 74.6–112.4 μg/m³ at rural and urban sites respectively. Furthermore, O3 peak concentration time in rural areas in O3 seasons (April–September) occurred at around 17:00–18:00 LST while in urban areas at around 15:00–16:00 LST, respectively. Air quality standards for O3 concentrations in Sile and Yalova rural sites were significantly exceeded during O3 season. This exceedance made a linkage between back trajectories and air masses with respect to the O3 levels. 72-hr back trajectories at an altitude of 500 m agl were computed by HYSPLIT model to assess the type of air masses which reach the area. AOT40 (accumulated exposure over a threshold of 40 ppb) index was performed for both vegetation and forestry standards and EU Directive were significantly exceeded at all rural stations.

In order to investigate the fungal spore tracers in fine particles (PM2.5), including mannitol and arabitol at an urban site in a Chinese megacity, PM2.5 samples were collected in Shanghai from May 22 to June 19, 2015. The analysis results showed that the average concentration of airborne mannitol and arabitol were 5.79 and 3.86 ng m⁻³, respectively. Mannitol and arabitol exhibited obvious positive correlations at ambient temperature, resulting from improving fungal spores formation rate and emission strength along with higher temperature. The concentrations of fungal spore tracers with Relative humidity-RH 70%–85% were higher than that RH>85% and RH<70%, which reflected that fungal spores released would be restrained under higher humidity. The concentrations between arabitol and mannitol showed negative correlation with wind speed, probably due to the dilution effect of wind. Three ions components (sulfate, nitrate and ammonium) exhibited poor correlations with fungal spore tracer. Based on the results, mannitol had a similar formation pathway with arabitol, resulting in strong correlation between them during our campaign. The number concentration of fungal spores was 10513.16 spores m⁻³, while fungal spores contributed about 1.91% for organic carbon OC using conversion factors.

Concentrations of naturally occurring radioactive gas can be high in caves and mines, and it has been shown that releases of radon (²²²Rn) to the outside environment through ventilation can be large. We assess airflow and associated activity concentrations of thoron (²²⁰Rn) and progeny (TnP) being released through a drainage pipe from an old mine-complex situated in thorium-rich bedrock. Outdoor thoron concentrations in this area have been thought to arise solely from thoron exhalation from the ground. However, thoron concentrations in outwards airflow in the drainage pipe range from 25 000 Bq m⁻³ to 42 000 Bq m⁻³ and discharges can in summer be as high as 1 GBq d⁻¹. The drainage pipe can be considered as a point source adding to exhalation from the soil and deposits of waste rock in the area. Statistical analyses including meteorological data suggest that outdoor temperature is the main factor affecting this airflow and that ventilation of these mines resembles chimney ventilation, but other weather variables may also contribute. During summer with warm outdoor temperatures, colder and denser air within the mines escapes through the drainage pipe, which is located on low ground. In winter, when outdoor temperatures are lower than those within the mines, the direction of airflow in the drainage pipe is inwards into the mines, while air escapes upwards and outwards through larger mine openings located on higher ground. Statistical outliers indicate Venturi effects by strong winds and syringe effects by internal water level.

Open burning emissions strongly influence smoke haze problems in Southeast Asia (SEA). The main objective of this study is to investigate the percent contribution of emissions from local and transboundary on air pollutant concentrations, particularly PM10 (particulate matter with a diameter of less than 10 μm), using the potential source contribution function (PSCF). A three-day backward trajectory (BWT) analysis of air mass movements at the Chiang Mai Air Quality Monitoring (CM-AQM) station in the dry season (February–April) during the years 2010–2015 was run and clustered. It was found that the air masses mainly originated from the southwest of the CM-AQM station. The correlation between the PM10 concentration and the number of active fires during the three-day BWT showed the highest correlation in April (R² = 0.64). The PSCF values showed that most of the high-potential sources (0.9–1.0) and emissions were transboundary from Myanmar (73.2%) and within Thailand (26.8%). The major open burning source during March and April was found in the agricultural areas of Myanmar, and the second-greatest source was found in the forested areas of Myanmar. However, the agricultural areas of Thailand contributed to the PM10 concentration in northern Thailand (NT) in February. Thus, this result shows that potential point sources of pollutants such as biomass burning, including those transported across national boundaries, can be investigated and determined their locations in the haze episodes of NT.

High-resolution Advanced Research Weather Research and Forecast model is used to understand the role of atmospheric stability on the short-term transport of a continuous release passive scalar plume in three different convective boundary layer regimes: highly convective, combined shear- and buoyancy and shear dominated. Friction velocity to convective velocity ratio and atmospheric stability parameter are used to classify the boundary layer regimes. The effect of release height on the plume transport is addressed by releasing the plumes at surface, near-surface and elevated heights. Total 144 simulations are performed by releasing the plume in the morning and afternoon times of January and August months and at three release heights. Results show that horizontal transport of the plume scales with the initial wind conditions for surface and near-surface releases, and the vertical transport scales with atmospheric stability parameter. Mean plume height and vertical dispersion parameter obtained by convective scaling laws reached their asymptotic values after getting well-mixed in the boundary layer. The dimensionless downwind distance for the mean plume height to reach its asymptote is found to follow a power-law with respect to the atmospheric stability paramter. The coefficient and exponent of the power-law observed are found to be functions of the plume release height normalized by the boundary layer depth.

The contamination of indoor air by molds constitutes an economic and health concern in many countries. Among fungi found in bioaerosols, some species like Aspergillus versicolor are known to be recurrent and toxinogenic. Several methods can be used to quantify this mold in bioaerosols, however, the lack of a standardized and rapid method to assess the human exposure to A. versicolor in indoor environments is a problem. In this study, the flow cytometry and qPCR techniques were used to quantitate A. versicolor in bioaerosols collected in 38 mold-damaged homes. A statistical analysis showed a correlation between qPCR and cultural approaches (r = 0.704, p < 0.001), and no significant difference (p = 0.153) between quantification with cultural and molecular approaches. Therefore a qPCR calibrated with flow cytometry could be routinely used to monitor A. versicolor in mold-damaged homes.