A comprehensive modelling approach has been developed to predict population exposure to the ambient air PM₂.₅ concentrations in different microenvironments in London. The modelling approach integrates air pollution dispersion and exposure assessment, including treatment of the locations and time activity of the population in three microenvironments, namely, residential, work and transport, based on national demographic information. The approach also includes differences between urban centre and suburban areas of London by taking account of the population movements and the infiltration of PM₂.₅ from outdoor to indoor. The approach is tested comprehensively by modelling ambient air concentrations of PM₂.₅ at street scale for the year 2008, including both regional and urban contributions. Model analysis of the exposure in the three microenvironments shows that most of the total exposure, 85%, occurred at home and work microenvironments and 15% in the transport microenvironment. However, the annual population weighted mean (PWM) concentrations of PM₂.₅ for London in transport microenvironments were almost twice as high (corresponding to 13–20 μg/m³) as those for home and work environments (7–12 μg/m³). Analysis has shown that the PWM PM₂.₅ concentrations in central London were almost 20% higher than in the surrounding suburban areas. Moreover, the population exposure in the central London per unit area was almost three times higher than that in suburban regions. The exposure resulting from all activities, including outdoor to indoor infiltration, was about 20% higher, when compared with the corresponding value obtained assuming inside home exposure for all times. The exposure assessment methodology used in this study predicted approximately over one quarter (−28%) lower population exposure, compared with using simply outdoor concentrations at residential locations. An important implication of this study is that for estimating population exposure, one needs to consider the population movements, and the infiltration of pollution from outdoors to indoors.

Pollutant gases and particulate matters (PM) from livestock facilities can affect the health of animals and farm workers and lead to great social environmental risks. This paper presents a comprehensive study on the characteristics of ammonia (NH₃), nitrogen oxides (NOₓ), sulfur dioxide (SO₂) and PM (including PM₂.₅ and PM₁₀) in a 100,000-bird manure-belt layer house in suburb Beijing for three typical seasons of summer, autumn and winter. Indoor air was sampled at an exhaust fan of the mechanically ventilated commercial house. The monitored indoor concentrations of NH₃, NOₓ, SO₂, PM₂.₅ and PM₁₀ were 3.7–5.0 mg m⁻³, 17–58 μg m⁻³, 0–11 μg m⁻³, 100–149 μg m⁻³ and 354–828 μg m⁻³, respectively. The indoor NH₃ concentrations were largely influenced by the manure removal frequency. The NOₓ and SO₂ were mainly sourced from the ambient air, and the NOₓ was also partly sourced from manure decomposition in summer. The indoor PM₂.₅ and PM₁₀ were largely sourced from the ambient air and the indoor manure, respectively. The abundant indoor NH₃ caused significantly higher NH₄⁺ concentration in the indoor PM₁₀ (7.98 ± 9.04 μg m⁻³) than that in the ambient PM₁₀ (3.48 ± 3.52 μg m⁻³). Secondary inorganic ions (SO₄²⁻, NO₃⁻ and NH₄⁺) totally contributed 5.7% and 14.6% to the indoor and ambient PM₂.₅, respectively; they contributed 2.8% and 8.9% to the indoor and ambient PM₁₀, respectively. Organic carbon was the main component of the PM and accounted for 26.6% and 41.5% of the indoor PM₂.₅ and PM₁₀, respectively. Heavy metal elements (Zn, Cu and Cr) were likely transported from feed to manure and finally accumulated in the PM. Given the high emission potential, the air pollutants from animal production suggested potential risks for human health.

Pharmaceutically active compounds (PhACs) are widely found in the environment due to vast human consumption. Lots of work has been devoted to investigating the occurrence and seasonal variations globally. To fully understand characteristics and cross-year variation of PhACs in Beijing, 35 PhACs were analyzed in 46 sites across Beijing from both urban and suburban areas. Concentrations of target PhACs were ranged from levels of ng L⁻¹ to μg L⁻¹. Metoprolol (524 ng L⁻¹), caffeine (390 ng L⁻¹) and acetaminophen (156 ng L⁻¹) were the three most abundant non-antibiotics with the highest median concentration, and nalidixic acid (135 ng L⁻¹), erythromycin (64 ng L⁻¹) and sulfamethoxazole (77 ng L⁻¹) were the most abundant antibiotics. Urban and suburban areas are distinguished by PhAC composition in cluster analysis due to different wastewater collection rate. The ratio of easily removable compound group and hardly removable group was then proposed to reflect the wastewater collection rate. The compositional comparison of PhACs in WWTPs’ effluents and their receiving rivers further illustrates the impact of WWTPs in urban area. Higher proportion of antibiotics (>30%) in suburban area reflected the impact of presence of livestock farms, which should be concerned. Further statistical analyses show an improving trend of wastewater collection rate, and excluding metoprolol, an anti-hypertension medicine, the total concentration of 13 target PhACs was reduced by 72% during 2013–2017.

Concentrations of unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) were examined in road dusts from some representative areas with different land-use types in northern Vietnam, providing updated information about the occurrence, sources, and risks of these pollutants in Southeast Asian region. The Vietnamese road dusts were contaminated with low to moderate levels of PAHs and Me-PAHs as compared to those from other countries in the world. Concentrations of PAHs and Me-PAHs (Σ34PAHs) decreased in the order: urban (median 1800; range 1100–5500) ≈ industrial (1300; 550–10,000) > suburban (450; 310–1300) ≈ rural road dust (330; 210–2300 ng g⁻¹), suggesting an urban-rural declining trend and effects of urbanization-industrialization processes in PAH emission extent in Vietnam. The profiles and diagnostic ratios of PAHs and Me-PAHs in our samples revealed that these compounds were mainly derived from pyrogenic sources rather than petrogenic sources. Traffic emissions (e.g., vehicle exhaust, tire debris, and possible leaks of fuels, oils, and lubricants) were estimated as principal sources of PAHs and Me-PAHs, especially in the urban and industrial areas. Other pyrogenic sources (e.g., coal, wood, and biomass combustion) were also existed in the industrial, suburban, and rural areas, reflecting PAH origins from thermal industrial processes, open burning of agricultural by-products, and domestic energy utilization. Persons working outdoors and children in the urban and industrial areas were estimated to receive higher intake doses of PAHs and Me-PAHs, which were one to two orders of magnitude higher than those estimated for other groups. Except for potential cancer risk estimated for the occupational groups in the industrial area under the worst exposure scenarios, the non-cancer and cancer risk levels were generally acceptable; however, more comprehensive risk assessment considering other exposure pathways (e.g., inhalation and diet) is needed.

The fast economic development of southwest China has resulted in significant increases in the concentrations of reactive nitrogen (Nr) in the atmosphere. In this study, an urban (Chengdu, CD), suburban (Shifang, SF) and agriculture (Yanting, YT) – dominated location in the Sichuan Province, southwest China, were selected to investigate the atmospheric composition of Nr, their concentrations and deposition rates. We measured Nr concentrations in precipitation (NH₄⁺, NO₃⁻ and organic N (DON)), the gas phase (NH₃ and NO₂), and the aerosol particles (PM₂.₅), and calculated their fluxes over a two year period (2014–2016). Total annual N deposition rates were 49.2, 44.7 and 19.8 kg N ha⁻¹ yr⁻¹ at CD, SF and YT, respectively. Ammonia concentrations were larger at the urban and suburban sites than the agricultural site (12.2, 14.9, and 4.9 μg N m⁻³ at CD, SF and YT, respectively). This is consistent with the multitude of larger sources of NH₃, including city garbage, livestock and traffic, in the urban and suburban areas. Monthly NO₂ concentrations were lower in warmer compared to the colder months, but seasonal differences were insignificant. Daily PM₂.₅ concentrations ranged from 7.7 to 236.0, 5.0–210.4 and 4.2–128.4 μg m⁻³ at CD, SF and YT, respectively, and showed significant correlations with fine particulate NH₄⁺ and NO₃⁻ concentrations. Ratios of reduced to oxidized N were in the range of 1.6–2.7. This implies that the control of reduced Nr especially in urban environments is needed to improve local air quality.

Investigating the nature of PM₁₀ is crucial to differentiate sources and their relative contributions. In this study we compared the levels, and the chemical and mineralogical properties of PM₁₀ particles sampled in different seasons at monitoring stations representative of urban background, urban traffic and suburban traffic areas of Naples city. The aims were to relate the PM₁₀ load and characteristics to the location of the monitoring stations, to investigate the different sources contributing to PM₁₀ and to highlight PM₁₀ seasonal variability. Bulk analyses of chemical species in the PM₁₀ fraction included total carbon and nitrogen, δ¹³C and other 20 elements. Both natural and anthropogenic sources were found to contribute to the exceedances of the EU PM₁₀ limit values. The natural contribution was mainly related to marine aerosols and soil dust, as highlighted by X-ray diffractometry and SEM-EDS microscopy. The percentage of total carbon suggested a higher contribution of biogenic components to PM₁₀ in spring. However, this result was not supported by the δ¹³C values which were seasonally homogeneous and not sufficient to extract single emission sources. No significant differences, in terms of PM₁₀ load and chemistry, were observed between monitoring stations with different locations, suggesting a homogeneous distribution of PM₁₀ on the studied area in all seasons. The anthropogenic contribution to PM₁₀ seemed to dominate in all sites and seasons with vehicular traffic acting as a main source mostly by generation of non-exhaust emissions Our findings reinforce the need to focus more on the analysis of PM₁₀ in terms of quality than of load, to reconsider the criteria for the classification and the spatial distribution of the monitoring stations within urban and suburban areas, with a special attention to the background location, and to emphasize all the policies promoting sustainable mobility and reduction of both exhaust and not-exhaust traffic-related emissions.

The concept of thresholds shows important implications for environmental and resource management. Here we derived potential landscape thresholds which indicated abrupt changes in water quality or the dividing points between exceeding and failing to meet national surface water quality standards for a rapidly urbanizing city on the Eastern Coast in China. The analysis of landscape thresholds was based on regression models linking each of the seven water quality variables to each of the six landscape metrics for this coupled land-water system. We found substantial and accelerating urban sprawl at the suburban areas between 2000 and 2008, and detected significant nonlinear relations between water quality and landscape pattern. This research demonstrated that a simple modeling technique could provide insights on environmental thresholds to support more-informed decision making in land use, water environmental and resilience management.

Microplastics (MPs) and microfibers (MFs) in stormwater have been poorly investigated. Data on their intra and inter rain events variability over time are still sparse. For the first time, the variability of microlitter concentrations in stormwater has been studied. MF and MP concentrations were investigated in stormwater runoff at the outlet of the suburban catchment at Sucy-en-Brie (a suburb of Paris, France), during four rain events. Median MF and MP concentrations were 1.9 and 29 items/L, with an interquartile range of 2.3 and 36 items/L, respectively (N = 18). A different pattern was observed between MFs and MPs. While no relationship or trends were observed for MFs, the highest MP concentrations were observed before the flow rate peak of the rain events. This could indicate a difference in the behaviour between MFs and MPs. We estimated the median MP mass concentration to be 56 μg/L with an interquartile range of 194 μg/L, whereas the mass concentration of macroplastics was estimated to be 31 μg/L with an interquartile range of 22 μg/L at the same sampling site, in a previous study. For this sampling site, MPs and macroplastics have the same order of magnitude. This study may have strong implications on microplastic assessment in urban waters.

Heavy metals in atmospheric dust can directly pollute the soil, water and sediment, causing serious harm to human health. In this study, the temporal and spatial distribution characteristics of heavy metals in atmospheric deposition in western Taihu Lake were studied. We established 10 sampling sites to collect atmospheric deposition for two years in different seasons. The atmospheric deposition flux follows the order urban area (95.6 g m⁻²·a⁻¹) > suburban area (80.2 g m⁻²·a⁻¹) > forestland (56.8 g m⁻²·a⁻¹). The concentrations of heavy metals in atmospheric deposition show trends of high values in the winter and low values in the summer and are significantly negatively correlated with distance from the city. The pollution level of Igₑₒ-Cd is 6, which is very high, and that of E-Cd is 219, which means high risk. Heavy metals in atmospheric deposition are mainly taken up via hand-mouth intake, and the harm to children is significantly higher than the harm to adults. The highest health risk assessment values for the four analyzed heavy metals in atmospheric deposition are located near the city and in suburbs (within 5 km of the city center), that is, in areas where human activities are concentrated. The health risk assessment values in areas outside the suburbs are low; these areas are less affected by human activities. The health risk assessment values of heavy metals in the winter and spring are higher than those in the summer and autumn. The Pb isotope ratios show that the main sources of heavy metals in atmospheric deposition and local soil are human activities, such as industry and coal combustion, with less input from natural sources. Heavy metals in atmospheric deposition in the western part of Taihu Lake not only directly threaten local human health but also enter Taihu Lake, posing a serious threat to the Taihu Lake ecosystem.

We assessed the contribution of transboundary air pollutants (TAPs) transported from China to Tokyo using the Pb₍₀.₅<Dₚ < ₁₎/Cu₍₂.₅<Dₚ < ₁₀₎ index. We conducted intensive observations over four seasons during 2014–2015 and analyzed ionic components and thirteen elements in size-segregated aerosols collected at the top of a 30-m-high tower in a hilly forested area of the Field Museum Tamakyuryo (FM Tama), in a western suburb of Tokyo. In order to evaluate if the Pb₍₀.₅<Dₚ < ₁₎/Cu₍₂.₅<Dₚ < ₁₀₎ ratio can be applied in Tokyo as the megacity, the annual average concentration of Pb at Cape Hedo, Kumamoto city, on the west side of Japan, was higher than that of Pb at Tokyo, on the east side; this result indicates that TAPs affect western Japan more than eastern Japan. We inferred the main source of Cu to be braking abrasion from cars at local scale on the basis of its enrichment factor and size distribution. From the Pb₍₀.₅<Dₚ < ₁₎/Cu₍₂.₅<Dₚ < ₁₀₎ ratio and sulfate concentration, we inferred that the highest contribution of TAPs to the total mass concentration in Tokyo occurred in spring, when TAPs accounted for 55%, 72%, and 53% of the total mass concentration in the 0.1 < Dp < 0.5, 0.5 < Dp < 1, and 1 < Dp < 2.5 fractions, respectively. These results can contribute to assessment of TAPs in Tokyo.