Search

PM 2.5 pollution is a widespread environmental and health problem, particularly in China. Besides leading to well-known diseases in the respiratory system, PM 2.5 can also alter immune function to induce or aggravate allergic diseases. To determine whether there are temporal and spatial differences in the allergic responses to PM 2.5 , monthly samples were collected from four regions (urban, industrial, suburban, and rural areas) through a whole year in Nanjing city, China. Inorganic chemical components (metals and water-soluble ions) of PM 2.5 were analyzed, and the rat basophil cells (RBL-2H3) exposed to PM 2.5 were assessed through quantitative measures of degranulation (β-hex and histamine) and pro-inflammation cytokine (IL-4 and TNF-α) expression. The highest levels of β-hex were measured in winter and spring PM 2.5 from urban and industrial areas, or autumn PM 2.5 from suburban and rural areas. With respect to histamine, autumn PM 2.5 samples were most potent irrespective of the location. Autumn and winter PM 2.5 induced higher levels of IL-4 than spring and summer samples. However, spring and autumn PM 2.5 caused higher levels of TNF-α. The concentrations of water-soluble ions (NH 4 + , K + and Cl - ), as well as heavy metals (Pb and Cr), were directly and statistically correlated to the inflammation observed in vitro. In general, the differences between regional and seasonal PM 2.5 in stimulating cell degranulation may depend on endotoxin and airborne allergen content of PM 2.5 . The heavy metals and water-soluble ions in PM 2.5 were mostly anthropogenic, which increased the particles' mass-based cellular inflammatory potential, therefore, their health risks, e.g. from vehicular exhaust, coal, and biomass combustion, cannot be ignored., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Air pollution is a serious environmental issue. As a key aerosol component, PM 2.5 associated toxic trace metals pose significant health risks by inhalation and ingestion, but the evidences and mechanisms were insufficient and not well understood just by their total environmental concentrations. To accurately assess the potential risks of airborne metals, a series of in vitro physiologically based tests with synthetic human lung and gastrointestinal fluids were conducted to assess both the bioaccessibility and bioavailability of various PM 2.5 bound metals in the respiratory and digestive systems from both urban and industrial areas of Nanjing city. Moreover, the chemical acellular toxicity test [dithiothreitol (DTT) assay] and source analysis were performed. Generally, the bioaccessibility and bioavailability of investigated metals were element and body fluid dependent. Source oriented metals in PM 2.5 showed diverse bioaccessibility in different human organs. The PM 2.5 induced oxidative potential was mainly contributed by the bioaccessible/bioavailable transition metals such as Fe, Ni and Co from metallurgic dust and traffic emission. Future researches on the toxicological mechanisms of airborne metals incorporating the bioaccessibility, bioavailability and toxicity tests are directions., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Environmental air pollutants pose significant threats to public health, especially the toxicity and diseases caused by the atmospheric fine particulate matters (PM 2.5 ). Since the health risks vary with both the concentrations and compositions of PM 2.5 which are determined by aerosol sources, how are their toxic effects relevant to the pollution level becomes an important issue, such as the haze episodes covering clean and polluted days. With the transition from non-pollution to pollution stage, daily PM 2.5 samples were collected from both the urban and industrial areas of Nanjing city, eastern China, covering a typical haze event in autumn-winter. Their unpropitious effects on human lung epithelial cells (A549) were compared by in vitro toxicity assays and chemical component analysis. Both air levels and cytotoxic effects of PM 2.5 varied with the transition of haze event. Although the concentration of PM 2.5 in air is of course the highest in pollution stage driven by local stable meteorological condition, unit mass of them posed higher toxicity (lower cell viability and higher IL-6) but induced lower cell oxidative (evidences of ROS and NQO1 mRNA expression) and inflammatory cytokine TNF-α responses than those particles during non-pollution stage. These patterns were explained by the metals and water-soluble components decreased with the haze development. Non-soluble particulate carbonaceous aerosol compositions might play a significant role in inducing cytotoxicity. Moreover, the regional pattern of episode pollution weakened the spatial variation within a city scale. Since the haze development intensified both the quantity and toxicity of PM 2.5 in air, the health risks of overall aerosol exposure were synthetically amplified during haze weather, so the increased air particles with higher toxic components from fuel combustion sources should be key targets of pollution control., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Atmospheric fine particulate matter (PM 2.5 ) can harm human health, but the chemical composition and toxicity of PM 2.5 pollution might vary with weather conditions. In order to investigate the impacts of snowfall weather on aerosol characteristics and toxicity by changing particle sources and components, the daily PM 2.5 samples were collected before, during, and after a snowfall event in urban, industrial, suburban, and rural areas of Nanjing city in eastern China, for both chemical composition analysis and cytotoxicity tests. After 24 h exposure to these PM 2.5 , the cell activity, oxidative stress indicators and inflammatory factor expression levels of human lung epithelial cells A549 were measured by ELISA, and DNA damage was determined by comet assay. Although the concentrations of PM 2.5 in the air were reduced during snowfall, they posed stronger cytotoxicity, genetic toxicity and inflammatory responses to A549 cells. Related to the elevated mass concentrations of some components accumulated in PM 2.5 during snowfall, As, Co, Cr, Sr, V, water-soluble Na + and Ca 2+ showed positive correlations with toxicity indicators. Therefore, snowfall will clean air by deposition, but also make the PM 2.5 components remaining in air mostly anthropogenic by covering ground soil/dust, thus increase the particle's mass-based cytotoxicity and their health risks still cannot be ignored, such as the heavy metals and water-soluble ions from automobile exhaust and coal combustion., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The atmospheric fine particulate matters (PM 2.5 ) induce significant negative effects on human health, such as in the form of oxidative stress and pro-inflammatory response. Organic pollutants are important harmful and toxic compositions in PM 2.5 , risks of which usually show temporal and spatial variations. To investigate the toxic effects of airborne organic pollutants on human lung epithelial cells A549, the PM 2.5 samples were collected monthly from both urban and industrial areas during a whole year in Nanjing, eastern China. After exposure to organic components extracted from these PM 2.5 , the cell viability, lactate dehydrogenase content, oxidative stress index level and inflammatory factor expression level were measured. Supported by the concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, results showed that, organic components of PM 2.5 from cold season (winter and spring) typically influenced cell membrane, cell oxidation and inflammatory damage, while the urban samples of warm season (summer and autumn) impacted cell viability more prominently. Spatially, the toxicity of samples from industrial sources was generally stronger than that from urban source, but urban samples induced much stronger damage to cell membranes than industrial one. The correlations between the PAHs, n-alkanes contents and toxicity parameters indicated that, the airborne organic components derived from motor vehicle exhaust and coal combustion were possibly the key toxic sources., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Contaminants in urban soils can directly pose significant human health risks through oral ingestion, particle inhalation, and dermal contact, especially for children in public parks. Both non-carcinogenic and carcinogenic risks of heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) were characterized in 40 surface soils (exposed lawns) from 14 urban parks in Xiamen, China. Results based on total metal concentrations may overestimate the actual risks in comparison with oral bioaccessibility assessment that were estimated by a simplified physiologically based extraction test (SBET). After considering the soil-specific bioaccessibility (Cd>Cu>Pb>Mn>Zn>Co~Ni>Cr), the non-cancer hazard of Pb to children via oral ingestion should be a consideration though its Hazard Index (HI) was below one. The overall cancer risks to adults still exceeded the target value 10(-6), mainly contributed by Cr (93.8%) and Pb (6.19%) via dermal contact (68.3%) and oral ingestion (30.4%). To produce a more realistic estimation for human health risks of metal contamination in urban soils, a framework combining land use type and bioaccessibility is recommended and thereby should be applied for the derivation of risk-based, site-specific soil guidelines., (Copyright © 2012 Elsevier B.V. All rights reserved.)