Particulate matter,PM 10 & PM 2.5 levels,and airborne mutagenicity in Chiang Mai,Thailand

Daily levels of particulate matter (PM) in the ambient air (PM 2.5 and PM 10) were measured in a northern city of Thailand (Chiang Mai) from March 1998 to October 1999. Twenty-four-hour air particulate matter samples were collected each day with Airmetric Minivol portable air samplers. Monthly averages of PM 2.5 from four stations in Chiang Mai varied from 15.39 to 138.31microg/m(3) and 27.29 to 173.40 microg/m(3) for PM 10. The PM 2.5 annual average was 58.48 mg/m(3) and PM 10, 86.38 microg/m(3). Daily PM 2.5 (24h values) during the winter months in Chiang Mai frequently exceeded 200-300 microg/m(3). The maximum concentrations of PM 2.5 (24h average) in Chiang Mai air from December 1998 to April 1999 were 2.8-, 3.5-, 4.2-, 6.5- and 3.2-fold higher than the US Environmental Protection Agency (US EPA), PM 2.5, 24h standard of 65 microg/m(3). From May to October, the mean 24h levels of PM 2.5 and PM 10 were at acceptable levels. The data shows that during the winter season (December to March), levels of PM 2.5 and PM 10 in the Chiang Mai atmosphere are very high, and there may be significant health implications associated with these high concentrations. During the summer season, the fine particles were generally within the acceptable levels. To our knowledge, these are the first measurements of PM 2.5 to be reported for the city of Chiang Mai and they indicate considerable ambient fine particle exposures to the Chiang Mai population. In addition, dichloromethane extracts of airborne particulate matter PM 2.5 or PM 10 collected in the months of winter in the city of Chiang Mai were mutagenic to Salmonella typhimurium strain TA100 without metabolic activation. The mutagenicity appeared to track particle concentrations and increased in the presence of S9 mix.     

近20年来京津冀地区土壤风蚀扬尘颗粒物排放变化

京津冀地区是我国大气污染严重区域,土壤扬尘颗粒物排放变化研究对于改善京津冀地区空气质量具有重要意义。收集2000-2019年京津冀地区气候、土壤、植被覆盖数据,分析近20年来京津冀地区土壤扬尘颗粒物排放变化,揭示其变化的影响因素。结果显示2000-2019年京津冀地区土壤扬尘源总悬浮颗粒物（TSP）排放系数均值为1.79 t km^-2 a^-1,其中PM10占8.99%,PM2.5占0.25%。近20年土壤扬尘源TSP排放系数具有下降趋势,PM10和PM2.5排放系数变化过程与TSP一致。上述变化主要受气候因子变化影响,其次受植被覆盖度影响。分析发现近20年来京津冀地区土壤扬尘源TSP排放系数变化主要受年降水量影响。沧州市、天津市和石家庄市土壤扬尘源TSP、PM10和PM2.5排放系数均值较高,张家口市、保定市和沧州市土壤扬尘源TSP排放量占京津冀地区总量的19.18%、12.98%和11.63%。耕地土壤扬尘排放量最大占京津冀地区总量的59.83%,是抑制土壤扬尘源颗粒物排放的重点关注对象,其次为草地占15.66%。2019年邢台市土壤扬尘源PM10排放占观测值比例最高为12.66%,石家庄市和天津市占比也较高分别为11.09%和10.30%,沧州市和邯郸市占比分别为8.63%和8.02%。上述地区环境管理部门均应关注土壤扬尘源颗粒物排放对空气质量的影响。     

Release behavior of small sized daughter allergens from Cryptomeria japonica pollen grains during urban rainfall event

In Japan, Cryptomeria japonica pollen (with diameter ~30 μm) is scattered during each spring season. Daughter allergenic particles, which are smaller in size than their parent pollen grain and are abundant in fine particles (the particle sizes < 1.1 μm, PM_1.1), are released in the atmosphere. The daughter allergenic particles of pollen can be transported in the urban atmosphere for a long period of time after their release. In particular, the daily variation delays in the peaks of allergenic Cry j 1 concentrations compared with the peaks of airborne parent pollen counts were observed in high levels during 1 or 2 sunny days after rainfall. In addition, long range transportation of Asian dusts (ADS) from the East Asian continent was also found during the pollen scattering seasons in Japan. Therefore, the interaction between pollen and air pollutants, including ADS, should be of concern. Thus, in this study, the morphological change of Cryptomeria japonica pollen and the elution behavior of its allergenic contents (Cry j 1) were investigated. Our results confirmed the existence of fine daughter allergen particles, which are clearly differ from the parent pollen grains in size. Fine allergenic particles in atmosphere were increased, while coarse allergenic particles were decreased on sunny days after rainfall. However, the correlation between the mass concentrations of fine particles and mass levels of Cry j 1 in coarse particles (the particle sizes > 7.0 μm) was poor. The possible reason may be pollen burst at high humidity before rainfall. Additionally, Cry j 1 contents were emitted from the so-called Ubisch body, which contains allergenic Cry j 1 abundantly when pollen was in contact with rainfall. In particular, we found that 60% of allergenic Cry j 1 contents released in air polluted rainfall contained Ca²⁺ ion derived from road dust and ADS. Therefore, rainfall should be a main factor to induce transition of pollen allergenic contents to fine particles. In conclusion, allergenic particles which are small sized and translated into fine particles by rainfall can be inhaled into the lower respiratory tract and contribute to the hypersensitivity of asthma.     

Particle size distribution of the major Alternaria alternata allergen,Alt a 1, derived from airborne spores and subspore fragments

Fungal fragments are abundant immunoreactive bioaerosols that may outnumber the concentrations of intact spores in the air. To investigate the importance of Alternaria fragments as sources of allergens compared to Alternaria spores, we determined the levels of Alternaria spores and Alt a 1 (the major allergen in Alternaria alternata spores) collected on filters within three fractions of particulate matter (PM) of different aerodynamic diameter: (1) PM_>10, (diameter>10 μm); (2) PM_2.5-10 (2.5–10μm); (3) PM_2.5 (0.12–2.5 μm). The airborne particles were collected using a three stage high-volume ChemVol cascade impactor during the Alternaria sporulation season in Poznań, Poland (30 d between 6 July and 22 September 2016). The quantification of Alt a 1 was performed using the enzyme-linked immunosorbent assay. High concentrations of Alt a 1 were recorded during warm and dry d characterized by high sunshine duration, lack of clouds and high dew point values. Atmospheric concentrations of Alternaria spores correlated significantly (r = 0.930, p < 0.001) with Alt a 1 levels. The highest Alt a 1 was recorded in PM_2.5-10 (66.8 % of total Alt a 1), while the lowest in PM_2.5 (<1.0 %). Significantly more Alt a 1 per spore (>30 %) was observed in PM_2.5-10 than in PM_>10. This Alt a 1 excess may be derived from sources other than spores, e.g. hyphal fragments. Overall, in outdoor air the major source of Alt a 1 are intact Alternaria spores, but the impact of other fungal fragments (hyphal parts, broken spores, conidiophores) cannot be neglected, as they may increase the total atmospheric Alt a 1 concentration.     

Involvement of nitro-compounds in the mutagenicity of urban Pm2.5 and Pm10 in Turin

Fine particles can be active carriers of toxic compounds into the alveoli of the lungs. Among these compounds are numerous mutagens and carcinogens. The direct mutagenicity per unit mass of fine particulate matter (PM) is significantly higher than that of coarse particles, especially in urban areas. In this study, the mutagenic properties of urban PM2.5 and PM10 were evaluated, and the role of nitro-compounds was estimated. PM2.5 and PM10 samplings, and measurements of NOx and some PAHs were performed daily in 2007 in Turin, following a consolidated in vitro test - the Salmonella mutagenicity assay - conducted with organic extracts of PM2.5 and PM10. The mutagenic properties were assessed for each month of sampling with Salmonella typhimurium strain TA98 and TA98-derived strains: a nitroreductase-deficient mutant strain (TA98NR) and an additional nitroreductase-producing plasmid strain (YG1021). The annual measured mean levels of PM2.5 and PM10 were 34±20 and 48±18μg/m(3). The PM2.5/PM10 ratio ranged from 0.36 to 0.89. The Salmonella assay showed higher mutagenicity in autumn/winter (20±15 TA98NR; 54±39 TA98; 173±161 YG1021 net revertants/m(3)) compared with spring/summer (2±2 TA98NR; 7±8 TA98; 24±27 YG1021 net revertants/m(3)) (p<0.01). There are also statistically significant seasonal differences in the gravimetric analysis data. The number of TA98 net revertants per μg of PM2.5 is 6.5 times greater than per μg PM10. Moreover, the bioassay results showed an amplified response in the YG1021 strain and a reduced response in the TA98NR strain. The net revertant ratio TA98NR/YG1021 is 11±4 for organic extracts of PM2.5 and 13±6 for extracts of PM10 (p<0.01). There is a significant correlation between the NOx and PAH concentrations. These findings illustrate the relevant role of nitro compounds, and they underline the priority in improving preventive measures to reduce air pollution by nitrated molecules.     

Occurrence of molecular abnormalities of cell cycle in L132 cells after in vitro short-term exposure to air pollution PM2.5

To improve the knowledge of the underlying mechanisms implying in air pollution Particulate Matter (PM)-induced lung toxicity in humans, we were interested in the sequential occurrence of molecular abnormalities from TP53-RB gene signaling pathway activation in the L132 target human lung epithelial cell model. The most toxicologically relevant physical and chemical characteristics of air pollution PM_2.5 collected in Dunkerque, a French highly-industrialized sea-side city, were determined. L132 cells were exposed during 24, 48 and 72 h to Dunkerque City's PM_2.5 (i.e. Lethal Concentration (LC)₁₀ = 18.84 μg PM/mL or 5.02 μg PM/cm²; LC₅₀ = 75.36 μg PM/mL or 20.10 μg PM/cm²), TiO₂ and desorbed PM (i.e. dPM; EqLC₁₀ = 15.42 μg/mL or 4.11 μg PM/cm²; EqLC₅₀ = 61.71 μg/mL or 16.46 μg PM/cm²), benzene (7 μM) or Benzo[a]Pyrene (B[a]P; 1 μM). Dunkerque City's PM_2.5 altered the gene expression and/or the protein concentration of several key cell cycle controllers from TP53-RB gene signaling pathway (i.e. P53; BCL2; P21; cyclin D1, cyclin-dependent kinase 1; retinoblastoma protein) in L132 cells, thereby leading to the occurrence of cell proliferation and apoptosis together. The activation of the critical cell cycle controllers under study might be related to PM-induced oxidative stress, through the possible involvement of covalent metals in redox systems, the metabolic activation of organic chemicals by enzyme-catalyzed reactions, and phagocytosis. Taken together, these results might ask the critical question whether there is a balance or, in contrast, rather an imbalance between the cell proliferation and the apoptosis occurring in PM-exposed L132 cells, with possible consequences in term of PM-induced lung tumorgenesis.     

Human occupancy as a source of indoor airborne bacteria

Exposure to specific airborne bacteria indoors is linked to infectious and noninfectious adverse health outcomes. However, the sources and origins of bacteria suspended in indoor air are not well understood. This study presents evidence for elevated concentrations of indoor airborne bacteria due to human occupancy, and investigates the sources of these bacteria. Samples were collected in a university classroom while occupied and when vacant. The total particle mass concentration, bacterial genome concentration, and bacterial phylogenetic populations were characterized in indoor, outdoor, and ventilation duct supply air, as well as in the dust of ventilation system filters and in floor dust. Occupancy increased the total aerosol mass and bacterial genome concentration in indoor air PM(10) and PM(2.5) size fractions, with an increase of nearly two orders of magnitude in airborne bacterial genome concentration in PM(10). On a per mass basis, floor dust was enriched in bacterial genomes compared to airborne particles. Quantitative comparisons between bacterial populations in indoor air and potential sources suggest that resuspended floor dust is an important contributor to bacterial aerosol populations during occupancy. Experiments that controlled for resuspension from the floor implies that direct human shedding may also significantly impact the concentration of indoor airborne particles. The high content of bacteria specific to the skin, nostrils, and hair of humans found in indoor air and in floor dust indicates that floors are an important reservoir of human-associated bacteria, and that the direct particle shedding of desquamated skin cells and their subsequent resuspension strongly influenced the airborne bacteria population structure in this human-occupied environment. Inhalation exposure to microbes shed by other current or previous human occupants may occur in communal indoor environments.     

Estimating the acute health effects of coarse particulate matter accounting for exposure measurement error

In air pollution epidemiology, there is a growing interest in estimating the health effects of coarse particulate matter (PM) with aerodynamic diameter between 2.5 and 10 μm. Coarse PM concentrations can exhibit considerable spatial heterogeneity because the particles travel shorter distances and do not remain suspended in the atmosphere for an extended period of time. In this paper, we develop a modeling approach for estimating the short-term effects of air pollution in time series analysis when the ambient concentrations vary spatially within the study region. Specifically, our approach quantifies the error in the exposure variable by characterizing, on any given day, the disagreement in ambient concentrations measured across monitoring stations. This is accomplished by viewing monitor-level measurements as error-prone repeated measurements of the unobserved population average exposure. Inference is carried out in a Bayesian framework to fully account for uncertainty in the estimation of model parameters. Finally, by using different exposure indicators, we investigate the sensitivity of the association between coarse PM and daily hospital admissions based on a recent national multisite time series analysis. Among Medicare enrollees from 59 US counties between the period 1999 and 2005, we find a consistent positive association between coarse PM and same-day admission for cardiovascular diseases.     

Assessing the in vitro toxicity of the lunar dust environment using respiratory cells exposed to Al<Subscript>2</Subscript>O<Subscript>3</Subscript> or SiO<Subscript>2</Subscript> fine dust particles

Prior chemical and physical analysis of lunar soil suggests a composition of dust particles that may contribute to the development of acute and chronic respiratory disorders. In this study, fine Al₂O₃ (0.7 μm) and fine SiO₂ (mean 1.6 μm) were used to assess the cellular uptake and cellular toxicity of lunar dust particle analogs. Respiratory cells, murine alveolar macrophages (RAW 264.7) and human type II epithelial (A549), were cultured as the in vitro model system. The phagocytic activity of both cell types using ultrafine (0.1 μm) and fine (0.5 μm) fluorescent polystyrene beads was determined. Following a 6-h exposure, RAW 264.7 cells had extended pseudopods with beads localized in the cytoplasmic region of cells. After 24 h, the macrophage cells were rounded and clumped and lacked pseudopods, which suggest impairment of phagocytosis. A549 cells did not contain beads, and after 24 h, the majority of the beads appeared to primarily coat the surface of the cells. Next, we investigated the cellular response to fine SiO₂ and Al₂O₃ (up to 5 mg/ml). RAW 264.7 cells exposed to 1.0 mg/ml of fine SiO₂ for 6 h demonstrated pseudopods, cellular damage, apoptosis, and necrosis. A549 cells showed slight toxicity when exposed to fine SiO₂ for the same time and dose. A549 cells had particles clustered on the surface of the cells. Only a higher dose (5.0 mg/ml) of fine SiO₂ resulted in a significant cytotoxicity to A549 cells. Most importantly, both cell types showed minimal cytotoxicity following exposure to fine Al₂O₃. Overall, this study suggests differential cellular toxicity associated with exposure to fine mineral dust particles.     

大气细颗粒污染物 PM2.5 浓度及对肺上皮细胞炎性因子的影响

目的:研究大气细颗粒污染物(PM2.5)浓度及对肺上皮细胞(A549细胞)炎性因子的影响。方法:测定2013年1月至2013年12月北京市某城区PM2.5浓度,比较不同PM2.5浓度对A549细胞炎性因子IL-6、TNF-α表达水平的影响。结果:北京市细颗粒污染物PM2.5日均值春季、夏季、秋季、冬季分别为174.3μg/m3、143.5μg/m3、166.7μg/m3、189.6μg/m3,四季超标率差异无统计学意义(P>0.05);大气细颗粒污染物PM2.5对肺上皮细胞IL-6、TNF-α的影响,春季、夏季、秋季、冬季四季之间差异无统计学意义(P>0.05);随着PM2.5浓度升高IL-6、TNF-α表达水平升高,差异有统计学意义(P<0.05);随着染毒时间延长IL-6、TNF-α表达水平升高,差异有统计学意义(P<0.05)。结论:大气细颗粒污染物浓度升高会使肺上皮细胞炎性因子表达增强。     

Effects of Particle Matters on Plant: A Review

The particle matter, particularly the suspended particle matter (PM ≤ 2.5) in the air is not only a risk factor for human health, but also affects the survival and physiological features of plants. Plants show advantages in the adsorption of particle matter, while the factors, such as the leaf shape, leaf distribution density and leaf surface microstructure, such as grooves, folds, stomata, flocculent projections, micro-roughness, long fuzz, short pubescence, wax and secretory products, appeared to play an important role determing their absorption capacity. In this paper, the research progress on the capture or adsorption of atmospheric particles was summarized, and the forest vegetation and woody plants were discuessed. In addition, special attentions were paid to the effect of haze-fog weather on greenhouse plant, the different responses of plant leaves to dust particles and suspended particles, as well as the effect of suspended particles on morphological change of plants. In the future, research should focus on the mechanism of the influence of particulate matter on plants. More advanced effective and convenient research methods like spectral detection method also need to be developed. This paper may provide reference for future studies on plants’ response to haze and particle matter.     

Cytotoxicity of PM(2.5) and PM(2.5--10) ambient air pollutants assessed by the MTT and the Comet assays

Ambient air particulate matters are classified into two distinct modes in size distribution, namely the coarse and fine particles. Correlation between high particulate concentration and adverse effects on human populations has long been recognized, however, the toxicology of these adverse effects has not been clarified. In the current report, the cytotoxic effects of the solvent-extractable organic compounds (SEOC) from fine particles smaller than 2.5 microm (PM(2.5)) and from coarse particles between 2.5-10 microm (PM(2.5-10)) were studied. Nine 24h consecutive monthly samples were tested to determine the correlation between cytotoxicity and total SEOC in two size fractions of particulate air pollution. Cytotoxicity of SEOC was measured by two micro-scale mammalian cells-based bioassays: the MTT cell proliferation assay, and the Comet assay for the detection of DNA damage. A well-defined mammalian cell line - Rat 6 rodent fibroblast was employed in the study. The SEOC extracts of air particulate matters were sub divided into two equal parts. One part was dissolved in DMSO, the other in KOH/hexane and then conjugated with bovine serum albumin to produce a lipid-soluble fraction for testing. The DMSO fraction would contain mainly the polycyclic aromatic hydrocarbons (PAH), alkanes and alkanols, while the lipid-soluble fraction would be enriched with fatty acids. The results from MTT assay showed that cytotoxicity of the PM(2.5) was much more severe than the PM(2.5-10), suggesting that toxic SEOC were confined to the fine particles. By and large, the DMSO solubles were much more toxic than the lipid solubles. The degree of cytotoxicity of the DMSO soluble samples is positively correlated to the amount of particulates present in the ambient air. For the PM(2.5), the winter samples were significantly more toxic than the summer samples in terms of cell killing, which seemed to be a direct reflection of the total loading of organic matter in the samples. Results from Comet assays showed that SEOC samples of PM(2.5) derived from winter months induced DNA damage at dosages resulting in no obvious cell killing in the MTT assay. Thus, long-term exposure to non-killing dosage of air pollutants may lead to the accumulation of DNA lesions, which may be one of the mechanisms responsible for the chronic adverse health effects of particulate air pollution.     

Foraging trip duration of honeybee increases during a poor air quality episode and the increase persists thereafter

Increased concentration of airborne particulate matter (PM) in the atmosphere alters the degree of polarization of skylight which is used by honeybees for navigation during their foraging trips. However, little has empirically shown whether poor air quality indeed affects foraging performance (foraging trip duration) of honeybee. Here, we show apparent increases in the average duration of honeybee foraging during and after a heavy air pollution event compared with that of the pre‐event period. The average foraging duration of honeybees during the event increased by 32 min compared with the pre‐event conditions, indicating that 71% more time was spent on foraging. Moreover, the average foraging duration measured after the event did not recover to its pre‐event level. We further investigated whether an optical property (Depolarization Ratio, DR) of dominant PM in the atmosphere and level of air pollution (fine PM mass concentration) affect foraging trip duration. The result demonstrates the DR and fine PM mass concentration have significant effects on honeybee foraging trip duration. Foraging trip duration increases with decreasing DR while it increases with increasing fine PM mass concentration. In addition, the effects of fine PM mass concentration are synergistic with overcast skies. Our study implies that poor air quality could pose a new threat to bee foraging.     

亚热带常绿树种对不同粒径颗粒物的滞留能力

可吸入颗粒物和细颗粒物是大部分城市的首要污染物,对人体健康和环境都有重要影响;而城市植物能吸附大气颗粒物,进而有效降低大气颗粒物浓度。为了深入探究不同树种叶表面特征与自身滞尘效益之间的关系,该研究以浙江省三种常见城市绿化树种(青冈、冬青、红花檵木)为对象,采用重量法提取各样本在3个粒径上(8~100,2.5~8,0.45~2.5μm)的单位叶面积滞尘量(μg·cm~(-2)),并结合叶面积指数估测全株滞尘量。结果表明:三种供试植物叶片对颗粒物平均单位叶面积滞留量在30.4~63.7μg·cm~(-2)之间,而平均单木滞尘量每株在1.36-9.36 g之间。红花檵木因其叶表粗糙、具有绒毛等特征,对颗粒物(0.45~100μm)有最大的吸附能力(63.74±12.0μg·cm~(-2));对于大颗粒物(8~100μm)和细颗粒物(0.45~2.5μm),三种植物叶片均对其分别具有最大(40.9%~57.5%)、最小(15.6%~20.6%)的吸附能力;对于单木滞尘量,青冈因其具有较大叶面积指数等特征,对颗粒物总吸附效果更佳(每株9.36g)。该研究结果表明城市绿化树种对减缓大气颗粒物污染起到重要作用。     

Organic extracts of urban air pollution particulate matter (PM2.5)-induced genotoxicity and oxidative stress in human lung bronchial epithelial cells (BEAS-2B cells)

Traffic is a major source of particulate matter (PM), and ultrafine particulates and traffic intensity probably contribute significantly to PM-related health effects. As a strong relationship between air pollution and motor vehicle-originated pollutants has been shown to exist, air pollution genotoxicity studies of urban cities are steadily increasing. In Korea, the death rate caused by lung cancer is the most rapidly increased cancer death rate in the past 10 years. In this study, genotoxicity of PM2.5 (<2.5μm in aerodynamic diameter particles) collected from the traffic area in Suwon City, Korea, was studied using cultured human lung bronchial epithelial cells (BEAS-2B) as a model system for the potential inhalation health effects. Organic extract of PM2.5 (CE) generated significant DNA breakage and micronucleus formation in a dose-dependent manner (1μg/cm(3)-50μg/cm(3)). In the acid-base-neutral fractionation of PM2.5, neutral samples including the aliphatic (F3), aromatic (F4) and slightly polar (F5) fractions generated significant DNA breakage and micronucleus formation. These genotoxic effects were significantly blocked by scavenging agents [superoxide dismutase (SOD), sodium selenite (SS), mannitol (M), catalase (CAT)]. In addition, in the modified Comet assay using endonucleases (FPG and ENDOIII), CE and its fractions (F3, F4, and F5) increased DNA breakage compared with control groups, indicating that CE and fractions of PM2.5 induced oxidative DNA damage. These results clearly suggest that PM2.5 collected in the Suwon traffic area has genotoxic effects and that reactive oxygen species may play a distinct role in these effects. In addition, aliphatic/chlorinated hydrocarbons, PAH/alkylderivatives, and nitro-PAH/ketones/quinones may be important causative agents of the genotoxic effects.     

Seasonal variability of bacteria in fine and coarse urban air particulate matter

The current knowledge about the microbial communities associated with airborne particulate matter, particularly in urban areas, is limited. This study aims to fill this gap by describing the microbial community associated with coarse (PM10) and fine (PM2.5) particulate matter using pyrosequencing. Particulate matter was sampled on Teflon filters over 3 months in summer and 3 months in winter in Milan (Italy), and the hypervariable V3 region of the gene 16S rRNA amplified from the DNA extracted from the filters. The results showed large seasonal variations in the microbial communities, with plant-associated bacteria dominating in summer and spore-forming bacteria in winter. Bacterial communities from PM10 and PM2.5 were also found to differ from each other by season. In all samples, a high species richness, comparable with that of soils, but a low evenness was found. The results suggest that not only can the sources of the particulate influence the presence of specific bacterial groups but also that environmental factors and stresses can shape the bacterial community.     

Mutagenic activity of airborne particulate matter in a petrochemical industrial area

Exposure to airborne particulate matter has adverse effects on human health and ecosystem. Mutagenic activity of airborne particulate organic matter extracts in three time periods from total suspended particles (TSP) and particles less than 10 μm (PM10) was evaluated in an area under the influence of a petrochemical industry located in the town of Triunfo, Brazil. The extracts were investigated using the Salmonella/microsome assay, with the microsuspension method. The extracts were obtained by sonication extracted using dichloromethane (DCM) solvent. The fractions were tested for mutagenicity with the Salmonella typhimurium strains TA98 (with and without metabolic activation), TA98NR and TA98/1,8DNP₆; or YG1021 and YG1024. A positive frameshift mutagenic response was observed for the environmental samples during the different periods. The responses according to percentage of extractable organic matter (EOM%), EOM/m³, revertants/μg (rev/μg) and revertants/m³ (rev/m³) were lower for TSP than for PM10 extracts. The highest rev/m³ values were observed in PM10 extract samples collected in winter, July 2005, in the presence (13.79 rev/m³) or absence (6.87 rev/m³) of S9 fraction. Similarly in the first (1995) or second period (2000) the highest values for TSP were observed in winter, but with lower activity (3.00 and 0.89 rev/m³ respectively). The responses observed for the nitrosensitive strains suggest the contribution of nitro, amino and/or hydroxylamino derivatives of PAHs to the total mutagenicity of matter extracted from airborne particles. The Salmonella/microsome assay was a sensitive method to define areas contaminated by genotoxic compounds, even in samples with TSP or PM10 values that are acceptable according to legal environmental quality standards, favoring environmental control measures with an effective response seen in the population's improved quality of life.     

Transcriptomic Analyses of the Biological Effects of Airborne PM2.5 Exposure on Human Bronchial Epithelial Cells

Epidemiological studies have associated high levels of airborne particulate matter (PM) with increased respiratory diseases. In order to investigate the mechanisms of air pollution-induced lung toxicity in humans, human bronchial epithelial cells (16HBE) were exposed to various concentrations of particles smaller than 2.5 μm (PM2.5) collected from Beijing, China. After observing that PM2.5 decreased cell viability in a dose-dependent manner, we first used Illumina RNA-seq to identify genes and pathways that may contribute to PM2.5-induced toxicity to 16HBE cells. A total of 539 genes, 283 up-regulated and 256 down-regulated, were identified to be significantly differentially expressed after exposure to 25 μg/cm² PM2.5. PM2.5 induced a large number of genes involved in responses to xenobtiotic stimuli, metabolic response, and inflammatory and immune response pathways such as MAPK signaling and cytokine-cytokine receptor interaction, which might contribute to PM2.5-related pulmonary diseases. We then confirmed our RNA-seq results by qPCR and by analysis of IL-6, CYP1A1, and IL-8 protein expression. Finally, ELISA assay demonstrated a significant association between exposure to PM2.5 and secretion of IL-6. This research provides a new insight into the mechanisms underlying PM2.5-induced respiratory diseases in Beijing.     

Aerosol lead and associated elements in Beijing,China

The relative importance of local and regional sources of lead and associated elements in fine and coarse aerosol particles of an urban atmosphere was assessed by means of a two-day study, July 20 and 30, 1980 in Beijing, China. Five near-ground locations were selected for aerosol sampling by cascade impactors and elemental analysis by proton induced X-ray emission (PIXE): the imperial palace courtyard, a park, near two streets, and a mid-street traffic island. These sites, ranked in order of increasing traffic intensity and fugitive surface dust, showed that concentrations of major dust constitutents, represented by coarse particle (>2 μm diameter) Si, Al, and Ca, increased correspondingly. Pb, as well as Zn, As, and Cu, were present mainly in fine (<2 μm) particles; their concentrations were unrelated to traffic, indicating they resulted mainly from regional combustion or other sources. However, these elements also were present in coarse particles at concentrations that varied with the major dust elements and were relatively enriched, compared to average earth crust rock material, by factors of more than 100 (Pb), 50 (Zn), and 10 (Cu). Nonurban Beijing shows much smaller coarse aerosol enrichments of Pb, Zn, and Cu, indicating urban contamination of surface dust. Published data from St. Louis, USA show both fine and coarse aerosol Pb and Zn. Compared with Beijing, fine and coarse concentrations in St. Louis are similar for Pb, but lower for Zn, Ca, and Fe. Both Pb and Zn are enriched relative to earth crust composition to a greater degree in St. Louis than Beijing in both fine and coarse particle size ranges. The results suggest that heavy metals from combustion occur in the air as fine particles and, after deposition on the surface, as reentrained coarse particles of fugitive dust. Both many contribute to human exposures of these heavy metals.     

Particulate Matter on Foliage of 13 Woody Species: Deposition on Surfaces and Phytostabilisation in Waxes – a 3-Year Study

Particulate matter (PM) as an air pollutant can be harmful for human health through allergic, mutagenic and carcinogenic effects. Although the main focus is on decreasing air pollution, after PM has been emitted to the atmosphere, one of the realistic options to decrease it's concentrations in urbanized area will be phytoremediation. This study compared the capacity to capture PM from air of seven tree species commonly cultivated in Poland (Catalpa bignonioides Walter, Corylus colurna L., Fraxinus pennsylvanica Marsh., Ginkgo biloba L., Platanus × hispanica Mill. ex Muenchh., Quercus rubra L., Tilia tomentosa Moench ‘Brabant’) and six shrub species (Acer tataricum subsp. ginnala (Maxim.) Wesm., Sambucus nigra L., Sorbaria sorbifolia (L.) A.Br., Spiraea japonica L.f., Syringa meyeri C.K. Schneid. ‘Palibin’, Viburnum lantana L.). Significant differences were found between species in mass of total PM accumulation for two PM categories and three size fractions determined and in amount of waxes. A positive correlation was found between in-wax PM of diameter 2.5–10 μm and amount of waxes, but not between amount of waxes and amount of total PM or of any size fraction.