Size-fractionated Particulate Matter Research Articles

Size-fractionated particulate air pollution and myocardial infarction emergency hospitalization in Shanghai, China

BackgroundFine particulate matter (PM2.5) air pollution has been associated with increased risks of acute myocardial infarction (AMI), but it remains unknown about the potentially differentiated effects of size-fractionated particulate matter on AMI risk. ObjectiveTo identify the specific size ranges that dominate the effects of particulate matter on AMI onset. MethodsWe conducted a time-series study in Shanghai, China from January 2014 to December 2018. We evaluated particle size distribution of 0.01 μm to 2.5 μm from an environmental supersite and AMI emergency hospitalizations from the largest cardiovascular hospital in Shanghai. We used over-dispersed generalized additive models to estimate the associations of size-fractionated particle number concentrations (PNC) with AMI and its types. ResultsWe identified a total of 4720 AMI emergency hospitalizations. PM2.5 was significantly associated with increased AMI risk on the concurrent day. The associations were significant only for PNC < 0.3 μm. For an IQR increase of PNCs for size ranges 0.01–0.03 μm, 0.03–0.05 μm, 0.05–0.10 μm and 0.10–0.30 μm, AMI hospitalizations increased by 6.68% (95% CI: 2.77%, 10.74%), 6.53% (95% CI: 2.08%, 11.17%), 5.78% (95% CI: 0.92%, 10.88%) and 5.92% (95% CI: 1.31%, 10.74%), respectively. The associations of PNC < 0.05 μm remained significant when adjusting for other air pollutants. There were consistently much stronger associations of particles with ST-segment elevation AMI than those with non-ST-segment elevation AMI. ConclusionsThis epidemiological investigation suggested that ultrafine particles, especially those <0.05 μm, may be mainly responsible for the acute AMI risk induced by PM2.5.

Toxic potentials of particulate and gaseous air pollutant mixtures and the role of PAHs and their derivatives

BackgroundAir pollution, which represents a major environmental risk to human health, comprises a complex mixture of compounds where only little is known about its specific toxicities. ObjectivesThis study examined the specific toxicities associated with ambient air pollutant mixtures with respect to gas/particle partitioning, particulate matter (PM) size, pollutant polarity and bioaccessibility from PM, and evaluated the contribution of PAHs and their oxygenated and nitrated derivatives (OPAHs, NPAHs). MethodsAir samples (gas phase, PM10 and size-segregated PM), were collected at urban (in winter and summer) and background (winter) sites in the Czech Republic. The total and bioaccessible concentrations were addressed using organic solvent extraction and simulated lung fluid extraction, respectively. Organic extracts were also further fractionated according to polarity. Aryl hydrocarbon receptor (AhR)-mediated activity, anti-/estrogenicity, anti-/androgenicity, thyroid receptor (TR)-mediated activity and cytotoxicity for bronchial cells were determined by human cell-based in vitro bioassays. The contribution of studied compounds to observed effects was assessed by both modelling and reconstructing the mixtures. ResultsSignificant effects were detected in the sub-micrometre size fraction of PM (estrogenicity, androgenicity, TR- and AhR-mediated activities) and in the gas phase (TR-mediated activity, antiandrogenicity). Compounds interacting with TR showed high bioaccessibility to simulated lung fluid. Relatively lower bioaccessibility was observed for estrogenicity and AhR-mediated activity. However, the toxicity testing of reconstructed mixtures revealed that the targeted pollutants are not the main contributors, except for urban PM air pollution in winter, where they accounted for 5–88% of several effects detected in the original complex environmental samples. DiscussionStudied toxicities were mostly driven by polar compounds largely attributed to the easily inhalable PM1, which is of high relevance for human health risk assessment. Except of parent PAHs in some cases, the targeted compounds contributed to the detected effects mostly to a relatively low extent implying huge data gaps in terms of endocrine disruptive potencies of targeted substances and the significance of other polar compounds present in ambient air.

Association of particulate matter air pollution with leukocyte mitochondrial DNA copy number

BackgroundAmbient particulate matter (PM) has been associated with mitochondrial damage and dysfunction caused by excessive oxidative stress, but the associations between long-term PM exposure and leukocyte mitochondrial DNA copy number (mtDNAcn), a biomarker of mitochondrial dysfunction due to oxidative stress, are less studied. ObjectivesTo investigate the associations between short-, intermediate- and long-term exposure (1-, 3- and 12-months) to different size fractions of PM (PM2.5, PM2.5-10 and PM10) and leukocyte mtDNAcn in a cross-sectional study. MethodsThe associations between each of the PM exposure metrics with z scores of log-transformed mtDNAcn were examined using generalized linear regression models in 2758 female participants from the Nurses’ Health Study (NHS). Monthly exposures to PM were estimated from spatio-temporal prediction models matched to each participants’ address history. Potential effect modification by selected covariates was examined using multiplicative interaction terms and subgroup analyses. ResultsIn single-size fraction models, increases in all size fractions of PM were associated with decreases in mtDNAcn, although only models with longer averages of PM2.5 reached statistical significance. For example, an interquartile range (IQR) increase in 12-month average ambient PM2.5 (5.5 μg/m3) was associated with a 0.07 [95% confidence interval (95% CI): −0.13, −0.01; p-value = 0.02] decrease in mtDNAcn z score in both basic- and multivariable-adjusted models. Associations for PM2.5 were stronger after controlling for PM2.5-10 in two size-fraction models. ConclusionsOur study suggests that long-term exposure to ambient PM2.5 is associated with decreased mtDNAcn in healthy women.

Seasonal variation of endocrine disrupting potentials of pollutant mixtures associated with various size-fractions of inhalable air particulate matter

Ambient air pollution, namely exposure to air particulate matter (PM), has been shown to be connected with a number of adverse health effects. At least part of the effects can be caused by organic pollutant mixtures associated with PM, which can elicit a wide range of specific toxic potentials. These potentials could be affected by seasonal variation of pollutant mixtures and PM size fraction. To examine this, six size subfractions of PM10 were collected at rural and urban site in the Czech Republic in a year-long sampling campaign. The samples were assessed for aryl hydrocarbon (AhR)-mediated activity, estrogenicity and anti-androgenicity using mammalian cell models. The concentrations of detected toxic potentials differed among seasons. The greatest levels were observed in samples collected during winter when AhR-mediated effects and estrogenicity were at least 10-times greater than in summer. While the observed potentials were mostly less pronounced in samples from rural area, during winter, their AhR-mediated activity was twice as great as at the urban site. This was probably caused by the low-quality of fuel used for heating at the rural site. Assessed toxic potentials were associated mainly with PM size fractions with lesser aerodynamic diameters (<1 μm). Toxic potentials were compared with data from chemical analyses covering 102 chemicals from different pollutant groups to model their contribution to the observed effects. For AhR-mediated activity, chemical analyses explained on average 44% of the effect and the main identified effect-drivers were polycyclic aromatic hydrocarbons. For estrogenicity and anti-androgenicity, detected chemicals were able to explain on average less than 1.6% and 11% of the potentials, with their highest explicability reaching 13% and 57%, respectively. This was affected by the lack of data on specific toxic potency of some detected air pollutants, but also indicates a possible role of further not analyzed chemicals in these effects.

High Particulate Matter Burden of Cigarettes from the United Arab Emirates and Germany: Are There Country-Specific Differences?

Although the big tobacco companies offer the same cigarette brands across countries, little is known about the potential regional differences of the particulate matter (PM) emissions of apparently equal brands. PM emissions of three cigarette brands (Marlboro Gold, Winston Red resp. Classic, Parliament Platinum resp. Night Blue) from the United Arab Emirates (UAE) and Germany were analysed. Second-hand smoke was produced in a 2.88 m3 measuring cabin by an automatic environmental tobacco smoke emitter. PM size fractions PM10, PM2.5, and PM1 were detected in real-time using laser aerosol spectrometry. Depending on the PM fraction Marlboro cigarettes from UAE showed 33%–35% higher PM amounts. Moreover, Winston cigarettes from UAE showed distinctly higher PM values (28–31%) than the German counterparts. The “lighter” Parliament from UAE emitted 3%–9% more PM than the German one. The measured mean PM10 values laid between 778 and 1163 µg/m3 (mean PM2.5: 777–1161 µg/m3; mean PM1: 724–1074 µg/m3). That means smoking in enclosed rooms causes massive PM burden. The PM emission of equal or similar tobacco products from different countries can differ distinctly. Hence, the declaration of PM emission values, besides nicotine, tar, and carbon monoxide amounts, should be obligatory worldwide. Furthermore, complete information about the ingredients and production processes of tobacco products should be provided to health officials and the public. This can help to minimise or ban substances or product designs that make smoking even more harmful, and to enhance the awareness of the risks of smoking.

Relationships between air particulate matter capture efficiency and leaf traits in twelve tree species from an Italian urban-industrial environment

Air pollution in the urban environment is widely recognized as one of the most harmful threats for human health. International organizations such as the United Nations and the European Commission are highlighting the potential role of nature in mitigating air pollution and are now funding the implementation of Nature-Based Solutions, especially at the city level. Over the past few decades, the attention of the scientific community has grown around the role of urban forest in air pollution mitigation. Nevertheless, the understanding on Particulate Matter (PM) retention mechanisms by tree leaves is still limited. In this study, twelve tree species were sampled within an urban park of an industrial city. Two techniques were used for leaf analysis: Vacuum/Filtration and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy, in order to obtain a quali-quantitative analysis of the different PM size fractions. Results showed that deposited PM loads vary significantly among species. Different leaf traits, including micro and macromorphological characteristics, were observed, measured and ranked, with the final aim to relate them with PM load. Even if no significant correlation between each single leaf characteristic and PM deposition was observed (p > 0.05), multivariate analysis revealed relationships between clusters of leaf traits and deposited PM. Thus, by assigning a score to each trait, an Accumulation index (Ai) was calculated, which was significantly related to the leaf deposited PM load (p ≤ 0.05).

Identification of cement in atmospheric particulate matter using the hybrid method of laser diffraction analysis and Raman spectroscopy

The production of cement is associated with the emissions of dust and particulate matter, nitrogen oxides (NOx), sulfur dioxide (SO2), carbon monoxide (CO), heavy metals, and volatile organic compounds into the environment. People living near cement production facilities are potentially exposed to these pollutants, including carcinogens, although at lower doses than the factory workers. In this study we focused on the distribution of fine particulate matter, the composition, size patterns, and spatial distribution of the emissions from Spassk cement plant in Primorsky Krai, Russian Federation. The particulate matter was studied in wash-out from vegetation (conifer needles) using a hybrid method of laser diffraction analysis and Raman spectroscopy. The results showed that fine particulate matter (PM10 fraction) extended to the entire town and its neighbourhood. The percentage of PM10 in different areas of the town and over the course of two seasons ranged from 34.8% to 65% relative to other size fractions of particulate matter. It was further shown that up to 80% of the atmospheric PM content at some sampling points was composed of cement-containing particles. This links the cement production in Spassk-Dalny with overall morbidity of the town population and pollution of the environment.

Relationship between indoor and outdoor size-fractionated particulate matter in urban microenvironments: Levels, chemical composition and sources

Exposure to particulate matter (PM) has been associated with adverse health outcomes, particularly in susceptible population groups such as children. This study aims to characterise children's exposure to PM and its chemical constituents. Size-segregated aerosol samples (PM0.25, PM0.25–0.5, PM0.5–1.0, PM1.0–2.5 and PM2.5–10) were collected in the indoor and outdoor of homes and schools located in Lisbon (Portugal). Organic and elemental carbon (OC and EC) were determined by a thermo-optical method, whereas major and trace elements were analysed by X-Ray Fluorescence. In school, the children were exposed to higher PM concentrations than in home, which might be associated not only to the elevated human occupancy but also to outdoor infiltration. The pattern of PM mass size distribution was dependent on the location (home vs. school and indoor vs. outdoor). The presence of EC in PM0.25 and OC in PM0.25–0.5 was linked to traffic exhaust emissions. OC and EC in PM2.5–10 may be explained by their adhesion to the surface of coarser particles. Generally, the concentrations of mineral and marine elements increased with increasing PM size, while for anthropogenic elements happened the opposite. In schools, the concentrations of mineral matter, anthropogenic elements and marine aerosol were higher than in homes. High mineral matter concentrations found in schools were related to the close proximity to busy roads and elevated human occupancy. Overall, the results suggest that exposure to PM is relevant and highlights the need for strategies that provide healthier indoor environments, principally in schools.

Evaluation of the effectiveness of a portable air cleaner in mitigating indoor human exposure to cooking-derived airborne particles

Gas cooking is an important source of airborne particulate matter (PM) indoors. Exposure to cooking-derived PM can lead to adverse human health impacts on non-smokers, especially in poorly-ventilated residential homes. Most of the previous studies on gas cooking emissions mainly focused on fine particles (PM2.5) with little information on their size-fractionation. Moreover, studies dealing with mitigation of indoor human exposure to cooking-derived PM are currently sparse. Therefore, a systematic study was conducted to investigate the characteristics of PM2.5 and size-fractionated PM derived from five commonly used cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying in a poorly-ventilated domestic kitchen under controlled experimental conditions. Additionally, an indoor portable air cleaner was employed as a mitigation device to capture cooking-derived PM and improve indoor air quality (IAQ). Results revealed that the oil-based deep-frying cooking released the highest airborne particles which were about 170 folds higher compared to the baseline levels for PM2.5 mass concentrations. The use of the air cleaner showed a statistically significant (p < 0.05) reduction in the indoor PM2.5 levels. Moreover, PM<0.25 (particles with diameter ≤ 250 nm) showed a very high mass concentration (378.2 μg/m3) during deep-frying, raising human health concern. A substantial reduction (~60–85%) in PM<0.25 mass concentrations and their total respiratory deposition doses (RDD) in the human respiratory tract was observed while using the air cleaner during the five cooking methods. Furthermore, morphological characteristics and the relative abundance of trace elements in cooking-derived PM were also investigated. This study provides useful insights into the assessment and mitigation of indoor human exposure to cooking-derived PM.

Size-fractionated carbonaceous aerosols down to PM0.1 in southern Thailand: Local and long-range transport effects

In this study, size-fractionated particulate matters (PM) down to ultrafine (PM0.1) particles were collected using a cascade air sampler with a PM0.1 stage, in Hat Yai city, Songkhla province, southern Thailand during the year 2018. The particle-bound carbonaceous aerosols (CA) as elemental carbon (EC) and organic carbon (OC) were quantified with the thermal/optical reflectance method following the IMPROVE_TOR protocol. The concentrations of different temperature carbon fractions (OC1-OC4, EC1-EC3 and PyO) in the size-fractionated PM were evaluated to discern OC and EC correlations as well as those between char-EC and soot-EC. The results showed that biomass burning, motor vehicle, and secondary organic aerosols (SOC) all contributed to the size-fractionated PM. The OC/EC ratios ranged from 2.90 to 4.30 over the year, with the ratios of PM2.5-10 being the highest, except during the open biomass burning period. The concentration of CA was found to increase during the pre-monsoon season and had its peak value in the PM0.5-1.0 fraction. The long-range transport of PMs from Indonesia, southwest of Thailand toward southern Thailand became more obvious during the pre-monsoon season. Transported plumes from biomass burning in Indonesia may increase the concentration of OC and EC both in the fine (PM0.5-1.0 and PM1.0-2.5) and coarse (PM2.5-10 and PM>10) fractions. The OC fraction in PM0.1 was also shown to be significantly affected by the transported plumes during the pre-monsoon season. Good OC and EC correlations (R2 = 0.824–0.915) in the fine particle fractions indicated that they had common sources such as fossil fuel combustion. However, the lower and moderate correlations (R2 = 0.093–0.678) among the coarser particles suggesting that they have a more complex pattern of emission sources during the dry and monsoon seasons. This indicates the importance of focusing emission control strategies on different PM particle sizes in southern Thailand.

PM10 and PM2.5 Qualitative Source Apportionment Using Selective Wind Direction Sampling in a Port-Industrial Area in Civitavecchia, Italy

The possibility to discriminate between different emission sources and between natural and anthropogenic contributions is a key issue for planning efficient air pollution reduction and mitigation strategies. Moreover, the knowledge of the particulate matter (PM) chemical composition for the different size fractions is recognized as increasingly important, in particular with respect to health effects of exposed population. This study is focused on the characterization of PM10 and PM2.5 main sources located in the Civitavecchia harbor-industrial area (Central Italy), namely a large coal-fired power plant, a natural gas power plant, the harbor area, the vehicular traffic (due to both the local traffic and the highway crossing the area) and small industrial activities. The approach was based on PM10/PM2.5 samples monthly collected for one year and a further relative chemical characterization of organic and inorganic fractions. Wind-select sensors, allowing a selective PM10 and PM2.5 sampling downwind to specific emission sources, were used for the overall sampling. This methodology manages to explain specific emission patterns and to assess the concentration levels of the micro pollutants emitted by local sources and particularly toxic for health. A descriptive statistical analysis of data was performed, also verifying the occurrence of legislative threshold exceedances. Moreover, in order to highlight the contribution of specific sources, the differences in the measured micro pollutants concentrations between wind directions, PM size fractions and sampling sites have been investigated, as well as the seasonal trends of pollutants concentrations. These results allow to highlight that the applied methodology represents a valid support in source apportionment studies.

Particulate matter emissions of less harmful-looking super-slim size cigarettes appealing to women: a laser spectrometric analysis of second-hand smoke.

Slim tobacco products shall appear by their look less harmful. In 2013, the European Union ministers discussed to ban them. However, only a ban on small package sizes was realized. To add more data for exposure risk assessment of slim tobacco products, the particulate matter (PM) amount in second-hand smoke (SHS) of super-slim size cigarettes compared with a king size brand was investigated. PM amount of four super-slim size cigarette types of the brand Couture was analysed in comparison with the king-size reference cigarette. Therefore, SHS was produced in an enclosed space with a volume of 2.88m3 by an automatic environmental tobacco smoke emitter. PM size fractions PM10, PM2.5 and PM1 were measured in real time using a laser aerosol spectrometer. SHS of Couture Gold contained about 36% and Couture Purple about 28% more PM than the reference cigarette. In contrast, Couture Green emitted about 37% and Couture Silver about 53% less PM than the reference cigarette. Depending on the brand, the PM2.5 mean concentrations increased up to 1538μg/m3. This exceeds the 24-h mean concentration of at most 25μg/m3 according to the WHO Air quality guidelines about 62-fold. Smoking in enclosed rooms leads to a massive increase of PM. The PM pollution by slim-size tobacco products are substantial and sometimes higher than by king size tobacco products. Therefore, SHS exposure from slim-size tobacco products is not less harmful to health. Decision makers should take this aspect in consideration.

Refined assessment of size-fractioned particulate matter (PM2.5/PM10/PMtotal) emissions from coal-fired power plants in China

Chinese coal-fired power plants (CFPPs) are experiencing large-scale and rapid retrofitting of ultralow emission (ULE), causing significant changes in emission level of particulate matter (PM) from CFPPs. In this study, based on coal ash mass balance over the whole process, an integrated emission factors (EFs) database of three size-fractioned particulate matters (PM2.5, PM10, and PMtotal) for CFPPs is constructed, which covers almost all typical ULE technical routes installed in CFPPs. To verify the reliability of PM EFs established in this study, we compare those with related results based on field tests. Overall, the gaps in the EFs of PM2.5, PM10, and PMtotal obtained by the two methods are not outrageous within a reasonable range. By combined with the refined size-fractioned PM EFs and unit-based activity level database, a detailed high-resolution emission inventory of PM2.5, PM10, and PMtotal from Chinese CFPPs in 2017 is established, with the corresponding total emissions of 143, 207, and 267 kt, respectively. Our estimation of PMtotal emission is comparable to the official statistics announced by China Electricity Council (CEC), which further demonstrates the reliability of PM EFs constructed in this study. Moreover, potential reductions of PM from CFPPs at two stages before and after 2017 are assessed under three application scenarios of major ULE technical routes. We forecast the final annual emissions of PM2.5, PM10, and PMtotal until 2020 will be reduced further, which fall within the range of 86–111 kt, 120–157 kt, and 142–184 kt, respectively, if all CFPPs achieve ULE requirements under the three scenarios. We believe our integrated database of PM EFs of CFPPs has good universality, and the forecast results will be helpful for policy guidance of ULE technologies, emissions inventory compilation, and regional air quality simulation and management.

Effects of Personal Exposures to Micro- and Nano-Particulate Matter, Black Carbon, Particle-Bound Polycyclic Aromatic Hydrocarbons, and Carbon Monoxide on Heart Rate Variability in a Panel of Healthy Older Subjects

As a non-invasive method, heart rate variability (HRV) has been widely used to study cardiovascular autonomous control. Environmental epidemiological studies indicated that the increase in an average concentration of particulate matter (PM) would result in a decrease in HRV, which was related to the increase of cardiovascular mortality in patients with myocardial infarction and the general population. With rapid economic and social development in Asia, how air pollutants, such as PM of different sizes and their components, affect the cardiovascular health of older people, still need to be further explored. The current study includes a 72 h personal exposure monitoring of seven healthy older people who lived in the Taipei metropolitan area. Mobile equipment, a portable electrocardiogram recorder, and the generalized additive mixed model (GAMM) were adopted to evaluate how HRV indices were affected by size-fractionated PM, particle-bound polycyclic aromatic hydrocarbons (p-PAHs), black carbon (BC), and carbon monoxide (CO). Other related confounding factors, such as age, sex, body mass index (BMI), temperature, relative humidity (RH), time, and monitoring week were controlled by fixed effects of the GAMM. Statistical analyses of multi-pollutant models showed that PM2.5–10, PM1, and nanoparticle (NP) could cause heart rate (HR), time-domain indices, and frequency-domain indices to rise; PM1–2.5 and BC would cause the frequency-domain index to rise; p-PAHs would cause HR to rise, and CO would cause time-domain index and frequency-domain index to decline. In addition, the moving average time all fell after one hour and might appear at 8 h in HRVs’ largest percentage change caused by each pollutant, results of which suggested that size-fractionated PM, p-PAHs, BC, and CO exposures have delayed effects on HRVs. In conclusion, the results of the study showed that the increase in personal pollutant exposure would affect cardiac autonomic control function of healthy older residents in metropolitan areas, and the susceptibility of cardiovascular effects was higher than that of healthy young people. Since the small sample size would limit the generalizability of this study, more studies with larger scale are warranted to better understand the HRV effects of simultaneous PM and other pollution exposures for subpopulation groups.

Temporal variation and distribution of size fractionated: platinum group elements and heavy metals in total suspended particulate

Heavy metals and PGEs are accumulating in the environment, due to industrial activities and car emissions. In this research, we chose the heavy industrial city (Changji, China) as a study area, and used ICP-MS to examine concentrations of some platinum group elements (PGEs) [platinum (Pt), palladium (Pd), and rhodium (Rh)] and heavy metals in total suspended particulate (TSP) in arid urban environment. We also investigated seasonal variation and distribution of size-fractionated atmospheric particulate matter for PGEs and heavy metals in TSP. The results indicated that PGEs and heavy metal concentrations in TSP followed the same seasonal trend: winter > autumn > spring > summer; this may be attributed to seasonal variation in pollution sources in Changji. However, there was a difference between PGEs and heavy metal distributions in size-fractionated atmospheric particulate matter in TSP. The highest concentrations of PGEs were not observed in the smallest size fraction of atmospheric particulate matter, while the concentrations of heavy metals increased as particulate matter size decreased. The emission mechanism of PGEs may lead to this special distribution of size fractionated.

Analysis of Particulate Matter Concentration Variability and Origin in Selected Urban Areas in Poland

The work presents the results of research and analyses related to measurements of concentration and chemical composition of three size fractions of particulate matter (PM), PM10, PM2.5 and PM1.0. The studies were conducted in the years 2014–2016 during both the heating and non-heating season in two Polish cities: Wrocław and Poznań. The studies indicate that in Wrocław and Poznań, the highest annual concentrations of particulate matter (PM1.0, PM2.5, and PM10) were observed in 2016, and the mean concentrations were respectively equal to 18.16 μg/m3, 30.88 μg/m3 and 41.08 μg/m3 (Wrocław) and 8.5 μg/m3, 30.8 μg/m3 and 32.9 μg/m3 (Poznań). Conducted analyses of the chemical composition of the particulate matter also indicated higher concentrations of organic and elemental carbon (OC and EC), and water-soluble ions in a measurement series which took place in the heating season were studied. Analyses with the use of principal component analysis (PCA) indicated a dominating percentage of fuel combustion processes as sources of particulate matter emission in the areas considered in this research. Acquired results from these analyses may indicate the influence of secondary aerosols on air quality. In the summer season, a significant role could be also played by an influx of pollutants—mineral dust—originating from outside the analyzed areas or from the resuspension of mineral and soil dust.

Size distribution of particulate matter in runoff from different leaf surfaces during controlled rainfall processes

The presence of plant leaves has been shown to lower the risks of health problems by reducing atmospheric particulate matter (PM). Leaf PM accumulation capacity will saturate in the absence of runoff. Rainfall is an effective way for PM to “wash off” into the soil and renew leaf PM accumulation. However, little is known about how PM wash-off varies with PM size and health problems caused by particulate pollution vary with PM size. This study thus used artificial rainfall with six plant species to find out how size-fractioned PM are washed off during rain processes. Total wash-off masses in fine, coarse and large fractions were 0.6–10.3 μg/cm2, 1.0–18.8 μg/cm2 and 4.5–60.1 μg/cm2 respectively. P. orientalis (cypress) and E. japonicus (evergreen broadleaved shrub) had the largest wash-off masses in each fraction during rainfall. P. cerasifera (deciduous broadleaved shrub) had the largest cumulative wash-off rates in each fraction. Rainfall intensity had more influence on wash-off masses and rates of large particles for six species and for small particles in evergreen species, but limited effect on wash-off proportions. Wash-off proportions decreased in large particles and increased in small particles along with rainfall. The results provide information for PM accumulation renewal of plants used for urban greening.

Different cardiorespiratory effects of indoor air pollution intervention with ionization air purifier: Findings from a randomized, double-blind crossover study among school children in Beijing

Indoor air pollution is associated with numerous adverse health outcomes. Air purifiers are widely used to reduce indoor air pollutants. Ionization air purifiers are becoming increasingly popular for their low power consumption and noise, yet its health effects remain unclear. This randomized, double-blind crossover study is conducted to explore the cardiorespiratory effects of ionization air purification among 44 children in Beijing. Real or sham purification was performed in classrooms for 5 weekdays. Size-fractionated particulate matter (PM), black carbon (BC), ozone (O3), and negative air ions (NAI) were monitored, and cardiorespiratory functions were measured. Mixed-effect models were used to establish associations between exposures and health parameters. Real purification significantly decreased PM and BC, e.g. PM0.5, PM2.5, PM10 and BC were decreased by 48%, 44%, 34% and 50%, respectively. O3 levels were unchanged, while NAI was increased from 12 cm-3 to 12,997 cm-3. Real purification was associated with a 4.4% increase in forced exhaled volume in 1 s (FEV1) and a 14.7% decrease in fractional exhaled nitrogen oxide (FeNO). However, heart rate variability (HRV) was altered negatively. Interaction effects of NAI and PM were observed only on HRV, and alterations in HRV were greater with high NAI. Ionization air purifier could bring substantial respiratory benefits, however, the potential negative effects on HRV need further investigation.

Characterization of Indoor Air Quality on a College Campus: A Pilot Study.

Recent construction trends on college campuses have demonstrated a shift to designing buildings with features focused on sustainability. However, few studies have investigated indoor air quality in institutions of higher education, particularly in sustainably designed buildings. The objective of this study was to evaluate the association of building and occupancy on indoor air quality within and between higher education buildings. We measured particulate matter, formaldehyde, carbon dioxide, and nitrogen oxides in LEED certified, retrofitted, and conventional building types on a college campus. Three size fractions of particulate matter were measured in each building. We conducted multi-zonal, 48-h measurements when the buildings were occupied and unoccupied. Outdoor particulate matter was significantly higher (PM2.5 = 4.76, PM4 = 17.1, and PM100 = 21.6 µg/m3) than in classrooms (PM2.5 = 1.7, PM4 = 4.2, and PM100 = 6.7 µg/m3) and common areas (PM2.5 = 1.3, PM4 = 4.2, and PM100 = 4.8 µg/m3; all p < 0.001). Additionally, concentrations of carbon dioxide and particulate matter were significantly higher (p < 0.05) during occupied sampling. The results suggest that occupancy status and building zone are major predictors of indoor air quality in campus buildings, which can, in turn, increase the concentration of contaminants, potentially impacting occupant health and performance. More research is warranted to reveal building features and human behaviors contributing to indoor exposures.

Impacts of In-Cabin Exposure to Size-Fractionated Particulate Matters and Carbon Monoxide on Changes in Heart Rate Variability for Healthy Public Transit Commuters

To evaluate the cardiovascular impact of traffic-related pollutant exposure on healthy young adults, the research team has collected the primary data of in-cabin exposure to air pollutants and heart rate variability (HRV). Twenty young healthy college students were recruited in Taipei metropolitan area. In addition to electrocardiogram, personal exposure to air pollutants, i.e., particulate matter (PM) and carbon monoxide (CO), and weather conditions, including temperature and relative humidity (RH), on campus, bus, and mass rapid transit were monitored continuously. The following HRV parameters were evaluated using generalized additive mixed model to adjust for personal and meteorological variables: heart rate (HR), the square root of the mean of the sum of the squares of differences between adjacent normal-to-normal (NN) intervals (r-MSSD), the standard deviation of all NN intervals (SDNN), the percentage of successive NN interval differences greater than 50 ms (pNN50), low-frequency power (LF), high-frequency power (HF), total power (TP), and LF/HF. They were assessed to find out the association between in-cabin exposure and HRV parameters. Compared with the HRV parameters measured on campus, the percent changes in r-MSSD, SDNN, pNN50+1, LF, HF, and TP decreased when the participants were in public transits. After adjusting for all locations, 5 min moving averages of PM2.5–10 and PM1 were significantly associated with the increase in the percent changes in HR and SDNN. Additionally, 5 min moving averages of PM2.5–10 exposure were significantly associated with the decrease in the percent change in HF, while it was significantly associated with the increase of the percent change in LF/HF. The reduction of the percent change in HR was also found to be significantly associated with 5 min CO moving averages. To conclude, current analyses have shown that size-fractionated PMs and CO exposure in public transits might lead to significant changes of HRV parameters for healthy young adults.