Exposure to airborne particulate matter in the ambient, indoor, and occupational environments

Exposure to airborne particulate matter results in various adverse health effects. Unlike other pollutants, such as ozone, sulfur dioxide, carbon monoxide, and oxides of nitrogen, for which there is significant exposure, particulate matter exposure is much more complex because it is not a single chemical species or even a limited number of chemical species. Particulate matter includes various chemical species in particles having a wide range of diameters and shapes that have widely varying toxicities. People are exposed to particles in the ambient environment, in indoor spaces, and in the occupational environment. This article reviews the information available on the concentrations of particulate matter and its composition in these general environmental categories.     

Inter- and intra-subject variability of kinetics of airway exhalation and deposition of particulate matter in indoor polluted environments

PM(2.5) generated by indoor combustion activities can contribute significantly to personal PM exposure. The aims of this study were: (1) to validate a device specifically designed to study the kinetics of particle exhalation and the percentage of airway particle deposition (%DEP) in polluted indoor environments (welding fumes, environmental tobacco smoke - ETS) and (2) to assess the intra- and inter-subject variability of the signal. The device was tested on 14 subjects exposed to welding fumes and 10 subjects exposed to environmental tobacco smoke (ETS), performing repeated measures at different environmental PM concentrations. The intra-subject variability of the signal for particles with diameter 0.3-1.0 μm showed a geometric mean of %CV always below 6%, despite the values of %DEP. In the welding fume study, the increase in airborne 0.5-1.0 μm PM concentrations between the consulting room and production department was explainable in terms of increased density due to the metallic composition of particles. The %DEP of 0.3-1.0 μm ETS particles decreased with airborne PM concentration due to the technical limits of a laser particle counter and the perturbation induced by the physical characteristics of ETS PM. However, also at those extreme conditions, the signal remained repeatable and the individual susceptibility to PM remained substantially unaltered. In conclusion, the versatility and portability of our device, together with the repeatability of the signal, confirmed that the kinetics of exhaled particles and %DEP could be routinely measured in polluted environments and used to define individual susceptibility to airborne particles.     

Study on suspended particulate matter and polycyclic aromatic hydrocarbons in indoor and outdoor air

Summary To study changes in the concentration of suspended particulate matter (SPM) in indoor and outdoor air, a new portable sampler (AND sampler) was designed that could separately collect particles exhibiting aerodynamic diameters of > 10 m, 2–10 m, and < 2 m. The relationship between the airborne particle concentration in indoor air and that in outdoor air varied with the aeordynamic diameter of the particles. The concentration of SPM in the indoor air increased in proportion to that in the outdoor air. The concentration of polycyclic aromatic hydrocarbons (PAH) in SPM also varied with the aerodynamic diameter of the particles. Fine particles exhibiting an aerodynamic diameter of < 2 m contained high concentration of PAH. The concentrations of benzo(k)fluoranthene, benzo(a)pyrene, and benzo (ghi) perylene in indoor air increased in proportion to those in outdoor air.     

Characterization of fine particulate matter in Ohio: indoor, outdoor, and personal exposures

Ambient, indoor, and personal PM2.5 concentrations were assessed based on an exhaustive study of PM2.5 performed in Ohio from 1999 to 2000. Locations in Columbus, one in an urban corridor and the other in a suburban area were involved. A third rural location in Athens, Ohio, was also established. At all three locations, elementary schools were utilized to determine outdoor, indoor, and personal PM2.5 concentrations for fourth and fifth grade students using filter-based measurements. Three groups of 30 students each were used for personal sampling at each school. Continuous ambient PM2.5 mass concentrations were also measured with tapered element oscillating microbalances (TEOMs). At all three sites, personal and indoor PM2.5 concentrations exceeded outdoor levels. This trend is consistent on all week days and most evident in the spring as compared to fall and winter. The ambient PM2.5 concentrations were similar among the three sites, suggesting the existence of a common regional source influence. At all the three sites, larger variations were found in personal and indoor PM2.5 than ambient levels. The strongest correlations were found between indoor and personal concentrations, indicating that personal PM2.5 exposures were significantly affected by indoor PM2.5 than by ambient PM2.5. This was further confirmed by the indoor to outdoor (I/O) ratios of PM2.5 concentrations, which were greater when school was in session than non-school days when the students were absent.     

Evaluation of cytokine expression in BEAS cells exposed to fine particulate matter (PM2.5) from specialized indoor environments

Fine particles were collected in three indoor environments and an outdoor reference site. Samples were acid and aqueous extracted for metal analyses and cytokine expression study using a BEAS-2B line. Results revealed that the average PM(2.5) concentration indoors was 5.8 μg/m(3) while outside, it was 9.4 μg/m(3). The airborne metal concentrations in indoor air ranged from 0.01 ng/m(3) (Cd) to 620 ng/m(3) (Al). All metals analyzed were higher indoors when compared to outdoor (I/O ratio) indicating a contribution from the workplace. Some metals were more efficiently extracted (e.g., Ni, V, As) in the aqueous phase than others (e.g., Fe and Al). Toxicological assays showed that the aqueous extracts at 20% induced IL-6 and subsequently inhibited it at a higher concentration (50%); both IL-8 and MCP-1 were inhibited at 20 and 50%. As, Ni and V concentrations seem to be the most important metals associated with the cytokine induction/inhibition response probably due to the higher bioavailability.     

Occurrence of metals in various size fractions of particulate matter

Size distributions of trace metals of specific health concern (Pb, Cd, Cr, Ni, Cd, V, Zn and Fe) in the fine (PM2.5) and coarse (PM2.5-10) fractions of suspended particulate matter were evaluated. Samples were collected through a year in three sites (traffic oriented and urban background in the urban area of Rome, and remote, in the Regional Park of Simbruini Mountains). Mean concentrations never exceeded the values recommended by WHO and EU. During winter season, levels of Cr, Cd, Pb and Zn resulted higher than in summer, in both fine and coarse fractions. The series of Pb, Cd, and V concentrations clearly showed a predominant fine-particle distribution, whereas Cr, Mn and Ni were more equally distributed between the coarse and fine fractions. Fe prevailed in the coarse mode at the urban sites. At the urban sites mean concentrations of the different metals were from 4 to 22 times higher than at the remote site. For various metals the distribution mode, as well as the seasonal trends of the concentrations, showed significant differences between urban and remote site. In busy and densely populated urban areas, without relevant industrial emissions, anthropogenic sources of metallic species seem still to give a contribution to air pollution, though a trend downwards, compared to previous surveys, was observed, particularly for Pb.     

Predictors of indoor fine particulate matter in infants’ bedrooms in Denmark

Background

Particulate matter (PM) in ambient air is responsible for adverse health effects in adults and children. Relatively little is known about the concentrations, sources and health effects of PM in indoor air.

Objective

To identify sources of fine PM in infants’ bedrooms.

Methods

We conducted 1122 measurements of fine PM (PM_2.5 and black smoke) in the bedrooms of 389 infants and registered indoor activities and characteristics of the house. We used mixed models to identify and quantify associations between predictors and concentrations.

Results

The concentration of PM_2.5 was 2.8 times (95% confidence interval [CI], 1.4–5.5 times) higher in houses where people smoked; the concentration increased by 19% (95% CI, 15–23%) per doubling of the amount of tobacco smoked and decreased by 16% (95% CI, 9–27%) per 5-m increase in the distance between the smoking area and the infant’s bedroom. Frying without a range hood was associated with a 32% (95% CI, 12–54%) higher PM_2.5 concentration per time per day, whereas frying with use of a range hood did not increase the concentration in the infant’s bedroom. Use of a fireplace, stove, candles or vacuum-cleaner, interior rebuilding or renovation, local traffic, inner city residence and cold season increased the fine PM concentration. Open windows decreased the PM_2.5 concentration in homes with smokers but increased the concentration in non-smoking homes.

Conclusions

We identified several sources of fine PM in infants’ bedrooms. The concentrations can be reduced by use of a range hood for frying, by not using candles, a fireplace or a stove, by increasing the distance between the bedroom and the smoking area and by opening windows in houses of smokers. Smoking is a strong predictor of fine PM in infants’ bedrooms and should be avoided.     

Evaluation of the vehicle contributions of metals to indoor environments

A large number of diesel vehicles carrying gravel and sand shuttle back and forth every day on the major thoroughfares (Tai-16 and Tai-21) from Shinyi to Jiji in Nantou, Taiwan. A total of 10 stations along the major thoroughfares were selected as the exposure sites, whereas a small village located ～9?km from a main traffic route was selected as the control site. Outdoor and indoor aerosol samples were collected using high-volume samplers and Harvard samplers, respectively. The metal concentrations of outdoor and indoor PM(10) at the exposure sites were, respectively, higher than those at the control site. The plots between metal contents in the aerosols and road dust showed that diesel vehicles contributed significant amounts of metals to the outdoor and indoor aerosols at the exposure sites. Household dust samples along the roadside within 30?m of the main road in the small towns were collected using the wipe method. Based on the results of principal component analysis (PCA), three major components for household dust were identified: resuspended from road dust, brake wear and diesel emissions. Enrichment factors were applied to assess the contribution of pollution sources to household dust. These factors were calculated with respect to unpolluted river dust samples (EF(river)) and road dust (EF(road)). The differences between EF(river) and EF(road) could be mainly attributed to the effects of resuspension by passing vehicles. Approximately 72%, 68%, 68%, 73% and 86% of the vehicle-related metals Pb, Zn, Cu, Ni and Mo content, respectively, in household dust were the result of the resuspension of road dust by passing vehicles. The data of daily intakes of five metals (i.e., Fe, Pb, Cu, Ni and Mo) from inhalation and ingestion pathways showed that the doses from the ingestion pathway were much higher than those from the inhalation pathway.     

Measurement of vertical concentration profiles of airborne particulate matter in indoor environments: Implications for refinement of models and monitoring campaigns

Vertical concentration profiles of airborne particulate matter were measured in four different indoor environments- library, coffee room, workshop and undergraduate student hostel- on the University Campus at Sutton Bonington. Measurements were carried out using an electronically-controlled lifting platform carrying a real-time optical particle monitor for sampling air sequentially at different heights within the breathing zone. Data was automatically logged at the different receptor levels, for the determination of the average vertical concentration profile of the various particle size ranges which include inhalable, thoracic, alveolic, PM10 and PM2.5. Vertical concentration profiles measured in these different indoor environments exhibited different characteristics but in almost all cases it was clear that different height groups of the population are exposed to different concentrations of the pollutant. This has implications on setting of air quality standards for the protection of public health. The results indicate that we may have to re-think the whole concept of air quality standards and develop protocols for indoor air quality monitoring and modelling which would take into account the above-mentioned factor.     

Occurrence of polychlorinated terphenyls (PCTs) in indoor particulate matter.

In the course of a routine investigation concerned with polychlorinated biphenyl (PCB) contamination of dust collected in classrooms of a junior high school, a group of electron capture detector (ECD)-sensitive compounds with high boiling points were found in addition to PCBs. Using gas chromatographic-mass spectrometric techniques, these compounds were identified as polychlorinated terphenyls (PCTs). Additional measurements indicated that the PCTs were present only in particulate matter collected from the tops of fluorescent light frames but not in air samples obtained concomitantly in the classrooms. Attempts to identify the PCT emission source were unsuccessful. A survey of the literature revealed that PCTs are ubiquitously distributed environmental contaminants, although no data on their indoor occurrence have been reported to date. In view of the toxic effects of PCTs, which seem to be as important as those of PCBs, further attention should be given to the possible presence of PCTs in indoor environments.     

Identification of sources of atmospheric particulate matter and trace metals in Constantine,Algeria

Very few previous investigations of respirable PM have been undertaken in the city of Constantine, Algeria. In general, air quality in Algeria and other Maghreb countries has not been extensively studied because of the insufficient number of researchers involved in this field and the unreliability of the few air quality monitoring networks installed in Algeria. It is therefore of utmost importance to address this problem in order to estimate the concentration levels of PM10 and their origins. The purpose of this study was to identify the different sources of PM10 and some chemical elements (Pb, Cu, Zn, Fe, K, Ca, Na, Mg) at a traffic site at Zouaghi, in the south of Constantine, using different statistical methods: factor analysis (FA) to categorise the different trace elements according to their origin, and the enrichment factor (EF) to identify terrigenous elements and those having a marine origin. We also used back-trajectories clustering to identify potential distant sources that contribute to particulate pollution and metallic elements in our site.     

Tuberculosis Risk among Medical Trainees,Pune, India

During 2012–2013, at a public hospital in Pune, India, 26 (3.9%) cases of tuberculosis were reported among 662 medical trainees, representing an estimated incidence of 3,279 cases/100,000 person-years. Three of these infections were isoniazid-resistant, 1 was multidrug-resistant, and 1 occurred in a trainee who had fulminant hepatitis after starting treatment for TB.     

Viruses in acute gastroenteritis in children in Pune, India

A 2-year study from January 1981 to December 1982 was undertaken to determine the role of viruses in the causation of diarrhoea in hospitalized children in Pune, Maharashtra State, India. The stool samples of 426 children (213 diarrhoeal and 213 non-diarrhoeal controls) were investigated by electron microscopy and ELISA for the presence of viruses. Six morphologically distinct viruses were visualized: rotavirus, coronavirus-like particles (CVLP), adenovirus, astrovirus, calicivirus and small round virus-like particles (SRV). Rotavirus was detected in 28.6% of the diarrhoeal patients and in 1.4% of the controls. The frequency of infection with rotavirus was highest in the children aged less than 5 years. The mean age of rotavirus-positive patients was 11 months. Although rotavirus was detected in almost every month, there has a seasonal trend for colder months when CVLP cases were fewest. However, the prevalence of CVLP was greater in the control group (23.0%) rather than in those with diarrhoea (8.9%). In the control group, CVLP were detected more frequently during the summer months. An inverse relationship between CVLP and rotavirus was observed in children. Adenovirus, astrovirus, calicivirus and SRV were detected in a small proportion of children with and without clinical symptoms of gastroenteritis.     

Outbreak of Mucormycosis in Coronavirus Disease Patients,Pune, India

We provide an overview of the epidemiology and clinical course of mucormycosis in the coronavirus disease (COVID-19) pandemic era. We conducted a retrospective chart review of 178 patients with clinical or diagnostic, endoscopically or histopathologically confirmed rhino-sino-orbital or cerebral mucormycosis after COVID-19 treatment during the second wave of COVID-19 in Pune, India. Median time to symptom onset from COVID-19 detection was 28 days. Moderate or severe COVID-19 was seen in 73% of patients and diabetes in 74.2%. A total of 52.8% received steroids. Eschar over or inside the nose was seen in 75%, but baseline clinical and laboratory parameters were mostly unremarkable. Bone penetration was present in ≈90% of cases, 30% had soft-tissue swelling of the pterygopalatine fossa and 7% had cavernous sinus thrombosis, and 60% had multifocal mucormycosis. Of the 178 study cases, 151 (85%) underwent surgical debridement. Twenty-six (15%) died, and 16 (62%) of those had multifocal mucormycosis.     

Implications of individual particulate matter component toxicity for population exposure

There is currently much debate regarding which chemical or physical characteristics of particulate matter are responsible for the adverse health effects apparent in epidemiological studies. Toxicological data suggest that the strongest evidence for adverse effects is associated with primary combustion emissions. In contrast, few toxicological studies have observed effects from secondary inorganic particulate components resulting from emissions of ammonia, sulphur dioxide and nitrogen oxides. A study has been performed to examine the contribution of different emission source sectors to the total exposure associated with a variety of individual PM_2.5 components in Europe using the CMAQ air quality model. The results suggest that secondary particulate mass dominates PM_2.5 concentrations, being responsible for 82% of total anthropogenic exposure, with agriculture the dominant contributing sector. However, if the toxic component of PM_2.5 lies in the primary fraction, agriculture contributes less than 3% of primary particulate exposure, with the majority due to emissions from residential sources, transport and industry. Taken together, these results suggest that identification of the particulate matter fraction responsible for toxicity is critical for designing effective emission reduction policies and that the assumption that all PM_2.5 mass is equally toxic may lead to a focus on reducing secondary particulate pre-cursor emissions, which will deliver little in terms of reducing adverse health effects.     

Effect of copper binding by suspended particulate matter on toxicity

The kinetics of Cu(II) interactions with Susquehanna River (mid-Atlantic, USA) particle suspensions using the copper ion selective electrode (Cu-ISE) method indicated that the concentration of Cu2+ in both the suspension and filtrate was kinetically controlled; the reaction of Cu(II) in the suspension was faster than that in the filtrate. Bioassay tests were performed in continuous flow-through bioassay systems to examine the effect of kinetics of Cu(II) interactions with suspended solids on the toxicity of Cu to Ceriodaphnia dubia. The toxicity curves were displaced to higher total Cu concentration as the reaction time increased, indicating that such interaction of Cu with solids was time dependent. Further, the toxicity curves overlapped for reaction times of 6 and 24 h, indicating that the reaction was relatively rapid and that equilibrium was achieved within 6 h. The survival of organisms was related to the free Cu2+ concentration but deviated from the result for bioassays in which dissolved organic matter (DOM) rather than particles reacted with the added Cu(II) to affect the free Cu2+ concentration. It may be interpreted that, besides the toxic effect of Cu2+, particles exert adverse influences on the organisms.     

Influenza surveillance in Pune, India, 1978-90.

Continuous surveillance of influenza was carried out in Pune between 1978 and 1990. Most of the cases were identified during investigation of 16 outbreaks of influenza in Pune over this period. The majority of cases were children. Ten of the outbreaks occurred during rainy seasons. A total of 290 isolates consisting of several antigenic variants of influenza type A (H3N2), type A (H1N1), and type B viruses were isolated from throat/nasal swabs that were processed in chick embryos and MDCK cell culture and identified using the haemagglutination inhibition test. These variants circulated every year or in alternate years. Nearly two-thirds of the influenza virus isolates (181 out of 290) were from children aged < 10 years. Seasonal analysis indicated that the highest number of isolates (174) were collected during the rainy months of July, August and September, with the maximum number (93) in July.     

室内可吸入颗粒物污染与哮喘和肺癌的相关性研究综述

室内可吸入颗粒物(inhalable particulate matter,PM₁₀)污染可能受室外PM₁₀污染影响,但其主要来源、成分与室外PM₁₀存在较大差异。大气污染越来越严重,哮喘和肺癌发病率的升高使人们更加关注PM₁₀与哮喘、肺癌的关系。室内空气污染尤其是室内PM₁₀污染在肺癌、哮喘发生发展中的作用成为学者们研究的新重点。本文从室内PM₁₀污染现状、室内PM₁₀污染与哮喘、肺癌的相关性进行了综述。现有研究结果提示室内PM₁₀可能与哮喘、肺癌的发生发展相关,但尚缺乏强有力的全面系统深入的实证研究,结论尚待进一步探究。今后应加强对室内PM₁₀主要污染成分对疾病作用机理方面的深究。     

兰州市冬季室内外颗粒物污染特征及其理化特性研究

目的探讨兰州市冬季室内外颗粒物污染特征及其理化特性。方法于2012年11月至2013年1月在不同采样点(混合区、工业区、郊区、公共场所)连续采集大气颗粒物(PM2.5和PM10)样品,分别采用离子色谱法和原子吸收分光光度法测定PM2.5和PM10中水溶性离子(F-、Cl-、NO3-、SO42-、Na+、NH4+、K+、Mg2+、Ca2+)和重金属(Fe、Pb、Cd和Cu)。结果调查期间PM2.5和PM10浓度均超过GB 3095—2012《环境空气质量标准》二级标准限值。除公共场所PM2.5外,其余采样点PM2.5和PM10污染均呈现为室外高于室内;室内颗粒物中水溶性离子主要为SO42-、NO3-、Cl-和NH4+,室外主要为SO42-、NO3-和Cl-;水溶性离子对PM2.5的贡献室外高于室内,对PM10的贡献则相反;室内外颗粒物中重金属污染均表现为室外高于室内,城区高于郊区,且Fe污染水平整体较高,Pb、Cd分别在混合区和工业区污染较重。结论本次调查的兰州市冬季室内外颗粒物污染较为严重,应进一步关注颗粒物中水溶性离子、铅、镉的污染水平。