Particulate matter concentration levels during intense haze event in an urban environment

This study assessed concentration levels of particulate matter (PM) in the ambient environment of Ilorin metropolis, Nigeria, during haze episodes. Meteorological data (wind speed and direction, rainfall data, sunshine data, relative humidity and temperature) were obtained. Aerocet 531S particle counter (MetOne Instruments, USA) was used to measure four mass concentration ranges of PM (PM_1.0, PM_2.5, PM₁₀ and the total suspended particles (TSP)) in 10 locations taking into consideration land use patterns. Surfer® version 8 (Golden Software LLC, USA) was used to model the spatial variation of particulate matter concentration levels using kriging interpolation griding method. Human exposure assessment was done using the total respiratory deposition dose (TRDD) estimates and statutory limit breach (SLB) approaches. The appearance of dominating weak southern atmospheric wind flow was observed as wind speed ranged from 0 to 6.811 m/s while solar radiation periods ranged from 0.3 to 3.5 h/day. The relative humidity of the metropolis ranged between 28 and 57%, while daily temperature was 15 to 36 °C. Highest concentration levels of PM measured were 73.4, 562.7, 7066.3 and 9907.8 μg/m³ for PM_1.0, PM_2.5, PM₁₀ and TSP, respectively. Very strong negative correlations existed between the PM concentration levels and microclimatic parameters. Spatial variation of the concentration level as modelled using Surfer® version 8 indicated that particulate concentration level increases from south to north. Concentration levels of PM for the 24-h averaging period were generally above the 24-h threshold limit value set by the regulatory agencies for all the locations.     

Study of size and mass distribution of particulate matter due to crop residue burning with seasonal variation in rural area of Punjab, India

Emission from field burning of agricultural crop residue is a common environmental hazard observed in northern India. It has a significant potential health risk for the rural population due to respirable suspended particulate matter (RSPM). A study on eight stage size segregated mass distribution of RSPM was done for 2 wheat and 3 rice crop seasons. The study was undertaken at rural and agricultural sites of Patiala (India) where the RSPM levels remained close to the National Ambient Air quality standards (NAAQS). Fine particulate matter (PM(2.5)) contributed almost 55% to 64% of the RSPM, showing that, in general, the smaller particles dominated during the whole study period with more contribution during the rice crop as compared to that of wheat crop residue burning. Fine particulate matter content in the total RSPM increased with decrease in temperature. Concentration levels of PM(10) and PM(2.5) were higher during the winter months as compared to that in the summer months. Background concentration levels of PM(10), PM(2.5) and PM(10-2.5) were found to be around 97 ± 21, 57 ± 15 and 40 ± 6 μg m(-3), respectively. The levels increased up to 66, 78 and 71% during rice season and 51, 43 and 61% during wheat crop residue burning, respectively. Extensive statistical analysis of the data was done by using pair t-test. Overall results show that the concentration levels of different size particulate matter are greatly affected by agricultural crop residue burning but the total distribution of the particulate matter remains almost constant.     

Seasonal variability of endotoxin in ambient fine particulate matter

Endotoxin is a toxic, pro-inflammatory compound that has been detected in indoor air and dust in homes and occupational settings, and also in outdoor air. Data on the outdoor sampling of endotoxin are limited. Currently, little is known about the seasonal variation and influence of temperature on outdoor endotoxin levels. In the present study, we report endotoxin levels in fine fraction particulate matter with a 50% aerodynamic cutoff diameter of 2.5 microm (PM2.5) and describe the seasonal variation of endotoxin in Munich, Germany. In 1999-2000, PM2.5 was collected at forty outdoor monitoring sites across Munich. Approximately four samples were collected at each site for a total of 158 samples. Endotoxin concentrations in the PM2.5 samples were determined using the kinetic chromogenic Limulus Amebocyte Lysate (LAL) assay. The geometric mean endotoxin concentration was 1.07 EU mg PM2.5(-1) (95% C.I.: 0.915-1.251) or 0.015 EU m(-3) of sampled air (95% C.I.: 0.013-0.018). Munich endotoxin levels were significantly related to ambient temperature (p < 0.0001) and percent relative humidity (p < 0.0001). Sampling periods with higher average temperatures yielded higher levels of endotoxin in PM2.5 (r = 0.641), whereas decreases in percent relative humidity were associated with increased endotoxin levels in PM2.5 (r = -0.388). Endotoxin levels were significantly higher during the warmer seasons of spring [means ratio (MR): 2.5-2.7] and summer (MR: 2.1-3.0) than during winter. Although temperature and relative humidity do not explain all of the variability in endotoxin levels, their effects were significant in our data set. Temperature effects and seasonal variation of endotoxin should be considered in future studies of outdoor endotoxin.     

Vehicular particulate matter emissions in road tunnels in Sao Paulo, Brazil

In the metropolitan area of S?o Paulo, Brazil, ozone and particulate matter (PM) are the air pollutants that pose the greatest threat to air quality, since the PM and the ozone precursors (nitrogen oxides and volatile organic compounds) are the main source of air pollution from vehicular emissions. Vehicular emissions can be measured inside road tunnels, and those measurements can provide information about emission factors of in-use vehicles. Emission factors are used to estimate vehicular emissions and are described as the amount of species emitted per vehicle distance driven or per volume of fuel consumed. This study presents emission factor data for fine particles, coarse particles, inhalable particulate matter and black carbon, as well as size distribution data for inhalable particulate matter, as measured in March and May of 2004, respectively, in the Janio Quadros and Maria Maluf road tunnels, both located in S?o Paulo. The Janio Quadros tunnel carries mainly light-duty vehicles, whereas the Maria Maluf tunnel carries light-duty and heavy-duty vehicles. In the Janio Quadros tunnel, the estimated light-duty vehicle emission factors for the trace elements copper and bromine were 261 and 220 microg km(-1), respectively, and 16, 197, 127 and 92 mg km(-1), respectively, for black carbon, inhalable particulate matter, coarse particles and fine particles. The mean contribution of heavy-duty vehicles to the emissions of black carbon, inhalable particulate matter, coarse particles and fine particles was, respectively 29, 4, 6 and 6 times higher than that of light-duty vehicles. The inhalable particulate matter emission factor for heavy-duty vehicles was 1.2 times higher than that found during dynamometer testing. In general, the particle emissions in S?o Paulo tunnels are higher than those found in other cities of the world.     

Investigation of indoor environmental quality in Shanghai metro stations, China

A field study was carried out in Shanghai metro stations to gather and evaluate information about the real environment. The thermal environment and particulate matter levels were monitored in this study. The mean thermal sensation vote in metro stations was 0.91, and the mean thermal neutral temperature was 20.6°C. Although 92.1% of subjects voted that the thermal environment was acceptable, the condition of air quality in Shanghai metro stations was not good. The mean levels of PM1.0, PM2.5, and PM10 were 0.231 ± 0.152, 0.287 ± 0.177, and 0.366 ± 0.193 mg/m³, respectively. The contribution of PM1.0 to PM2.5 and PM2.5 to PM10 was up to 79% and 76%, respectively. This means that fine particles or ultrafine particles constituted the preponderant part of metro station particulate matter.     

Effect of ventilation rate on air cleanliness and energy consumption in operation rooms at rest

The interrelationships between ventilation rate, indoor air quality, and energy consumption in operation rooms at rest are yet to be understood. We investigate the effect of ventilation rate on indoor air quality indices and energy consumption in ORs at rest. The study investigates the air temperature, relative humidity, concentrations of carbon dioxide, particulate matter (PM), and airborne bacteria at different ventilation rates in operation rooms at rest of a medical center. The energy consumption and cost analysis of the heating, ventilating, and air conditioning (HVAC) system in the operation rooms at rest were also evaluated for all ventilation rates. No air-conditioned operation rooms had very highest PM and airborne bacterial concentrations in the operation areas. The bacterial concentration in the operation areas with 6–30 air changes per hour (ACH) was below the suggested level set by the United Kingdom (UK) for an empty operation room. A 70% of reduction in annual energy cost by reducing the ventilation rate from 30 to 6 ACH was found in the operation rooms at rest. Maintenance of operation rooms at ventilation rate of 6 ACH could save considerable amounts of energy and achieve the goal of air cleanliness.     

Statistical Analysis of Air Pollutants and Meteorological Parameters in Afyon, Turkey

In this study, the relation between sulfur dioxide (SO₂) and particulate matter (PM) concentrations periodically measured in the city of Afyon’s atmosphere with meteorological factors such as precipitation, humidity, temperature, wind velocity, and inversion were investigated. The mean values of SO₂ and PM concentrations measured during the winter months of October–March 1990–1999 were correlated with the meteorological parameters of the same period. Simple and multiple linear regression analysis were utilized to evaluate the contribution of meteorological variables. The statistical results show that the pollutants, i.e., SO₂ and PM are dependent upon humidity, temperature, and inversion at the 1% significance level; while the dependence of both pollutants with temperature is negative when those of humidity and inversion are positive. Two models in which temperature and inversion are dependent with multiple variables are recommended for predicting the contribution of meteorological parameters on SO₂ and PM. In addition, the relationship between humidity, temperature, and inversion with pollutants is also determined using nonlinear (polynomial) models.     

Composition of heavy metals and airborne fibers in the indoor environment of a building during renovation

The renovation of a building will certainly affect the quality of air in the vicinity of where associated activities were undertaken, this includes the quality of air inside the building. Indoor air pollutants such as particulate matter, heavy metals, and fine fibers are likely to be emitted during renovation work. This study was conducted to determine the concentration of heavy metals, asbestos and suspended particulates in the Biology Building, at the Universiti Kebangsaan, Malaysia (UKM). Renovation activities were carried out widely in the laboratories which were located in this building. A low-volume sampler was used to collect suspended particulate matter of a diameter size less than 10 μm (PM??) and an air sampling pump, fitted with a cellulose ester membrane filter, were used for asbestos sampling. Dust was collected using a small brush and scope. The concentration of heavy metals was determined through the use of inductively coupled plasma-mass spectroscopy and the fibers were counted through a phase contrast microscope. The concentrations of PM?? recorded in the building during renovation action (ranging from 166 to 542 μg m?3) were higher than the value set by the Department of Safety and Health for respirable dust (150 μg m?3). Additionally, they were higher than the value of PM?? recorded in indoor environments from other studies. The composition of heavy metals in PM?? and indoor dust were found to be dominated by Zn and results also showed that the concentration of heavy metals in indoor dust and PM?? in this study was higher than levels recorded in other similar studies. The asbestos concentration was 0.0038 ± 0.0011 fibers/cc. This was lower than the value set by the Malaysian Department of Occupational, Safety and Health (DOSH) regulations of 0.1 fibers/cc, but higher than the background value usually recorded in indoor environments. This study strongly suggests that renovation issues need to be considered seriously by relevant stakeholders within the university in order to ensure that the associated risks toward humans and indoor environment are eliminated, or where this is not feasible, minimized as far as possible.     

Ambient concentrations of airborne endotoxin in two cities in the interior of British Columbia, Canada

This study measured and analyzed the outdoor airborne endotoxin concentration, on particulate matter (PM2·? and PM1?), for two cities in the interior of British Columbia, Canada. Samples were collected throughout one seasonal cycle, from October 2005 to September 2006. It was found that concentrations were generally highest in the summer and fall, and lowest in the winter and spring. Temperature and relative humidity were found to be most influential, with highest endotoxin concentrations recorded during warm periods and moderate relative humidity (35 to 75 percent). No clear association of concentration with wind direction was observed. Results were comparable between the two cities considered in this study, and concentrations were similar to or slightly higher than those reported by other studies considering urban locations. Endotoxin concentration was also found to be positively associated with agricultural dust sources identified by a source apportionment study conducted at one of the sampling locations.     

库尔勒市大气颗粒物污染特征与影响因素分析

针对库尔勒市PM 10、PM 2.5年均浓度超标现象,基于市区3个环境监测站2013—2017年的逐时观测数据,分析PM 10、PM 2.5污染特征、成因及其主要影响因素。结果表明:①2013—2017年库尔勒市PM 10年均浓度变化较大且无明显趋势,PM 2.5年均浓度整体呈下降趋势;②季节尺度上,库尔勒市PM 10在每年2—5月呈现高浓度,PM 2.5高浓度期则为10月至翌年5月;③城郊的开发区站PM 10浓度最高,老城区的州政府站PM 2.5浓度最高,在PM 10和PM 2.5的高浓度期空间差异尤其显著;④PM 10与风速显著正相关,来自塔克拉玛干沙漠的风蚀沙尘颗粒物是库尔勒地区颗粒污染物的主要来源;⑤库尔勒市PM 10主要为外源输入,PM 2.5则以城市内源为主,相对湿度、风速、风向、温度等气象条件是影响大气颗粒物浓度及分布的重要因素。     

Influence of Meteorological Parameters on Particulates and Atmospheric Pollutants at Taichung Harbor Sampling Site

Atmospheric aerosol particles and metallic concentrations, ionic species were monitored at the Experimental harbor of Taichung sampling site in this study. This work attempted to characterize metallic elements and ionic species associated with meteorological conditions variation on atmospheric particulate matter in TSP, PM_2.5, PM_2.5–10. The concentration distribution trend between TSP, PM_2.5, PM_2.5–10 particle concentration at the TH (Taichung harbor) sampling site were also displayed in this study. Besides, the meteorological conditions variation of metallic elements (Fe, Mg, Cr, Cu, Zn, Mn and Pb) and ions species (Cl⁻, NO₃ ⁻, SO₄ ²⁻, NH₄ ⁺, Mg²⁺, Ca²⁺ and Na⁺) concentrations attached with those particulate were also analyzed in this study. On non-parametric (Spearman) correlation analysis, the results indicated that the meteorological conditions have high correlation at largest particulate concentrations for TSP at TH sampling site in this study. In addition, the temperature and relative humidity of meteorological conditions that played a key role to affect particulate matter (PM) and have higher correlations then other meteorological conditions such as wind speed and atmospheric pressure. The parameter temperature and relative humidity also have high correlations with atmospheric pollutants compared with those of the other meteorological variables (wind speed, atmospheric pressure and prevalent wind direction). In addition, relative statistical equations between pollutants and meteorological variables were also characterized in this study.     

乌鲁木齐市可吸入颗粒物污染水平及其与气象因素的相关性分析

为了解可吸入颗粒物污染水平与气象因素之间的关系,从2008年9月—2010年2月采集乌鲁木齐市可吸入颗粒物样品,并对其随时间的变化特征及其与气象因素之间的相关性进行了统计分析。结果表明,采样时间内可吸入颗粒物中PM2.5和PM2.5-10的质量浓度的范围分别为38.2~468.7μg/m3和20.8~243.1μg/m3,平均浓度分别为134.2μg/m3和69.2μg/m3。可吸入颗粒物同时受几种气象因素的影响,其浓度与温度、能见度、风速呈负相关,与湿度呈正相关。     

Investigation into presence of atmospheric particulate matter in Marikana, mining area in Rustenburg Town, South Africa

An investigation to find out presence of particulate matter in Marikana, a mining area in Rustenburg town, South Africa, was carried out in the months of August and November of 2008. Samples were collected for measurements of particulate matter (PM) of particle diameters of PM10, PM2.5, and PM1. After gravimetric analysis of daily measurements, it was found that PM10 concentration values ranged between 3 and 9 ??g/m³, PM2.5 concentration values ranged between 16 and 26 ??g/m³, and PM1 concentration values ranged between 14 and 18 ??g/m³ for the month of August 2008. For the month of November, it was found that PM10 concentration values ranged between 2 and 8 ??g/m³, PM2.5 concentration values ranged between 0 and 5 ??g/m³, and PM1 concentration values ranged between 4 and 15 ??g/m³. This study was undertaken as preliminary work having in mind that mining activities could be emitting high levels of particulate matter in the atmosphere which might be degrading the quality of the air. It was observed, however, that the daily particulate matter especially of PM10 emitted were quite low when compared to laid down International Air Quality Standards. The standards did not give guidelines for particulate matter of diameter 2.5 ??m. It was concluded that particulate matter came from three major sources: platinum mining, domestic biomass burning, and traffic emissions due to fuel burning.     

乌鲁木齐市冬季大气颗粒物PM_(10) 和PM_(2.5)污染水平及相关性研究

为研究乌鲁木齐市冬季采暖期间大气颗粒物污染特征,通过采样和在线监测二种手段分析了2015年1~2月大气颗粒物样品,采用重量法分析颗粒物质量浓度,并对其相关性进行分析。结果表明:依据《环境空气质量标准》(GB 3095-2012),采样期间乌鲁木齐市大气PM_(10) 和PM_(2.5)的日均质量浓度均超过了国家二级标准,颗粒物污染严重;PM_(10) 和PM_(2.5)存在显著相关性,PM_(2.5)和PM_(10) 浓度的比值均大于0.5,采暖期PM2.5对乌鲁木齐市大气颗粒物贡献显著。     

The composition of PM10 as collected by a conventional TEOM, a modified TEOM and a Partisol gravimetric monitor at a kerbside site in the North East of England

The composition of airborne particulate matter sampled by a conventional TEOM, an experimental modified TEOM, operated at a lower temperature but fitted with a drier to remove moisture and a Partisol, installed at a kerbside site in the North East of England, has been investigated. The results indicate that there is a seasonal variation in the composition of PM(10) as sampled by the three monitors, with chloride concentration being significantly higher in the winter. The Partisol was found to sample a higher mass of chloride and nitrate, however the differences between the monitors was only significant for chloride. Both TEOM's were found to sample a greater mass of sulphate, although the variability in the data collected meant that significance of the results was not proven statistically. The range of artifacts associated with PM(10) monitors is reviewed. Difficulties in the interpretation of results due to the variable nature of airborne particulate matter and the ability of filter based systems to accurately represent the composition of atmospheric particles are considered.     

青岛市区春夏季大气能见度与颗粒物的关系

利用青岛市灰霾综合观测站2012年3月2日-2012年6月7日期间的监测数据,分析了青岛市区大气能见度与不同粒径颗粒物质量浓度的日变化特征,比较了各级别大气能见度下不同粒径颗粒物质量浓度及所占比例的相关性,研究了相对湿度对大气能见度和颗粒物质量浓度相关性的影响.结果表明,监测时段大气能见度与颗粒物质量浓度呈现较好的负相关,每天大气能见度最低值出现在早晨07:00--09:00;剔除相对湿度高于90％的前提下,PM2.5是影响大气能见度的主要因子,随着其在PM1o中所占比例上升,大气能见度级别不断下降,相关系数为-0.84;不同相对湿度区间下,PM2.5对大气能见度的影响最明显,其中,相对湿度为60％ ～ 70％,大气能见度与颗粒物质量浓度之间的相关性最好.     

Characterisation of particulate matter on the receptor level in a city environment

Airborne particulate matter (PM) has become one of the dominant pollutants with the increasing material and energy demand due to global economic growth. The main objective of this research is to provide a comprehensive receptor level characterisation of the particulate matter collected in a city environment. Particulate matter samples were collected on Tapered Element Oscillating Microbalance (TEOM) filters from five monitoring sites over a period of 1 year. An Andersen eight-stage cascade impactor was also used to collect airborne PM samples from three other locations to compare with the samples collected by TEOM. All the samples were then subjected to individual particle morphology and chemical composition analysis by SEM/EDS. Bulk chemical composition of the samples were also analysed through ICP–OES. Based on these analyses, possible sources of the PM samples were identified. The results showed that the monitoring sites in residential environments were dominated by transportation-derived particles and other migratory particulates. Monitoring sites near the city centre were dominant by particles from transportation, with biological particles abundant for the site closer to a river. The monitoring station located close to the industrial area, despite only 200 m away from a motorway, has low contribution of non-exhaust particulates from vehicles. Instead, the particulates collected from this site were dominated by industrial sources. An air dispersion modelling package was also used to model the particulate matter dispersion in the city area for the period of sampling. The results from the model showed that the points of high emissions were around industrial areas.     

Hydroxyl radical generation by electron paramagnetic resonance as a new method to monitor ambient particulate matter composition

Epidemiological studies have demonstrated the relationship between exposure to ambient particulate matter (PM) and health effects in those with cardiopulmonary diseases. The free radical generating activity of particles has been suggested as a unifying factor in the biological activity of PM in toxicological studies but so far has not been applied as a method for environmental monitoring of PM. The purpose of this study was to characterize hydroxyl radical (OH*) production by different size fractions of PM, to use as an alternative method for monitoring of PM composition and activity. We have developed a method, using electron paramagnetic resonance (EPR), to measure OH* radical formation in suspensions of particles in the presence of hydrogen peroxide and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a specific spin-trap. Samples of ambient particulate matter (PM) of different size fractions were collected from various sites on various filters. PM deposited on filters as well as suspensions in water retain its ability to generate OH* and this generation is determined by concentration of hydrogen peroxide and soluble metals. However, large variations in OH* radical formation and kinetics were found with different soluble metals and within metals (Fe, V) with different valencies. The method was applied to environmental monitoring in Hettstedt-Zerbst, situated in South-Eastern Germany, where it showed a relation to Cu-content of PM. The method was also applied in Duisburg, where the PMI fraction showed the highest DMPO-OH* generation but was not linked to particle counts. The method integrates metal bioavailability and reactivity and can provide a better understanding of the effect of small variations in mass concentrations on health.     

Seasonal evaluation and spatial variability of suspended particulate matter in the vicinity of a large coal-fired power station in India—A case study

Coal combustion in the power sector gives rise to the emission of primary and secondary particulate pollutants. Since the emission of pollutants depends on coal quality and combustion technology, and given that transport, transformation and deposition of contaminants depend on regional climatic conditions, specific studies for the power stations is needed to evaluate their environmental impacts. Monitoring of ambient respirable suspended particulate matter (RSPM) and suspended particulate matter (SPM) levels around a large coal-fired power station in India was carried out. The specific objectives were the determination of spatial and seasonal variability in RSPM and SPM levels, and their relationship with meteorological parameters such as wind velocity and relative humidity. The results have shown a marked seasonal trend and spatial variability in RSPM and SPM levels in the study area. Higher concentrations of ambient RSPM and SPM were found in downwind monitoring stations compared to upwind direction. Ratios of RSPM to SPM and correlation coefficient values between RSPM and SPM along with meteorological parameters were also worked out. Relative humidity and wind velocity have shown an inverse relation with particulate deposition pattern.     

Monitoring of cotton dust and health risk assessment in small-scale weaving industry

The present study describes the estimation of particulate matter (cotton dust) with different sizes, i.e., PM(1.0), PM(2.5), PM(4.0), and PM(10.0 μm) in small-scale weaving industry (power looms) situated in district Hafizabad, Punjab, Pakistan, and the assessment of health problems of workers associated with these pollutants. A significant difference was found in PM(1.0), PM(2.5), PM(4.0), and PM(10.0) with reference to nine different sampling stations with p values <0.05. Multiple comparisons of particulate matter with respect to size, i.e. PM(1.0), PM(2.5), PM(4.0), and PM(10.0), depict that PM(1.0) differs significantly from PM(2.5), PM(4.0), and PM(10.0), with p values <0.05 and that PM(2.5) differs significantly from PM(1.0) and PM(10.0), with p values <0.05, whereas PM(2.5) differs non-significantly from PM(4.0), with a p value >0.05 in defined sampling stations on an average basis. Majority of the workers were facing several diseases due to interaction with particulate matter (cotton dust) during working hours. Flue, cough, eye, and skin infections were the most common diseases among workers caused by particulate matter (cotton dust).