Average Mass Concentrations Of PM Research Articles

Characteristics of PM1.0, PM2.5, and PM10, and Their Relation to Black Carbon in Wuhan, Central China

Hourly average monitoring data for mass concentrations of PM1, PM2.5, PM10, and black carbon (BC) were measured in Wuhan from December 2013 to December 2014, which has a flourishing steel industry, to analyze the characteristics of PM and their relation to BC, using statistical methods. The results indicate that variations in the monthly average mass concentrations of PM have similar concave parabolic shapes, with the highest values occurring in January and the lowest values appearing in August or September. The correlation coefficient of the linear regression model between PM1 and PM2.5 is quite high, reaching 0.99. Furthermore, the proportion of PM1 contained within PM2.5 is roughly 90%, directly proving that ultrafine particles whose diameter less than 1 μm may be a primary component of PM2.5 in Wuhan. Additionally, better seasonal correlation between PM and BC occurs only in summer and autumn, due to multiple factors such as topography, temperature, and the atmosphere in winter and spring. Finally, analysis of the diurnal variation of PM and BC demonstrates that the traffic emissions during rush hour, exogenous pollutants, and the shallow PBLH with stagnant atmosphere, all contribute to the severe pollution of Wuhan in winter.

Chemical Composition and Light Extinction Contribution of PM2.5 in Urban Beijing for a 1-Year Period

Daily PM_(2.5) samples were collected in Beijing across four consecutive seasons from June 2012 to April 2013. Major water-soluble inorganic ions, carbonaceous species and elements were analyzed to investigate their temporal variations and evaluate their contributions to visibility impairment over different seasons and under different pollution levels. The mass concentrations of PM_(2.5) ranged from 4.3 to 592.4 μg m-3, with an annual average of 112.4±94.4 μg m^(-3). The predominant components of PM_(2.5) were secondary inorganic ions (NH_4^+, NO_3^- and SO_4^(2-)) and carbonaceous compounds, which accounted for 45.9% and 24.1% of the total PM_(2.5) mass, respectively. Distinct seasonal variation was observed in the mass concentrations and chemical components of PM_(2.5). The average mass concentrations of PM_(2.5) were the highest in winter, followed by spring, and lowest in autumn. Light extinction coefficients (b_(ext)) were discussed over four seasons. (NH_4)_2SO_4 was the largest contributor (28.8%) to b_(ext), followed by NH_4NO_3 (24.4%), organic matter (19.5%), elemental carbon (7.4%), and coarse mass (7.2%), while fine soil, sea salt, NO_2 and Rayleigh made minor contributions, together accounting for 12.7% of b_(ext). During the polluted periods, the contributions of (NH_4)_2SO_4 and NH_4NO_3 to b_(ext) increased dramatically. Therefore, in addition to control primary particulate emissions, the reduction of their precursors like SO_2, NO_x and NH_3 could effectively improve air quality and visibility in Beijing.

Characteristics of Particle Matter Pollution and its Control in Beijing

"Particulate matter," or PM, is a complex mixture of extremely small particles and liquid droplets. PM is usually divided into PM10 and PM2.5. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. PM2.5 causes the greatest health problems, and reduces the visibility (haze). Beijing is the capital of the Peoples’ Republic of China. The PM pollution in Beijing not only poses huge economic, environmental and healthy loses, but also impacts on the China government’s credibility and international image. The paper analyzed the characteristics of PM pollution and put up with some suggestions in order to provide some theoretical guidance for the government implementing environmental protection policy and pollution control measures. The paper indicates that the average mass concentration of PM in Beijing varies with time; PM emissions have increased in recent years; PM2.5 and PM10 are the primary air pollutants in Beijing; and finally the government should take effective measures to control particle pollution to realize the people’s hope that the sky becomes blue again.

Particle Size Distribution of Ambient Aerosols in an Industrial Area

Aerosol samples of PM(10) and PM(2.5) were collected from 38 sampling locations in and around the industrial area. The 24 h average mass concentration of PM(10) and PM(2.5) was 137.5 and 61.5 μg/m(3) respectively during summer, 122 and 97.5 μg/m(3) respectively in winter and 70 and 54 μg/m(3) respectively during post monsoon season. The relative contribution of coarse, fine and ultrafine particle to ambient air was analyzed for its temporal and seasonal variability in an industrialized area. This paper aims to establish baseline between PM(10) and PM(2.5) mass concentration levels.

Water-soluble ions in atmospheric aerosols measured in Xi'an, China: Seasonal variations and sources

Daily PM 2.5 and water-soluble inorganic ions (Na +, NH 4 +, K +, Mg 2+, Ca 2+, Cl −, NO 3 − and SO 4 2−) were collected in Xi'an (34.23°N, 108.88°E), China from March 2006 to March 2007. PM 2.5 was collected using battery-powered mini-volume samplers. And the ions were determined by ion chromatography from the measured aerosol mass. The annual average mass concentration of PM 2.5 was found to be 194.1 ± 78.6 μg m − 3 , which exceeded substantially the international guidelines for health concerns. The seasonal average mass concentration of PM 2.5 was highest in winter (266.8 μg m − 3 ) and lowest in summer (138.6 μg m − 3 ). The three highest abundant ions were SO 4 2−, NO 3 −, and NH 4 +, with average concentrations of 35.6 ± 19.5 μg m − 3 , 16.4 ± 10.1 μg m − 3 , and 11.4 ± 6.8 μg m − 3 , which were accounted for 18.7%, 8.0%, and 5.7% of the PM 2.5 mass, respectively. The major ions were in the species of (NH 4) 2SO 4, NH 4HSO 4 and NH 4NO 3, and their concentrations were highest in winter, due to high coal combustion. The concentrations of Ca 2+ were higher in spring than other seasons, due to the higher mineral dust concentrations. Ca 2+ was strongly correlated with CO 3 2−, which was calculated as the difference in the measured cations minus anions. Ion balance calculations indicate that the PM 2.5 was acidic, and this result is consistent with the measurement of pH values. Sulfur oxidation ratio was higher in summer and autumn, which implies that the formation of secondary sulfate-rich particles is favored by warm and relatively moist weather. Nitrogen oxidation ratio was highest in autumn.

Characterization and morphological analysis of airborne PM2.5 and PM10 in Agra located in north central India

Abstract PM 2.5 and PM 10 samples were collected from road and semirural sites of Agra, the north central part of India. The average mass concentration of PM 10 was 278.67 ± 106.58 μg/m 3 and of PM 2.5 was 90.16 ± 7.21 μg/m 3 at roadside while at semirural site it was 234.54 ± 128.27 μg/m 3 for PM 10 and 89.12 ± 37.94 μg/m 3 for PM 2.5 . Scanning electron microscopy coupled with energy dispersive spectrometer (SEM-EDS) was used to understand the difference in terms of shapes, morphology, and elemental composition of aerosols in PM 10 and PM 2.5 and to further link them to the potential source as well as emission and transport of pollutants from different polluted areas. The SEM micrograph of PM 10 was different from PM 2.5 size range particles at both sites. EDS spectra indicates the three main groups of particles i.e., C, O rich particles, Si, Na and Al rich particles and Mg, Ca, Fe, K, S, Co rich particles on the basis of their percentage contribution in PM 10 and PM 2.5. PM 2.5 constituted C, O (95.93%), Si, Al, Na (2.63%), S, Fe, K, (1.41%) and PM 10 constituted O, C (72.16%), Si, Al, Na (24.58%), S, K, Fe, Co (3.24%) respectively at roadside whereas at semirural site, PM 2.5 and PM 10 constituted O, C (92.8%), Si, Al, Na (4.86%), Mg, K, Ca, Fe (2.32%), and O, C, (72.14%), Si, Na, Al (23.11%) and Mg, K, Ca, Fe (4.73%) respectively. Crustal elements such as Si, Na and Al rich particles are dominant excluding C and O in PM 10 and PM 2.5 at roadside as well as semirural site. Correlation between element and particulate matter indicates two groups in which one group is highly significant ( r > 0.90) and another group shows positive correlation ( r > 0.53 to 0.90). Soot, tarballs, carbonaceous and mineral type particles were observed at roadside while aluminosilicates, quartz, fly ash and soil dust particles were observed at semirural site in PM 2.5 and PM 10 respectively. It was concluded that SEM-EDS is a convenient method to identify the source of emission of particulate air pollution.

Characterisation of PM 10 atmospheric aerosols for the wet season 2005 at two sites in East Africa

Ambient daily PM 10 aerosol samples were collected at two sites in Tanzania in May and June 2005 (during the wet season), and their chemical characteristics were studied. The sites were a rural site in Morogoro and an urban kerbside site in Dar es Salaam. A Gent PM 10 stacked filter unit sampler with sequential Nuclepore polycarbonate filters, providing fine and coarse size fractions, and a PM 10 sampler with quartz fibre filters were deployed. Parallel collections of 24 h were made with the two samplers and the number of these collections was 13 in Morogoro and 16 in Dar es Salaam. The average mass concentration of PM 10 was 27 ± 11 μg/m 3 in Morogoro and 51 ± 21 μg/m 3 in Dar es Salaam. In Morogoro, the mean concentrations of organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) were 6.8, 0.51, and 2.8 μg/m 3, respectively. In contrast, higher mean concentrations (11.9, 4.6, and 3.3 μg/m 3, respectively) were obtained for Dar es Salaam. At both sites, species and elements, such as black carbon, NH 4 +, non-sea-salt SO 4 2−, K, and Ni (and at Dar es Salaam also V, As, Br, and Pb) were mainly present in the fine size fraction. The common crustal and sea-salt elements, including Na, Mg, Al, Si, Cl, Ca, Ti, Mn, Fe, and Sr, and also NO 3 − and P (and to a lesser extent Cu and Zn) were concentrated in the coarse particles. Aerosol chemical mass closure indicated that the PM 10 mass in Morogoro consisted, on average, of 48% organic matter (OM), 44% crustal matter, 4% sea salt, and 2% EC, while in Dar es Salaam OM, crustal matter, sea salt, and EC represented 37%, 32%, 9%, and 9% of the PM 10 mass. The contributions of the secondary inorganic aerosol (non-sea-salt sulphate, nitrate, and ammonium) were small, i.e., only 5% in total at each site. Carbonaceous materials and crustal matter were thus the most important components of the PM 10 mass. It is suggested that biomass burning is a major contributor to the OM; at Dar es Salaam there is also a very substantial contribution from traffic. A source apportionment calculation indicated that 68% of the OC at this site originated from traffic exhaust versus 32% from charcoal burning. The crustal matter at Morogoro is likely mainly attributable to soil dust resuspension, whereas in Dar es Salaam it is likely mostly resuspended road dust.

The relationship between physicochemical characterization and the potential toxicity of fine particulates (PM 2.5) in Shanghai atmosphere

Fine particulate matter with aerodynamic diameter less than 2.5 μm (PM 2.5) was collected at urban and suburban sites in Shanghai from April 2005 to March 2006. Average mass concentrations of PM 2.5 ranged from 43.5 to 149 μg m −3 in the urban area and 21.7 to 159 μg m −3 in suburban area. The mass levels of PM 2.5 sampled at urban and suburban sites showed seasonal variation with much higher values in winter and spring, lower values in summer, and the lowest in autumn. The results of environmental scanning electron microscopy (ESEM) showed that Shanghai PM 2.5 was consisted of soot aggregates, coal fly ashes, minerals, bio-particles and unidentified particles. Inductively coupled plasma atomic mission spectrum (ICP-AES) results showed total elements in Shanghai PM 2.5 increased gradually from summer to winter and remained at a relatively high level in spring. There was a significant difference in the mass of elements in PM 2.5 collected in urban and in suburban atmosphere. Enrichment factor (EF) analysis results demonstrated that K, Na, Ca, Mg, Al, Fe, Ba and Sr originated from natural sources, while As, Cu, Zn, Pb, Cd, Mn, Ni and Se were emitted from anthropogenic sources. The plasmid DNA assay showed that potential toxicity of Shanghai PM 2.5 collected at urban and suburban sampling sites, and in different seasons, varied greatly. Toxicity of the Shanghai urban winter PM 2.5 sample was much stronger compared to any of the other samples. Heavy metals in Shanghai PM 2.5, including Cu, Zn, Pb, Cd, Cr, Mn, and Ni, might have synergic-effects on plasmid DNA damage.

Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter

Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2004. Totally 30 sets of 24 h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal variations and secondary pollution characteristics of fine particles during the sampling periods were discussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM 2.5 and PM 10 in summer were 35 μg·m -3 and 57 μg·m -3 , respectively, and those in winter were 99 μg·m -3 and 135 μg·m -3 , respectively. The concentrations of both PM 2.5 and PM 10 in winter increased 184% and 137%, respectively, compared to those in summer. PM 2.5 accounted for 61% and 75% of PM 10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol components in PM 2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South China Sea in summer, and the air quality was good. The prevailing wind in winter was from Mainland China to the north, and the polluted air mass led to poor air quality.

Characterization of chemical species in atmospheric aerosols in a metropolitan basin

Ambient PM 10 aerosol samples were collected from Taiwan’s Taichung metropolitan basin between October 1997 and January 1998, and their chemical characteristics studied. The average mass concentration of PM 10 was 109.0 ± 54.1 μg/m 3. Carbonaceous materials, sulfate, nitrate, and ammonium were the most important contributors to the PM 10 component. On average, 64% of the PM 10 was made up of fine particles. During PM 10 episodes, average wind speed was 0.7 m/s and relative humidity was high, 83% on average, probably giving rise to stagnation of air pollutants and their entrapment close to the surface. With relative humidity <70%, NO 3 −, NH 4 +, SO 4 2−, carbonaceous materials, and PM 10 mass showed high correlation with maximum hourly average ozone (O 3M). Variation in atmospheric humidity may affect the gas-to-particle interactions of S and N species. The most significant contribution to PM 10 in the Taichung urban basin was from the photochemical formation of secondary aerosols and carbonaceous materials in the atmospheric environment.