The spatial-temporal pattern and influencing factors of negative air ions in urban forests, Shanghai, China

Negative air ions are natural components of the air we breathe Forests are the main continuous natural source of negative air ions （NAI）. The spatio-temporal patterns of negative air ions were explored in Shanghai, based on monthly monitoring in 15 parks from March 2009 to February 2010. In each park, sampling sites were selected in forests and open spaces. The annual variation in negative air ion concentrations （NAIC） showed peak values from June to October and minimum values from December to January. NAIC were highest in summer and autumn, intermediate in spring, and lowest in winter. During spring and summer, NAIC in open spaces were significantly higher in rural areas than those in suburban areas. However, there were no significant differences in NAIC at forest sites among seasons. For open spaces, total suspended particles （TSP） were the dominant determining factor of NAIC in sum- mer, and air temperature and air humidity were the dominant determining factors of NAIC in spring, which were tightly correlated with Shanghai＇s ongoing urbanization and its impacts on the environment. R is suggested that urbanization could induce variation in NAIC along the urban-rural gradient, but that may not change the temporal variation pattern. Fur- thermore, the effects of urbanization on NAIC were limited in non-vegetated or less-vegetated sites, such as open spaces, but not in well-vegetated areas, such as urban forests. Therefore, we suggest that urban greening, especially urban forest, has significant resistance to theeffect of urbanization on NAIC.

Factors influencing the concentration of negative air ions during the year in forests and urban green spaces of the Dapeng Peninsula in Shenzhen, China

Negative air ions(NAIs)benefit the mental and physical health of humans,but rapid urbanization can decrease the abundance of NAIs.Quantifying the spatial and seasonal distribution of NAIs and determining the factors that infl uence the concentration during urbanization is thus essential.In the present study of a typical developing urban district in southern China,negative air ion concentrations(NAICs)in 60 forests sites and 30 urban green spaces were quantifi ed on seven consecutive days in each of the four seasons.Large seasonal variations in NAIC were revealed in forests and urban green spaces with trough values in summer.NAIC progressively decreased from forests to urban green spaces and was infl uenced by local land morphology,vegetation characteristics,and climatic factors.The vast,heavily vegetated northeastern region was the richest area for NAIs,whereas the narrow central region(urbanized area)was the poorest,implying dramatic impacts of urbanization on the spatial distribution of NAIs.The relationship between air temperature and NAIC was better fi tted with a quadratic equation than a linear equation.Moreover,the NAIC was more sensitive to local morphology in urban green spaces than in urban forests,indicating the vulnerability of NAIs in urbanized areas.Therefore,the appropriate design of local urban morphology is critical.

Modification of Nano Tourmaline Surface Treatment Agent and Its Performance on Negative Ion Release

In this paper,a kind of wall fabric’s surface treatment agent modified with nonionic surfactant was reported.This surface treatment agent was prepared by using nano tourmaline powder dispersion in water with surfactant as dispersants by sand milling.Under the influence of different dispersants,the negative ions releasing amount of functional wall fabrics,the milling process and the storage stability of nano tourmaline powder dispersion were discussed.The results showed that nano tourmaline powder dispersion achieved the smallest average diameter of 44 nm and had best storage stability that the average diameter maintained below 200 nm in 17 days when the addition amount of dispersant was 20 percent of the tourmaline powders’weight.What is more,the quantity of negative ion releasing achieved 6500 ion/cm3 when addition amount of dispersant was 30 percent.This technique could be used to strengthen productivity of nano tourmaline powder dispersion.

The Studies on the Surface Organic Modification of Tourmaline Powder with Stearic Acid and Its Composite

Stearic acid modified tourmaline powder had been investigated to improve the compatibility and dispersed stability between tourmaline and polymer matrix. The experimental results indicated that the activation index was 100% and contact angle reached 120° when the ratio of the ore slurry is 5:50, the dosage of stearic acid and p-toluenesulfonic acid is 10% and 0.5% (of tourmaline powder’s quantity) respectively with reaction at 80°C for 6.0 h, and the modified tourmaline exhibited an excellent hydrophobic property. The introduction of stearic groups reduced the reunion of tourmaline particles clearly and improved the dispersivity in polymers, and the amount of negative ions released of modified tourmaline increased obviously for both modified tourmaline powders and its composite with polyamide-66 compared to the unmodified tourmaline. Moreover, the structure of modified tourmaline was also characterized by means of Fourier Transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, scanning electron microscope.

Generation and Determination of Negative Air Ions

This review intends to cover a range of brief description of the generation mechanisms,the determination of the concentration,and the identification of negative air ions(NAI).This is divided into two parts:(i)it pays attention to the generation of NAI,which contains natural and artificial methods.According to the variation of energy in the environment,different methods based on natural generation are introduced in detail.As for artificial generation of NAI,corona discharge is dominantly elaborated due to its preponderance in convenient to control of the concentration of ions.(ii)it tends to introduce the determination of NAI,containing quantitative and qualitative detection,by using ion counting device and mass spectrometer,respectively.

Research on Spatial Changes of Negative Air Ion Concentration in Hefei City

[Objective] The study aimed to discuss the spatial changes of negative air ion concentration in Hefei City. [Method] Based on the observation of air ions, temperature, relative humidity, the spatial changes of negative air ion concentration in different districts of Hefei City were ana- lyzed firstly, then the correlation between negative air ion concentration and meteorological factors was discussed. [ Result] Air cleanliness index （CI） of the parks, residential areas, industrial regions, transport stations and prosperous commercial districts was 0.86, 0.53, 0.37, 0.26 and 0.17 respectively, and the latter two regions suffered mild and moderate pollution separately. Daily variations of negative air ion concentration in the residential areas and parks of Hefei City were obvious, showing U shape, that is, the maximum values appeared in the morning and evening, while the minimum values could be found around 14 ：（30. There was no distinctly regular variation of negative air ion concentration in the prosperous com- mercial districts, transport stations and industrial areas. In Hefei City, the concentration of negative air ions showed an increasing trend from the ur- ban districts to the suburban districts; it was obviously higher in the residential areas and parks with numerous plants and waters compared with the prosperous commercial districts and transport stations. Negative air ion concentration correlated with relative humidity positively and temperature negatively, so the main meteorological factors influencing the negative air ion concentration in Hefei City were temperature and relative humidity. [ Coedusloa] The research could provide scientific references for city planning and greenbelt construction in future.

Distribution Characteristics of Air Anions in Beidaihe in Different Ecological Environments

Qinhuangdao is a provincial municipality under the jurisdiction of Hebei Province and a coastal city in China. Beidaihe is a district under the jurisdiction of Qinhuangdao and is a famous seaside scenic area. Alliance Peak, located in Beidaihe seashore scenic West. Jinshan mouth is the peak of the Union Peak, located in the easternmost Beidaihe waterfront. In this paper, we use the observed data of air negative ions in the Beidaihe, Qinhuangdao, Jinshanzui and Lianfeng Mountains for seven years to study the distribution characteristics of negative air ions in different ecological environments through meteorological observation. Research shows that the annual mean of air anion concentration fluctuates less. The annual mean is 1730 ind·cm-3, and the difference between the highest and lowest concentrations is 535 ind·cm-3. The average air anion concentration was the highest in August at 7785 ind·cm-3 and the lowest in January at 365 ind·cm-3. Negative air ions have obvious spatial characteristics, and negative ion concentrations of the sea and forest air are significantly high. The average annual mean of the sea is 3902 ind·cm-3, and that of the forest is 5403 ind·cm-3. The concentration of air anion changes daily, and daytime concentration is significantly lower than nighttime concentration. The highest peak appears at night or in the morning, while the lowest value appears between noon and afternoon. Inter-annual features and concentration of negative air ions, as well as annual rain days, total rainfall, thunderstorm days, and average relative humidity, are negatively related to the annual average temperature and sunshine hours. However, in the average concentration of negative air ions, the average correlation test of meteorological elements was insignificant. The air anion concentration is negatively correlated with the PM2.5 concentration of fine particulate matter. The concentrations of nitrogen dioxide, sulfur dioxide, and carbon monoxide in the fine particulate matter are negatively correlated with the ozone concentration, which is positively correlated with ozone concentration and is tested by significance. Atmospheric discharge (thunderstorm) can produce a considerable amount of air anion. Air negative ions are an important indicator of air quality, which is of great significance to the living environment. The distribution of negative ions in the study space and its influencing factors in order to provide a basis for air quality assessment in the region and provide references for the long-term research on air anion in different urban areas.

Effect of a commercial air ionizer on dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae(Acari:Pyroglyphidae) in the laboratory

Objective:To investigate the short and long tenn efficacy of a commercial air ionizer in killing Dermatophagoides pteronyssinus(D.pteronyssinus)and Dermalophagoides farinae(D.farinae)mites.Methods:The effect of a commercial ionizer on D.pteronyssinus and D.farinae was evaluated in the laboratory,using a specially designed test.Mortality was assessed after 6,16and 24 hours for direct exposure and after 24,36,48,60 and 72 hours for exposure in simulated mattress.New batches of mites were used for each exposure time.Results:LT_(50)for direct exposure of ionizer was 10 hours for D.pteronyssinus and 18 hours for D.farinae.The LT_(50)for exposure in simulated mattress was 132 hours or 5.5 days for D.pteronyssinus and 72 hours or 3days for D.farinae.LT_(95)for direct exposure of ionizer was 36 hours for D.pteronyssinus and D.farinae.Meanwhile,the LT_(95)for exposure in simulated mattress was 956 hours or 39.8 days for D.pteronyssinus and 403 hours or 16.8 days for D.farinae.Conclusions:This study demonstrates the increasing mite mortalities with increasing exposure time of a commercial ionizer and suggests that negative ions produced by an ionizer kill dust mites and can be used to reduce natural mile populations on exposed surfaces such as floors,clothes,curtains,etc.However,there is reduced efficacy on mites inside stuffed materials as in mattresses and furniture.

Spatial Distribution Characteristics of Negative Air Ion Concentrations in Danqinghe Experimental Forest,Harbin City

In recent years, air ions, especially of negative air ion has received a universal attention for its health function. The density of negative air ion has become one of the important indexes that measure the air quality grade. With the air ions counter made in Japan, the spatial distribution characteristics of negative air concentrations at specific time in Danqinghe Experimental Forest were measured and studied, Harbin City, and the air quality was assessed by using ion polarity ration (q) and air ion assessment index (CI). The results showed that at a given time, the average concentrations of negative air ions were different for different forest types, stand origins, tree species and different parts of Balan River. There was a clear difference in ion polarity ration and air ion assessment index, and the air quality in different environments were also quite different.

负离子陶瓷材料研究进展

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