Experimental Study on the Effect of Humidification on the Pollution Characteristics of Particulate Matter in the Office

Indoor air quality has a direct impact on human health. Indoor air quality has aroused great concern. This experimental study compares the effects of different water humidification on the indoor particulate pollution characteristics, and analyzes the mass concentration and the particulate number concentration distribution of different sizes of particulates with time under each condition of the purified water humidification, the tap water humidification and the cold boiled water humidification in the office. The results show that under the three kinds of wetting conditions, the concentration of the fine particulates is higher. More minerals are contained in the tap water and the cold boiled water, so the two kinds of humidification have more significant impact on indoor particulate matter. But the purified water humidification has nearly no significant effect on it. The calcium and magnesium ionic compounds are partly removed after the water boiled, so the cold boiled water humidification has less impact on the indoor particulate matter than the tap water humidification. The mass concentration and particulate number concentration of the particle may also be affected due to the frequency of ultrasonic vibration.

Fine Particulate Pollution Characteristics in Jinan City

The characteristics of fine particulate pollution(PM10 and PM2.5) were measured at urban and suburban sites in Jinan during the 2008-2009 heating and non-heating seasons.The results showed that PM10 and PM2.5 pollution was quite serious,and PM mass concentration was higher during the heating season than the non-heating season.PM was the highest in the chemical factory and lowest in the development zone.The mass concentrations of PM10 and PM2.5 were linearly related,and the mass concentration ratio of PM2.5/PM10 was up to 0.59 in urban areas.PM pollution in Jinan was related to local meteorological factors:PM2.5 mass concentration and humidity were positively correlated,and PM2.5 mass concentration was negatively correlated with both click on the temperature and wind speed,although wind speed varied more.

Analysis of VOCs Pollution Characteristics and Ozone Formation Potential Based on a Mobile Monitoring System in Beibei District

Based on a mobile monitoring system,101 volatile organic compounds(VOCs)in ambient air near a national control station in an industrial park were monitored during February 15-21 in 2022,and the pollution characteristics and ozone formation potential(OFP)of VOCs were analyzed.The results show that among the top 10 VOCs with higher mass concentration,there were 5 VOCs appearing in each day from February 15 to 21,including styrene,benzene,toluene,undecane and n-decane,which indicates that the sources of VOCs emission at the monitoring point were relatively stable.During the monitoring period,aromatic hydrocarbons contributed the most to the ozone formation potential of VOCs,accounting for above 70%,followed by alkanes and oxygen-containing compounds.The total OFP of aromatic hydrocarbons,alkanes and oxygen-containing compounds accounted for more than 90%,so they became the active components with the greatest influence on ozone formation.Aromatic hydrocarbons such as 1,2,4-trimethylbenzene,1,3,5-trimethylbenzene and m/p-dimethylbenzene,oxygen-containing organic compounds such as ethanol and acetone,and alkanes such as n-nonane and butane had high OFP,so they had a great effect on ozone formation.

Analysis on the Pollution Characteristics of Surface Runoff in Zhenjiang City

[Objective] The aim was to analyze the pollution characteristics of surface runoff in Zhenjiang City.[Method] On July 4 and August 16,2010,surface runoff samples were collected in different rainfall durations in Zhenjiang City,and the variation characteristics of suspended substance (SS),chemical oxygen demand (CODCr),ammonia nitrogen (NH3-N) and total phosphorus (TP) in surface runoff were analyzed.[Result] With the increase of rainfall duration,SS concentration in surface runoff of Zhenjiang City on July 4 and August 16,2010 went up firstly and then went down,with the maximum concentration of 1 240 and 160mg/L,respectively,and the decreasing rang of SS concentration in the late stage of rainfall on July 4 was obviously greater than that of August 16 due to stronger rainfall on July 4.The general variation of CODCr was similar to that of SS concentration,and the change range of CODCr on July 4 (32-212mg/L) was larger than that of August 16 (13-53mg/L).In addition,the variation trends of NH3-N and TP concentration were similar,namely they increased firstly and then reduced rapidly,and the decreasing range of NH3-N and TP concentration was greater than that of SS concentration in the late stage of rainfall.[Conclusion] The research results could provide references for the study on water quality variation characteristics and treatment of surface runoff.

Pollution characteristics and health risk assessment of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons during heating season in Beijing

Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,formation mechanism,and health risk assessment of them in heating season,particulate matter(PM)were collected in Beijing urban area from December 26,2017 to January 17,2018.PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS).Average daily concentrations of PAHs and NPAHs were(78±54)ng/m^(3)and(783±684)pg/m^(3),respectively.The concentrations of them were significantly higher at nighttime than at daytime,and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations.In the heating season,the dominant species of PAHs include benzo[b]fluoranthene,fluoranthene,pyrene,and chrysene,while 9-nitroanthracene,2+3-nitrofluoranthene,and 2-nitropyrene were dominant species for NPAHs.NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7μm particle size.Primary emissions such as biomass burning,coal combustion,and traffic emissions were the major sources of PAHs.NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals,as well as biomass burning during daytime.According to the health risk assessment,the total carcinogenic risk was higher in adults than in children.While upon oral ingestion,the carcinogenic risk in children was higher than that of adults,but the risk of adults was higher than children through skin contact and respiratory inhalation.

A preliminary study on pollution characteristics of surfactant substances in fine particles in the Beibu Gulf Region of China

The pollution characteristics of surfactant substances in fine particles(PM_(2.5))in spring were studied in the Beibu Gulf Region of China,68 samples of PM_(2.5)were collected at Weizhou Island in Beihai City from March 12 to April 17,2015.The Anionic Surfactant Substances(ASS)and Cationic Surfactant Substances(CSS)in the samples were analyzed using Byethyl Violet Spectrophotometry and Disulfide Blue Spectrophotometry,respectively.Combined with the data from backward trajectory simulation,the effects of air pollutants from remote transport on the pollution characteristics of surfactant substances in PM_(2.5)in the Beibu Gulf Region were analyzed and discussed.The results showed that the daily mean concentrations of ASS and CSS in spring in the Beibu Gulf Region were 165.20 pmol/m^(3)and 8.05 pmol/m^(3),and the variation ranges were 23.21–452.55 pmol/m^(3)and 0.65–31.31 pmol/m^(3),accounting for 1.82‰±1.65‰and 0.12‰±0.11‰of the mass concentration of PM_(2.5),respectively.These concentrations were lower than those in comparable regions around the world.There was no clear correlation between the concentrations of ASS and CSS in PM_(2.5)and the mass concentrations of PM_(2.5).Tourism and air transport had a positive contribution on the concentrations of ASS.The concentration of surfactant substances in PM_(2.5)was significantly impacted by wind speed and wind direction.Atmospheric temperature,air pressure and precipitation had little effect on the concentrations of surfactant substances.Surfactant substances in PM_(2.5)significantly impacted visibility.Results also showed that the main sources of surfactant substances were from the southern China and Southeast Asia.

Characteristics and Meteorological Conditions of Ozone Pollution in Shantou City

Based on routine monitoring data of air quality and meteorological data in Shantou City during 2015-2019,temporal-spatial variation characteristics of O 3 pollution and its correlation with meteorological conditions in Shantou City were explored.The research results showed that O 3 pollution days in Shantou City showed an increasing trend year by year,and O 3 pollution had far-distance transportation and the development trend from offshore Nan ao Island to urban district.In spring and autumn,there was serious O 3 pollution,and it was the most prominent in October.Its diurnal variation in O 3 pollution days was mainly wide-peak type in the afternoon,showing as that O 3 concentration declined slowly after the noon.In O 3 pollution days,higher O 3 concentration was easy to appear at night,causing that O 3 peak in the second day was uplifted,and there was continuous O 3 pollution.Combining backward trajectory analysis chart,it was found that Shantou was mainly affected by coastal transport of northerly polluted air mass,and it was transported into Shantou City from the east to the northeast.O 3 from long-distance transmission superimposed with locally generated O 3,which commonly pushed up the level of O 3 concentration.The weather of O 3 pollution in Shantou City had the characteristics of high temperature and low humidity.There was 25-30℃of temperature interval and 46%-60%of relative humidity interval,and it was accompanied by grade-2 easterly wind.

Analysis on the Current Situation, Impact and Source of Atmospheric Ozone Pollution in China

With the gradual improvement of PM 2.5 pollution in China,the problem of ozone pollution is becoming more and more serious.In recent years,ozone has become the only one of the six major air pollutants increasing year on year in China,and the primary pollutant of air pollution in many cities of China in summer.In this paper,pollution characteristics of ozone and its relationship with meteorological conditions in China s provincial capitals and some economically developed cities(27 cities in total),and temporal-spatial distribution rules of ozone in China were analyzed,and influence and main source of ozone in China were summarized.The results were as below:daily change of ozone concentration showed as single-peak type,and the maximum generally appeared at 15:00-16:00,while the minimum generally occurred at 07:00-08:00.Seasonal change of ozone concentration mainly showed as single-peak type.In summer,ozone concentration was the highest,followed by spring and autumn,and its concentration in winter was the lowest.The influence of meteorological factors on ozone showed as that there was significantly positive correlation between ozone and temperature,radiation quantity,and significantly negative correlation between ozone and humidity,NOx.Ozone near surface will have adverse effects on biosphere,climate and ecological environment.The source of ozone can be divided into two kinds:man-made and natural,and the most important source of near-surface ozone is man-made.

Atmospheric carbonyls in a heavy ozone pollution episode at a metropolis in Southwest China:Characteristics,health risk assessment,sources analysis

Ambient carbonyls were continuously observed in the field during a heavy ozone pollution episode in Chengdu, China from August 4 to August 19, 2019, and the pollution characteristics, atmospheric photochemical reactivity, human health risk, and sources of carbonyls were analyzed. Fifteen carbonyls were quantified with average total mixing ratios of 20.38 ppbv Formaldehyde(9.86 ppbv), acetone(4.41 ppbv), and acetaldehyde(3.57 ppbv) were the three most abundant carbonyls. During the heavy ozone pollution episode, the concentration of carbonyls was found to be higher on pollution days than on the clean days, and relatively higher in the daytime, especially at noon on the pollution days. This was influenced by the intensity of photochemical reactions and precipitation. The “weekend effect” with the concentration of carbonyls was higher on the weekends than on the weekdays was pointed out. Formaldehyde, acetaldehyde and hexaldehyde were the dominant oxidative species during the observation. The carcinogenic and non-carcinogenic risk values of formaldehyde and acetaldehyde were higher on pollution days than on clean days, and these values were higher compared with those of other cities in China and abroad. Long-term exposure to these compounds should therefore be avoided. Diagnostic ratios and correlation analysis together with backward trajectory analysis showed that primary emission and secondary formation accounted 66%-76% and 24%–34% of carbonyls in Chengdu, respectively, with primary emission being the main sources of carbonyls, and carbonyls from the surrounding cities and emission from natural sources also had a significant contribution to the carbonyls in Chengdu.

Study on the Migration Mechanism of Typical Characteristic Pollutants in Coking Enterprises

Groundwater pollution in north China is serious, which is mostly caused by complex factors. Aiming at the problems such as the unknown reasons for the differences in the migration characteristics of typical characteristic pollutants in the same medium and the unknown migration rules of complex pollutants in soil and groundwater, this paper selected a single sample and a mixed sample of typical characteristic pollutants in coking enterprises to carry out the static adsorption test. The results showed that the distribution coefficients of benzene series and aromatic hydrocarbon pollutants in soil-water were K_(d)benzene >K_(d)toluene >K_(d)ethylbenzene >K_(d)pyrene >K_(d)anthracene >K_(d)naphthene, and the distribution coefficients of ammonia nitrogen, phenols and cyanogen were K_(d)ammonia nitrogen >K_(d)phenols >K_(d)cyanogen. The overall distribution coefficient of benzene series was higher than that of PAHs, and it was easier to be adsorbed by silty loam. Different carbon and hydrogen mass and even electron distribution of typical characteristic pollutants led to differences in the migration characteristics of benzene and aromatic pollutants. The more carbon and hydrogen there were, the more even the electron distribution was, and the more difficult it was to migrate in the soil. Among the same kind of pollutants, the migration of complex pollutants was weaker than that of single pollutants. The research could provide the parameter basis for establishing the solute transport model of groundwater and the design basis for developing the related risk control and pollution prevention strategies.

Atmospheric pollution of agriculture-oriented cities in Northeast China: A case in Suihua

Agriculture-oriented cities in Northeastern China have experienced frequent atmospheric pollution events.Deeper understandings of the pollution characteristics,haze causes and effects of management on local air quality are crucial for conducting integrated management approaches for the sustainable development of agriculture-oriented cities.Taking a typical agriculture-dominant city(i.e.,Suihua)in Northeast China,we analyzed in detail the characteristics and causes of atmospheric pollution and evaluated the straw-burning prohibition using multisource data.The results showed a clear temporal pattern of air quality index(AQI)on an annual scale(i.e.,2015-April 2019),with two typical pollution periods occurring in late autumn and early spring.The large areas of concentrated straw burning at local and regional scales accounted for the first period(i.e.,October and November),while dust emissions and farming disturbances comprised the second period.The interannual variation in pollution periods among these years was large,showing similar trends from 2015 to 2017 and the postponed late-autumn pollution period in 2018.Our evaluation has shown that the prohibition effect of straw burning significantly improved air quality in 2018,with a reduction of 59%±88%in the PM2.5 concentrations in October and November compared to 2015–2017.However,From October to April of the following year,the improvement effect was not significant due to postponement of straw burning to February or March.Our analysis also highlighted the roles of meteorological conditions,Therefore,combined with the promotion of straw utilization,scientifically prescribed burning considering the burning amount and location,meteorological conditions and regional transportation should be implemented.

A review on source,occurrence,and impacts of microplastics in freshwater aquaculture systems in China

Microplastic pollution has become an increasingly important environmental issue worldwide in recent years because of its ubiquitous presence in different environmental media and its potential to affect the health of organisms and ecosystems.Aquaculture contributes significantly to the world's food production and nutritional supply,especially in developing countries.Widespread occurrence of microplastics in aquaculture systems has raised great concern regarding aquaculture production and food safety issues of aquaculture products.China is a world leader in aquaculture production,with freshwater aquaculture accounting for 59.1%of total aquaculture production of the world in 2020.Therefore,this review mainly focuses on recent research progress related to microplastic pollution in freshwater aquaculture systems in China.Results from the literature show that microplastics are present in freshwater aquaculture systems at abundances comparable to natural waterbodies in China.Microplastics can be ingested and remain in the body of aquaculture products.Exposure to microplastics can adversely affect the health of aquatic organisms and aquatic ecosystem functions.However,risks of microplastics in real world environment remain uncertain.Consumption of freshwater aquaculture products is not a major pathway for human exposure to microplastics.To provide scientific guidance for governmental decision-making and pollution control,future work should focus on progress in toxicological methodology and understanding the impacts of microplastics at community and ecosystem levels.