Research Progress on the Monitoring of Precursor of Atmospheric Ozone——Volatile Organic Compounds

Volatile organic compounds(VOCs)are important precursors of ozone and PM_(2.5).At present,VOCs have gradually become the focus of air pollution control after fine particles in China,and a series of documents,standards and planning on VOCs were issued from the state to each area.The analysis on source apportionment and control of VOCs have also become a hot spot in atmospheric environmental protection research of China at present stage.The research work on VOCs in ambient air is the basis and premise of scientific and effective prevention and control of VOCs pollution.In this paper,research progress on the monitoring of VOCs is introduced systemically,and main monitoring and evaluation methods of atmospheric VOCs are explored from monitoring analysis method,chemical reaction activity and health risk assessment.Moreover,concentration characteristics and source apportionment of VOCs in the regions at home and abroad that have carried out VOCs research work are compared and summarized.The research could provide reference for source apportionment of VOCs in other cities of China.

Analysis and Control of Air Pollution from Bus Exhaust in Shantou City

Air pollution from bus exhaust （one of main sources of urban haze） in Shantou City, Guangdong Province was surveyed, and the purification effect of a new device for removing soot particulates from bus exhaust was analyzed. The results show that the smoke intensity of all buses surveyed averages 3.59 m-1, exceeding the limit, and the maximum is 5.7 times higher than the limit. Among the buses inspected, the smoke intensity of 37% of buses is not up to standard. The removal rate of soot particulates from various buses equipped with the purification devJce averages 63.6%, and some buses are up to standard after their exhaust are purified, showing that the device has good purification effect. Therefore, installing the purification device in a bus is an effective way to control air pollution from bus exhaust and haze in a city.

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 of Sources of Atmospheric Fine Particulates in Nan'ao County

Based on on-line single particle aerosol mass spectrometry （SPAMS） with high time resolution, the sources of atmospheric fine particu- late matter in Nan＇ao County were analyzed. The results showed that during the monitoring period from March 24 to 27 in 2015, the primary source of fine particulate matter in Nao＇ao County was motor vehicle exhaust, that is, 24.7% of fine particulates were from motor vehicle exhaust, followed by biomass burning （17.2%）, fire coal （17.2%）, and sea salt （13.3%）. The proportions of fire coal and sea salt revealed the peculiarity of sources of atmospheric fine particulate matter in Nan＇ao County. Therefore, it is suggested that some measures should be adopted to limit tourist traffic to reduce the adverse impact of motor vehicle exhaust on ambient air quality in Nan＇ao County.

Comparison on Determination Results of Methane and Total Hydrocarbons by Glass Syringe Method and Air Bag Method

Samples at different setting time were determined by glass syringe method and air bag method, and their results were analyzed. The results showed that concentrations of methane and total hydrocarbons obviously declined with the prolonging of setting time by glass syringe method, and recovery rate of sample declined to 60% after 8 h. In air bag method, analysis results of methane and total hydrocarbons were stabler, and recovery rate of sample was 93% after 8 h.