[Establishment and Application of Foshan Ozone Concentration Forecast Equation].

The formation and changes of ozone (O3), a secondary pollutant in the atmosphere, are complex, and ozone forecasting has become one of the current problems in air pollution prevention and control. In this study, the relationships between the near-surface O3 concentration and meteorological elements (high- and low-level) in Foshan from 2014 to 2017 were analyzed, and the concentration forecasting equation was established, tested, and applied. The results showed that the near-surface O3 changed closely related to high- and low-level meteorological elements. Meteorological elements such as temperature and sunshine hours were significantly positively correlated with O3 concentration, whereas relative humidity, total (low) cloud cover, and wind speed were negatively correlated with O3. Heavy O3 pollution often occurred with meteorological conditions of low wind speed, sunny days and few clouds, low relative humidity, longer sunshine time, and higher temperature. The definitions of high-concentration O3 potential index (HOPI) and wind direction index (WDI) in the Foshan area could better characterize the meteorological conditions of O3 pollution. Considering 13 meteorological elements, such as HOPI and WDI at different heights, the O3 concentration forecasting equation in the Foshan area was established using multi-indicator stacking and multiple stepwise regression methods. Using the 2018 data, it was found that the correlation coefficient R between the simulated values and the measured values reached 0.82, and the forecast equation had a good fitting effect and predictability.

[Optical Absorption Properties of Brown Carbon Aerosols in Guangzhou].

In this work, we conducted measurements using a seven-wavelength aethalometer, an online OCEC analyzer, and a MARGA to investigate brown carbon (BrC) absorption properties and source origins during the winter of 2014 at Panyu station, Guangzhou. The results showed that the average absorption contributions of BrC decreased with an increase in wavelength, measured as 25.9%, 19.7%, 14.1%, 11.6%, and 7.7% at 370 nm, 470 nm, 520 nm, 590 nm, and 660 nm, respectively. Diurnal variations in BrC absorption and the concentrations of potassium cations (K+) and organic carbon (OC) was high at night and low during the day, which was attributed to biomass burning. This indicated that BrC was emitted from straw burning in rural areas and accumulated in the steady planetary boundary layer at night. Diurnal variations in the ratio of BrC absorption to OC concentrations showed a distinct dip during the afternoon, indicating that aged aerosol and secondary organic aerosol (SOA) had a weaker BrC absorption capacity. There was a good overall correlation between BrC absorption and K+ concentrations. BrC absorption was also moderately related to the concentrations of ammonium cations (NH4+) and nitrate anions (NO3-).

[A Method of Aerosol Particle Number Size Distribution Inversed by PM2.5 Mass Concentration in PRD].

The aerosol particle number size distribution(PNSD) is of great importance in calculating atmospheric radiation and optics. It can effectively supplement the inadequate observation of PNSD using the widely known aerosol mass concentration (PM2.5) measurement to invert PNSD. It would be valuable for research that needs PNSD data, like atmospheric visibility calculation. This paper created a PNSD inversed method based on the statistics and parameterization of the dry aerosol PM2.5 and PNSD dataset from the Guangzhou urban site's simultaneous measurements from November 2014 to January 2015. The inversed results appeared good in the accumulation mode, whereas more differences showed with higher PM2.5 loading. The applicability and stability of this method makes it preferable. It would provide advanced technical support for the visibility calculation and application in PRD.

[Characteristics Analysis of Sulfur Dioxide in Pearl River Delta from 2006 to 2010].

Based on the in-situ SO2 observation dataset from 2006 to 2010 in Pearl River Delta(PRD) , the temporal characteristics of SO2 are analyzed. The results show that the annual average volume fraction of surface SO2 in 2010 declines to a level below average values in recent years, with reducing the frequency of high concentration episodes occurring. The seasonal, monthly and diurnal characteristics of surface SO2 are influenced by particular weather conditions in the PRD. The Probability Distribution Function(PDF) of surface SO2 volume fraction are complicated. The PDF is different every month maybe caused by the variation of the seasonal factors.

[Study on air quality and pollution meteorology conditions of Guangzhou during the 2010 Asian games].

Based on the monitoring data of NO2, O3, SO2, PM, visibility, regional air quality index (RAQI) and the atmospheric transport and diffusion data from Nov. 4, 2010 to Dec. 10, 2010 in Guangzhou area, the variations of air quality and meteorological conditions during the Guangzhou Asian Games were analyzed. It was found that, during the Asian Games, the air quality was better than the air quality before or after the Asian Games. The visibility was greater than the visibility before or after the Asian Games, while the concentrations of PM1 and PM2.5 were lower. The correlation coefficient between visibility and the concentrations of PM1, PM2.5 indicated anti-correlation relationships. Daily and hourly concentrations of NO2 and SO2 met the primary ambient air quality standards, whereas the daily concentration of PM10 and hourly concentration of O3 met the secondary ambient air quality standards. Pollutants had been well controlled during the Asian Games. The concentration of SO2 in Guangzhou was influenced by local sources and long distance transmission, while the concentration of NO2 was significantly influenced by local sources. The emissions of NO2, SO2 and PM10 surrounding Guangzhou had a trend to affect the concentrations in Guangzhou, but the situation of O3 was opposite, the relatively high concentration of O3 in Guangzhou had tendency to be transported to the surrounding areas. The pollution meteorology conditions in the period of Asian Games were better than the conditions before or after the Asian Games. The decrease in the concentrations during the Asian Games did not only benefit from the emission control by the government, but also from the good meteorological conditions.