Evidence of impact of aerosols on surface ozone concentration in Tianjin, China

Hai, Bian; Si, Han; Tie, Xuexi; Sun, Min; Liu, Aixia

doi:10.1016/j.atmosenv.2007.03.041

Cited by 71 publications

(39 citation statements)

References 19 publications

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“…In most of the megacities and large urban complexes in the United States, the observed BC concentrations are lower (Murphy et al, 2011), so the change in photolysis frequencies due to aerosols is likely to be positive. In contrast, very high POA and BC emissions in the megacities in China have caused the reduction of photolysis frequencies and ozone concentrations (Bian et al, 2007). In addition, the aerosol radiative module developed in the present study is based on the aerosol modal approach in CMAQ, which is now widely used in air pollution simulations.…”

Section: Discussionmentioning

confidence: 99%

Aerosol effects on the photochemistry in Mexico City during MCMA-2006/MILAGRO campaign

et al. 2011

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Abstract. In the present study, the impact of aerosols on the photochemistry in Mexico City is evaluated using the WRF-CHEM model for the period from 24 to 29 March during the MCMA-2006/MILAGRO campaign. An aerosol radiative module has been developed with detailed consideration of aerosol size, composition, and mixing. The module has been coupled into the WRF-CHEM model to calculate the aerosol optical properties, including optical depth, single scattering albedo, and asymmetry factor. Calculated aerosol optical properties are in good agreement with the surface observations and aircraft and satellite measurements during daytime. In general, the photolysis rates are reduced due to the absorption by carbonaceous aerosols, particularly in the early morning and late afternoon hours with a long aerosol optical path. However, with the growth of aerosol particles and the decrease of the solar zenith angle around noontime, aerosols can slightly enhance photolysis rates when ultraviolet (UV) radiation scattering dominates UV absorption by aerosols at the lower-most model layer. The changes in photolysis rates due to aerosols lead to about 2-17 % surface ozone reduction during daytime in the urban area in Mexico City with generally larger reductions during early morning hours near the city center, resulting in a decrease of OH level by about 9 %, as well as a decrease in the daytime concentrations of nitrate and secondary organic aerosols by 5-6 % on average. In addition, the rapid aging of black carbon aerosols and the enhanced absorption of UV radiation by organic aerosols contribute substantially to the reduction of photolysis rates.

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Section: Discussionmentioning

confidence: 99%

Aerosol effects on the photochemistry in Mexico City during MCMA-2006/MILAGRO campaign

et al. 2011

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“…For example, Hai Bian (Bian et al, 2007;Han et al, 2009;Li et al, 2009;Gu et al, 2010) presented evidence that aerosol particles have a strong effect on the surface ozone concentration in Tianjin. However, O 3 concentration and its precursors were not systemically measured and the relationship between O 3 and its precursors was not analyzed.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Relationship between O3, NO and NO2 in Tianjin, China

Hai

Feng

et al. 2011

Aerosol Air Qual. Res.

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The continuous measurement of nitric oxide (NO), nitrogen dioxide (NO 2) , nitrogen oxides (NO x ) and ozone (O 3 ) was conducted in Tianjin from September 8 to October 15, 2006. The data were used to investigate the relationship between the O 3 distribution and its association with ambient concentrations of NO, NO 2 and NO x (NO and NO 2 ). The measured concentrations of the pollutants in the study area varied as a function of time, while peaks in NO, NO 2 and O 3 all occurred in succession in the daytime. The diurnal cycle of ground-level ozone concentration showed a mid-day peak and lower nighttime concentrations. Furthermore, an inverse relationship was found between O 3 NO, NO 2 and NO x . In addition, a linear relationship between NO 2 and NO x , as well as NO and NO x , and a polynomial relationship between O 3 and NO 2 /NO was found.The variation in the level of oxidant (O 3 and NO 2 ) with NO 2 was also obtained. It can be seen that OX concentration at a given location is made up of two parts: one independent and the other dependent on NO 2 concentration. The independent part can be considered as a regional contribution and is about 20 ppb in Tianjin.An obvious difference in NO, NO x and O 3 concentrations between weekdays and weekends was also found, but this difference did not appear in NO 2 .Lastly, the diurnal variation of O 3 concentration under different meteorological conditions was demonstrated and analyzed.

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“…NCP is one of the most populated and polluted regions in China. During the recent years, the rapid economical development has resulted in heavy atmospheric aerosol loadings in this region (Bian et al, 2007;Han et al, 2009;Tie et al, 2009;). The high aerosol concentrations induce severely environmental and climate problems.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the formation of fog and haze in North China Plain (NCP)

et al. 2011

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Abstract. North China Plain (NCP) is one of the most populated and polluted regions in China. During the recent years, haze and fog occur frequently and cause severely low visibility in this region. In order to better understand the impact of aerosol particles on the formation of haze and fog, a long-term record of haze and fog occurrences in the past 56 yr (from 1954-2009) over NCP is analyzed. The results show that there are rapid changes in the occurrences of haze and fog over NCP. The occurrences of haze and fog were low during 1970-1980, and reached a maximum during 1981-1998. After 1999, the occurrences of haze and fog slightly decreased. There was a nonlinear relationship between the occurrences of haze and fog. When the occurrence of haze was lower than 40 days yr −1 , the occurrence of fog was strongly proportional to the occurrence of haze. However, when the occurrence of haze was high (larger than 75 days yr −1 ), the occurrence of fog was not sensitive to the occurrence of haze. In order to better understand the relationship between the occurrences of haze and fog as well as the effect of aerosol particles on the formation of haze and fog, an in-situ field experiment was conducted during a period with a mixed occurrence of haze and fog. The analysis of the experiment suggests that there were considerably high aerosol concentrations during the measurement period with an averaged aerosol number concentration of 24 000 cm −3 . The measurement also shows that a large amount of aerosol particles can act as condensation nuclei to enhance the formation of fog droplets. As a result, a large amount of fog droplets (>1000 cm −3 ) with small size (5-6 µm) were observed during the fog period, resulting in extremely low visibility (less than 100 m).

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Evidence of impact of aerosols on surface ozone concentration in Tianjin, China

Cited by 71 publications

References 19 publications

Aerosol effects on the photochemistry in Mexico City during MCMA-2006/MILAGRO campaign

Aerosol effects on the photochemistry in Mexico City during MCMA-2006/MILAGRO campaign

Analysis of the Relationship between O3, NO and NO2 in Tianjin, China

Analysis of the formation of fog and haze in North China Plain (NCP)

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