Study of surface ozone behaviour at urban and forested sites in India

Khemani, L. T.; Momin, G. A.; Rao, P. S. P.; Vijayakumar, R.; Safai, P.D.

doi:10.1016/1352-2310(94)00293-t

Cited by 54 publications

(27 citation statements)

References 6 publications

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“…In our study, air masses have a strong marine influence, the observed enhancement of ground O 3 could be only at the expense of photochemistry rather than the transport of pollutant. A similar pattern of back trajectory was observed in other areas of the world (Khemani et al, 1995;Nishanth et al, 2012).…”

Section: Insupporting

confidence: 48%

Spatial Distribution and Temporal Variation in Ambient Ozone and Its Associated NOx in the Atmosphere of Jeddah City, Saudi Arabia

Hassan

Basahi

Ismail

et al. 2013

Aerosol Air Qual. Res.

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Concentrations of ambient ozone (O 3 ) and nitrogen oxides (NO x ) were measured continuously for a period of 12 months in the city of Jeddah from December 2011 to December 2012. Meteorological parameters, wind speed, temperature, and relative humidity were also monitored. Concentrations of ground O 3 were found to be highly dependent on the NO x diurnal cycle and wind speed. Nitrogen oxides were found to exceed air quality standards, especially in industrial sites, while O 3 concentrations were found to exceed 40 ppb, averaged over 1 h, on more than 24% of the measured days in the rural sites. Furthermore, they exceeded 30% in all other areas (i.e., the urban ones).O 3 and NO x were inversely related. The highest average NO x concentration (96 ppb) occurred in a rural area downwind of a desalination plant, while the average O 3 concentration peaked in a rural area upwind of a desalination plant, reaching 63.5 ppb, although it also reached 72.6 in another rural area, and we consider this latter result as the background figure in the present study. The seasonal variations of O 3 were more distinct than those of NO x . To the best of our knowledge, this is the first report providing comprehensive background information on air quality in an arid area of the developing world.

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Section: Insupporting

confidence: 48%

Spatial Distribution and Temporal Variation in Ambient Ozone and Its Associated NOx in the Atmosphere of Jeddah City, Saudi Arabia

Hassan

Basahi

Ismail

et al. 2013

Aerosol Air Qual. Res.

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“…In Indian region, various groups have been actively involved to carry out long term measurements of surface O 3 and its various precursors and their observations are quite relevant to estimate the regional air quality (Varshney and Aggarwal 1992;Khemani et al 1995;Lal et al 2000;Naja and Lal 2002;Nair et al 2002;Naja et al 2003;Jain et al 2005;Beig et al 2007;Ghude et al 2008;Reddy et al (2008a); Kumar et al 2010;David and Nair 2011;Singla et al 2011). Generally, O 3 is observed to be higher in winter and summer at measurement sites over the globe (Oltmans and Komhyr 1986;Janach 1989;Simmonds et al 2004;Oltmans et al 2006;Wang et al 2008;Tarasoval et al 2009).…”

Section: Introductionmentioning

confidence: 96%

Variations in surface ozone and NOx at Kannur: a tropical, coastal site in India

2012

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Continuous measurements of surface ozone (O 3 ), NOx (NO + NO 2 ) and meteorological parameters have been made in Kannur (11.9°N, 75.4°E, 5 m asl), India from November 2009 to October 2010. It was observed that O 3 and NOx showed distinct diurnal and seasonal variabilities at this site. The annual average diurnal profile of O 3 showed a peak of (30.3±10.4) ppbv in the late afternoon and a minimum of (3.2±0.7) ppbv in the early morning. The maximum value of O 3 mixing ratio was observed in winter (44±3.1) ppbv and minimum during monsoon (18.46±3.5) ppbv. The rate of production of O 3 was found to be higher in December (10.1 ppbv/h) and lower in July (1.8 ppbv/h) during the time interval 0800-1000 h. A correlation coefficient of 0.52 for the relationship between O 3 and [NO 2 ]/[NO] reveals the role of NO 2 photolysis that generates O 3 at this site. The correlation between O 3 and meteorological parameters indicate the influence of seasonal changes on O 3 production. Investigations were further extended to explore the week day weekend variations in O 3 mixing ratio at an urban site reveals the enhancement of O 3 . The variations of O 3 mixing ratio with seasonal air mass flows were elucidated with the aid of backward air trajectories. This study also indicates how vapor phase organic species present in the ambient air at this location may influence the complex chemistry involving (VOCs) that enhances the production of O 3 at this location.

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“…9f). Comparison of rate of change of surface ozone Comparison of monthly variation of surface ozone with other sites in India Joharapur with rural site Gadanki (Naja and Lal, 2002), and urban sites Pune (18.5 o N, 73.9 o E, 559 m) and Ahmedabad (Khemani, et al, 1995;Lal et al, 2000) ppbv for many days have been commonly observed (Aneja et al, 1999;Luo et al, 2000).…”

Section: Diurnal Variationsmentioning

confidence: 99%

“…Diurnal variation shows maximum O 3 concentration about 29.9 ± 5.7 ppbv in the afternoon (1600 h) and minimum about 7.0 ± 3.4 ppbv in the morning (0700 h), which is related to the possible increase in the precursor-gas load of ozone due to anthropogenic activities in the rural site. The ozone concentration begins to increase just after sunrise, and attains its maximum level in the afternoon due to photochemical production of O 3 mainly from oxidation of natural and anthropogenic hydrocarbons, carbon monoxide (CO), and methane (CH 4 ) by hydroxyl (OH) radical in the presence of a sufficient amount of NO x (Seinfeld and Pandis, 1998 (Khemani et al, 1995;Lal et al, 2000). concentrations (31 ppbv) were in April, while low concentrations (10.8 ppbv) occurred in July, attributable to variations in precursor gases and influence of changing meteorological parameters.…”

Section: Observation Site and General Meteorologymentioning

confidence: 99%

“…A few scattered O 3 measurements are available over urban sites (Khemani et al, 1995;Lal et al, 2000) and at the rural site, Gadanki (Naja and Lal, 2002) in India. However, all these studies seldom describe any variation of O 3 at a rural site except at Gadanki, which is located in southeast India about 800 km away from the present O 3 measurement site.…”

Section: Introductionmentioning

confidence: 99%

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