Case study of UV-B modification during episodes of urban air pollution

Repapis, C. C.; Mantis, Homer T.; Παλιατσός, Α. Γ.; Philandras, C. M.; Bais, A. F.; Meleti, C.

doi:10.1016/s1352-2310(97)00410-x

Cited by 35 publications

(19 citation statements)

References 6 publications

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“…Studies on the effects of increased UV-B show increased flowering duration (Conner and Neumeier, 2002), delayed flowering time (Sampson and Cane, 1999), and delayed or no change in flowering phenology of crop plants (Kakani et al, 2003). In contrast to these studies is the effect of decreased UV-B exposure in urban areas due to pollution (e.g., Papayannis et al, 1998;Repapis et al, 1998). If UV-B radiation affects flowering phenology, how does decreased UV-B exposure affect flowering?…”

Section: Photoperiodmentioning

confidence: 99%

Effects of urbanization on plant flowering phenology: A review

2006

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Studies of flowering and leafing phenology have dramatically increased during the last few decades because changes in plant phenology can be indicative of possible effects of climate change at multiple scales. This article reviews the available literature focusing on the effects of urbanization on flowering phenology. The literature of flowering phenology in urban environments suggests that spring-blooming plants in a variety of ecosystems in North America, Europe, and China tend to bloom earlier in the city than in the surrounding un-urbanized habitat. Moreover, ephemerals, early spring bloomers, and insect-pollinated plants in these environments tend to be more sensitive than perennials, mid-or late-spring bloomers, and wind-pollinated plants. Researchers attribute advanced flowering in urban environments to the Heat Island Effect. The potential ecological consequences of changes in flowering phenology in urbanized areas are not well understood or explicitly studied. However, studies in global biology have suggested that climate change may result in a series of important ecological consequences as well as human-related problems such as earlier and extended allergy seasons. More field-based studies are needed to elucidate this issue.

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Section: Photoperiodmentioning

confidence: 99%

Effects of urbanization on plant flowering phenology: A review

2006

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“…For these two reasons, a single-pass measurement might not be representative of the actual groundlevel cumulative UV measurements. 18 Recent studies have explored the various factors influencing surface UV variability, such as clouds 19 -22 and aerosols in urban [23][24][25][26] and rural locations. [27][28][29][30] It is important to analyze surface UV variations with simultaneous measurements of surface pollutants 31 to determine the actual, not derived, UV levels that reach the Earth's surface.…”

Section: Introductionmentioning

confidence: 99%

Daily Surface UV Exposure and Its Relationship to Surface Pollutant Measurements

Barnard

Saxena

Wenny

et al. 2003

Journal of the Air & Waste Management Association

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For the past 30 years, the stratospheric ozone layer has decreased in the Northern Hemisphere. The main effect of this ozone decrease was an expected increase in the UV radiation at the Earth's surface, but there has been no clear evidence of an increasing urban trend in surface UV. This study shows that specific air pollutants can reduce the increased surface levels of UV radiation and offers an explanation for why the expected surface UV increases have not been observed, especially in urban regions.A U.S. Environmental Protection Agency (EPA) UV monitoring site at the University of California at Riverside combined with air pollution data from a site operated by the California Air Resources Board in Rubidoux, CA, provided the basis of this study. The 1997 South Coast Ozone Study (SCOS-97) provided three key ingredients: black carbon, PM 10 concentrations, and collocated radiometric measurements. The Total Ozone Mapping Spectrometer (TOMS) satellite data were used to provide the stratospheric ozone levels that were included in the statistical model. All of these input parameters would be used to test this study's hypothesis: the expected increase of surface UV radiation, caused by decreases in stratospheric ozone, can be masked by increases in anthropogenic emissions. The values for the pollutants were 7:00 a.m.-5:00 p.m. averages of the instrument's values taken during summer 1997.A statistical linear regression model was employed using the stratospheric ozone, black carbon, PM 10 , and surface ozone concentrations, and the sin (⌰) and cos (⌰). The angle ⌰ is defined by ⌰ ϭ 2 (Julian date/365). This model obtained a coefficient of determination of 0.94 with an uncertainty level (p value) of less than 0.3% for all of the variables in the model except ground-level ozone. The final model, regressed against a data set from a remote, western North Carolina site, resulted in a coefficient of determination of 0.92. The model shows that black carbon can reduce the Diffey-weighted UV levels that reach the surface by as much as 35%, depending on the season.

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“…In addition, the spectral range studied in the present work is suitable for (i) estimating atmospheric constituents like ozone and NO 2 (KAMBEZIDIS et al, 1997a, (ii) studying part of the solar erythemal (sunburn) UV band and its eect on biological tissues (LORENTE et al, 1994;REPAPIS et al, 1998;PAPAYANNIS et al, 1998), (iii) studying luminous eciency and eye response (MCCARTNEY and UNSWORTH, 1978) and (iv) assessing the reduction of part of the photosynthetically active radiation (PAR), that is the radiation required by plants for the photosynthesis process (BLACKBURN and PROCTOR, 1983).…”

Section: Introductionmentioning

confidence: 99%

Determination of Ångström and Schüepp's Parameters from Ground-based Spectral Measurements of Beam Irradiance in the Ultraviolet and Visible Spectrum in Athens, Greece

Kambezidis¹,

Adamopoulos²,

Zevgolis³

2001

Pure appl. geophys.

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Ð This work estimates the A Ê ngstroÈ m coecients, assuming a linear behavior of the natural logarithm of aerosol optical thickness, ln d a (k), versus the natural logarithm of wavelength, ln k, in the urban environment of Athens for a period of one year. The calculation of the coecients a, b, was carried out using records of spectral beam irradiance in the 320±575 nm spectral range. The seasonal and diurnal variation of the coecients shows dierent features with generally higher values of b and lower values of a in summertime. The A Ê ngstroÈ m coecients are investigated with respect to various wind regimes and the results are discussed with a view to air pollution sources, climatic and topographic characteristics of the Athens basin. A similar study is also carried out for the SchuÈ epp's turbidity parameter.

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Case study of UV-B modification during episodes of urban air pollution

Cited by 35 publications

References 6 publications

Effects of urbanization on plant flowering phenology: A review

Effects of urbanization on plant flowering phenology: A review

Daily Surface UV Exposure and Its Relationship to Surface Pollutant Measurements

Determination of Ångström and Schüepp's Parameters from Ground-based Spectral Measurements of Beam Irradiance in the Ultraviolet and Visible Spectrum in Athens, Greece

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