Urban dew: Its composition and influence on dry deposition rates

Mulawa, Patricia A.; Cadle, Steven H.; Lipari, Frank; Ang, Carolina C.; Vandervennet, RenéT.

doi:10.1016/0004-6981(86)90009-0

Cited by 63 publications

(20 citation statements)

References 23 publications

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“…The vast majority of dew studies are rural (e.g., Sharma, 1976;Sudmeyer et al, 1994;Wittich, 1995;Kidron et al, 2000;Luo and Goudriaan, 2000), and urban climate studies seldom address moisture fluxes beyond evaporation (e.g., Oke et al, 1998;Spronken-Smith and Oke, 1999). Several studies have collected urban dew for chemical analysis (e.g., Mulawa et al, 1986;Schroder et al, 1989;Wagner et al, 1992;Okochi et al, 1996), but they tend to ignore the climatology of dew, and any potential urban-rural contrasts. Two climatological studies explicitly dealt with urban dew in the 1970s; neither is widely known.…”

Section: Introductionmentioning

confidence: 97%

Urban and rural dewfall, surface moisture, and associated canopy-level air temperature and humidity measurements for vancouver, canada

Richards

2005

Boundary-Layer Meteorology

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Canopy-level humidity is often less at night during fine weather in a mid-latitude city, compared to its rural surroundings. This feature has been attributed, in part, to reduced urban dew, but links are largely unproven, because urban dew data are rare. In this study, surface moisture (i.e., dew + guttation by blotting) and dewfall (by mini-lysimeter) were measured at rural and urban residential sites in Vancouver, Canada, during the summer of 1996. Air temperature and humidity were measured at both sites, and on rural-to-urban vehicle traverses. Weather and location effects were evident. Humidity data suggested the small (<1 g m )3 ) urban moisture excess observed on fine nights was linked to reduced urban dew. For grass, the frequency of moisture events, and surface moisture amounts, were similar for both sites. However, on grass, rural dewfall (mean=0.10 mm per night) was more than urban dewfall (mean=0.07 mm per night). On the other hand, data for a 'roof ' lysimeter (mean dewfall=0.12 mm per night) showed that an urban roof could rival rural grass as a favoured location for dewfall in Vancouver.

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Section: Introductionmentioning

confidence: 97%

Urban and rural dewfall, surface moisture, and associated canopy-level air temperature and humidity measurements for vancouver, canada

Richards

2005

Boundary-Layer Meteorology

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“…Various studies regarding chemical characterization of dew have been carried at urban places like in France (Beysens et al, 2006), in USA (Mulawa et al, 1986;Pierson et al, 1988), in Chile (Rubio et al, 2002(Rubio et al, , 2008(Rubio et al, , 2009, in Poland (Polkowska et al, 2008), in Germany (Acker et al, 2008), in India (Khare et al, 2000;Singh et al, 2006;Lakhani et al, 2012;Yadav and Kumar, 2014), in Japan (Okochi et al, 1996;Chiwa et al, 2003), in Taiwan (Simon et al, 2016). Galeket al (2016) analysed urban dew water formation efficiency and chemistry at sites near Wroclaw, Poland.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study on Fog and Dew Water Chemistry at New Delhi, India

Nath

Yadav

2018

Aerosol Air Qual. Res.

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Fog and dew, formed via different formation mechanisms, are suitable to study the liquid-gas-solid phase chemical interactions in the ambient atmosphere. A total of 24 fog and 19 dew samples were collected using Caltech Active Strand Cloud water Collector 2 and dew condensers, respectively, over New Delhi during winter months of 2014-15 and were characterised for pH and soluble inorganic ion using ion chromatograph. Dew samples were alkaline (pH = 6.26 ± 0.37) in comparison to natural rainwater pH of 5.6 and fog collected at rooftop (pH = 5.38 ± 1.3) and at ground level (pH = 5.96 ± 0.3). The volume weighted mean equivalents of cations followed the order NH ) and dew (Ca 2+ > NH 4 + > Mg 2+ ). The differences in the fog and dew composition are primarily linked to their formation processes.The agricultural fields and fossil fuel combustion were sources for ammonium, sulphates, nitrate and nitrite whereas locally resuspended crustal materials added calcium and magnesium carbonates. Vehicular and plant emissions, biomass burning and the oxidation of volatile organic compounds seems to be responsible for higher organic acids in dew and fog.

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“…It can, however, augment trace metal deposition if any dissolved metals are left behind after the water evaporates [Schroeder and Munthe, 1998]. Previous studies of major ions including some metals (e.g., Ca 2+ and Mg 2+ ) in dew noted concentrations similar or greater than those of precipitation [Mulawa et al, 1986;Wagner and Steele, 1992]. Gaseous oxidized mercury (GOM: any gaseous compound involving Hg 2+ ) is considerably more soluble in water than GEM (Henry's law coefficients at 20°C for Hg 0 and HgCl 2 : K Hg0 = 729 and K Hg(Cl)2 = 3.69 × 10 À5 Pa m 3 mol À1 , respectively ;Schroeder and Munthe [1998]).…”

Section: Introductionmentioning

confidence: 99%

Seasonal contribution of dewfall to mercury deposition determined using a micrometeorological technique and dew chemistry

2014

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[1] Deposition of mercury (Hg) to dew is thought to influence the diurnal dynamics of Hg species in the near-surface air, yet this depositional pathway is not well characterized and is seldom accounted for in Hg budgets. This study quantifies Hg deposition to dew on a seasonal basis at a high-elevation meadow in Shenandoah National Park, Virginia, and compares these rates with those for wet deposition and other forms of dry deposition. Dew samples were collected on a surrogate surface and analyzed for Hg concentrations (ng L À1 ), and dew depths (mm) were calculated using a micrometeorological approach based on the surface energy budget over 1 week period during each of the four seasons. Concentrations of Hg in dew (mean: 5.57 ng L À1 ) were lower than those observed in precipitation (mean weekly composite samples: 8.80 ng L À1 ). When dew deposition was scaled to the seasonal and annual levels, Hg deposition in dew was estimated to be 2-3 orders of magnitude smaller than wet deposition (estimated annual Hg deposition to dew/frost:~120 ng m À2 ; 2008 annual precipitation deposition:~12400 ng m À2 ). This disparity is attributed to the much lower dewfall amounts. Rates of Hg accumulation in dew were not related to gaseous elemental mercury (GEM) concentrations in the atmosphere nor were they related to measured GEM fluxes. They were, however, found to be similar to independently estimated rates of gaseous oxidized mercury (GOM) and particulate mercury (Hg p ) deposition during the nighttime, suggesting that dew scavenges GOM and Hg P from the atmosphere at the study site.Citation: Converse, A. D., A. L. Riscassi, and T. M. Scanlon (2014), Seasonal contribution of dewfall to mercury deposition determined using a micrometeorological technique and dew chemistry,

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Urban dew: Its composition and influence on dry deposition rates

Cited by 63 publications

References 23 publications

Urban and rural dewfall, surface moisture, and associated canopy-level air temperature and humidity measurements for vancouver, canada

Urban and rural dewfall, surface moisture, and associated canopy-level air temperature and humidity measurements for vancouver, canada

A Comparative Study on Fog and Dew Water Chemistry at New Delhi, India

Seasonal contribution of dewfall to mercury deposition determined using a micrometeorological technique and dew chemistry

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