Differences in airborne particle and gaseous concentrations in urban air between weekdays and weekends (original) (raw)
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Atmospheric Environment, 2008
Weekday and weekend ambient aerosol samples were collected from the city centre of Cairo, namely ''Ramsis'' during the summer season of the year 2006, and have been analyzed for water-soluble ionic species. The average concentrations of the total suspended particulate matter (TSP) and their water-soluble components were higher during weekdays than on weekends, indicating that the decreased traffic density on weekends leads to a decrease in the levels of the TSP and their water-soluble ionic species. The average concentrations of the TSP were 454 mg m À3 on weekdays and 298 mg m À3 on weekends. The weekday/weekend concentration ratios were 1.52 for TSP, 1.27 for SO 4 2À , 1.64 for Cl À , 1.54 for NO 3 À , 1.17 for NH 4 þ , 1.67 for Ca 2þ , 1.83 for Na þ , 1.75 for K þ and 1.73 for Mg 2þ. City centre of Cairo has high levels of the TSP and their water-soluble ionic species compared with many polluted cities in the world. Among all of the measured watersoluble components, SO 4 2À was the most abundant species followed by Ca 2þ on weekdays and weekends. The average mass ratios of NO 3 À /SO 4 2À in the TSP were 0.41 on weekdays and 0.34 on weekends, suggesting that the stationary source emissions were more predominant. The NH 4 þ /SO 4 2À molar ratios and its relation with the concentrations of TSP and Ca 2þ during the weekdays and weekends indicate that the chemical form of sulfate and ammonium in aerosol particles varies with TSP and Ca 2þ levels. At high TSP and Ca 2þ levels, and NH 4 þ /SO 4 2À molar ratios less than one, SO 4 2À in aerosol particles may be present as CaSO 4 and (NH 4) 2 SO 4 CaSO4CaSO 4 CaSO42H 2 O, whereas it is expected to be present as (NH 4) 2 SO 4 , (NH 4) 2 SO 4 CaSO4CaSO 4 CaSO42H 2 O and CaSO 4 at low levels of TSP and Ca 2þ , and NH 4 þ /SO 4 2À molar ratios between 1 and 2. The mean pH values of the TSP were 7.65 on weekdays and 6.97 on weekends, indicating that aerosol particles brought a large amount of crustal species, and might alleviate the tendency of acidification. The relationships between the concentrations of acidic components (NO 3 À and SO 4 2À) and basic components (NH 4 þ , Ca 2þ and Mg 2þ) on weekdays and weekends indicate that the acidity of aerosol particles is neutralized. Ca 2þ and NH 4 þ are the most dominant neutralization substances in Cairo atmosphere.
Atmospheric environment, 1984
Aktract-Data on massconcentration levels and particle size distribution based on samples simultaneously collected at three different areas of a city in winter and in summer were aualysed and compared. In summer concentrations were consistent at all three sites, while in winter wntly higher concentrations were recorded in a densely populated city eentre with traditional spaoe heating Tfic investi@ed correlations and regression equations indicate that the city Ccntre acts as a major source of particulate pollution in the winter time and that it influences air pollution in other parts of the town, especially in the south in the direction of prevalent NE winds. All comxntration levels were within the limits established by Whitby and Liu in Ametin cities. The part& size distribution was bimodal and very consistent for the three sites but there was a sigaificant shift towards smaller particles in winter.
Atmospheric Environment, 2006
During 1 year, twice per week (one working day and one sunday), 24-h averaged, separated fine and coarse atmospheric aerosol were measured, for total mass and chemical composition, in a suburban site on the outskirts of Lisbon. The relative concentration variability between working days and sundays allowed a better insight into the sources of atmospheric particulate matter. Receptor modelling based on Principal Component Analysis and Multilinear Regression applied to sunday and working day samples revealed marked differences during weekdays, in autumn/winter period. Based on the characteristics of the Principal Components it was possible to conclude that during autumn/winter, a predominant fraction of coarse and fine soil dust provides from anthropogenic activities, being presumably associated with road dust resuspension by road traffic. r
Journal of the Air & Waste Management Association, 2003
This paper analyzes day-of-week variations in concentrations of particulate matter (PM) in California. Because volatile organic compounds (VOCs) and oxides of nitrogen (NO x ) are not only precursors of ozone (O 3 ) but also of secondary PM, it is useful to know whether the variations by day of week in these precursors are also evident in PM data. Concentrations of PM Յ10 m (PM 10 ) and Յ2.5 m in aerodynamic diameter (PM 2.5 ) were analyzed. PM concentrations exhibit a general weekly pattern, with the maximum occurring late in the workweek and the minimum occurring on weekends (especially Sunday); however, this pattern does not prevail at all sites and areas. PM nitrate (NO 3 Ϫ ) data from Size Selective Inlet (SSI) samplers in the South Coast Air Basin (SoCAB) tend to be somewhat lower on weekends compared with weekdays. During 1988 -1991, the weekend average was lower than the weekday average at 8 of 13 locations, with an average decrease of 1%. During 1997-2000, the weekend average was lower than the weekday average at 10 of 13 locations, with an average decrease of 6%. The weekend averages are generally lower than weekday averages for sulfates, organic carbon, and elemental carbon. Because heavy-duty trucks typically represent a major source of elemental carbon, the weekend decrease in heavy-duty truck traffic may also result in a decrease in ambient elemental carbon concentrations.
Advances in Meteorology
Air quality in urban areas is deteriorating over time with the increased pollutant distribution levels mainly caused due to anthropogenic activities. In addition, these pollutant distribution levels may relate to changing meteorological conditions. However, the relationships were not researched in-depth in the context of Sri Lanka, a country with a significant impact on climate change. The main objective of this study was to provide a broader perspective on the seasonal variation of tiny particles in air (PM2.5 and PM10), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and sulfur dioxide (SO2) in two urban cities (Colombo and Kandy) in Sri Lanka over 3 years period (2018–2021) and the possible relationships between air pollution and meteorological variables. Results show that all the aforementioned pollutants except O3 consistently depict two peaks during the day, one in the morning (∼07:00–09:00 local time) and the other in the evening (∼18:00–20:00 local time). These pea...
Dependence of urban air pollutants on morning/evening peak hours and seasons
Archives of Environmental Contamination and Toxicology, 2019
Traffic emission is a major source of air pollution in urban cities of developing world. This paper shows dependence of traffic-related air pollutants in urban cities on morning/evening peak hours and winter/summer seasons. This research also shows the meteorological impact, such as temperature (T), relative humidity (RH), and wind speed (WS), on traffic-related air pollutants in urban cites. Based on the research output, the elevated level of PM concentration was observed between 1.8 and 6.7 times at all nearby roadway locations compared with background (IIT [ISM] campus). We have found 2.3, 2.4, 2.6 (morning) and 2.0, 2.1, and 2.1 (evening) times higher average PM 10 , PM 2.5 , and PM 1 concentrations, respectively, in the winter than summer monitoring periods across all locations, due to the stable boundary layer, lower mixing height, and lower friction velocity. It is indicated that urban meteorology plays a crucial role in increasing or decreasing exposed pollutant concentrations in various microenvironments. The analysis of PM 2.5 /PM 10 ratios was lower during whole campaign due to higher contribution of coarser particles generated by vehicles. During winter and summer seasons, 0.57 and 0.33 was observed, respectively. It is indicated that 57% and 33% of PM 10 makes up PM 2.5 particle, respectively. PM concentrations have showed a negative linear relationship with T and WS and positive relationship with RH in winter/summer seasons. Therefore, traffic and meteorology play a big role to increase or decrease in traffic-related air pollutants in urban air quality.
Observations of Weekday-Weekend Activity Patterns for Area Sources in the Los Angeles Area
Over the past 10 years, average peak ozone concentrations in Los Angeles were as much as 55% higher on weekends than on weekdays (under comparable meteorological conditions), eve n though weekend ozone precursor emissions are low relative to weekday emissions. During the summer of 2002, Sonoma Technology, Inc., (STI) extended previous research into weekday-weekend (WD-WE) emissions activity patterns. The objectives were (1) to corroborate our previous research, (2) to formulate improved diurnal and weekly emissions activity profiles for additiona l source categories, which are used as inputs to air quality models, and (3) to contribute (in conjunction with other concurrent research efforts) to the general understanding of weekday-to-weeke nd variability in air quality, which has been noted in Los Angeles and other urban areas. The project scope encompassed an array of emissions source categories: on-road mobile, off-road mobile, major poi nt, residential area, and small commercial a...
WEEKDAY/WEEKEND DIFFERENCES IN AIR QUALITY PARAMETERS IN DELHI, INDIA
A comprehensive database for pollution levels from the year 2006 to 2010 was analyzed for a main traffic intersection at ITO, Delhi. The study had come out to assert that pollution levels on weekend i.e. Saturday and Sunday relate to significantly lower concentration of pollutants as compared to that on weekdays i.e. from Monday to Friday by almost 2 to 6 times. On an average increase on only Sundays with respect to weekdays is CO by 3 times, PM2.5 by 1.18 times, NO by 1.62 times, NO2by 5.76 times, SO2by 1.27 times and O3 by 1.15 times. The pollution levels on Saturdays have been found intermediate. Pollution can hence be related to the weekly cycle of human activities. Emissions from vehicles serve as major sources of pollution. Hence viably possible solutions for pollution control can also be achieved by controlling the magnitude of traffic flow on roads. Similarly holiday effect is observed during public holiday, where the pollution levels reduce by at least 4% for O3 and PM and up to 11 to 14 % for NO, CO and NO2 from the pollution levels in the same week.
seasonal and diurnal changes in inorganic ions, carbonaceous matter and mass in ambient aerosol particles in an urban, background area hilkka timonen 1) *, minna aurela 1) , samara carbone 1) , Karri saarnio 1) , anna Frey 1) , sanna saarikoski 1) , Kimmo teinilä 1) , markku Kulmala 2) & risto hillamo 1)
Temporal variations of atmospheric aerosol in four European urban areas
Environmental Science and Pollution Research, 2011
The concentrations of PM(10) mass, PM(2.5) mass and particle number were continuously measured for 18 months in urban background locations across Europe to determine the spatial and temporal variability of particulate matter. Daily PM(10) and PM(2.5) samples were continuously collected from October 2002 to April 2004 in background areas in Helsinki, Athens, Amsterdam and Birmingham. Particle mass was determined using analytical microbalances with precision of 1 μg. Pre- and post-reflectance measurements were taken using smoke-stain reflectometers. One-minute measurements of particle number were obtained using condensation particle counters. The 18-month mean PM(10) and PM(2.5) mass concentrations ranged from 15.4 μg/m(3) in Helsinki to 56.7 μg/m(3) in Athens and from 9.0 μg/m(3) in Helsinki to 25.0 μg/m(3) in Athens, respectively. Particle number concentrations ranged from 10,091 part/cm(3) in Helsinki to 24,180 part/cm(3) in Athens with highest levels being measured in winter. Fine particles accounted for more than 60% of PM(10) with the exception of Athens where PM(2.5) comprised 43% of PM(10). Higher PM mass and number concentrations were measured in winter as compared to summer in all urban areas at a significance level p < 0.05. Significant quantitative and qualitative differences for particle mass across the four urban areas in Europe were observed. These were due to strong local and regional characteristics of particulate pollution sources which contribute to the heterogeneity of health responses. In addition, these findings also bear on the ability of different countries to comply with existing directives and the effectiveness of mitigation policies.