Determination of dry deposition of ozone: Comparison of different measuring techniques

Five methods were used to investigate the deposition of ozone. The measurements of the eddy diffusivity of heat using the Bowen ratio technique were slightly higher than but closely matched the measurements made for the momentum eddy diffusivity, measured simultaneously, using the profile technique. Similar flux values were obtained by the profile and eddy correlation method. Deposition velocities determined using the box method were higher than those calculated using an open top chamber

Greenhouse gas emissions as a result of spectators travelling to football in England

Transport remains a critical avenue in the attempt to reduce greenhouse gas (GHG) emissions and any significant effort to reduce travel GHG emissions will need to encourage a movement towards more fuel-efficient, less polluting behaviours. The aim of this paper is to calculate GHG emissions arising from the travel of spectators to and from football games within eight football tiers (3 to 10) in England, and to extrapolate this to a national level. The study comprised of 1649 participants with an average age of 42 years (M = 42.63, SD = 17.10). Participants travelled to and from games by walking, cycling, car, bus, train or taxi. The average distance travelled to and from games was 41.5 km. A Kruskal-Wallis test was conducted to evaluate differences in travel related GHG emissions between the eight football tiers during the 2012/13 season. The results indicate significant differences between football tiers' GHG emissions, H(7) = 46.474, p < 0.001. The annual GHG emission of spectators from the 8 tiers for the 2012/13 season was estimated at 56,237 tonnes of CO 2 e, accounting for less than 0.05% of transport emissions in England. Football authorities should have robust travel plans and educate spectators to employ more sustainable travel plans to games

Assessment of airborne particulate matter (PM<inf>2.5</inf>) in university classrooms of varrying occupancy

Air pollution is a major concern in Pakistan. Levels of particulate matter (PM2.5) in educational built environments, have not yet been studied comprehensively in Pakistan. This study was conducted to assess relationships between indoor and outdoor particulate matter in classrooms of the University of the Punjab, Lahore, using a DUSTTRAK Aerosol Monitor (TSI Model 8520). Sampling for PM2.5 concentrations was carried out simultaneously outdoors and indoors in different classrooms on the campus. According to the level of occupancy three classrooms were selected i.e. Classroom I: low occupancy, Classroom II: medium occupancy and Classroom III: high occupancy. Simultaneous outdoor measurements were carried out at rooftop of each classroom. A tracer method was used to measure the air change per hour in each classroom. The 24 hour average concentrations of PM2.5 in Classrooms I, II and III were observed to be 282 μg/m3, 75 μg/m3 and 673 μg/m3 whereas 24 hour average outdoor levels were 324 μg/m3, 121 μg/m3 and 998μg/m3 respectively. Results showed a significant impact of ambient air and occupancy level on PM2.5 levels inside classrooms and all observed values exceeded the WHO limits

Exposure to PM <inf>10</inf>, PM <inf>2.5</inf>, PM <inf>1</inf> and carbon monoxide on roads in Lahore, Pakistan

Particulate matter pollution is one of the major environmental concerns in Pakistan. Over the past 20 years there has been a considerable increase in the number of motor vehicles. The present study was conducted to assess journey time and roadside exposure to particulate matter and carbon monoxide along major roads of Lahore during November, 2007. Measurements of particulate mass and carbon monoxide were carried out continuously inside an air conditioned vehicle, while commuting, and outside the vehicle at 36 different locations in the city. Additionally, monitoring was undertaken at a background site throughout the period. The overall mean journey-time concentrations of PM 10, PM 2.5, PM 1, PM 10-2.5 and CO were 103 μg/m 3, 50 μg/m 3, 38 μg/m 3, 53 μg/m 3 and 8 ppm, respectively. At the roadside average PM 10, PM 2.5, PM 1, PM 10-2.5 and CO concentrations were 489 μg/m 3, 91 μg/m 3, 52 μg/m 3, 397 μg/m 3 and 4 ppm, respectively. The highest levels were found at the sites with traffic congestion reflecting, not only, the large contribution of automobile exhaust but also the resuspension of road dust. The majority of public transport vehicles in Lahore are not air-conditioned and it is very likely that commuters are exposed to the similar high levels of pollution. © Taiwan Association for Aerosol Research

Automotive related exposure to particulate air pollution in developing countries cities

Poor urban air quality in developing countriesis a growing public health challenge due to rises in population, industries, urbanization and vehiclesalong with insufficient air quality management. Among the range of air pollutants exposure to particulate matter (PM) is of greatest concern due to its association with chronic obstructive pulmonary diseases. The present study reports traffic related exposure to PM by the roads in Lahore, Pakistan. The measurements of mass and number of PM were carried out by GRIMM analysers (Model 1.108 and Model 1.101) and condensation particle counter (TSI 3781). The heavy metals concentration in PM was determined by Graphite Furnace Atomic Absorption Spectrophotometer (Unicam atomic absorption, Cambridge, UK).The mean hourly average concentration of PM10, PM2.5, PM1 and PM10 – 2.5 at the road siteswas higher during weekdays(305 μg/m3, 84 μg/m3, 61 μg/m3 and 222 μg/m3, respectively) in comparison to the weekend (136 μg/m3, 60 μg/m3, 40 μg/m3 and 76μg/m3, respectively). At the background site the levels in the same size fractions were 206μg/m3, 63μg/m3, 31μg/m3, and 143μg/m3, respectively. Likewise, the number concentration of ultrafine particles was considerably higher at road sites (417,003 #/m3) than the background(97,300 #/m3).The concentration of heavy metals in PM decreased in the following order: Si, Al, Zn, Mn, Cu, Ni, Cd, Pb. Overall, the concentration of PM10, PM2.5 and toxic metals (Mn, Cd, Ni) was substantially higher than guidelines by the WHO. Furthermore, relatively higher levels of the fine fraction (PM2.5 and PM1) in the background reflect their higher residence time and resultant increased risk of exposure to the wider public beyond that of the vicinity to automotive sources. Everyday commuters, mostly on two and three wheelers as well asthe residential population in urban areas are at an enhanced risk of exposure to high levels of particulate pollution

Ultrafine particles in rural and urban dwellings with different household fuel use in developing countries – An example from Pakistan

Exposure to indoor particulate matter (PM) is a major public health concern, in particular, in developing countries where solid fuels are typically used as a household energy source.Despite the fact that emission from these fuels can have a dominant fraction of ultrafine particles, exposure to PM is generally characterised in terms of mass concentration of PM10 and PM2.5. The present study was carried out to examine the number concentration of ultrafine particles in rural and urban Pakistani households with different fuels. Air samples were collected from kitchens, living rooms and courtyards of two rural sites (Site I - Solid fuel; Site II - Natural gas) and an urban site (Natural gas) by using condensation particle counters.At rural site –I the 24 hour mean concentration of particles in the kitchen, living room and outdoors was 40,991#/cm3 (± 7472), 30,291#/cm3 (± 13774) and 34,534#/cm3 (± 4947), respectively. During cooking the number concentration can increase significantly with an average hourly maximum value of 169,455#/cm3. Higher outdoors levels than in living rooms highlight the effect of cooking in open kitchens on ambient levels. At the rural site II the daily average number concentration in living rooms was in the range of 10,745 – 16,126 #/cm3 with a mean of 13,542 #/cm3.These values were more than half those in living rooms at rural site I. Whereas in the kitchen the 24hour mean was 27,446#/cm3 (± 4487). At the urban site the mean 24 hour average in the living rooms and kitchens was 45,466 #/cm3 (± 5919)and 65,904 #/cm3 (± 11490), respectively. The 24 hour mean concentration was more than double in the urban kitchens than in rural kitchens at site II. The 24 hour average outdoors was 33,424 #/cm3 (± 6037)– slightly lower than outdoors at rural site I. Overall, the number concentration was higher in kitchens using natural gas fuel at the urban site than in those with solid fuels and natural gas at rural sites. While between rural sites the households with solid fuel had higher concentrations than those with natural gas. Furthermore, outdoors at rural site-I households had higher concentrations as compared to urban household outdoors

Comparative study of particulate matter in the transport microenvironment (buses) of Pakistan and UK

Transport microenvironments can contain higher levels of particulate matter due to infiltration from the roads, vehicular exhaust and commuter’s activities. The present study monitored PM, CO2, CO, temperature and relative humidity levels in diesel-powered buses in Pakistan and United Kingdom. Two routes of almost the same travelling distance were selected in Pakistan and the UK. Indoor air quality of the buses was monitored to determine the exposure faced by the commuters on inter-city journeys. While the observed levels in both countries were not in compliance with the WHO guidelines, levels of particulate matter were much higher in Pakistan than the concentrations in UK

Socio-environmental determinants of exposure to water and sanitation related hazards in Pakistan

Inadequatewater and sanitation infrastructure leads to increased health risks to the population, in particular, children. The lack of access to improved water and sanitation facilities is a major cause of diarrheal diseases.At present, access to safe drinking water, improved sanitation facilities, good personal and food hygiene and health education are the main focus of intervention strategies. The knowledge on socio-environmental determinants of exposure to water and sanitation hazards can play a pivotal role supporting and guiding preventive measures for reducing the risk of exposure to water and sanitation related hazards. The present study was carried out to identify socio-environmental determinants of exposure to water and sanitation related hazards in Pakistan by taking the incidence of diarrhoea in under five years old as an archetypical disease of lack of access to improved water and sanitation facilities. A logit model has been used to predict the determinants of diarrhoea in under fives. The results indicate that household location, household size, number of children in the family,age of the mother, education of the mother, household head's employment, drinking water sources and toilet facility are important correlates of diarrhoea in children. The findings of the study may inform to prioritize the resource mobilization in capacity building towards designing the most effective prevention intervention strategies to reduce the risk of exposure to sanitation hazards

Heavy metal composition of particulate matter in rural and urban residential built environments in Pakistan

Heavy metals in outdoor and indoor airborne particulate matter (PM) and dust in different residential built environmentsat two rural and one urban site in Pakistan were analysed. An eight stage non-viable impactor (Thermo Fisher Scientific Inc., USA) loaded with EMP 2000 glass microfiber filter papers (Whatman, England) was used to collect airborne PM.The indoordust samples (settled dust) were collected from different indoor surfaces (floor, cupboards) in living rooms and kitchens from houses at rural sites. The outdoor samples were collected from courtyards of the houses.At the urban site dust samples were also collected by the roads at 27 different locations around Lahoreand at a background site (University of Veterinary and Animal Sciences).Additionally, samples of dung cake, used as solid fuel, at one of the rural sites were taken.Heavy metals (Si, Al, Zn, Mn, Cu, Ni, Cd, Pb, Co and As) were determined by Graphite Furnace Atomic Absorption Spectrophotometer. At rural site I, in general, the concentrations of metals were higher outdoors than indoors, except for slightly higher indoor levels of Cu (0.85μg/m3 indoor: 0.56 outdoorμg/m3), Si (3.31μg/m3 indoor: 3.17 outdoorμg/m3) and Pb(11.99 ng/m3 indoor: 9.32 outdoor ng/m3). At the rural site II the mean concentration were higher outdoors than indoors, excluding Ni which was considerably higher indoors (55.68 ng/m3) than outdoors (31.91 ng/m3).At the urban site,outdoors, Si had the highest concentration (3.46 μg/m3) followed by Al, Zn, Mn, Cu, Ni, Cd, Pb and Co. Similarly, the indoor levels had a maximum contribution from Si (12.30 μg/m3) followed by Al, Mn, Zn, Cu, Cd, As, Pb, Ni and Co.With reference to dust at rural site I the top five metals outdoors were Si (708 mg/kg), Al, Cu, Zn and Pb (52 mg/kg) while, indoors Al was highest (281 mg/kg), followed by Si, Cu, Zn and Pb (57 mg/kg). At rural site II, both outdoors and indoors, Al (274 mg/kg – outdoor: 266 mg/kg - indoor), Si, Zn, Cu and Pb (61 mg/kg – outdoor: 80 mg/kg - indoor) were the five most abundant metals.The main five metals in decreasing order of their concentration in the road dust around Lahore were Si (686 mg/kg), Al, Cu, Zn and Pb (81 mg/kg). On the other hand, the dust samples from the background site showed Si (345 mg/kg) > Al >Pb> Cu > Zn (73 mg/kg). The airborne metal concentration of Pb was within the guideline value of WHO (0.5 μg/m3) but the levels of Mn, Cd and Ni were higher at all sites than the guidelines proposed by European Commission and WHO highlighting the risk of exposure to toxic metals in non-occupational environments

The Impossibility Of Secure Two-Party Classical Computation

We present attacks that show that unconditionally secure two-party classical computation is impossible for many classes of function. Our analysis applies to both quantum and relativistic protocols. We illustrate our results by showing the impossibility of oblivious transfer.Comment: 10 page