Daily Emissions Research Articles

Spatiotemporal evolution pattern detection for heavy-duty diesel truck emissions using trajectory mining: A case study of Tianjin, China

Abstract Emissions from heavy-duty diesel trucks (HDDTs) pose a major threat to environment and human health. Understanding the behavior of pollutant emissions from HDDTs facilitate the formulation of traffic-related policy measures to mitigate the adverse effects. This study proposes a new method to estimate the emission inventory of HDDTs and analyze their spatiotemporal evolution characteristics. Multi-source data were fused to provide a complete picture of the transport environment. With the idea of modeling pollutant emissions by “single vehicle” and “road segment,” emission inventories were constructed with different spatiotemporal scales using localized emission factors. A spatiotemporal cube model was introduced to represent the high-resolution emission inventory. A hot-spot and local-outlier analysis were conducted to explore the spatiotemporal evolution mechanism of pollutant emissions. The megacity of Tianjin in China was taken as the area for the case study. The average daily emissions of CO, NOx, PM, and VOC are 12,978.18, 48,675.22, 712.6, and 1217.72 kg d−1, respectively. Temporally, the pollutant emission had a significant peak at 06:00, 11:00, and 18:00 and was affected by major festivals. Spatially, the distribution pattern of emission was policy-driven and closely related to its spatial location. It increases radially outward from the outer-ring road to the periphery. The hot-spot analysis identified 16 pollutant emission patterns. The road segment with persistent cold spots accounted for 48.27% of the roads, mainly distributed within the outer ring road. The road segments with intensifying and persistent hot spots accounted for 19.04% of roads, mainly distributed on the intercity highway. The locations with outlier values reached 12,027, accounting for 31.90%. The key time intervals of the occurrence of the outlier pattern are 11:00–12:00 and 01:00–02:00. Road segments showing only the low–low cluster pattern is mainly located within the outer ring roads. Those with only low–high outlier pattern exhibits a relatively scattered spatial distribution, which is affected by the heterogeneous distribution of HDDTs.

Ammonia emissions and dry deposition in the vicinity of dairy farms

We conducted the first research in the Czech Republic to measure ventilation and ammonia (NH 3 ) emission rates in a naturally ventilated animal building (dairy farm) during a five-day measurement period in June, combined with a three-month (May-July) monitoring of NH 3 concentration and dry deposition at 12 locations along horizontal gradients from the dairy farm up to the distance of 400 m. Passive diffusion-tube samplers were used to measure monthly NH 3 concentrations. Moisture (H 2 O) balance was used to determine ventilation rates of the dairy farm. Continuous measurements of gas concentrations (NH 3 ), temperature and relative humidity inside and outside the building were performed. The air exchange rate was 4.8 h –1 and the emission rate was 43.2 NH 3 g cow –1 d –1 for building. The emission rate was 126% of what was obtained using emission factors from the Czech national inventory (34.2 g cow –1 d –1 ). NH 3 concentrations and dry deposition fluxes decreased exponentially with distance from the dairy farm. Between May and July, mean predicted dry deposition fluxes ranged from 0.28 to 0.03 µg NH 3 m –2 s –1 at a distance of 50 and 400 m from the source, respectively. Dry NH 3 deposition over the nearest 400 m from the source accounted for 11.5% of daily emissions. The results confirm the short-range dispersion of NH 3 emitted from a point source found in other studies, but it may not be the same in other situations, since dispersion of NH 3 is dependent on the surrounding land-cover and on the number of animals in a barn.

Soil greenhouse gas emissions from Australian sports fields

Managed turf is a potential net source of greenhouse gas (GHG) emissions. While most studies to date have focused on non-sports turf, sports turf may pose an even greater risk of high GHG emissions due to the generally more intensive fertiliser, irrigation and mowing regimes. This study used manual and automated chambers to measure nitrous oxide (N2O) and methane (CH4) emissions from three sports fields and an area of non-sports turf in southern Australia. Over 213 days (autumn to late spring), the average daily N2O emission was 37.6 g N ha−1day−1 at a sports field monitored at least weekly and cumulative N2O emission was 2.5 times higher than the adjacent non-sports turf. Less frequent seasonal sampling at two other sports fields showed average N2O daily emission ranging from 26 to 90 g N ha−1 day−1. Management practices associated with periods of relatively high N2O emissions were surface renovation and herbicide application. CH4 emissions at all of the sports fields were generally negligible with the exception of brief periods when soil was waterlogged following heavy rainfall where emissions of up to 1.3 kg C ha−1 day−1 were recorded. Controlled release and nitrification inhibitor containing fertilisers didn’t reduce N2O, CH4 or CO2 emissions relative to urea in a short term experiment. The N2O emissions from the sports fields, and even the lower emissions from the non-sports turf, were relatively high compared to other land uses in Australia highlighting the importance of accounting for these emissions at a national level and investigating mitigation practices.

Emissão de CO2 do solo pela aplicação de fertilizantes orgânicos e minerais em ambiente controlado

Abstract – Swine production is fundamental in Brazil and it seeks suitable use for swine slurry (SS) in agricultural areas. The objective of this study was to evaluate the effects of SS and urea application, treated or not with nitrification inhibitor (DCD) and the way of fertilizer distribution, associated or not with crop residues, on CO2 emissions in a controlled environment. The soil used in this study was a Humic Dystrudept soil and daily and accumulated CO2 emissions were measured. Daily CO2 emissions increased with SS use. There was no difference considering the way the fertilizers were applied. The use of straw increased CO2 emissions. Accumulated CO2 emissions were higher under use of straw associated with SS.

Cause and Effect Evaluation of PM2.5 During Three Red Alerts in Beijing from 2015 to 2016

Beijing authorities issued three red alerts for heavy air pollution at 6 pm on December 7 and 7 am on December 18, 2015, and at 1 pm on December 15, 2016, respectively. To better understand the different causes of the three red alerts and assess the effectiveness of emergency measures dealing with heavy air pollution, the PM2.5 concentrations, meteorological conditions, weather conditions, and air mass transmission were analyzed during the red alerts using data from environmental and meteorological monitoring stations in Beijing. All three red alerts were affected by secondary transformation, but the high PM2.5 concentrations were mainly affected by meteorological conditions. During the first and second red alerts, the ground in Beijing was controlled by a uniform pressure field and the regional transport was mainly affected by southwestern and southern air masses. During the third red alert, the ground was under the control of a wide range of low pressure and affected by the superposition of southwestern and local air masses. During the third red alert, the PM2.5 pollution was the most serious. Its average concentration was the highest (273.6 μg·m-3), that is, 1.2 times and 1.3 times higher than that of the previous two alerts, respectively. The WRF-CMAQ model was used in combination with the emission reduction of each source to evaluate the effects of the emergency measures related to the third red alert. The results show that the average daily emission reduction of pollutants was 678.4 t, the average concentration of PM2.5 decreased by 79.1 μg·m-3, and the average reduction ratio was 26.9% after the emergency measures were implemented. The increase of coal-fires, traffic, and other sources control the emergency measures, early alert start-up time, and inter-region joint prevention and effectively mitigate the increasing PM2.5 concentration.

Air quality accountability: Developing long-term daily time series of pollutant changes and uncertainties in Atlanta, Georgia resulting from the 1990 Clean Air Act Amendments

The 1990 Clean Air Act Amendments codified major institutional changes relating to the management of air pollutants in the United States. Recent research years has attributed reduced emissions over the past two decades to regulations enacted under these Amendments, but none have separated long-term daily impacts of individual regulatory programs on multiple source categories under a consistent framework. Using daily emissions and air quality measurements along with a detailed review of national and local regulations promulgated after the Amendments, we quantify daily changes in emissions and air quality attributable to regulations on electricity generating units and on-road mobile sources. To quantify daily changes, we develop nine sets of counterfactual emissions and ambient air pollution concentration time series for 10 pollutants that assume individual regulatory programs and combinations thereof were not implemented. In addition to daily impacts, we estimate uncertainties in these results. These counterfactual daily ambient concentrations reveal high seasonality and increasing effectiveness of most regulations between 1999 and 2013. Monthly average counterfactual concentrations in scenarios that assume no new regulations on electricity generating units and mobile sources are greater than observed concentrations for all pollutants except ozone, which has seen increased wintertime concentrations accompany summertime decreases. By the end of the period, electricity generating unit emissions reductions under the Acid Rain Program and Clean Air Interstate Rule and their respective related local programs led to similar PM2.5 concentration decreases. Of the mobile source regulations, rules on gasoline and diesel vehicles led to similar reductions in annual PM2.5, and gasoline programs led to double the summertime ozone reductions as diesel programs. The nine sets of daily time series and their uncertainties were designed for use in air pollution accountability health studies.

Carbon exchange in a caatinga area during an unusually drought year

The objective of this study was to analyze the daily and seasonal variation of the carbon balance components in a caatinga area during an unusually drought year. Data were collected from a turbulent vortices covariance system installed at an area in Caatinga , in the region of Petrolina Municipality, State of Pernambuco, Brazil. Carbon dioxide flux data were collected in the year 2012, and the partitioning between gross primary productivity (GPP) and ecosystem respiration (Re). The vegetation cover index, weather elements and the soil water content were monitored. It was observed that the daily emissions of CO 2 flux was dependent upon photosynthetically active radiation in the first days after rainfall events, being influenced by the water vapor pressure deficit with the reduction in the soil water content. The occurrence of up to 2 mm rainfall promoted peaks of Re after long periods of drought. The measured NEP was equal to 468.18 gC m -2 year -1 . So, it is concluded that in years with severe drought, Caatinga may act as a source of carbon to the atmosphere.

Sustainable solid waste management system using multi-objective decision-making model: a method for maximizing social acceptance in Hoi An city, Vietnam.

The main aim of this study was to develop a decision support system for sustainable municipal solid waste management (MSWM) in Hoi An city (HAC), Vietnam. A face-to-face interview was conducted with local experts including authorities, citizens, waste collection contractors and recyclers to identify main objectives of waste management system and appropriate treatment methods. A multi-objective optimization model was proposed using non-linear programming approach. An interactive method known as reference point method (RPM) was applied for solving the problem with three objectives including cost minimization, landfill minimization and emission minimization. As a result, the efficient waste-flow-allocation and the optimal capacity of disposal facilities were determined by intense discussion and agreement among decision-makers. Waste incineration, anaerobic digestion, sanitary landfill and current recycling activities should be applied with a cost of about 2300 US$ daily. Also, the daily emission of various pollutants was about 35 metric tons, and the greenhouse gas (GHG) is 313 tons CO2-eq.

A CARBON FOOTPRINT FROM WOOD PELLET

Daily emissions of greenhouse gasses have a negative impact on the quality of the atmosphere. In almost every sector there is a certain emission of these gasses. This means that every sector, whether it is the energy, industry, transport sector or the household has a part in the degradation of the environment. In this connection, many models have been developed, whose task is to reduce greenhouse gas emissions and carbon dioxide as well to improve the environmental quality. This paper will discuss the carbon footprint model. A carbon footprint is the set of greenhouse gas emissions caused by something. It can be calculated for a product, service, person or even a country, and is used to understand the impact of human activity on the earth’s climate. Also, an analysis of carbon footprint using different types of fuel for heating households will be presented.

The Joint Effects of Income, Vehicle Technology, and Rail Transit Access on Greenhouse Gas Emissions

This paper examines the relationship between income, vehicle miles traveled (VMT), and greenhouse gas (GHG) emissions for households with varying access to rail transit in four metropolitan areas—Los Angeles, the San Francisco Bay Area, San Diego, and Sacramento—using data from the 2010–2012 California Household Travel Survey. Daily vehicle GHG emissions are calculated using the California Air Resources Board’s 2014 EMFAC (emission factors) model. Two Tobit regression models are used to predict daily VMT and GHG by income, rail transit access (within or outside 0.5 miles of a rail transit station in Los Angeles and the Bay Area, and linear distance to rail in San Diego and Sacramento), and metropolitan area. Comparing predicted VMT and GHG emissions levels, this paper concludes that predicted VMT and GHG emission patterns for rail access vary across metropolitan areas in ways that may be related to the age and connectivity of the areas’ rail systems. The results also show that differences in household VMT due to rail access do not scale proportionally to differences in GHG emissions. Regardless, the fact that GHG emissions are lower near rail transit for virtually all income levels in this study implies environmental benefits from expanding rail transit systems, as defined in this paper.

Ammonia emissions from an in-ground finisher hog manure tank

A large fraction of emitted and ultimately deposited ammonia (NH3) originates from swine waste storage. Understanding the factors that influence these emissions is important in determining how to mitigate NH3 loading of the atmosphere. Hog manure is stored in slurry pits, tanks, or lagoons. Ammonia emissions from a ground-level mid-western hog finisher manure tank collecting manure from a mean of 3508 animals was measured for 8–20 d each quarter of the year for two years. Forty of the 164 measurement days had sufficient measurements to represent entire days. These daily emissions averaged 0.44 g NH3 m−2h−1 (53.1 g d−1 AU−1, 7.2 g d−1 hd−1: AU = 500 kg animal mass, hd = 1 animal) with maximum emissions of 1.62 g NH3 m−2h−1 (194.2 g d−1 AU−1, 26.4 g d−1 hd−1). Emissions from the tank were greater on an area basis but comparable on an animal basis relative to emissions from much larger anaerobic lagoons. Emissions were correlated with air temperature and manure composition, but not wind speed or friction velocity- probably due to the turbulence created by the tank structure under all winds. Crusting of the manure surface in the tank corresponded with a non-significant 10% increase in NH3 emissions. A model of the tank emissions, based on nominal nitrogen loading rates from the literature and taking into account the configuration of the circular tank, had a mean bias error of 0.01 g NH3 m−2h−1 (0.9 g d−1 AU−1, 0.1 g d−1 hd−1) and a root mean square error of 0.26 g NH3m−2h−1 (31.6 d−1 AU−1, 4.3 g d−1 hd−1). Additional emissions measurements from such ground-level manure storage tanks with greater documentation of the manure liquid composition are needed to verify the modeling approach.

Pollution Characteristics of Organophosphorus Flame Retardants in a Wastewater Treatment Plant

Sewage water, the influent of the secondary sedimentation tanks, the final effluent, sludge from biological pools, and dewatered excess sludge samples from eight wastewater treatment plants (WWPTs) in Suzhou, including those from seven A2/O processes and one oxidation ditch process, were collected in 2017 to study the pollution characteristics of organophosphorus flame retardants (OPFRs) in WWPTs. Accelerated solvent extraction (ASE) combined with a solid-phase extraction method was used to detect the concentration of 10 organic phosphorus flame retardant (OPFRs). The removal efficiency of OPFRs was compared and final daily emissions were estimated. The results showed seven kinds of OPFRs were detected in the influent, final effluent, and sludge. The total content of OPFRs in the influent ranged from 0.74 to 222.65 μg ·L-1 (average 65.56 μg ·L-1), while the content in the final effluent was between 0.46 and 175.41 μg ·L-1 (average 22.99 μg ·L-1). The concentration in the effluent of the secondary sedimentation tank was between 0.48 and 178.14 μg ·L-1 (average 43.14 μg ·L-1). The daily emission of OPFRs in final effluent was 36.69-2177.12 g ·d-1. The content in the dewatered excess sludge was between 89.32 and 596.24 μg ·g-1 dw (average 249.35 μg ·g-1 dw), the minimum daily emission was 3.57-7.15 kg ·d-1, and the maximum was 47.70-95.40 kg ·d-1. The oxidation ditch process has a good removal rate of OPFRs, at 92%, while the A2/O process removal rate covered a large range from 11%-99%. Three chlorinated OPFRs, TCEP, TCPP, and TDCPP, were the main components in the influent and final effluent, mainly because of the large consumption of OPFRs and also because the removal rate by the traditional wastewater treatment technology was low.

Greenhouse gas emission responses to sugarcane straw removal

Sugarcane straw has been identified as an important feedstock to increase bioenergy production. However, changes in greenhouse gas (GHG) emissions due to straw removal are not yet understood. We hypothesized that partial straw removal changes decomposition rates and could change GHG fluxes. We performed a field experiment within the largest sugarcane-producing region of Brazil (São Paulo state) to assess GHG fluxes and straw decomposition. The treatments were: no-removal – 12 Mg ha−1 left on soil surface; medium removal – 6 Mg ha−1; high removal – 3 Mg ha−1; and total removal – bare soil. Static chambers were used to quantify GHG fluxes, and straw decomposition was measured using bottomless plastic boxes over a period of 180 days. Our findings showed that GHG were affected by the straw removal, although daily emissions were highly variable. Cumulative CO2 and N2O emissions were 35–45% lower under bare soil compared to other removal; however under no removal the CH4 uptake was 40% higher compared to bare soil. High straw decomposition was found in the no-removal, which decreased with the removal intensity. C released by straw decomposition was estimated between 0.5 and 3.1 Mg ha−1. By analyzing the C balance in C equivalent (Ceq) between decomposition and emissions we estimated that about 3.5 Mg ha−1 of straw are necessary to neutralize GHG emissions from soil and straw decomposition. Finally, we suggest that medium straw (∼6 Mg ha−1) maintenance would be a suitable strategy to increase bioenergy production and preserves adequate soil cover, as well as offsetting losses in soil C stocks.

Reducing GHG emissions while improving diet quality: exploring the potential of reduced meat, cheese and alcoholic and soft drinks consumption at specific moments during the day

BackgroundThe typical Western diet is associated with high levels of greenhouse gas (GHG) emissions and with obesity and other diet-related diseases. This study aims to determine the impact of adjustments to the current diet at specific moments of food consumption, to lower GHG emissions and improve diet quality.MethodsFood consumption in the Netherlands was assessed by two non-consecutive 24-h recalls for adults aged 19–69 years (n = 2102). GHG emission of food consumption was evaluated with the use of life cycle assessments. The population was stratified by gender and according to tertiles of dietary GHG emission. Scenarios were developed to lower GHG emissions of people in the highest tertile of dietary GHG emission; 1) reducing red and processed meat consumed during dinner by 50% and 75%, 2) replacing 50% and 100% of alcoholic and soft drinks (including fruit and vegetable juice and mineral water) by tap water, 3) replacing cheese consumed in between meals by plant-based alternatives and 4) two combinations of these scenarios. Effects on GHG emission as well as nutrient content of the diet were assessed.ResultsThe mean habitual daily dietary GHG emission in the highest tertile of dietary GHG emission was 6.7 kg CO2-equivalents for men and 5.1 kg CO2-equivalents for women. The scenarios with reduced meat consumption and/or replacement of all alcoholic and soft drinks were most successful in reducing dietary GHG emissions (ranging from − 15% to − 34%) and also reduced saturated fatty acid intake and/or sugar intake. Both types of scenarios lead to reduced energy and iron intakes. Protein intake remained adequate.ConclusionsReducing the consumption of red and processed meat during dinner and of soft and alcoholic drinks throughout the day leads to significantly lower dietary GHG emissions of people in the Netherlands in the highest tertile of dietary GHG emissions, while also having health benefits. For subgroups of the population not meeting energy or iron requirements as a result of these dietary changes, low GHG emission and nutritious replacement foods might be needed in order to meet energy and iron requirements.

A high temporal-spatial vehicle emission inventory based on detailed hourly traffic data in a medium-sized city of China.

To improve the accuracy and temporal-spatial resolution for a vehicle emission inventory in a medium-sized city with a strip road network, this study was conducted based on detailed hourly traffic-flow data for each day of 2014, and covered all road types and regions in the city of Foshan. Detailed hourly emission characteristics and sources in five regions were analysed. The results showed that the total vehicle emissions of CO, NOX, VOCs, and PM2.5 were 13.10 × 104, 0.23 × 104, 4.46 × 104, and 0.18 × 104 tons, respectively. Motorcycles (MCs) and light passenger cars (LPCs) were the dominant contributors of CO emissions, while buses and heavy passenger cars (HPCs) were the dominant contributors for NOX. As a whole, the daytime contributions to total emissions were close to 80%, and emissions during the peak periods accounted for almost 40%. Specifically, the hourly emissions of each pollutant on workdays were higher than on non-workdays (maximum up to 64.2%), and for some roads the early peak periods changed significantly from workdays to non-workdays. At expressways, artery roads, and local roads, the daily emission intensities of CO, NOx, and PM2.5 in Foshan were close to or even higher than that of Beijing. On a regional scale, the temporal variation of vehicle emissions on workdays at artery roads of different regions were similar. In addition, the higher emission intensities of CO and VOCs were identified in DaLiang-RongGui (DLRG) and that of NOX and PM2.5 were in Central Region (CR). These results are meaningful for decision-makers to help provide more detailed vehicle pollution control measures in Foshan with a strip road network and only one ring road.

Effect of different levels of lucerne (Medigo sativa) in diet on rumen fermentation and energy metabolism of ewes

A study was conducted to examine the effect of different levels of dietary lucerne (Medigo sativa) on rumen fermentation and energy metabolism in ewes. Four groups of ewes (6 in each) were fed experimental ration, containing nutrients as per NRC (2001). The concentrate in ration of groups T100, T200 and T400 was replaced by lucerne hay to provide saponin at the rate of 100, 200 and 400 mg/kg body weight, respectively. Ruminal pH, protozoal count, volatile fatty acid production and ammonia nitrogen concentration were determined on 0, 3, 7, 14 and 28 days of experiment. There was no significant difference among the groups for pH, total volatile fatty acid, acetate, propionate and butyrate per cent. The total protozoa in strained rumen liquor on 0 day in the treatments T00, T100, T200, and T400 were 2.79, 2.75, 2.80 and 2.67x106/ml respectively. On 3, 7, 14 and 28 day of saponin feeding, there was significant (P<0.05) reduction in protozoal population. The ammonia nitrogen in treatments T200 and T400 were significantly (P<0.05) lower than the control group on 3, 7, 14 and 28 day of saponin feeding. Methane emission was measured in respiration chamber for 48 h in continuation. Daily methane emission in T00, T200, T200, and T400 were 10.52, 9.92, 9.84 and 8.14 l/d, respectively. Compared to T00 group, reduction in daily methane production due to saponin feeding were 5.70, 6.46 and 22.62% in T100, T200, and T400, respectively. Loss of methane energy as per cent of (digestible energy was 8.49, 7.63, 7.37 and 6.48%, respectively for treatments T100, T200, and T400. From the study, it can be concluded that lucerne saponin significantly reduced the methane production and total protozoal count in rumen liquor. It can significantly increase the nitrogen retention along with the efficiency of energy utilization in sheep.

Greenhouse Gas Emissions Under Different Drainage and Flooding Regimes of Cultivated Peatlands

AbstractGlobally, approximately 10–20% of peatlands have been drained for agricultural purposes. A strategy to protect peatlands and mitigate carbon dioxide (CO2) emissions, while continuing agricultural production, is the use of intermittent flooding and drainage. A potential drawback of this strategy could be increases in methane (CH4) and nitrous oxide (N2O) emissions. The objective of this study was to compare greenhouse gas (GHG) emissions from peatlands under various flooding–drainage cycles. A laboratory study was performed using intact soil cores subjected to different durations of flooding and drainage for 6 months. Average daily emissions of CO2 and N2O were significantly higher (P &lt; 0.001) under drained (667 ± 37 mg CO2–C m−2 d−1 and 135 ± 19 μg N2O–N m−2 d−1) than flooded conditions (86 ± 6 mg CO2–C m−2 d−1 and 48 ± 2 μg N2O–N m−2 d−1). Methane emissions were not influenced by drained/flooded conditions, with an average rate of 116 ± 11 μg CH4–C m−2 d−1. Peaks of CH4 and N2O emissions were observed after flooding events and lasted less than 24 h. The peak emissions were approximately 8 and 19 times higher than the mean CH4 and N2O emissions, respectively. Carbon dioxide was the dominant component of GHGs, irrespective of hydrologic regime, accounting for more than 92% of overall global warming potential. Global warming potential was inversely proportional to the flooding period, indicating that prolonging the flooding period of peatlands would help mitigate soil oxidation and GHG emissions and enhance sustainability of these agricultural peatlands.

Exploring the heavy air pollution in Beijing in the fourth quarter of 2015: assessment of environmental benefits for red alerts

In recent years, Beijing has experienced severe air pollution which has caused widespread public concern. Compared to the same period in 2014, the first three quarters of 2015 exhibited significantly improved air quality. However, the air quality sharply declined in the fourth quarter of 2015, especially in November and December. During that time, Beijing issued the first red alert for severe air pollution in history. In total, 2 red alerts, 3 orange alerts, 3 yellow alerts, and 3 blue alerts were issued based on the adoption of relatively temporary emergency control measures to mitigate air pollution. This study explored the reasons for these variations in air quality and assessed the effectiveness of emergency alerts in addressing severe air pollution. A synthetic analysis of emission variations and meteorological conditions was performed to better understand these extreme air pollution episodes in the fourth quarter of 2015. The results showed that compared to those in the same period in 2014, the daily average emissions of air pollutants decreased in the fourth quarter of 2015. However, the emission levels of primary pollutants were still relatively high, which was the main intrinsic cause of haze episodes, and unfavorable meteorological conditions represented important external factors. Emergency control measures for heavy air pollution were implemented during this red alert period, decreasing the emissions of primary air pollutants by approximately 36% and the PM2.5 concentration by 11%‒21%.

Estimating Trends of Mean Monthly Ozone Emission in Urbanised Areas of Malaysia

AbstractA 21 year (1992 – 2012) daily ozone emission data of a highly urbanised district in Malaysia was analysed with the aim of estimating the trend of ozone emission and relating this trend to the socio – economic and climatic characteristics of the area. Daily ozone emission dataset used in this study were obtained from the World Ozone and Ultraviolet Data Centre (WOUDC). The data were aggregated to obtain the mean monthly emission data. Descriptive and inferential statistical analyses were conducted to describe the datasets. Trend of the ozone emission was estimated with the use of MANN - KENDALL test. The magnitude of the trend was derived by the use of ordinary least-square fitting and the significance of trend was also tested with the use of MANN-KENDALL tool. The results of the statistical analysis indicated that the highest ozone emission occurred during the south western monsoon (May to August) period and these mean monthly ozone emission differed significantly over the study period. The trend analysis indicated a yearly decrease of between 0.069 ppt to 9.45 ppt for all the months except for the month of June when the predicted ozone concentration increased between 0.403 ppt and 0.414 ppt over 2020 to 2100. Furthermore, the results indicated that the ozone emission datasets yielded good estimates (predictive power of over 90%) with polynomial regression model. It could be concluded that the results of this study provided useful evidence for the importance of the climatic factors such as ambient air temperature, relative humidity on ozone formation. More so, this study could be useful in developing baseline information for assessing the health impact of ozone emission and for urban airshed modelling.

Materializing Exposure: Developing an Indexical Method to Visualize Health Hazards Related to Fossil Fuel Extraction.

How can STS researchers collaborate with communities to design environmental monitoring devices that more effectively express their experiences and address gaps in regulation? This paper describes and shows the results of a novel method of visualizing environmental emissions of corrosive gases such as hydrogen sulfide (H2S) exposure using photographic paper. H2S is a neurotoxic and flammable gas that smells like rotten eggs and is frequently associated with oil and natural gas extraction. Communities living with oil and gas development in Wyoming report odors of rotten eggs and describe symptoms of H2S exposure. H2S is recognized as an acute and chronic threat to human and environmental health and oil and gas companies are required to have plans in place to prevent and respond to accidental, high concentration releases of H2S. They are not, however, required to monitor, report or prevent routine daily emissions. Yet 15-25% of the oil and gas wells in the US are predicted to contain H2S, and some communities surrounded by multiple wells report chronic, routine exposure. Chronic exposure is difficult to represent with current tools for monitoring H2S because they are designed to measure acute workplace exposure. Informed by STS theories of black boxes and regimes of imperceptibility that focus on the need to revise not only regulations but also material tools of science, this paper describes the development of an indexical approach to visualizing this hazard. In indexical design, the reactive sensing element of a scientific instrument is brought to the foreground. The silver in the photopaper is an index as it tarnishes with H2S exposure. Discolored tests strips can be arranged together to form data-rich maps of the exposure landscape where this discoloration both represents how the gas spreads through a space and is a physical trace of the gas. Preliminary results in the form of data-rich maps show that regulating H2S emissions as primarily accidental is inappropriate and fails to adequately protect human health.