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1.
An empirical model has been devised to predict concentrations of PM 10 at background and roadside locations in London. Factors to calculate primary PM 10 and PM 2.5 concentrations are derived from annual mean NO X, PM 2.5 and PM 10 measurements across London and south east England. These factors are used to calculate daily means for the primary and non-primary PM 10 fractions for the London area. The model accurately predicts daily mean PM 10 and EU Directive Limit values across a range of sites from kerbside to rural. Predictions of future PM 10 can be made using the expected reductions in secondary PM 10 and site specific annual mean NO X predicted from emission inventories and dispersion modelling. The model suggests that the EU Directive Limit values will be exceeded close to many of London's busiest roads, and perhaps at central background sites should there be a repeat of 1996 meteorological conditions during 2005. A repeat of 1997 meteorology conditions during 2005 would lead to the EU Limit Value being exceeded alongside the busiest central London roads only. The model is applicable for London and south east England but the methodology could be applied elsewhere at a city or regional level. The model relies on the currently observed ratio between NO X and PM 10. This ratio has remained constant over the last 4 years but might change in the future. The NO X:PM 10 ratio derived from measurements and used in this model, implies that emission inventories might over estimate primary PM 10 by more than 50%. 相似文献
2.
Bursa is one of the largest cities of Turkey and it hosts 17 organized industrial zones. Parallel to the increase in population, rapidly growing energy consumption, and increased numbers of transport vehicles have impacts on the air quality of the city. In this study, regularly calibrated automatic samplers were employed to get the levels of air pollution in Bursa. The concentrations of CH 4 and N-CH 4 as well as the major air pollutants including PM 10, PM 2.5, NO, NO 2, NO x, SO 2, CO, and O 3, were determined for 2016 and 2017 calendar years. Their levels were 1641.62?±?718.25, 33.11?±?5.45, 42.10?±?10.09, 26.41?±?9.01, 19.47?±?16.51, 46.73?±?16.56, 66.23?±?32.265, 7.60?±?3.43, 659.397?±?192.73, and 51.92?±?25.63 µg/m 3 for 2016, respectively. Except for O 3, seasonal concentrations were higher in winter and autumn for both years. O 3, CO, and SO 2 had never exceeded the limit values specified in the regulations yet PM 10, PM 2.5, and NO 2 had violated the limits in some days. The ratios of CO/NO x, SO 2/NO x, and PM 2.5/PM 10 were examined to characterize the emission sources. Generally, domestic and industrial emissions were dominated in the fall and winter seasons, yet traffic emissions were effective in spring and summer seasons. As a result of the correlation process between O x and NO x, it was concluded that the most important source of O x concentrations in winter was NO x and O 3 was in summer. 相似文献
4.
Improvement of air quality models is required so that they can be utilized to design effective control strategies for fine particulate matter (PM 2.5). The Community Multiscale Air Quality modeling system was applied to the Greater Tokyo Area of Japan in winter 2010 and summer 2011. The model results were compared with observed concentrations of PM 2.5 sulfate (SO 42-), nitrate (NO 3?) and ammonium, and gaseous nitric acid (HNO 3) and ammonia (NH 3). The model approximately reproduced PM 2.5 SO 42? concentration, but clearly overestimated PM 2.5 NO 3? concentration, which was attributed to overestimation of production of ammonium nitrate (NH 4NO 3). This study conducted sensitivity analyses of factors associated with the model performance for PM 2.5 NO 3? concentration, including temperature and relative humidity, emission of nitrogen oxides, seasonal variation of NH 3 emission, HNO 3 and NH 3 dry deposition velocities, and heterogeneous reaction probability of dinitrogen pentoxide. Change in NH 3 emission directly affected NH 3 concentration, and substantially affected NH 4NO 3 concentration. Higher dry deposition velocities of HNO 3 and NH 3 led to substantial reductions of concentrations of the gaseous species and NH 4NO 3. Because uncertainties in NH 3 emission and dry deposition processes are probably large, these processes may be key factors for improvement of the model performance for PM 2.5 NO 3?. Implications: The Community Multiscale Air Quality modeling system clearly overestimated the concentration of fine particulate nitrate in the Greater Tokyo Area of Japan, which was attributed to overestimation of production of ammonium nitrate. Sensitivity analyses were conducted for factors associated with the model performance for nitrate. Ammonia emission and dry deposition of nitric acid and ammonia may be key factors for improvement of the model performance. 相似文献
5.
This study aimed to characterize air pollution and the associated carcinogenic risks of polycyclic aromatic hydrocarbon (PAHs) at an urban site, to identify possible emission sources of PAHs using several statistical methodologies, and to analyze the influence of other air pollutants and meteorological variables on PAH concentrations.The air quality and meteorological data were collected in Oporto, the second largest city of Portugal. Eighteen PAHs (the 16 PAHs considered by United States Environment Protection Agency (USEPA) as priority pollutants, dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were collected daily for 24 h in air (gas phase and in particles) during 40 consecutive days in November and December 2008 by constant low-flow samplers and using polytetrafluoroethylene (PTFE) membrane filters for particulate (PM 10 and PM 2.5 bound) PAHs and pre-cleaned polyurethane foam plugs for gaseous compounds. The other monitored air pollutants were SO 2, PM 10, NO 2, CO, and O 3; the meteorological variables were temperature, relative humidity, wind speed, total precipitation, and solar radiation. Benzo[a]pyrene reached a mean concentration of 2.02 ng?m ?3, surpassing the EU annual limit value. The target carcinogenic risks were equal than the health-based guideline level set by USEPA (10 ?6) at the studied site, with the cancer risks of eight PAHs reaching senior levels of 9.98?×?10 ?7 in PM 10 and 1.06?×?10 ?6 in air. The applied statistical methods, correlation matrix, cluster analysis, and principal component analysis, were in agreement in the grouping of the PAHs. The groups were formed according to their chemical structure (number of rings), phase distribution, and emission sources. PAH diagnostic ratios were also calculated to evaluate the main emission sources. Diesel vehicular emissions were the major source of PAHs at the studied site. Besides that source, emissions from residential heating and oil refinery were identified to contribute to PAH levels at the respective area. Additionally, principal component regression indicated that SO 2, NO 2, PM 10, CO, and solar radiation had positive correlation with PAHs concentrations, while O 3, temperature, relative humidity, and wind speed were negatively correlated. 相似文献
6.
To identify the characteristics of air pollutants and factors attributing to the formation of haze in Wuhan, this study analyzed the hourly observations of air pollutants (PM 2.5, PM 10, NO 2, SO 2, O 3, and CO) from March 1, 2013, to February 28, 2014, and used hybrid receptor models for a case study. The results showed that the annual average concentrations for PM 2.5, PM 10, NO 2, SO 2, O 3, and CO during the whole period were 89.6 μg m ?3, 134.9 μg m ?3, 54.9 μg m ?3, 32.4 μg m ?3, 62.3 μg m ?3, and 1.1 mg m ?3, respectively. The monthly variations revealed that the peak values of PM 2.5, PM 10, NO 2, SO 2, and CO occurred in December because of increased local emissions and severe weather conditions, while the lowest values occurred in July mainly due to larger precipitation. The maximum O 3 concentrations occurred in warm seasons from May to August, which may be partly due to the high temperature and solar radiation. Diurnal analysis showed that hourly PM 2.5, PM 10, NO 2, and CO concentrations had two ascending stages accompanying by the two traffic peaks. However, the O 3 concentration variations were different with the highest concentration in the afternoon. A case study utilizing hybrid receptor models showed the significant impact of regional transport on the haze formation in Wuhan and revealed that the mainly potential polluted sources were located in the north and south of Wuhan, such as Baoding and Handan in Hebei province, and Changsha in Hunan province. Implications: Wuhan city requires a 5% reduction of the annual mean of PM 2.5 concentration by the end of 2017. In order to accomplish this goal, Wuhan has adopted some measures to improve its air quality. This work has determined the main pollution sources that affect the formation of haze in Wuhan by transport. We showed that apart from the local emissions, north and south of Wuhan were the potential sources contributing to the high PM 2.5 concentrations in Wuhan, such as Baoding and Handan in Hebei province, Zhumadian and Jiaozuo in Henan province, and Changsha and Zhuzhou in Hunan province. 相似文献
7.
Covid-19 lockdowns have improved the ambient air quality across the world via reduced air pollutant levels. This article aims to investigate the effect of the partial lockdown on the main ambient air pollutants and their elemental concentrations bound to PM2.5 in Hanoi. In addition to the PM2.5 samples collected at three urban sites in Hanoi, the daily PM2.5, NO2, O3, and SO2 levels were collected from the automatic ambient air quality monitoring station at Nguyen Van Cu street to analyze the pollution level before (March 10th–March 31st) and during the partial lockdown (April 1st–April 22nd) with “current” data obtained in 2020 and “historical” data obtained in 2014, 2016, and 2017. The results showed that NO2, PM2.5, O3, and SO2 concentrations obtained from the automatic ambient air quality monitoring station were reduced by 75.8, 55.9, 21.4, and 60.7%, respectively, compared with historical data. Besides, the concentration of PM2.5 at sampling sites declined by 41.8% during the partial lockdown. Furthermore, there was a drastic negative relationship between the boundary layer height (BLH) and the daily mean PM2.5 in Hanoi. The concentrations of Cd, Se, As, Sr, Ba, Cu, Mn, Pb, K, Zn, Ca, Al, and Mg during the partial lockdown were lower than those before the partial lockdown. The results of enrichment factor (EF) values and principal component analysis (PCA) concluded that trace elements in PM2.5 before the partial lockdown were more affected by industrial activities than those during the partial lockdown. 相似文献
8.
ABSTRACT Fuel-based emission factors for 143 light-duty gasoline vehicles (LDGVs) and 93 heavy-duty diesel trucks (HDDTs) were measured in Wilmington, CA using a zero-emission mobile measurement platform (MMP). The frequency distributions of emission factors of carbon monoxide (CO), nitrogen oxides (NO x), and particle mass with aerodynamic diameter below 2.5 μm (PM 2.5) varied widely, whereas the average of the individual vehicle emission factors were comparable to those reported in previous tunnel and remote sensing studies as well as the predictions by Emission Factors (EMFAC) 2007 mobile source emission model for Los Angeles County. Variation in emissions due to different driving modes (idle, low- and high-speed acceleration, low- and high-speed cruise) was found to be relatively small in comparison to intervehicle variability and did not appear to interfere with the identification of high emitters, defined as the vehicles whose emissions were more than 5 times the fleet-average values. Using this definition, approximately 5% of the LDGVs and HDDTs measured were high emitters. Among the 143 LDGVs, the average emission factors of NO x, black carbon (BC), PM 2.5, and ultrafine particle (UFP) would be reduced by 34%, 39%, 44%, and 31%, respectively, by removing the highest 5% of emitting vehicles, whereas CO emission factor would be reduced by 50%. The emission distributions of the 93 HDDTs measured were even more skewed: approximately half of the NO x and CO fleet-average emission factors and more than 60% of PM 2.5, UFP, and BC fleet-average emission factors would be reduced by eliminating the highest-emitting 5% HDDTs. Furthermore, high emissions of BC, PM 2.5, and NO x tended to cluster among the same vehicles. IMPLICATIONS This study presents the characterization of on-road vehicle emissions in Wilmington, CA, by sampling individual vehicle plumes. Approximately 5% of the vehicles were high emitters, whose emissions were more than 5 times the fleet-average values. These high emitters were responsible for 30% and more than 50% of the average emission factors of LDGVs and HDDVs, respectively. It is likely that as the overall fleet becomes cleaner due to more stringent regulations, a small fraction of the fleet may contribute a growing and disproportionate share of the overall emissions. Therefore, long-term changes in on-road emissions need to be monitored. 相似文献
9.
Two indicator pollutants, carbon monoxide (CO) for mobile source influence and sulfur dioxide (SO 2) for stationary source influence, were used to estimate source-type contributions to ambient NO 2 levels in a base year and to predict NO 2 concentrations in a future year. For a specific source-receptor pair, the so-called influence coefficient of each of three source categories (mobile sources, power plants, and other stationary sources) was determined empirically from concurrent measurements of CO and SO 2 concentrations at the receptor site and CO and SO 2 emissions from each source category in the source area. Those coefficients, which are considered time invariant, were used in conjunction with the base year and future year NO x emission values to estimate source-type contribution to ambient NO 2 levels at seven study sites selected from the Greater Los Angeles area for both the base year period, 1974 through 1976, and the future goal year of 1987 in which the air quality standards for NO 2 are to be attained. The estimated NO 2 air quality at the seven sites is found to meet the national annual standard of 5 pphm and over 99.9% of total hours, the California 1-hr NO 2 standard of 25 pphm in 1987. The estimated power plant contributions to ambient NO 2 levels are found to be considerably smaller than those to total NO x emissions in the area. Providing that reasonably complete air quality and emissions data are available, the present analysis method may prove to be a useful tool in evaluating source contributions to both short-term peak and long-term average NO 2 concentrations for use in control strategy development. 相似文献
10.
A highly resolved temporal and spatial Pearl River Delta (PRD) regional emission inventory for the year 2006 was developed with the use of best available domestic emission factors and activity data. The inventory covers major emission sources in the region and a bottom–up approach was adopted to compile the inventory for those sources where possible. The results show that the estimates for SO 2, NO x, CO, PM 10, PM 2.5 and VOC emissions in the PRD region for the year 2006 are 711.4 kt, 891.9 kt, 3840.6 kt, 418.4 kt, 204.6 kt, and 1180.1 kt, respectively. About 91.4% of SO 2 emissions were from power plant and industrial sources, and 87.2% of NO x emissions were from power plant and mobile sources. The industrial, mobile and power plant sources are major contributors to PM 10 and PM 2.5 emissions, accounting for 97.7% of the total PM 10 and 97.2% of PM 2.5 emissions, respectively. Mobile, biogenic and VOC product-related sources are responsible for 90.5% of the total VOC emissions. The emissions are spatially allocated onto grid cells with a resolution of 3 km × 3 km, showing that anthropogenic air pollutant emissions are mainly distributed over PRD central-southern city cluster areas. The preliminary temporal profiles were established for the power plant, industrial and on-road mobile sources. There is relatively low uncertainty in SO 2 emission estimates with a range of −16% to +21% from power plant sources, medium to high uncertainty for the NO x emissions, and high uncertainties in the VOC, PM 2.5, PM 10 and CO emissions. 相似文献
11.
In 1995, Taiwan's Environmental Protection Administration (EPA/TW) instituted a policy of levying emission taxes on polluters in order to combat the rampant national issue of pollution. Since that time, pollution control strategies, tightening exhaust emission standards for industry, improvements in fuel quality, and new stricter vehicle emission standards, etc., have been implemented. This study evaluates the effectiveness of these measures and examines the improvement of Taiwan's air quality. In this paper, we conduct a detailed analysis of change in the concentrations of pollutants (SO 2, NO x and particulate matter [PM]) between two three-year periods (from 1996 to1998 and from 2000 to 2002). The pollution levels were generally lower in the latter period. Concentrations at 14 EPA/TW stations in central Taiwan were simulated and source apportionment analyses in three of Central Taiwan's largest cities were conducted using a trajectory transfer-coefficient air quality model. Correlation coefficients ( r) between simulations and observations for the monthly means of the concentrations of SO 2, NO x, PM 2.5 and PM 10 during the study periods at the 14 stations are 0.56, 0.63, 0.70 and 0.31, respectively. The sulfur control policy greatly reduced SO 2 concentration island-wide, a stringent emission standard put into place for gasoline vehicles reduced NO x concentration along highways, and an emissions tax placed on construction sites, as well as a regular program for road-dust sweeping, reduced primary particulate matter. Among all of the pollution abatement policies implemented, the most effective method for reducing PM 2.5 concentrations in the three largest cities involved the reduction of fine ammonium sulfate aerosols from point sources (56–63% of net PM 2.5 reduction). The next largest reduction was attributed to a diminishment in primary PM 2.5 emanating from point sources (27–56% of net PM 2.5 reduction). Secondary particulate matter, especially sulfate, was reduced from distances up to 150 km leeward of major pollution point sources such as Taichung Power Plant. 相似文献
12.
Our study was an attempt to conduct a comprehensive and systematical examination of the holiday effect, defined as the difference in air pollutant concentrations between holiday and non-holiday periods. This holiday effect can be applied to other countries with similar national or cultural holidays. Hourly and daily surface measurements of six major air pollutants from thirteen air quality monitoring stations of the Taiwan Environmental Protection Administration during the Chinese New Year (CNY) and non-Chinese New Year (NCNY) periods were used. We documented evidence of a “holiday effect”, where air pollutant concentrations were significantly different between holidays (CNY) and non-holidays (NCNY), in the Taipei metropolitan area over the past thirteen years (1994–2006).The concentrations of NO x, CO, NMHC, SO 2 and PM 10 were lower in the CNY than in the NCNY period, while the variation in the concentration of O 3 was reversed, which was mainly due to the NO titration effect. Similar differences in these six air pollutants between the CNY and NCNY periods were also found in the diurnal cycle and in the interannual variation. For the diurnal cycle, a common traffic-related double-peak variation was observed in the NCNY period, but not in the CNY period. Impacts of dust storms were also observed, especially on SO 2 and PM 10 in the CNY period. In the 13-year period of 1994–2006, decreasing trends of NO x and CO in the NCNY period implied a possible reduction of local emissions. Increasing trends of SO 2 and PM 10 in the CNY period, on the other hand, indicated a possible enhancement of long-range transport. These two mechanisms weakened the holiday effect. 相似文献
13.
The Van Nuys Tunnel experiment conducted in 1987 by Ingalls et al. (see A&WMA Paper 89-137.3), to verify automotive emission inventories as part of the Southern California Air Quality Study (SCAQS), gave higher CO and HC emission-rate values than expected on the basis of automotive-emission models—by factors of approximately 3 and 4, respectively. The CO/NO X and HC/NO X emission-rate ratios moreover were higher than expected—by similar factors (NO X emission rates were about as expected). The purpose of the present paper is to review the literature on dynamometer and on-road (in tunnels and along roadways) testing of in-use vehicles, and on urban-air CO/HC/NO X concentration ratios, to see whether the Van Nuys Tunnel results are reasonable in terms of previous experience. The conclusions are that (1) on-road CO and HC emissions higher than expected have been reported before, (2) on-road CO and HC emissions consistent with the Van Nuys Tunnel results have been reported before, and (3) on-road CO/NO X and HC/NO X emission-rate ratios higher than expected have been reported before. The Van Nuys Tunnel NO X results actually are lower than in other on-road experiments, and the CO/NO X and HC/NO X ratios consequently are higher. The higher-than-predicted CO/NO X and HC/NO X ratios at Van Nuys and other on-road sites suggest richer operation on-road than predicted or than observed in the inuse- vehicle dynamometer tests which serve as the model inputs. Support for these suggestions and conclusions is found in comparison of urban-air and emission-inventory HC/NO X ratios. 相似文献
14.
The U.S. Environmental Protection Agency (EPA), state and local agencies have focused their efforts in assessing secondary fine particulate matter (aerodynamic diameter ≤2.5 µm; PM 2.5) formation in prevention of significant deterioration (PSD) air dispersion modeling. The National Association of Clean Air Agencies (NACAA) developed a method to account for secondary PM 2.5 formation by using sulfur dioxide (SO 2) and nitrogen oxides (NO x) offset ratios. These ratios are used to estimate the secondary formation of sulfate and nitrate PM 2.5. These ratios were first introduced by the EPA for nonattainment areas in the Implementation of the New Source Review (NSR) Program for Particulate Matter Less than 2.5 Micrometers (PM 2.5), 73 FR 28321, to offset emission increases of direct PM 2.5 emissions with reductions of PM 2.5 precursors and vice versa. Some regulatory agencies such as the Minnesota Pollution Control Agency (MPCA) have developed area-specific offset ratios for SO 2 and NO x based on Comprehensive Air Quality Model with Extensions (CAMx) evaluations for air dispersion modeling analyses. The current study evaluates the effect on American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) predicted concentrations from the use of EPA and MPCA developed ratios. The study assesses the effect of these ratios on an electric generating utility (EGU), taconite mine, food processing plant, and a pulp and paper mill. The inputs used for these four scenarios are based on common stack parameters and emissions based on available data. The effect of background concentrations also evaluates these scenarios by presenting results based on uniform annual PM 2.5 background values. This evaluation study helps assess the viability of the offset ratio method developed by NACAA in estimating primary and secondary PM 2.5 concentrations. An alternative Tier 2 approach to combine modeled and monitored concentrations is also presented. Implications: On January 4, 2012, the EPA committed to engage in rulemaking to evaluate updates to the Guideline on Air Quality Models (Appendix W of 40 CFR 51) and, as appropriate, incorporate new analytical techniques or models for secondary PM2.5. As a result, the National Association of Clean Air Agencies (NACAA) developed a screening method involving offset ratios to account for secondary PM2.5 formation. The use of this method is promising to evaluate total (direct and indirect) PM2.5 impacts for permitting purposes. Therefore, the evaluation of this method is important to determine its viability for widespread use. 相似文献
15.
A network of 10 stations, with passive sampling for VOCs (including benzene), NO 2, and SO 2, over 2-week periods, grab sampling for CO, and 48-h pumped sampling for PM 10, was set up to make an air quality survey for 12 months around Aberdeen Harbour. Benzene, CO, SO 2 and PM 10 were always well below the AQS target values. However, NO 2 frequently showed a pronounced gradient across the harbour reaching its highest concentrations at the city end, indicating that the road traffic was the principal source of the pollution. This was backed up by the predominance of aromatics in the VOCs in the city centre, derived from petrol engined vehicles, compared to the predominance of alkanes and alkenes around the docks, derived from diesel engined heavy trucks and possibly ships. Black carbon on the PM 10 filters also showed a gradient with highest levels in the city centre. It is proposed that for such surveys in future, NO 2 and black carbon would be the two most informative parameters.This emissions inventory has shown first, that trucks contribute very little to the total, and second, that the ro-ro ferries are the major contributors as they burn light fuel oil while the oil platform supply vessels burn low-sulphur marine gas oil with around 0.1% S. When the whole picture of the emissions from the city is considered, the emissions from the harbour constitute only a small part. 相似文献
16.
Abstract The objective of this project is to demonstrate how the ambient air measurement record can be used to define the relationship between O 3 (as a surrogate for photochemistry) and secondary particulate matter (PM) in urban air. The approach used is to develop a time-series transfer-function model describing the daily PM 10 (PM with less than 10 μm aerodynamic diameter) concentration as a function of lagged PM and current and lagged O 3, NO or NO 2, CO, and SO 2. Approximately 3 years of daily average PM 10, daily maximum 8-hr average O 3 and CO, daily 24-hr average SO 2 and NO 2, and daily 6:00 a.m.-9:00 a.m. average NO from the Aerometric Information Retrieval System (AIRS) air quality subsystem are used for this analysis. Urban areas modeled are Chicago, IL; Los Angeles, CA; Phoenix, AZ; Philadelphia, PA; Sacramento, CA; and Detroit, MI. Time-series analysis identified significant autocorrelation in the O 3, PM 10, NO, NO 2,CO, and SO 2 series. Cross correlations between PM 10 (dependent variable) and gaseous pollutants (independent variables) show that all of the gases are significantly correlated with PM 10 and that O 3 is also significantly correlated lagged up to two previous days. Once a transfer-function model of current PM 10 is defined for an urban location, the effect of an O 3-control strategy on PM concentrations is estimated by calculating daily PM 10 concentrations with reduced O 3 concentrations. Forecasted summertime PM 10 reductions resulting from a 5 percent decrease in ambient O 3 range from 1.2 μg/m 3 (3.03%) in Chicago to 3.9 μg/m 3 (7.65%) in Phoenix. 相似文献
17.
In the present study, a modified approach was adopted to quantify the assimilative capacity (i.e., the maximum emission an area can take without violating the permissible pollutant standards) of a major industrial cluster (Manali, India) and to assess the effectiveness of adopted air pollution control measures at the region. Seasonal analysis of assimilative capacity was carried out corresponding to critical, high, medium, and low pollution levels to know the best and worst conditions for industrial operations. Bottom-up approach was employed to quantify sulfur dioxide (SO 2), nitrogen dioxide (NO 2), and particulate matter (aerodynamic diameter <10 μm; PM 10) emissions at a fine spatial resolution of 500 × 500 m 2 in Manali industrial cluster. AERMOD (American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model), an U.S. Environmental Protection Agency (EPA) regulatory model, was used for estimating assimilative capacity. Results indicated that 22.8 tonnes/day of SO 2, 7.8 tonnes/day of NO 2, and 7.1 tonnes/day of PM 10 were emitted from the industries of Manali. The estimated assimilative capacities for SO 2, NO 2, and PM 10 were found to be 16.05, 17.36, and 19.78 tonnes/day, respectively. It was observed that the current SO 2 emissions were exceeding the estimated safe load by 6.7 tonnes/day, whereas PM 10 and NO 2 were within the safe limits. Seasonal analysis of assimilative capacity showed that post-monsoon had the lowest load-carrying capacity, followed by winter, summer, and monsoon seasons, and the allowable SO 2 emissions during post-monsoon and winter seasons were found to be 35% and 26% lower, respectively, when compared with monsoon season. Implications: The authors present a modified approach for quantitative estimation of assimilative capacity of a critically polluted Indian industrial cluster. The authors developed a geo-coded fine-resolution PM10, NO2, and SO2 emission inventory for Manali industrial area and further quantitatively estimated its season-wise assimilative capacities corresponding to various pollution levels. This quantitative representation of assimilative capacity (in terms of emissions), when compared with routine qualitative representation, provides better data for quantifying carrying capacity of an area. This information helps policy makers and regulatory authorities to develop an effective mitigation plan for air pollution abatement. 相似文献
18.
Abstract One-hour average ambient concentrations of particulate matter (PM) with an aerodynamic diameter <2.5 μm (PM 2.5) were determined in Steubenville, OH, between June 2000 and May 2002 with a tapered element oscillating microbalance (TEOM). Hourly average gaseous copollutant [carbon monoxide (CO), sulfur dioxide (SO 2), nitrogen oxide (NO x), and ozone (O 3)] concentrations and meteorological conditions also were measured. Although 75% of the 14,682 hourly PM 2.5 concentrations measured during this period were ≤17 μg/m 3, concentrations >65 μg/m 3 were observed 76 times. On average, PM 2.5 concentrations at Steubenville exhibited a diurnal pattern of higher early morning concentrations and lower afternoon concentrations, similar to the diurnal profiles of CO and NO x. This pattern was highly variable; however, PM 2.5 concentrations >65 μg/m 3 were never observed during the mid-afternoon between 1:00 p.m. and 5:00 p.m. EST. Twenty-two episodes centered on one or more of these elevated concentrations were identified. Five episodes occurred during the months June through August; the maximum PM 2.5 concentration during these episodes was 76.6 μg/m 3. Episodes occurring during climatologically cooler months often featured higher peak concentrations (five had maximum concentrations between 95.0 and 139.6 μg/m 3), and many exhibited strong covariation between PM 2.5 and CO, NO x, or SO 2. Case studies suggested that nocturnal surface-based temperature inversions were influential in driving high nighttime concentrations of these species during several cool season episodes, which typically had dramatically lower afternoon concentrations. These findings provide insights that may be useful in the development of PM 2.5 reduction strategies for Steubenville, and suggest that studies assessing possible health effects of PM 2.5 should carefully consider exposure issues related to the intraday timing of PM 2.5 episodes, as well as the potential for toxicological interactions among PM 2.5 and primary gaseous pollutants. 相似文献
19.
We measured toxic air pollutants along Oba Akran road in Lagos to evaluate pedestrian exposure. PM 10, CO, O 3, NO 2, SO 2, CH 4, noise, wind velocity and temperature were measured simultaneously with portable analyzers. Our results showed that pedestrian exposure to PM 10 (with an average of 274.6 μg m −3 for all samples) and CO (with an average of 19.27 ppm for all samples) was relatively high. CO is a traffic-related pollutant, so the influence of the local traffic emissions on CO levels is strong. The high concentration of the PM 10 measured at the three environments also suggests that the traffic is a major source of ultrafine particles. The overall average concentrations for the 72-day experimental period for SO 2, NO 2 and O 3 are 101.2, 62.5 and 0.32 ppb respectively, all of which are below the US national ambient air quality standards. Strong traffic impacts can be observed from the concentrations of some of these pollutants measured in these three environments. Most clear is a reflection of diesel truck traffic activity rich in black carbon concentrations. The diurnal variation of O 3 and NO 2 also showed that NO 2 was depleted by photochemically formed O 3 during the day and replenished at night as O 3 was destroyed. A multivariate statistical analysis (Principal Component Analysis, Factor Analysis) has been applied to a set of data in order to determine the contribution of different sources. It was found that the main principal components, extracted from the air pollution data, were related to gasoline combustion, oil combustion and ozone interactions. 相似文献
20.
This paper evaluates the relative impact on air quality of harbour emissions, with respect to other emission sources located in the same area. The impact assessment study was conducted in the city of Taranto, Italy. This area was considered as representative of a typical Mediterranean harbour region, where shipping, industries and urban activities co-exist at a short distance, producing an ideal case to study the interaction among these different sources. Chemical and meteorological field campaigns were carried out to provide data to this study. An emission inventory has been developed taking into account industrial sources, traffic, domestic heating, fugitive and harbour emissions. A 3D Lagrangian particle dispersion model (SPRAY) has then been applied to the study area using reconstructed meteorological fields calculated by the diagnostic meteorological model MINERVE. 3D short term hourly concentrations have been computed for both all and specific sources. Industrial activities are found to be the main contributor to SO 2. Industry and traffic emissions are mainly responsible for NO x simulated concentrations. CO concentrations are found to be mainly related to traffic emissions, while primary PM 10 simulated concentrations tend to be linked to industrial and fugitive emissions. Contributions of harbour activities to the seasonal average concentrations of SO 2 and NO x are predicted to be up to 5 and 30 μg m −3, respectively to be compared to a overall peak values of 60 μg m −3 for SO 2 and 70 μg m −3 for NO x. At selected urban monitoring stations, SO 2 and NO x average source contributions are predicted to be both of about 9% from harbour activities, while 87% and 41% respectively of total concentrations are predicted to be of industrial origin. 相似文献
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