Air Quality Situation Research Articles

Pre and Post Covid-19 Lockdown: How the AQI of Three Major Cities of Pakistan will Change?

Pakistan being in the list of developing countries has shown tremendous response towards the control of pandemic COVID-19. This paper evaluates the pre and post COVID 19 lockdown situation of air quality and provides an evidence of the air quality amid the lockdown and how it started to improve. The air quality indexes of three major cities of Pakistan i.e. Karachi, Islamabad and Lahore are compared, taking into account the indexes before and after the imposition of lockdown. The city wide presence of major pollutants like Sulphur Dioxide and Nitrogen Dioxide also reduced. The results show how taking serious measures can help in reducing the air pollution and help the environment to restore. Following analytical approach and situational analysis certain inferences have been drawn that the air quality index has worsen, and the atmospheric condition have turn out to be shoddier than the pre-pandemic situation. In the last section certain policy recommendations have been provided in order to maintain a healthy air quality.

The effect of lockdown on the outcomes of COVID-19

In the midst of the Coronavirus pandemic, a cross country lockdown is forced in India at first for three weeks from 24th Walk to fourteenth April 2020 and reached out up to third May 2020. Because of the constrained limitations, contamination level in urban areas the nation over radically hindered just inside a couple of days which polarize conversations with respect to lockdown to be the strong elective measures to be actualized for controlling air contamination. The current article, in the long run, chipped away at this heading to view the air quality situation in the midst of the lockdown time frame logically with uncommon reference to the megacity Delhi. With the guide of air quality information of seven toxin boundaries (PM10, PM2.5, SO2, NO2, CO, O3 and NH3) for 34 checking stations spread over the megacity, we have utilized Public Air Quality File (NAQI) to show the spatial example of air quality in pre and during-lockdown stages. The outcomes showed that during lockdown air quality is fundamentally improved. Among the chose toxins, centralizations of PM10 and PM2.5 have seen the greatest decrease (>50%) in contrast with the pre-lockdown stage. In contrast with the most recent year (for example 2019) during the said time span, the decrease of PM10 and PM2.5 is as high as about 60% and 39% separately. Among different toxins, NO2 (−52.68%) and CO (−30.35%) level have likewise decreased during-lockdown stage. About 40% to half improvement in air quality is distinguished soon after four days of starting lockdown. About 54%, 49%, 43%, 37% and 31% decrease in NAQI have been seen in Focal, Eastern, Southern, Western and Northern pieces of the megacity. Generally, the investigation is believed to be a valuable enhancement to the administrative bodies since it indicated the contamination source control could constrict the air quality. Brief such source control in an appropriate time span may recuperate the climate.

Composition of aerosol particles generated at different phases of biomass burning processes; laboratory and field investigations

This study is focused on the investigations of bushfire-originated smoke particle released during different prescribed burning events conducted between May 2018 and August 2019 in Toohey forest region, Queensland, Australia. Particle size/mass distribution along with corresponding elemental content had been comprehensively measured and the results were compared against outcomes obtained during the combustion of similar vegetation under controlled laboratory conditions. It was found that the concentration of coarse particle with the sizes above 1 μm was higher during natural bushfire events, whereas the contributions of PM1 was higher in the laboratory burns. Elemental analysis of different size fractions (<0.96 μm, 0.96–2.5 μm, and >2.5 μm) confirmed eight mutual elements determined for both cases (Na, K, Mg, Ca, Zn, Al, Fe, S), however, level of elements such as Ca, Mg, Al, and S were significantly higher in cases of prescribed fires. Such discrepancies between field and laboratory results could be attributed to the presence of soil and duff layers unavoidable in natural bushfires and absence thereof in the laboratory burns, which confirms substantial influence of such layers on the general air quality situation across bushfires affected regions.

Hidden black carbon air pollution in hilly rural areas—a case study of Dinaric depression

Air pollution is not an exclusively urban problem as wood burning is a widespread practice in rural areas. As we lack information on the air quality situation in rural mountainous regions, our aim is to examine equivalent black carbon (eBC) pollution in a typical rural karst area in the settlement of Loški Potok (Slovenia). eBC mass concentrations were measured by Aethalometer (AE-33) at two sites in Retje karst depression. The rural village station was located at the bottom of the karst depression whereas the rural background station was positioned at the top of the hill. We show the diurnal variation of equivalent black carbon mass concentrations for different seasons. In the populated karst depression, the major source of eBC pollution are households using wood as a heating fuel reaching the highest mass concentrations in winter. Diurnal pattern of eBC from biomass burning and traffic differ due to different source activity and it is influenced by typical formation of a cold air pool from late afternoon until late morning, restricting the dispersion of local emissions. The large difference in mass concentrations between the lowest part of the village (rural station) and the top of the hill (rural background station) indicates that in a vertically stratified and stable atmosphere local sources of black carbon have a major impact on air quality conditions in the area studied. Since in Alpine and Dinaric regions there are many similar inhabited areas, we can expect similar air quality conditions also in other rural hilly areas with limited self-cleaning air capacity.

An Approach for Quantifying a Regional Haze Stress: Case Study in Three Cities of Taiwan

This study proposes an approach of evaluating the haze stress index (HSI) and quantifying people’s feelings for haze stress. The three special municipalities in Taiwan were selected as representative cities of slightly, moderately, and heavily contaminated with fine particulate matter (PM2.5) to evaluate the adaptability of the proposed approach. Equations with weightings of parameters to evaluate four temporal HSIs—hourly, daily, monthly, and yearly HSIs—were established. The parameters were measured PM2.5, relative humidity, and secondary organic aerosol (represented by the sum of measured O3 and NO2). The results of evaluating the HSIs in the three cities demonstrated that the inverse-variance weighting method is the best because the haze stress sensitivities in the four temporal periods were higher than those obtained using the unit and variance weighting methods to respond to the real situation of air quality. Variation in the four temporal HSIs for the three cities demonstrates that the variation increases with an increasing level of air pollution. When comparing between 2015 and 2018, the fractional reductions in HSIs in the slightly, moderately, and heavily contaminated cities were ≤18.4%, ≤10.8%, and ≤11.3%, respectively. It is recommended that the HSIs are categorized into five haze stress groups based on the haze stress level. The people’s feelings in the three cities on the haze stresses were represented using the established quantifying descriptors in detail. The results show that the proposed approach can provide quantification indices of haze stress and people’s feelings in a regional haze, thereby firmly establishing the governmental improvement policy.

Inflammatory responses of urban air PM modulated by chemical composition and different air quality situations in Nanjing, China

The health risks of air pollutants and ambient particulate matter (PM) are widely known. PM composition and toxicity have shown substantial spatiotemporal variability. Yet, the connections between PM composition and toxicological and health effects are vaguely understood. This is a crucial gap in knowledge that needs to be addressed in order to establish air quality guidelines and limit values that consider the chemical composition of PM instead of the current assumption of equal toxicity per inhaled dose. Here, we demonstrate further evidence for varying toxicological effects of urban PM at equal mass concentrations, and estimate how PM composition and emission source characteristics influenced this variation.We exposed a co-culture model mimicking alveolar epithelial cells and macrophages with size-segregated urban ambient PM collected before, during, and after the Nanjing Youth Olympic Games 2014. We measured the release of a set of cytokines, cell cycle alterations, and genotoxicity, and assessed the spatiotemporal variations in these responses by factorial multiple regression analysis. Additionally, we investigated how a previously identified set of emission sources and chemical components affected these variations by mixed model analysis.PM-exposure induced cytokine signaling, most notably by inducing dose-dependent increases of macrophage-regulating GM-CSF and proinflammatory TNFα, IL-6, and IL-1β concentrations, modest dose-dependent increase for cytoprotective VEGF-A, but very low to no responses for anti-inflammatory IL-10 and immunoregulatory IFNγ, respectively. We observed substantial differences in proinflammatory cytokine production depending on PM sampling period, location, and time of day. The proinflammatory response correlated positively with cell cycle arrest in G1/G0 phase and loss of cellular metabolic activity. Furthermore, PM0.2 caused dose-dependent increases in sub-G1/G0 cells, suggesting increased DNA degradation and apoptosis. Variations in traffic and oil/fuel combustion emissions contributed substantially to the observed spatiotemporal variations of toxicological responses.

An Emerged Challenge of Air Pollution and Ever-Increasing Particulate Matter in Pakistan; A Critical Review

This study, for the first time, aims to evaluate the situation of air quality in Pakistan critically; through a detailed assessment of sources, policies, and key challenges to identify the plausible way forward. Air pollution and particulate matter have merged as a global challenge in recent years because of its growing health and socio-economic risks. The intensity and impacts of these risks have become more pronounced, especially in developing countries like Pakistan that lack adequate warning, protection, and management systems. Various epidemiological studies have linked poor air quality with different health disorders and increasing death rates. In Pakistan, mortality rates as a result of exposure to increased levels of air pollutants, especially particulate matter, are alarming. According to the World Bank’s estimates, Pakistan’s annual burden of disease from outdoor air pollution is responsible for around 22,000 premature adult deaths and 163,432 DALYs (disability-adjusted life years) lost. The concentration of major air pollutants in Pakistan, such as NOx, O3, and SO2 have also been increasing significantly over the last two decades. Several studies are also reporting multiple instances of air quality around the major cities of Pakistan being consistently exceeding the national guidelines. During teh year 2019 PM2.5 cocnentrations in the city of Lahore revealed that almost every single day was in exceedance of the WHO and national air quality standards. Although the substantial effects of these rising pollutant concentrations in Pakistan have been stated in a few studies, however, the total extent, nature of contributing factors, and consequences remain inadequately understood. This study aims to use data available from monitoring stations, satellites, and literature to highlight the gaps in our understanding and emphasize the critical challenges associated with poor air quality faced in Pakistan. Topmost is the lack of air quality monitoring systems followed by poor initiatives by policymakers and enforcement agencies. A way forward while addressing these key challenges is also discussed, which focuses on the development of flexible monitoring, new technologies, and monitoring approaches in addition to communications among the various public, private agencies, and all relevant stakeholders.

AIR QUALITY MONITORING AND DATA MANAGEMENT IN GERMANY – STATUS QUO AND SUGGESTIONS FOR IMPROVEMENT

Abstract. This paper proposes a novel approach to facilitate air quality aware decision making and to support planning actors to take effective measures for improving the air quality in cities and regions. Despite many improvements over the past decades, air pollutants such as particulate matter (PM), nitrogen dioxide (NO2) and ground-level ozone (O3) pose still one of the major risks to human health and the environment. Based on both a general analysis of the air quality situation and regulations in the EU and Germany as well as an in-depth analysis of local management practices requirements for better decision making are identified. The requirements are used to outline a system architecture following a co-design approach, i.e., besides scientific and industry partners, local experts and administrative actors are actively involved in the system development. Additionally, the outlined system incorporates two novel methodological strands: (1) it employs a deep neural network (DNN) based data analytics approach and (2) makes use of a new generation of satellite data, namely Sentinel-5 Precursor (Sentinel-5P). Hence, the system allows for providing areal and high-resolution (e.g., street-level) real-time and forecast (up to 48 hours) data to inform decision makers for taking appropriate short-term measures, and secondly, to simulate air quality under different planning options and long-term actions such as modified traffic flows and various urban layouts.

Assessment of airborne particles and bioaerosols concentrations in a waste recycling environment in Brazil

This study aims to assess the concentrations of size-fractioned particle mass (PM1.0, PM2.5, PM4.0, PM10) and number (PNC0.3, PNC0.5, PNC1.0, PNC2.5), bacteria, and fungi in a Materials Recycling Facility (MRF) in Brazil. The measurements were performed inside the waste processing shed (P1) and in the outdoor environment (P2) during working days in winter and spring of 2017, and summer of 2019. A total of 2,400 min of PM, 1,440 min of PNC, and 216 samples of bioaerosols were collected in the morning and afternoon. P1 has the strongest air contamination with mean values of 475.5 ± 563.7 µg m−3 for PM10, 58.6 ± 36.0 cm−3 for PNC0.3, 1,088.8 ± 825.2 colony-forming units per cubic meter (CFU m−3) for bacteria, and 2,738.3 ± 1,381.3 CFU m−3 for fungi. The indoor/outdoor ratios indicated the large influence of indoor sources due to the activities performed inside P1 that promote the generation and resuspension of pollutants. Gram-positive bacteria dominated with 58.6% of indoor samples. Overall, our results show a critical indoor air quality situation in a Brazilian MRF, which may cause several health risks for waste pickers. Finally, we call attention to the lack of occupational exposure limits for bioaerosols in industrial workplaces and mainly in MRFs.

Analysis of Ambient Air Quality Based On Exceedance Factor and Air Quality Index for Siliguri City, West Bengal

Bad air is one of the key concerns for most of the urban centres today, and Siliguri is no exceptions to this. In order to assess the air quality of Siliguri, Exceedance factor (EF) method was applied based on the average annual concentration of the pollutants named as; NO2, SO2, PM2.5 and PM10 and it is found that PM2.5 and PM10 are the major pollutants that pose a severe threat for the city. After applying the EF method, it is found that the values of PM2.5 was between moderate to high pollution level and for PM10 it falls under high to critical pollution level. On the other hand, the concentration of NO2 and SO2 falls under moderate to low pollution level. Through trend analysis of the various pollutants, it is found that their concentration was varying in nature. In case of PM10, the trend shows high concentration which exceeds national standard; whereas PM2.5 shows its concentration near towards violating the national standard soon if not checked. In contrast, trends of NO2 and SO2 were recorded lower than the national standard. The present situation of ambient air of Siliguri was analyzed based on Air Quality Index which reveals that air quality of the city can be classified into two seasons, i.e. clean air period (from April to October) and polluted period (from November to March). Lastly, the annual trends of PM2.5 and PM10 were constructed as they are the major pollutants, and it shows their skewed nature during winter months which results in smog episodes. It unveils how critical the situation of air quality of Siliguri became especially during winter months which seek immediate attention. Thus the study tries to present a vivid scenario about the present air quality of Siliguri, which concludes with some of the suggestions to restrain the air quality.

Artificial intelligence-enabled context-aware air quality prediction for smart cities

Metropolitan areas around the world are experiencing a surge in air pollution levels due to different anthropogenic causes, making accurate air quality prediction a critical task for public health. Although many prediction systems have been researched and modelled, many of them have neglected the different effects that air pollution has on each individual citizen. Hence, we present a novel context prediction model that includes context-aware computing concepts to merge an accurate air pollution prediction algorithm (using Long Short-Term Memory Deep Neural Network) with information from both surrounding pollution sources (e.g., bushfire incidents, traffic volumes) and user’s health profile. This model is then integrated into a tool called My Air Quality Index (MyAQI), which is further implemented and evaluated in a real-life use case set up in Melbourne Urban Area (Victoria, Australia). Results obtained with MyAQI show both that (i) high precision levels are reached (90–96%) when forecasting air quality situations in four air quality monitoring stations, and (ii) the proposed model is highly adaptable to users’ individual health condition effects under the same airborne pollutant levels.

A Decade of Air Quality in Bogotá: A Descriptive Analysis

In this work we apply a rigorous and reproducible data analytics process for validation and analysis of the historical data from Bogota (Colombia) air quality monitoring network since 1998. The reasons for addressing this research study stem from the lack of a consistent approach for cleaning, validating and reporting air quality data. By analyzing the whole dataset, we are aiming at providing citizens and the city authorities with a clear view of the current situation of air quality and of its historical evolution. Without any loss of generality, we focus our analysis on both respirable and fine particulate matter (PM10 and PM2.5) concentrations, which in Bogota and worldwide are source of concern for their negative impacts on human health. We develop a reproducible and flexible data cleaning methodology for particulate matter concentration data reported by the local authorities, which allows customizing and applying configurable validation rules. Then, we present statistical descriptive analyses by providing intuitive data visualizations, characterizing historical and spatial change of air pollutant levels. Results raise concerns for the high percentage of invalid data, as well as the high levels of PM2.5 and PM10 ambient concentrations as observed in the valid portion of the available data, which frequently exceed national and international air quality standards. The data exhibit encouraging signs of air quality improvement, particularly for PM10. However, the analyses indicate that significant differences exist across Bogota, and particularly in the south-west zone of the city annual concentrations of particulate matter are up to three or four times the WHO recommendations. We are confident on the methodology and results from our analysis are useful both for local environmental authority and the general public to help in obtaining consistent conclusions from the available data.

Influenza-like illness prediction using a long short-term memory deep learning model with multiple open data sources

The influenza problem has always been an important global issue. It not only affects people’s health problems but is also an essential topic of governments and health care facilities. Early prediction and response is the most effective control method for flu epidemics. It can effectively predict the influenza-like illness morbidity, and provide reliable information to the relevant facilities. For social facilities, it is possible to strengthen epidemic prevention and care for highly sick groups. It can also be used as a reminder for the public. This study collects information on the influenza-like illness emergency department visits to the Taiwan Centers for Disease Control, and the PM2.5 open-source data from the Taiwan Environmental Protection Administration's air quality monitoring network. By using deep learning techniques, the relevance of short-term estimates and the outbreak calculation method can be determined. The techniques are published by the WHO to determine whether the influenza-like illness situation is still in a stage of reasonable control. Finally, historical data and future forecasted data are integrated on the web page for visual presentation, to show the actual regional air quality situation and influenza-like illness data and to predict whether there is an outbreak of influenza in the region.

Tackling difficult problems through collaboration among multi-disciplinary research and industry

Healthy building is a new trend after green buildings in the world. “WELL” was launched as the first guideline for healthy buildings in 2014 in USA. In 2017, China Healthy Building Assessment Standard was launched. Good indoor air quality is an important part for healthy buildings. The score of indoor air quality accounts for nearly 25 in the total score (100) in Healthy Building Assessment Standard (T/ASC 02-2016). The indoor air quality items in the standards are mainly based upon China Indoor Air Quality Standard (GB/T 18883-2001). However, the target indoor air pollutants in the both standards (T/ASC 02-2016 and GB/T 18883-2001) are not determined based upon the indoor air quality investigations in China. In order to revise the China Indoor Air Quality Standard (GB/T 18883-2001) and improve or develop the relevant indoor air quality control techniques, it’s necessary to know the important and unsolved problems in indoor air quality control in China. From them, the important scientific problems and key technical problems in China can be identified, and the gaps between the control demands and the levels of the related industries in China can be recognized. Then, various control approaches and strategies can be developed effectively. For this purpose, we present a series of important and unsolved problems in indoor air quality control in China: Identify the target indoor air pollutants and the corresponding thresholds based upon China’s indoor air quality situations, develop energy efficient engineering approaches to simultaneously control indoor air climate and quality, and develop the approach of scientific evaluation for indoor air quality control effect. The important scientific and key technical problems behind them are: The method of determining the target indoor air pollutants, the method of determining the thresholds of the target indoor air pollutants, the principle and method to overall control of indoor air climate and quality, the method of scientific evaluation for indoor air quality control effect not only based upon the concentrations of the target indoor air pollutants but also based upon the human health response. We are carrying out a national research project whose title is “study on fundamental problems and key technical approaches in indoor air quality control”. Based upon its research advance, we put forward a framework and understanding of solving the aforementioned problems: (1) Determining the target indoor air pollutants based upon the burden of diseases of indoor air pollutants in China. In the study, the burden of diseases of all target indoor air pollutants is obtained so that the overall burden of diseases of indoor air pollution can be roughly estimated. It’s a quantitative index to show the importance of indoor air quality problems in China. (2) Determining the corresponding thresholds of the indoor air pollutants based upon the control feasibility and the health benefit. The healthy benefit can be evaluated by the reduction of burden of diseases of the target indoor air pollutants which can also be equivalent as the reduction of economic loss. (3) Developing inverse problem and variation method to identify the optimal control systems and operative strategies. It’s an original novel approach for indoor air quality control. (4) Developing some partial space and/or partial time control approaches for indoor air quality. (5) Developing novel evaluation method for control effect by using biomarker-based techniques. (6) Narrowing or even removing the gaps between the indoor air quality control related industries. The indoor air quality control standards in those industries shouldn’t conflict each other. (7) Applying various newly-developed sensors and big data techniques to understand the links between the indoor air quality and human health response. New on-line monitoring sensors with acceptable precision, together with some new big-data analysis methods are strongly needed. To tackling the above problems which are related to many disciplines, collaboration among multi-disciplinary research and industries is very important.

Examination of Air Pollutants Influence on Human Health on The Frequency of Hospital Admissions in Hungary

Many studies have shown that the increased atmospheric concentration of pollutants has an intensified health risk on lung-, heart- and cardiovascular disease sufferers, as well as the increasing willingness of morbidity and mortality. Therefore, the monitoring of the air pollutants is particularly important. The goal of the recent study was to show a complex picture about Veszprem county’s air quality situation and to discover the relationships between the selected air pollutants (PM10, CO, NO2, SO2, O3) concentration and the picked health diseases (cardiovascular diseases, respiratory diseases, gastrointestinal disorders, ischemic heart disease, cerebrovascular disease, and chronic lower respiratory diseases). Ambient air pollution and hospital admission data for the research were obtained for 2005–2013. According to the calculations; it was found that there was a moderate relation between the air pollutants concentrations and the health diseases.

Examination of Air Pollutants Influence on Human Health on The Frequency of Hospital Admissions in Hungary

Many studies have shown that the increased atmospheric concentration of pollutants has an intensified health risk on lung-, heart- and cardiovascular disease sufferers, as well as the increasing willingness of morbidity and mortality. Therefore, the monitoring of the air pollutants is particularly important. The goal of the recent study was to show a complex picture about Veszprem county’s air quality situation and to discover the relationships between the selected air pollutants (PM10, CO, NO2, SO2, O3) concentration and the picked health diseases (cardiovascular diseases, respiratory diseases, gastrointestinal disorders, ischemic heart disease, cerebrovascular disease, and chronic lower respiratory diseases). Ambient air pollution and hospital admission data for the research were obtained for 2005–2013. According to the calculations; it was found that there was a moderate relation between the air pollutants concentrations and the health diseases.

The Relationship Between the Actual Level of Air Pollution and Residents’ Concern about Air Pollution: Evidence from Shanghai, China

This study explored the relationship between the actual level of air pollution and residents’ concern about air pollution. The actual air pollution level was measured by the air quality index (AQI) reported by environmental monitoring stations, while residents’ concern about air pollution was reflected by the Baidu index using the Internet search engine keywords “Shanghai air quality”. On the basis of the daily data of 2068 days for the city of Shanghai in China over the period between 2 December 2013 and 31 July 2019, a vector autoregression (VAR) model was built for empirical analysis. Estimation results provided three interesting findings. (1) Local residents perceived the deprivation of air quality and expressed their concern on air pollution quickly, within the day on which the air quality index rose. (2) A decline in air quality in another major city, such as Beijing, also raised the concern of Shanghai residents about local air quality. (3) A rise in Shanghai residents’ concern had a beneficial impact on air quality improvement. This study implied that people really cared much about local air quality, and it was beneficial to inform more residents about the situation of local air quality and the risks associated with air pollution.

Long-Term Trends in PAH Concentrations and Sources at Rural Background Site in Central Europe

An increased burden due to polycyclic aromatic hydrocarbons (PAH) is a long-term air quality problem in Central and Eastern Europe. Extensive PAH monitoring has been implemented at the National Atmospheric Observatory Košetice (NAOK), a rural background site in the Czech Republic, as a representative for Central Europe. Data from NAOK are used for evaluation of PAH concentration trends and source apportionment. In total, concentrations of 14 PAHs in particulate matter (PM10) and in the gas phase between 2006 and 2016 were evaluated. The highest concentrations were measured at the beginning of the study period in 2006. Mean annual concentrations of benzo(a)pyrene, for example, showed a weak, however statistically significant decreasing trend. The positive matrix factorization (PMF) was used to determine the sources of PAHs at NAOK, with three factors resolved. The probable origin areas of PMF factors were identified by the conditional bivariate probability function (CBPF) and the potential source contribution function (PSCF) methods. The NAOK is affected by local sources of PAHs, as well as by regional and long-range transport. The PAH concentrations correlate negatively with industrial production and traffic intensity. High PAH emissions have been linked to local heating, suggesting that the planned replacement of obsolete combustion sources in the households could improve the overall air quality situation, not only with respect to PAHs.

Efficacy of occupancy-based smart ventilation control strategies in energy-efficient homes in the United States

Proper ventilation of residences is essential for occupant health and comfort, and is responsible for a significant portion of energy consumption in homes. This study examines a method for providing adequate ventilation in homes while reducing energy consumption and peak demand: “smart” control of ventilation through sensing of occupancy and modulation of ventilation fans. We first conducted a detailed simulation study of advanced California homes with several occupancy-based ventilation control strategies. We then look at how general these results are nationally through a second simulation campaign in 15 ASHRAE climate zones. All simulations compared equivalent indoor air quality situations and assessed energy savings benefits. A key difference from previous demand-controlled ventilation strategies is that our study includes the effects of building related contaminants that are continuously emitted, irrespective of occupancy status, consistent with the requirements in ASHRAE Standard 62.2–2016. Under this new assumption, it is very difficult to extract substantial energy savings using only occupancy sensing. For the baseline strategy, savings were less than 10% of ventilation energy and sometimes negative in all cases analyzed other than leakier 2-story homes. Addition of a pre-occupancy flush period increases savings somewhat, but savings are still less than 15% other than in 2-story leakier homes.

Impact of a nitrogen emission control area (NECA) on the future air quality and nitrogen deposition to seawater in the Baltic Sea region

Abstract. Air pollution due to shipping is a serious concern for coastal regions in Europe. Shipping emissions of nitrogen oxides (NOx) in air over the Baltic Sea are of similar magnitude (330 kt yr−1) as the combined land-based NOx emissions from Finland and Sweden in all emission sectors. Deposition of nitrogen compounds originating from shipping activities contribute to eutrophication of the Baltic Sea and coastal areas in the Baltic Sea region. For the North Sea and the Baltic Sea a nitrogen emission control area (NECA) will become effective in 2021; in accordance with the International Maritime Organization (IMO) target of reducing NOx emissions from ships. Future scenarios for 2040 were designed to study the effect of enforced and planned regulation of ship emissions and the fuel efficiency development on air quality and nitrogen deposition. The Community Multiscale Air Quality (CMAQ) model was used to simulate the current and future air quality situation. The meteorological fields, the emissions from ship traffic and the emissions from land-based sources were considered at a grid resolution of 4×4 km2 for the Baltic Sea region in nested CMAQ simulations. Model simulations for the present-day (2012) air quality show that shipping emissions are the major contributor to atmospheric nitrogen dioxide (NO2) concentrations over the Baltic Sea. In the business-as-usual (BAU) scenario, with the introduction of the NECA, NOx emissions from ship traffic in the Baltic Sea are reduced by about 80 % in 2040. An approximate linear relationship was found between ship emissions of NOx and the simulated levels of annual average NO2 over the Baltic Sea in the year 2040, when following different future shipping scenarios. The burden of fine particulate matter (PM2.5) over the Baltic Sea region is predicted to decrease by 35 %–37 % between 2012 and 2040. The reduction in PM2.5 is larger over sea, where it drops by 50 %–60 % along the main shipping routes, and is smaller over the coastal areas. The introduction of NECA is critical for reducing ship emissions of NOx to levels that are low enough to sustainably dampen ozone (O3) production in the Baltic Sea region. A second important effect of the NECA over the Baltic Sea region is the reduction in secondary formation of particulate nitrate. This lowers the ship-related PM2.5 by 72 % in 2040 compared to the present day, while it is reduced by only 48 % without implementation of the NECA. The effect of a lower fuel efficiency development on the absolute ship contribution of air pollutants is limited. Still, the annual mean ship contributions in 2040 to NO2, sulfur dioxide and PM2.5 and daily maximum O3 are significantly higher if a slower fuel efficiency development is assumed. Nitrogen deposition to the seawater of the Baltic Sea decreases on average by 40 %–44 % between 2012 and 2040 in the simulations. The effect of the NECA on nitrogen deposition is most significant in the western part of the Baltic Sea. It will be important to closely monitor compliance of individual ships with the enforced and planned emission regulations.