Urban Environmental Pollution Research Articles

General Review of Smartphone Usability in Noise Mapping

The global urban population is steadily increasing, with more than half of the world's population currently residing in cities, and this trend is expected to double by 2050. As urbanization continues, noise pollution becomes a significant concern, affecting over 60% of major city dwellers and impacting human health on both physiological and psychological levels. To address this issue, governments and organizations are striving to develop effective noise assessment, regulation, and mitigation policies. This literature review explores the role of noise mapping and the potential of smartphones in collecting noise data to inform these policies. Traditional noise mapping techniques and smartphone-based data collection methods are discussed, along with their importance in urban planning, environmental studies, and public health. Key research questions are identified, including the methodologies employed for smartphone-based noise mapping, the accuracy of smartphone-collected data compared to traditional measurements, practical applications, challenges, and emerging trends. The review reveals that smartphones offer a cost-effective and widespread means of gathering noise data, enabling real-time insights and enhancing various domains' practical applications. However, challenges such as data accuracy, privacy concerns, and device limitations must be addressed. The future of smartphone-based noise mapping looks promising, with advancements in sensor technologies, artificial intelligence, and data analysis tools empowering researchers, urban planners, and policymakers to make informed decisions about noise pollution in urban environments.

Impacts of pilot carbon emission trading policies on urban environmental pollution: Evidence from China

The trading of carbon emissions is a crucial regulatory method to address environmental pollution issues. This study takes China's carbon emission trading pilot policy established in 2013 as a quasi-natural experiment and uses the DID model to empirically test the urban panel data from 2006 to 2019. The results show that the carbon emission trading pilot policy can effectively reduce urban environmental pollution, and this effect is more noticeable in mid-western cities, northern cities, cities with fewer resources, and large-scale cities. In addition, to address the urban environmental pollution problem through this policy, the government is encouraged to raise its environmental protection awareness and put more effort into the innovation of technology. In general, this study uses carbon emission trading policies from China to confirm that market-based incentive environmental regulation tools can effectively reduce environmental pollution in urban areas. These findings can provide more theoretical support and empirical evidence for the government to use mechanisms of the market to effectively solve pollution problems, improve ecological environment quality, and accelerate the realization of green economy.

Assessment of Societal Health Risks: Spatial Distribution and Potential Hazards of Toxic Metals in Street Dust Across Diverse Communities

On a global scale, the urban design of city centers is a topic of discussion concerning various aspects such development and its impact on public health. This research examines the health effects of urban agglomeration in city centers with compact, close development. In this work, the potentially toxic metals in street dust were studied by collecting and measuring street dust samples, measuring trace metal concentrations, and using index assessment, spatial analysis, correlation analysis, and health risk assessment models. Eskişehir, located in the part of Central Anatolia close to the Aegean region, west Türkiye, has been widely recognized as one of the most popular, known for having many narrow and old buildings in urban environments. The present paper investigates the atmospheric dust-related chemical speciation, urban environmental pollution, and human health risks in Eskişehir City by studying 66 dust samples collected at 11 points in the selected streets in August 2023. the study found that the concentrations of trace elements followed the order Cr > Ni > Pb > Cd > Cu. The primary source of these high levels is believed to be traffic-related contamination involving Cd, Pb, and Ni. The assessment of non-carcinogenic health risks has shown that the significant sources of potential toxic metals exposure for both children and adults are i) through ingestion and ii) dermal contact. The Hazard index (HI) for selected metals decreased in the order Cr > Pb > Ni > Cd > Cu for both children and adults without imposing possible non-carcinogenic risk (HI<1). On the contrary, Cr posed cancer risks above the safety threshold (> 10-4) through ingestion. Based on the available findings, Eskişehir still suffers from considerable environmental and ecological degradation and severe health risks due to street dust contamination. However, while high pollution was detected in the city center, where there is commercial land use, low values were observed in the region, rich with the water surface, bicycle paths, landscape design, and where traffic is slowed down.

Evaluation of self-cleaning performance of TiO2-intermixed and TiO2-coated cement mortars under natural sunlight

Self-cleaning cementitious materials have gained significant attention due to urban environmental pollution. In this study, nano-TiO2 (NT) was first mixed with cement mortar. Second, NTs were coated on fresh cast mortars and on hardened surfaces. Photocatalytic efficiency was evaluated using Rhodamine B under natural sunlight with three types of cement: white Portland (WPC), ordinary Portland (OPC), and Portland pozzolana cement (PPC). Among them, PPC cement mortars exhibited superior photocatalytic performance compared to WPC and OPC even with lower dosages of NT. The order of photocatalytic efficiency was highest for the hard-coat followed by fresh-coat and then intermix sample. Furthermore, Rietveld analysis for crystal structure refinement was used, and crystallography analysis (VESTA software) confirmed the presence of specific atoms and bonds in the crystal structure of PPC with NT. Microstructural analysis using XRD, SEM, and EDAX revealed underlying structural changes and thus quantified the hydration products.

Environmental Policy Overlays and Urban Pollution and Carbon Reduction—Evidence from China

The in-depth promotion of environmental pollution prevention and control is a must for China to move towards green development, and the effectiveness of urban environmental pollution control largely depends on the selection of these environmental policies and the synergistic application of these policies. This paper empirically tests three environmental policies’ mixed and synergistic effects using Chinese urban data from 2000 to 2017. This study found that (1) the three environmental policies significantly curb urban environmental pollution and show synergistic effects. (2) The three types of environmental policies can have a superimposing effect by strengthening financial inputs and increasing environmental concern, as well as a complementary effect by improving the efficiency of environmental protection enforcement and the institutional environment. The synergy between the central environmental protection inspection policy and the environmental information disclosure policy is more of a superposition effect than a complementary effect due to the similarity of the policy objectives. (3) The synergistic effect of environmental policies is affected by factors such as the age of the principal officials and financial pressure. The younger the age of the principal officials and the cities with less financial pressure are more capable of utilizing the synergistic effect of environmental policies to form a situation where the market, the government, the public, and the enterprises work together to govern the city. This paper provides new ideas for exploring the synergies and mechanisms of environmental policies and theoretical references for the design, implementation, and effects of environmental policy portfolios in the 14th Five-Year Plan period.

Locating Electrified Aircraft Service to Reduce Urban Congestion

The relentless expansion of urban populations and the surge in e-commerce have increased the demand for rapid delivery services, leading to an increase in truck traffic that contributes to urban congestion, environmental pollution, and economic inefficiencies. The critical challenge this poses is not only in managing urban spaces efficiently but also in aligning with global sustainability goals. This study addresses the pressing need for innovative solutions to reduce reliance on truck transportation in congested urban areas without compromising the efficiency of freight delivery systems. This study contributes a novel approach that leverages electrified and autonomous aircraft (EAA) cargo shuttles to shift the bulk of air transportable freight from road to air, specifically targeting underutilized airports and establishing vertiports in remote locations. By applying data mining techniques to analyze freight flow data, this research identifies key commodity categories and metropolitan statistical areas (MSAs) where the implementation of EAA services could significantly mitigate truck-induced congestion. The findings reveal that targeting a select few commodities and MSAs can potentially decrease truck traffic, with electronics emerging as the dominant commodity category, and cities like Los Angeles and Chicago as prime candidates for initial EAA service deployment. Stakeholders in urban planning, transportation logistics, and environmental policy will find this study’s insights beneficial. This work lays a foundation for future innovations in sustainable urban mobility and logistics.

Submicron aerosol pollution in Greater Cairo (Egypt): A new type of urban haze?

Greater Cairo, the largest megacity of the Middle East North Africa (MENA) region, is currently suffering from major aerosol pollution, posing a significant threat to public health. However, the main sources of pollution remain insufficiently characterized due to limited atmospheric observations. To bridge this knowledge gap, we conducted a continuous 2-month field study during the winter of 2019–2020 at an urban background site, documenting for the first time the chemical and physical properties of submicron (PM1) aerosols. Crustal material from both desert dust and road traffic dust resuspension contributed as much as 24 % of the total PM1 mass (rising to 66 % during desert dust events), a figure not commonly observed in urban environments. Our observations showed significant decreases in black carbon concentrations and ammonium sulfate compared to data from 15 years ago, indicating an important reduction in both local and regional emissions as a result of effective mitigation measures. The diurnal variability of carbonaceous aerosols was attributed to emissions emanating from local traffic at rush hours and nighttime open biomass burning. Surprisingly, semi-volatile ammonium chloride (NH4Cl) originating from local open biomass and waste burning was found to be the main chemical species in PM1 over Cairo. Its nighttime formation contributed to aerosol water uptake during morning hours, thereby playing a major role in the build-up of urban haze. While our results confirm the persistence of a significant dust reservoir over Cairo, they also unveil an additional source of highly hygroscopic (semi-volatile) inorganic salts, leading to a unique type of urban haze. This haze, with dominant contributors present in both submicron (primarily as NH4Cl) and supermicron (largely as dust) modes, underscores the potential implications of heterogeneous chemical transformation of air pollutants in urban environments.

Optimization of LID Strategies for Urban CSO Reduction and Cost Efficiency: A Beijing Case Study

Combined sewer overflow (CSO) can lead to serious urban water environment pollution and health risks to residents. Low Impact Development (LID) facilities are one of the important measures to alleviate CSO and have been widely applied. The rational selection of LID facility types, locations, and scales is the most important task, which can effectively improve resource utilization efficiency. Based on the NSGA-II multi-objective optimization algorithm and coupled with the SWMM sewer network hydraulic model, this study takes the combined sewer overflows and the construction cost of LID facilities as optimization objectives and optimizes the types and scales of LID layout in the study area, including eight different return periods. By using the Pareto frontier and visualizing the results of the model, the effects of different rainfall return periods on the CSO control and investment cost of LID layout schemes are compared. The results show the following: (1) the optimization model can demonstrate the relationship between CSO control volume and LID construction cost under different LID layout schemes through the Pareto frontier, showing three different trends, indicating that the relationship between overflow volume and investment cost is nonlinear; (2) with the increase in rainfall intensity, higher requirements are proposed for LID schemes to meet CSO control targets, leading to a decrease in the number of Pareto frontier solution sets. Under larger rainfall intensities, it is difficult to achieve the same overflow control effect by increasing the scale of LID construction. Therefore, considering constraining the LID construction cost between RMB 5.3 and 5.38 million is helpful to determine the most suitable solution; (3) in the optimal layout schemes under different return periods, 87.3% of the locations where LID is deployed have similar scales. Based on these locations with a relatively large proportion of deployment, it can be determined that special attention should be paid to spatial positions in LID planning and construction. This study provides valuable insights for solving combined sewer overflow problems and optimizing urban drainage management and provides guidance for future planning and decision-making processes.

The Optimization of Split Demand Route Planning Under Metro-Truck Collaborative Distribution

With the evolution of people's consumption habits and the rapid growth of urban logistics, the number of trucks and delivery frequency has increased significantly, exacerbating urban traffic congestion and environmental pollution. Consequently, there is an urgent need to improve the current inefficient and highly polluted distribution mode. Currently, in most cities in China, the metro passenger flow is insufficient, and the capacity is excessive during off-peak hours, resulting in underutilized carriage capacity. The integration of surface and underground transport resources can effectively address these issues and facilitate complementary advantages and win–win cooperation between express companies and metro enterprises. This study proposes an innovative problem of split demand route planning in the cooperative distribution system involving express companies and subways. A cooperative distribution model is developed to minimize the total cost, and solved by the Cuckoo Search algorithm to obtain the optimized solution. The model is applied to the urban rail transit network in Changchun, and the results demonstrate that it is effective in reducing truck mileage and distribution costs. Compared to the single delivery pattern by trucks, the cooperative distribution approach proves to be more cost-effective and environmentally friendly.

Soil microbial responses to multipollutant exposures in megacity's parks of Beijing

Soil life revolves around microorganisms that are crucial for soil ecosystems and health. In megacities, the combined exposure of multiple pollutants exerts a significant impact on the structures and functions of soil microorganisms; however, there is a lack of empirical studies on this topic. Hence, we conducted a study including urban parks in Beijing, China. The results indicate that bacteria were abundant in the soils of Beijing parks, showing the same dominant groups but different rare groups. The dominant groups included Actinobacteria and Proteobacteria. Candidate phyla radiation bacteria, a large evolutionary radiation of bacterial lineages whose members remain mostly uncultivated, were the main specialists. Under the combined exposure of multiple pollutants, the structures of soil microbial communities in different parks were similar. Community change due to pollutants (31%) was greater than that due to natural factors (2.4%). Among multipollutants, organophosphate esters, led by dibutyl phosphate, had the highest influence on microbial abundance and distribution. An increase in dibutyl phosphate concentration decreased the abundance of Firmicutes, while the abundance of Synergistota was increased. The interactions among pollutants affecting the bacteria were different. Bis(2-chloroethyl) phosphate, nickel and benzo[g,h,i]perylene influenced microorganisms by working with organophosphate esters. High-molecular-weight polycyclic aromatic hydrocarbons, such as benzo[a]pyrene and benzo[g,h,i]perylene, mainly acted on the functional genes and thus affected multiple biogeochemical cycles. Benzo[a]anthracene, bis(2-chloroethyl) phosphate, and arsenic were the primary pollutants affecting metabolic pathways. Our research helps to better understand the impacts of urban environmental pollution on soil microorganisms.

Investigation of the Effect of Aerosol Deposition by Applying Electrostatic Fields

Particulate matter (PM) constitutes a significant risk factor for environmental health regarding ambient air quality. An epidemiological investigation has determined that inadequate air quality is associated with the development of lung and cardiovascular diseases, chronic ailments, respiratory infections, and a significant number of fatalities on a global scale. According to the World Health Organization (WHO), the annual mortality rate due to air pollution is around 7 million individuals. The necessity for researching air quality, climate change, and the challenges posed by particulate matter (PM) is widely recognized. While reducing ambient air quality, it is essential to consider the limitations of current technical control methods. This article focuses on developing and implementing advanced technology to mitigate particle pollution in urban environments. The comparison of empirical data and computational simulations has demonstrated the efficacy of utilizing pulsed radio waves to reduce particulate matter. The control technique exhibits a threefold increase in the rate of PM concentration reduction compared to gravity settling. The approach's efficacy was evaluated through controlled trials conducted in controlled chambers and urban environments, demonstrating up to 50% reductions. The validation of the implemented test case results of the control technology was performed using historical data while considering the existence of radio waves. The coagulation process demonstrated and verified the effectiveness of reducing particle matter. The employed methodology has been shown to encourage outcomes concerning mitigating particulate matter contamination within urban and industrial environments.

A data-driven approach for PM2.5 estimation in a metropolis: random forest modeling based on ERA5 reanalysis data

Air pollution in urban environments, particularly from fine particulate matter (PM2.5), poses significant health risks. Addressing this issue, the current study developed a Random Forest (RF) model to estimate hourly PM2.5 concentrations in Ankara, Türkiye. Utilizing ERA5 reanalysis data, the model incorporated various meteorological and environmental variables. Over the period 2020–2021, the model’s performance was validated against data from eleven air quality monitoring stations, demonstrating a robust coefficient of determination (R2) of 0.73, signifying its strong predictive capability. Low root mean squared error (RMSE) and mean absolute error (MAE) values further affirmed the model’s precision. Seasonal and temporal analysis revealed the model’s adaptability, with autumn showing the highest accuracy (R2 = 0.82) and summer the least (R2 = 0.51), suggesting seasonal variability in predictive performance. Hourly evaluations indicated the model’s highest accuracy at 23:00 (R2 = 0.93), reflecting a solid alignment with observed data during nocturnal hours. On a monthly scale, November’s predictions were the most precise (R2 = 0.82), while May presented challenges in accuracy (R2 = 0.49). These seasonal and monthly fluctuations underscore the complex interplay of atmospheric dynamics affecting PM2.5 dispersion. By integrating key determinants such as ambient air temperature, surface pressure, total column water vapor, boundary layer height, forecast albedo, and leaf area index, this study enhances the understanding of air pollution patterns in urban settings. The RF model’s comprehensive evaluation across time scales offers valuable insights for policymakers and environmental health practitioners, supporting evidence-based strategies for air quality management.

How Much Do Urban Terminal Delivery Paths Depend on Urban Roads – A Research Based on Bipartite Graph Network

The structural deficiencies of the terminal delivery path often make it the main culprit of urban traffic congestion and environmental pollution. Traditional studies of express networks regarded them as an independent entity, ignoring the endogenous role of urban road network morphology and structure. To solve this problem, this paper explored the spatial dependency of terminal delivery routes in Xi'an City based on the idea of a bipartite graph network. A spatial dependency matrix of delivery paths–urban roads was constructed by abstracting delivery paths as node-set A and urban roads as node-set B. In addition, three spatial dependencies indexes, including degree centrality, betweenness centrality and closeness centrality were introduced to analyse the coupling features of these two objects. The results show that these dependency measures can reflect the coupling features of urban terminal delivery paths and urban roads. Firstly, degree centrality demonstrates terminal delivery path coverage and coupling hierarchy and scale-free nature. Secondly, betweenness centrality presents the road utilisation balance of terminal delivery paths. Thirdly, closeness centrality explains how easy it is for delivery paths to connect with others.

Plastics in Agricultural and Urban Soils: Interactions with Plants, Micro-Organisms, Inorganic and Organic Pollutants: An Overview of Polyethylene (PE) Litter

Over the last few decades, different types of plastics have been found in different soil types with documented or potential negative effects on the environment, the flora and fauna inhabiting the soils, and subsequently human health. This article is a global review of the consequences of the interactions of plastics with soil, plants, soil microbes, and organic or inorganic pollutants depending on land use. It focuses on the various types of polyethylene, a widely used material with a strong presence in both agricultural and urban soils. Although the chemical formula (C2H4)n remains the same in its various classifications, the chemical behavior of polyethylene in soil varies and directly depends on its density, branching, crystallinity, and relative molecular mass, resulting in many and various differences in the properties but also in the behavior of the two main forms of polyethylene, low and high density. However, beyond the chemical composition of plastics, the climatic conditions that apply in both urban and rural areas determine the degree of corrosion as well as their shape and size, also affecting the chemical reactions that directly or indirectly affect them. In agricultural soils, plants and the microbiome present mainly in the rhizosphere seem to dramatically influence the behavior of plastics, where the interaction of all these parameters leads to changes in the availability of nutrients (phosphorus and potassium), the percentage of organic matter and the nitrogen cycle. In urban soils, the increase in temperature and decrease in humidity are the main parameters that determine the adsorption of heavy metals and organic pollutants on the surface of plastics. Although the presence of plastics is considered inevitable, perhaps a more thorough study of them will lead to a reduction in the risks of pollution in urban and rural environments. This research provides a promising perspective on the potential contribution of MP PEs to the sustainable management of soil systems.

Mobile measurements and street-level modelling to assess outdoor and indoor personal exposure to air pollution in urban environment

Mobile measurements and street-level modelling to assess outdoor and indoor personal exposure to air pollution in urban environment

Study on financial cost evaluation of urban water environment management and pollution prevention and control

Abstract Nowadays, water pollution has become a major factor restricting social development. To address this, the government has issued a series of policy documents to control water environmental pollution and achieved certain results. However, on the whole, the prevention and control of the pollution of water environments requires a large amount of capital investment, but the corresponding results and benefits are not significant. Hence, this paper takes Shanghai, Nanjing, Hangzhou, and Hefei as examples to study the financial cost-effectiveness of the governance of urban water environments from the two dimensions of time and space. It is concluded that the cost of water environmental treatment has a negative effect on the comprehensive benefit of environmental treatment in the region in the short term and a positive effect in the long term, which indicates that water environmental pollution treatment is work that needs to be adhered to for a long time, and long-term planning is also needed for cost input. On this basis, strategies to improve the cost efficiency of water pollution treatment are presented.

Evaluation of Changes in the Function of Green Open Spaces in Public Facilities in the City of Banda Aceh (Case Study: Blang Padang Field Area)

The existence of the Blang Padang Field as a green open space (RTH) in Banda Aceh City based on its natural weight, is included in the category of non-natural areas or built areas. This built area has ecological, social and recreational functions for the surrounding community in Banda Aceh City. This area is used as a tourism zone and public open space, where this area is often used as a gathering location or meeting friends for people who live and visit the city of Banda Aceh. People usually enjoy the atmosphere of the Blang Padang field by spreading mats or sitting directly on the green grass. Based on the type of open space, the Blang Padang field is included in the public open space category. According to the Regulation of the Minister of Agrarian Affairs and Spatial Planning/Head of the National Land Agency of the Republic of Indonesia Number 14 of 2022, the proportion of green public open space in the city park consisting of at least 85% green cover and the rest being environmentally friendly non-green cover. This proportion can provide a balanced urban ecosystem which can increase the availability of clean air needed by people in urban areas. In addition, clean air can also increase the value of the beauty and comfort of a city. The condition of the Blang Padang Field area is currently starting to be used as an area of economic activity, causing a decrease in ecological quality, such as increasing air temperature and urban environmental pollution. The focus of this research is to evaluate the percentage of pavement area and green area in the Blang Padang Field area. The results can determine changes in function that occur in green open space in the area. The research method used is descriptive quantitative method. Data collection techniques were carried out through observation, interviews, literature studies and documentation studies. The results showed that the area of Blang Padang is 95,521m2 (9.5 Ha). The pavement area is 28,442m2 (2.8 Ha) with a percentage of 29.77% of the total area. Based on the results obtained, the most concerning factor is the increase in the permanent pavement area. The use of pavement on the Blang Padang field has exceeded the minimum required limit. The pavement area is used as parking facilities for both two- and four-wheeled wheels, culinary facilities and sports facilities.

Population-land spatial coupling in urban non-core region and environmental pollution: evidence from urbanization in China

Urban non-core region land exploitation and population immigration toward urban non-core areas, two fundamentals of urbanization in China, challenge the environment; however, the pollution effect remains unclear. Using prefecture-level data in China between 2003 and 2020, our study investigates the pollution effect of population-land spatial coupling in the urban non-core region. The empirical results demonstrate that excessive urban non-core region land expansion alone negatively impacts the environment. Meanwhile, outward spatial population distribution in a town, primarily measured by the relative proportion of the urban non-core region population size, directly aggravates environmental pollution on the one hand and indirectly improves the environment by alleviating the adverse effect of land-led urbanization. These findings remain robust under various regional heterogeneity analyses and still stand regardless of the investigated pollutants. The practical implications suggest that breaking through the population-land spatial coupling when the urban core region is small is advisable; meanwhile, efforts in maintaining the coupling, especially for areas with sizeable peripheral land exploitation, should be held.

Untreated Rainfall Runoff Water Quality Characteristics of Different Land Uses in Infilled Lake Areas—The Case of Wuhan Shahu

Fast urbanization in developing countries contributes to heavier pollution in urban water environments, as urbanization enhances land development and even requires lake filling to meet urban land needs, which produces significant water runoff pollution. Centralized construction brings heavier non-point source pollution, which is one of the most crucial types of pollution in urban areas. However, the pollution caused by urbanization in infilled lake areas is lack of attention. To reduce the negative impact of pollution brought on by urbanization, it is important to monitor the characteristics of runoff water qualities and their relationship with rainfall features. In this study, runoff water quality was monitored from 10 rainfall events, totaling 157 samples in the Wuhan Shahu area, an infilled lake area, to characterize the pollutant event mean concentrations (EMCs) and to explore the different effects of land-use types. COD (chemical oxygen demand), TN (total nitrogen), and TP (total phosphorus) were selected as water quality indicators. The results show that the pollutants have a significant spatial variation. Residential runoff had the largest COD (averaged EMC = 54.02 (mg/L)) and TN (averaged EMC = 2.69 (mg/L)) pollution, while road runoff had the second largest COD (averaged EMC = 48.05 (mg/L)) and TN (2.572 (mg/L)) pollution. The TP pollution level is opposite to COD and TN, as commercial and green spaces have heavier pollution, while the differences in TP pollution levels between the four types of land are not significant. The release of organic matter and nitrogen is closely related to human activities on land types, while phosphorus emission is relatively stable, indicating that it is not easily affected or controlled. In addition, the variation in pollutants between land types is also related to a certain extent. The correlation analysis shows that parameters like antecedent dry days (ADDs), rainfall intensity, and rainfall duration most significantly affect the EMCs of commercial and green spaces. Phosphorus pollutants on roads are harder to reduce. These results may help researchers to identify the specific pollutant source and find an effective method to reduce pollution in infilled lake areas and other areas.

Indoor cooking and cleaning as a source of outdoor air pollution in urban environments.

Indoor sources of air pollution, such as from cooking and cleaning, play a key role in indoor gas-phase chemistry. The focus of the impact of these activities on air quality tends to be indoors, with less attention given to the impact on air quality outside buildings. This study uses the INdoor CHEmical Model in Python (INCHEM-Py) and the Advanced Dispersion Modelling System (ADMS) to quantify the impact cooking and cleaning have on indoor and outdoor air quality for an idealised street of houses. INCHEM-Py has been developed to determine the concentrations of 106 indoor volatile organic compounds at the point they leave a building (defined as near-field concentrations). For a simulated 140 m long street with 10 equi-distant houses undertaking cooking and cleaning activities, the maximum downwind concentration of acetaldehyde increases from a background value of 0.1 ppb to 0.9 ppb post-cooking, whilst the maximum downwind chloroform concentrations increase from 1.2 to 6.2 ppt after cleaning. Although emissions to outdoors are higher when cooking and cleaning happen indoors, the contribution of these activities to total UK emissions of volatile organic compounds is low (less than 1%), and comprise about a quarter of those emitted from traffic across the UK. It is important to quantify these emissions, particularly as continued vehicle technology improvements lead to lower direct emissions outdoors, making indoor emissions relatively more important. Understanding how indoor pollution can affect outdoor environments, will allow better mitigation measures to be designed in the future that can take into account all sources of pollution that contribute to human exposure.