Effects Of Urban Air Pollution Research Articles

Impact of Urban Air Quality on Total Factor Productivity: Empirical Insights from Chinese Listed Companies

Urban air quality is inextricably linked to the operations of micro-firms. This paper employs the “Qinling-Huaihe” River demarcation as an instrumental variable to construct a regression discontinuity design (RDD) coupled with the two-stage least squares (2SLS) approach. This methodological framework is utilized to investigate the influence of urban air quality on the corporate total factor productivity (CTFP) of publicly listed manufacturing firms from 2015 to 2020. Drawing on the broken windows theory of urban decay and the general equilibrium theory, this research elucidates a significant adverse effect of urban air pollution on CTFP. We rigorously confirm the validity of the RDD by conducting covariate continuity tests and manipulating distributional variables. Furthermore, the robustness of the baseline regression outcomes is substantiated through a series of sensitivity, robustness, and endogeneity checks, employing alternative instrumental variables. The analysis extends to examining the heterogeneity across environmental attributes, regional features, and green branding. The mechanistic investigation reveals that public environmental concerns, financing constraints, and investments in technological innovation serve as mediators in the nexus between urban air pollution and CTFP. Additionally, it is observed that environmental regulation exerts a positive moderating influence, whereas female leadership has a negative impact in this context. The imperative for timely environmental governance is underscored by these findings, which offer crucial insights for policymakers seeking to refine business environment strategies and for corporations aiming to pursue sustainable growth.

Determinants of honeybee hive survival and its implications for urban biodiversity in Toronto and Montreal: A Canadian case study

Cities are shown to provide favourable conditions for western honeybees (Apis mellifera) by protecting them from agricultural pesticides and offering a greater diversity of flora. Nevertheless, while current research primarily focuses on the causes of pollinator – and particularly honeybee – decline, including pesticide exposure, climate change, and habitat fragmentation, little attention is dedicated to urban apiculture and factors associated with the survival of honeybees within cities. Here, we analyse data from 3,697 honeybee hives in Montreal and Toronto to assess the effect of urban and environmental factors on hive survival. We find ground-level ozone concentrations, the height at which hives are located, and the number of surrounding hives to be negatively associated with hive survival, which may point towards an issue of hive saturation. Conversely, vegetation density and the COVID-19 pandemic are positively associated with the likelihood of hive survival, emphasizing the effect of urban air pollution. These findings highlight the need for urban planners to consider neighborhood-scale environmental factors to identify potential venues for enhancing honeybee survival within cities beyond existing urban beekeeping initiatives.

There Is Still a Need for a Comprehensive Investigation of the Health Consequences of Exposure to Urban Air with Special Regard to Particulate Matter (PM) and Cardiovascular Effects

Air pollution is a foremost public health problem worldwide. The pulmonary effects of air pollution have been well established for decades, and substantial epidemiological evidence is consistently showing that both acute and chronic exposure to air pollution is linked to cardiovascular morbidity and mortality. The underlying cause for this link is, however, still unknown, and many questions remain open. Most of the epidemiological studies focusing on health consequences of exposure to urban air used data from air monitoring stations or—when applying personal sampling or monitoring—measured a limited number of components to assess the exposure. On the other hand, studies conducting a decent exposure characterization and measuring a relatively large number of components with personal sampling had little or no focus on the effects and investigated only a few biomarkers. The number of research studies on this topic is huge, but at the same time, it seems as if there was no need for a comprehensive examination of the effects of urban air pollution on health. Researchers and research supporting organizations, in their fascination with the search for “novelty” and “beyond state-of-the-art”, do not seem to be aware of that they will never be able to assemble the whole picture from the puzzle pieces of research activities focusing only on certain aspects. Without a comprehensive investigation, we might never be able to answer such questions as (i) which of the urban air pollutants are forerunners in causing health effects, especially cardiovascular effects? (ii) Which biomarkers have the best predictor performance in early effects? (iii) Are there biomarkers or combinations of biomarkers that can help determine the degree of individual susceptibility and sensitivity and the dependence of these by different factors (e.g., age, gender, and physical activity)? The authors of this article aim to go through the already investigated—at the same time, essential—elements of the topic and propose a more comprehensive study, which, of course, can be expanded, debated, and improved.

The Effect of Urban Air Pollution from Traffic on Semen Quality

Background: We examined sperm quality in a cohort of city policemen in the capital city of Prague, an area experiencing elevated air pollution levels as a result of a substantial rise in traffic. As the control group, policemen working in Ceske Budejovice were selected due to this city’s location in a nonindustrial area characterized by substantially lower pollution levels compared to Prague

And then came this number PM2.5: Atmospheric particulate matter, sociotechnical imaginaries, and the politics of air quality data

This article employs the concept of sociotechnical imaginaries to examine the broader political ecology of particulate air pollution, especially the connections between novel technoscientific practices of making pollution perceptible and data-driven modes of urban governance. Drawing on ethnographic material from Beijing, a city notorious for its pervasive smog, the article highlights the role of air quality data—such as particulate matter measurements (PM2.5) and air quality indexes (AQI)—not only in informing citizens of the health-threatening air pollution but also in influencing new regimes of visibility and shaping practices of urban citizenship. Through the conceptual lens of sociotechnical imaginaries, the article shows that air quality data, increasingly shared digitally in the form of real-time continuous data streams, are not merely technoscientific indexes, nor are they value-neutral. Rather, their conceptualization is informed by technocractic visions of human-air relations and shaped by digital infrastructures. Learning from Beijing, the article argues that in order to generate an expanded understanding of the life-structuring effects of urban air pollution in the era of data-driven urbanism, political ecology of urban air needs to be considerate of how the numbers, which represent pollution, are conceptualized, amassed, and circulated, as well as what and whom they include or exclude.

Spatio-Temporal Air Pollutant Characterization for Urban Areas

Urban pollution has now become increasingly recognized as an important determinant of air pollution in developed countries. The effect of urban air pollution in developing countries, on the other hand, has not been adequately addressed in the data Spatio-temporal time series. Thus, this study was intended to characterize the effect of urbanization on air pollution for an urbanized Klang Valley, Malaysia using Spatio-temporal data from 2008 to 2017. The Air Pollution Index (API) data and local pollutant concentration were employed to establish the links between urban air pollution. The analysis will be supported by determining the source of pollutants during the study period using Principal Component Analysis (PCA). The study identified that Carbon monoxide (CO), Nitrogen Dioxide (NO2), and Ozone (O3) are the major air pollution that has contributed to degrading air quality in the Klang Valley due to the vehicles, combustion process, and industries.

Environmental regulation, economic development and air pollution in the cities of China: Spatial econometric analysis based on policy scoring and satellite data

Air pollution has become a key problem to be solved in the process of sustainable development in China. Most existing research on environmental regulation has focused on one dimension or several aspects of environmental regulation. This paper quantitatively scored environmental policies in China from multiple dimensions to construct the index of environmental regulation and used a spatial econometric model and satellite-monitored PM2.5 data for 280 cities in 2002–2016 to analyze the effects of environmental regulation on city air pollution treatment in the country. The empirical results showed that (a) there was a significant positive correlation for the spatial distribution of air pollution in China (0.87 in 2007) and the current air pollution situation was susceptible to the effects of its previous (the time lag effect of urban air pollution in eastern China is the strongest, which was 0.347); (b) environmental regulation could significantly improve the air pollution situation in the cities of northern and eastern regions; (c) the decomposition of the spatial spillover effect confirmed the role of environmental regulation in improving air quality in the region or surrounding areas. (d) we found the inverted U-shaped relationship between city economic development and air pollution in southern cities, the environmental Kuznets curve was verified; In the future, breaking the “barriers” in pollution treatment between regions and strengthening regional conversation and cooperation are effective approaches to treating air pollution.

Effect of urban air pollution on CRP and coagulation: a study on inpatients with acute exacerbation of chronic obstructive pulmonary disease

PurposeAcute exacerbation of chronic obstructive pulmonary disease (AECOPD) is an important event in the course of chronic obstructive pulmonary disease that negatively affects patients’ quality of life and leads to higher socioeconomic costs. While previous studies have demonstrated a significant association between urban air pollution and hospitalization for AECOPD, there is a lack of research on the impact of particulate matter (PM) on inflammation and coagulation in AECOPD inpatients. Therefore, this study investigated the association of changes in coagulation function and C-reactive protein (CRP) with PM levels in the days preceding hospitalization.Patients and methodsWe reviewed the medical records of AECOPD patients admitted to Putuo Hospital, Shanghai University of Traditional Chinese Medicine, between March 2017 and September 2019. We analyzed the association of coagulation function and CRP level in AECOPD patients with PM levels in the days before hospitalization. Multivariate unconditional logistic regression analyses were used to evaluate the adjusted odds ratio (OR) and 95% confidence interval (CI) for the association of CRP data with hospitalization day. Kruskal–Wallis tests were used to evaluate mean aerodynamic diameter of ≥ 2.5 μm (PM2.5) exposure on the day before hospitalization; we assessed its association with changes in prothrombin time (PT) in AECOPD inpatients with different Global Initiative for Chronic Obstructive Lung Disease (GOLD) classes.ResultsThe peripheral blood PT of AECOPD patients with PM2.5 ≥ 25 mg/L on the day before hospitalization were lower than those of patients with PM2.5 < 25 mg/L (t = 2.052, p = 0.041). Patients with severe GOLD class exposed to greater than 25 mg/L of PM2.5on the day before hospitalization showed significant differences in PT (F = 9.683, p = 0.008). Peripheral blood CRP levels of AECOPD patients exposed to PM2.5 ≥ 25 mg/L and PM10 ≥ 50 mg/L on the day before hospitalization were higher than those of patients exposed to PM2.5 < 25 mg/L and PM10 < 50 mg/L (t = 2.008, p = 0.046; t = 2.637, p = 0.009). Exposure to < 25 mg/L of PM2.5 on the day before hospitalization was significantly associated with CRP levels (adjusted OR 1.91; 95% CI 1.101, 3.315; p = 0.024).ConclusionExposure of patients with AECOPD to high PM levels on the day before hospitalization was associated with an increased CRP level and shortened PT. Moreover, PM2.5 had a greater effect on CRP level and PT than mean aerodynamic diameter of ≥ 10 μm (PM10). AECOPD patients with severe GOLD class were more sensitive to PM2.5-induced shortening of PT than those with other GOLD classes.

Urban air pollution induces alterations in redox metabolism and mitochondrial dysfunction in mice brain cortex

Previous reports indicate that the central nervous system (CNS) is a target of air pollution, causing tissue damage and functional alterations. Oxidative stress and neuroinflammation have been pointed out as possible mechanisms mediating these effects. The aim of this work was to study the chronic effects of urban air pollution on mice brain cortex, focusing on oxidative stress markers, and mitochondrial function. Male 8-week-old BALB/c mice were exposed to filtered air (FA, control) or urban air (UA) inside whole-body exposure chambers, located in a highly polluted area of Buenos Aires city, for up to 4 weeks. Glutathione levels, assessed as GSH/GSSG ratio, were decreased after 1 and 2 weeks of exposure to UA (45% and 25% respectively vs. FA; p < 0.05). A 38% increase in lipid peroxidation was found after 1 week of UA exposure (p < 0.05). Regarding protein oxidation, carbonyl content was significantly increased at week 2 in UA-exposed mice, compared to FA-group, and an even higher increment was found after 4 weeks of exposure (week 2: 40% p < 0.05, week 4: 54% p < 0.001). NADPH oxidase (NOX) and glutathione peroxidase (GPx) activities were augmented at all the studied time points, while superoxide dismutase (Cu,Zn-SOD cytosolic isoform) and glutathione reductase (GR) activities were increased only after 4 weeks of UA exposure (p < 0.05). The increased NOX activity was accompanied with higher expression levels of NOX2 regulatory subunit p47phox, and NOX4 (p < 0.05). Also, UA mice showed impaired mitochondrial function due to a 50% reduction in O2 consumption in active state respiration (p < 0.05), a 29% decrease in mitochondrial inner membrane potential (p < 0.05), a 65% decrease in ATP production rate (p < 0.01) and a 30% increase in H2O2 production (p < 0.01). Moreover, respiratory complexes I-III and II-III activities were decreased in UA group (30% and 36% respectively vs. FA; p < 0.05). UA exposed mice showed alterations in mitochondrial function, increased oxidant production evidenced by NOX activation, macromolecules damage and the onset of the enzymatic antioxidant system. These data indicate that oxidative stress and impaired mitochondrial function may play a key role in CNS damage mechanisms triggered by air pollution.

An assessment of ambient air quality using AQI and exceedance factor for Udaipur City, Rajasthan (India)

Air pollution is a severe issue of concern worldwide due to its most significant environmental risk to human health today. All substances that appear in excessive amounts in the environment, such as PM10, NO2, or SO2, may be associated with severe health problems. Anthropogenic sources of these pollutants are mainly responsible for the deterioration of urban air quality. These sources include stationary point sources, mobile sources, waste disposal landfills, open burning, and similar others. Due to these pollutants, people are at increased risk of various serious diseases like breathing problems and heart disease, and the death rate due to these diseases can also increase. Hence, air quality monitoring is essential in urban areas to control and regulate the emission of these pollutants to reduce the health impacts on human beings. Udaipur has been selected for the assessment of air quality with monitored air quality data. Air quality monitoring stations in Udaipur city are operated by the CPCB (Central Pollution Control Board) and RSPCB (Rajasthan State Pollution Control Board). The purpose of this study is to characterize the level of urban air pollution through the measurement of PM10, NO2, or SO2 in Udaipur city, Rajasthan (India). Four sampling locations were selected for Udaipur city to assess the effect of urban air pollution and ambient air quality, and it was monitored for a year from 1st January 2019 to 31st December 2019. The air quality index has been calculated with measured values of PM10, NO2, and SO2. The concentration of PM10 is at a critical level of pollution and primarily responsible for bad air quality and high air quality Index in Udaipur city.

Exposure to Intermittent Noise Exacerbates the Cardiovascular Response of Wistar-Kyoto Rats to Ozone Inhalation and Arrhythmogenic Challenge.

Noise has become a prevalent public health problem across the world. Although there is a significant amount of data demonstrating the harmful effects of noise on the body, very little is known about how it impacts subsequent responses to other environmental stressors like air pollution, which tend to colocalize in urban centers. Therefore, this study was conducted to determine the effect of intermittent noise on cardiovascular function and subsequent responses to ozone (O3). Male Wistar-Kyoto rats implanted with radiotelemeters to non-invasively measure heart rate (HR) and blood pressure (BP), and assess heart rate variability (HRV) and baroreflex sensitivity (BRS) were kept in the quiet or exposed to intermittent white noise (85-90dB) for one week and then exposed to either O3 (0.8ppm) or filtered air. Left ventricular function and arrhythmia sensitivity were measured 24h after exposure. Intermittent noise caused an initial increase in HR and BP, which decreased significantly later in the regimen and coincided with an increase in HRV and BRS. Noise caused HR and BP to be significantly elevated early during O3 and lower at the end when compared to animals kept in the quiet while the increased HRV and BRS persisted during the 24h after. Lastly, noise increased arrhythmogenesis and may predispose the heart to mechanical function changes after O3. This is the first study to demonstrate that intermittent noise worsens the cardiovascular response to inhaled O3. These effects may occur due to autonomic changes and dysregulation of homeostatic controls, which persist one day after exposure to noise. Hence, co-exposure to noise should be taken into account when assessing the health effects of urban air pollution.

Effect of time-varying exposure to air pollution on subjective well-being

Urban air pollution is significant enough to affect the subjective feelings and health of local residents in China. However, different air pollutants experienced over different time frames have different impacts on subjective well-being. This study analyzed hourly air pollution data and telephone survey data to assess the different time effects of air pollution (Air Quality Index, Particulate Matter PM2.5, PM10, and SO2) on subjective well-being in the short-term, the medium-term, and over the long-term exposure in Shandong, China. The results showed that the short-term effects of different air pollutants on subjective well-being were not significant; however, exposure to air pollution over the medium-term and long-term significantly lowered subjective well-being of local residents. The negative effect of exposure to long-term air pollution was significantly worse compared to exposure to the medium-term air pollution. Second, high urban green coverage and adequate public medical services can obviously improve the subjective well-being of local residents. Finally, it was found that urban residents with lower personal expectations and higher trust in local government in Shandong usually experienced higher levels of subjective well-being. The different time effects of urban air pollution may reveal deep-seated issues for urban environmental governance, and can provide information to create public policies and practical recommendations.

Children breathe their own air: Reflections on children’s geographies, the urban political ecology of air pollution, and ongoing participatory action research with undergraduates near an east London primary school

The health effects of urban air pollution are particularly acute for children. This paper details a research project with undergraduates drawing on UPE and children’s geography that attempts to address the uneven burdens of air pollution in an east London neighbourhood.

The effect of urban air pollutants in Germany: eco-efficiency analysis through fractional regression models applied after DEA and SFA efficiency predictions

Cities and living standards contribute intensively to air pollution, an environmental risk factor which causes diseases. Recently, in developed countries, the majority of cities has grown rapidly and has experienced increasing environmental problems. In this article we analyze the effect of urban air pollution considering the available data for the years 2007, 2010 and 2013 in 24 German cities. Proposing a new model, we start the analysis using data envelopment analysis (DEA) and stochastic frontier analysis (SFA) to predict eco-efficiency scores for the 24 German cities. Afterwards, it is applied fractional regression to infer about the influencing factors of the eco-efficiency scores, at the city level. Results suggest a significant impact over eco-efficiency due to the excess of PM10, the average temperature, the average of NO2 concentration and rainfall. The findings in this study hold important implications for policymakers and urban planners in Germany, especially those that coordinate environmental protection and economic development in cities. Therefore, interventions to reduce urban air pollution can be accomplished on different regulatory levels, leading to synergistic effects as the decrease of climate change effects and noise.

Urban air pollution induces redox imbalance and epithelium hyperplasia in mice cornea

The aim of the study was to evaluate the time course of the effects of urban air pollutants on the ocular surface, focusing on the morphological changes, the redox balance, and the inflammatory response of the cornea.8-week-old mice were exposed to urban or filtered air (UA-group and FA-group, respectively) in exposure chambers for 1, 2, 4, and 12 weeks. After each time, the eyes were enucleated and the corneas were isolated for biochemical analysis.UA-group corneas exhibited a continuous increase in NADPH oxidase-4 levels throughout the exposure time, suggesting an increased production of reactive oxygen species (ROS). After 1 week, an early adaptive response to ROS was observed as an increase in antioxidant enzymes. After 4 weeks, the enzymatic antioxidants were decreased, meanwhile an increase of the glutathione was shown, as a later compensatory antioxidant response. However, redox imbalance took place, evidenced by the increased oxidized proteins, which persisted up to 12 weeks. At this time point, corneal epithelium hyperplasia was also observed. The inflammatory response was modulated by the increase in IL-10 levels after 1 week, which early regulates the release of TNF-α and IL-6.These results suggest that air pollution alters the ocular surface, supported by the observed cellular hyperplasia. The redox imbalance and the inflammatory response modulated by IL-10 play a key role in the response triggered by air pollutants on the cornea. Taking into account this time course study, the ocular surface should also be considered as a relevant target of urban air pollutants.

Contribution of an environmental monitoring system to evaluate the potential effect of urban air pollution

The growth of the world’s population has been followed by the increase of residents living in urban areas, which very often results in additional pressures concerning space, ecosystems, infrastructures, facilities and the way of life. The impact of pollutants, emitted into the atmosphere, on materials is enormous and could be irreversible. The effects of the air pollution in façades and on the structural systems lead to unexpected costs for the buildings maintenance and may be avoided if pollution monitoring systems exists.This work presents a methodology to evaluate, on a regular basis, the potential impact of air pollution on historical buildings. It uses a monitoring system to collect samples of particulate matter (PM10 and PM2.5), particulate matter concentration levels and weather parameters. It is possible to act, in time, for the preservation and protection of this historical heritage by joining all of these data. This methodology could complement the studies of the environmental impact assessments on the historical buildings from the outdoor air pollution sources and contributes to the preservation and protection of the historical buildings. This work is being applied in the Portuguese midsized city of Vila Real, where the urban pollution assessment and their effects in urban historical buildings was considered the main goal.

When the wind blows: spatial spillover effects of urban air pollution in China

This paper estimates air pollution spillover effects in Chinese cities. Estimation of this spillover effect is complicated because neighboring cities share similar business/pollution cycles, and changes in wind direction can be frequent. To circumvent these empirical challenges, we propose a new approach exploiting spatial and temporal variations in PM2.5 concentrations for major cities in China’s Eastern Monsoon Region during the monsoon season. We find large pollution spillover effects. Estimates based on our preferred model specification suggest that a city’s average PM2.5 concentration increases by 0.33 (or 0.26) units during the winter (or summer) monsoon season, if PM2.5 concentrations in cities upwind of this city increase by one unit. Estimated spillover effects in plain and non-plain regions are 14%–16% larger and 45%–71% smaller, respectively, than the baseline estimates. The percentage contributions of PM2.5 pollution from upwind cities to local PM2.5 levels vary by region and can be as large as 50%.

Cytogenetic study of traffic policemen occupationally exposed to vehicle Exhaust in Erbil City/ Iraqi Kurdistan Region

Police personnel play a pivotal role in any society by ensuring security and stability. They constitute a special occupational group with exposure to violence at their work, which directly and indirectly affects their health. The first aim of this study was to assess the cytogenetic effects of urban air pollution by analyzing the chromosomal aberration frequencies and mitotic index in peripheral blood lymphocytes of traffic policemen in Erbil city. The present study was carried out on 40 traffic policemen who were worked in different streets in Erbil city included four main streets (30, 40 , 60 and 100) Meter streets so many factors were studied included smoking habit and duration of work ( less than five years and more than five years) and 20 controls at different age groups range between (22-50) years. The second objective of the present study is to know the common health problems among traffic policemen in Erbil city. The results suggest that there were a significant increase in the chromosomal aberrations included (Dicentric chromosome, chromatid gap, centromeric break and centromeric gap) in traffic policemen when compared to the controls but significant decreases in mitotic index were shown. The highest value of chromosomal aberrations was centromeric gap and lowest value of mitotic index were both founded in traffic policemen who were worked at 100 Meter street with duration of exposure for more than five years and who were smoker. Also the results suggested different health problems among traffic policemen included (respiratory, skin, eye ,neurologic and infertility problems). Most policemen with health problems are suffering from respiratory, eye and neurologic problems while fewer of them are suffering from infertility problems.

Air Pollution Exposure during School Commutes

Background Understanding of how school location impacts children’s air pollution exposure and the ability of children to walk and bike to school has been a policy issue of interest in recent years. Smart growth advocates encourage districts to locate schools in “walkable” locations, often near high-volume roadways while health professionals emphasize the importance of minimizing near-roadway exposure and support decisions to distance school locations from major roadways. As states implement laws to site schools away from high-volume roadways, such policies often lead to school locations that are disconnected from neighborhoods and accessible only by motorized transport modes. This study analyzes children’s air pollution exposure during school travel and during the school day and assesses exposure for children walking to a nearby school in a heavy diesel/heavy traffic area compared to their exposure if they were required to be bussed or driven to a remote school located in a low diesel/low traffic environment. Methods Researchers selected two neighborhoods with different air quality environments – heavy-diesel/heavy-traffic and low-diesel/low-traffic – with a synthetic sample of students. Home-to-school commuting routes were created for three modes: walk, automobile, and school bus. Air pollution exposure along each route was estimated using models developed from the Near-Road Exposures and Effects of Urban Air Pollutants (NEXUS) study, which are calibrated to capture conditions in 2010 during typical school travel periods for the Detroit metropolitan area. Daily average exposures for pollutant NOx were estimated by breaking the average school day into 5 phases (AM Commute, Unload, School Day, Load, PM Commute). Results Commuting exposure to NOx for all modes was lower for children at the low-diesel/low-traffic school than those at the high-diesel school. When children were driven or bussed outside of their neighborhood to the more distant, low-diesel school, time-weighted daily average cumulative NOx exposure was the greatest at ~340 μg/m3 if bussed and ~175 μg/m3 if driven (compared to 190 and 152 respectively if they had taken these modes to their local high-diesel neighborhood school). Conclusions Local school environments still largely drive the daily cumulative exposures to air pollutants among children; however, the exposures during school commutes are not negligible. In particular, our simulated implementation of policies that use buses to transport children to better air quality environments found no association with net reductions in daily exposure.

Outdoor Ambient Air Pollution and Neurodegenerative Diseases: the Neuroinflammation Hypothesis.

Accumulating research indicates that ambient outdoor air pollution impacts the brain and may affect neurodegenerative diseases, yet the potential underlying mechanisms are poorly understood. The neuroinflammation hypothesis holds that elevation of cytokines and reactive oxygen species in the brain mediates the deleterious effects of urban air pollution on the central nervous system (CNS). Studies in human and animal research document that neuroinflammation occurs in response to several inhaled pollutants. Microglia are a prominent source of cytokines and reactive oxygen species in the brain, implicated in the progressive neuron damage in diverse neurodegenerative diseases, and activated by inhaled components of urban air pollution through both direct and indirect pathways. The MAC1-NOX2 pathway has been identified as a mechanism through which microglia respond to different forms of air pollution, suggesting a potential common deleterious pathway. Multiple direct and indirect pathways in response to air pollution exposure likely interact in concert to exert CNS effects.