Pollution Abatement Policies Research Articles

Exploration of radical chemistry, precursor sensitivity and O3 control strategies in a provincial capital city, northwestern China

As the core city in northwestern China, Xi'an has suffered from serious O3 pollution in recent years. An observational model, coupled with the Master Chemical Mechanism (V3.3.1) and comprehensive data, analyzed atmospheric oxidation capacity (AOC), O3 formation mechanism, precursor sensitivity and control strategies in Xi'an. The study examined two periods (period I and II), with notable temperature and humidity differences. Despite lower precursor levels in period I, an O3 episode (peak value: 102.68 ppb) occurred only in period I, highlighting the crucial influence of meteorological conditions. Higher removal rate of primary pollutants occurs in period I, but meteorological conditions may not alter the dominant factor of AOC. Period I exhibited markedly high OH reactivity, with aromatics, alkenes, and NOx being the main contributors. HONO photolysis (50.78%) in the morning and O3 photolysis (34.13%) in the afternoon were the main HOx sources in period I, while HONO photolysis (62.86–80.68%) was significant at daytime for period II. Higher temperatures in period I accelerated all reaction rates involved in radical cycling, especially emphasizing RO2 + NO → RO + NO2. The results of sensitivity analysis showed that O3 sensitivity regime is VOC-limited in Xi'an, but the specific reactive species target VOC reductions emissions exhibited discrepancies for two distinct periods. A 20% decrease in VOCs and a 50% decrease in NOx (VOCs/NOx = 0.4) was proposed to be the optimal solution to achieve the O3 control target in period I. This study enhances our understanding of O3 formation under different meteorological conditions and provides scientific evidence for O3 pollution abatement policies in northwestern China, with potential applicability to other cities in this region and similar countries.

Nitrogen modulates the ozone response of Mediterranean wheat: Considerations for ozone risk assessment

The experiment was conducted in an Open Top Chamber facility located in the Mediterranean basin to investigate how nitrogen (N) fertilization affects the response of wheat to ozone (O3) exposure. The study considered the response of Artur Nick, a modern wheat cultivar commonly used in the area, to three O3 exposure levels (ambient and elevated ambient, +20 and +40 nL L−1 O3), and two N fertilization doses (100 and 200 kg ha−1). Measurements included leaf gas exchange, leaf chlorophyll content, leaf and grain N content, plant growth and yield parameters. Ozone × N interactive effects were studied and quantified based on accumulated O3 concentrations above a 40 nL L−1 threshold (AOT40) and phytotoxic O3 dose (POD) indices, which are used in O3-risk assessments, from which critical levels (CL) for a 5 % effect were derived.Results revealed that O3 impacts on growth and yield parameters were stronger under the highest N fertilization dose. In consequence, O3 Critical Levels (CL) were as much as 3–4 times lower for grain yield in the high-N compared to the low-N treatment. Interestingly, O3 limited the fertilizer stimulus, strongly reducing the N use efficiency for grain yield and the agronomic efficiency of N for protein yield. Another important aspect was that 71 % of the POD was accumulated before anthesis, stressing the potential importance of O3 exposure during the vegetative phase of wheat under Mediterranean conditions, which is usually considered less important than post-anthesis exposure.In conclusion, this study suggests the need to consider crop N management in the derivation of O3 CLs, due to its effect on dose-response relationships used for CL derivation, including the potential O3 effects in N use efficiency. Therefore, N modulation could be considered in the O3-risk assessment methodology to be applied in risk exercises when negotiating air pollution abatement policies.

Transdisciplinary Research as a Means of Protecting Human Health, Ecosystems and Climate by Engaging People to Act on Air Pollution

Abstract Air pollution harms the health of humans, nature and wildlife, agricultural crops and livestock and climate. As a result, it hinders the attainment of Sustainable Development Goals 3 (Good Health and Wellbeing), 7 (Affordable and Clean Energy), 11 (Sustainable Cities and Communities) and 13 (Climate Change). In order to improve human and (agro-)ecosystem health, One Health approaches for better air quality must account for local knowledge, cultural practices and priorities. People with lower socio-economic status often have limited awareness of air pollution yet are affected most through personal exposure and increased food prices. This case trialled a new, co-created transdisciplinary approach to air pollution awareness raising in the Mukuru community in Nairobi, Kenya. The pilot study used interviews, storytelling, participatory mapping, theatre, playful activities and music with the aim of discovering affected communities’ perceptions of air pollution, increasing understanding and empowering people to demand that policy makers develop and implement effective, inclusive air pollution abatement policies. Information © The Authors 2024

Achieving Infant Mortality SDG 3 Target in South Asia and Sub-Saharan Africa: Does Carbon Emission Matter?

This study is necessitated by the high rate of infant mortality in South Asia (SA) and Sub-Saharan Africa (SSA) and the need to enhance the chances of these regions achieving SGD 3. The endemic nature of infant mortality in these regions constitutes a threat to attaining the 2030 sustainable development goal (SDG) 3 target. This study examined whether carbon emission matters and how other socioeconomic factors militate against the attainment of the infant mortality target in SA and SSA for the period 1981–2019. The study analyzed annual panel series using the robust least squares estimator. The result revealed that carbon emission per capita is the most critical impediment to attaining the SDG 3 target (25 infant mortality rate per 1000 in 2030) in SA and SSA. Fortunately, an increment in per capita income would be the strategic action to attaining the infant mortality target in these regions, and it is imperative to promote maternal education through improvement in female school enrollment rates. While the South Asian economies could afford to rely on foreign direct investment (FDI) inflows in addition to the aforementioned strategies, the SSA countries should not strongly depend on FDI to address the menace of infant mortality, rather improved social spending that is devoid of corruption and other systemic encumbrances would be more productive in arresting infant mortality in this region. Also, policymakers in Sub-Saharan African economies are encouraged to rely less on FDI and are strongly advised to improve government social spending and to implement pollution abatement policies and environmental regulations in line with international treaties and best practices.

Outdoor Air Pollution and Childhood Respiratory Disease: The Role of Oxidative Stress

The leading mechanisms through which air pollutants exert their damaging effects are the promotion of oxidative stress, the induction of an inflammatory response, and the deregulation of the immune system by reducing its ability to limit infectious agents' spreading. This influence starts in the prenatal age and continues during childhood, the most susceptible period of life, due to a lower efficiency of oxidative damage detoxification, a higher metabolic and breathing rate, and enhanced oxygen consumption per unit of body mass. Air pollution is involved in acute disorders like asthma exacerbations and upper and lower respiratory infections, including bronchiolitis, tuberculosis, and pneumoniae. Pollutants can also contribute to the onset of chronic asthma, and they can lead to a deficit in lung function and growth, long-term respiratory damage, and eventually chronic respiratory illness. Air pollution abatement policies, applied in the last decades, are contributing to mitigating air quality issues, but more efforts should be encouraged to improve acute childhood respiratory disease with possible positive long-term effects on lung function. This narrative review aims to summarize the most recent studies on the links between air pollution and childhood respiratory illness.

Assessing Multiple Inequalities and Air Pollution Abatement Policies

Addressing inequality is recognized a worldwide development objective. The literature has primarily focused on examining economic or social inequality, but rarely on environmental inequality. Centering the discussion on economic or social factors does not provide a holistic view of inequality because it is multidimensional and several facets may overlap imposing a disproportionate burden on vulnerable communities. This study investigates the magnitude of air quality inequality in conjunction with economic and social inequalities in Bogotá (Colombia). It explores where inequalities overlap and assesses alleviation measures by tackling air pollution. We develop a composite index to estimate performance in socioeconomic and air quality characteristics across the city and evaluate inequality with a variety of measures. Using an atmospheric chemical transport model, we simulate the impact of three air pollution abatement policies: paving roads, industry fuel substitution, and diesel-vehicle renewal on fine particle concentrations, and compute their effect on inequality. Results show that allocation of air quality across Bogotá is highly unequal, exceeding economic or social inequality. Evidence also indicates that economic, social and air quality disparities intersect, displaying the southwest as the most vulnerable zone. Paving roads is found to be the most progressive and cost-effective policy, reducing overall inequality between 11 and 46 percent with net benefits exceeding US$1.4 billion.

Political differences in air pollution abatement under the Clean Air Act

In this paper, we study how local politics affect state level implementation of a critical federal environmental policy, the Clean Air Act, in the electricity generation sector. The analysis focuses on the installation of capital intensive air pollution abatement technology in highly regulated “nonattainment” areas, which violate federal air quality standards. The primary research design uses a regression discontinuity in the vote share for Republican governors and event study analyses of close elections. In nonattainment areas, Republican gubernatorial control differentially decreases new air pollution abatement capital spending by 90% and the probability of installing the most effective nitrogen oxide abatement technology by nine percentage points, relative to attainment areas and the counterfactual of Democratic gubernatorial control. The health benefits from reduced nitrogen oxide emissions in nonattainment areas likely exceed the additional costs of new air pollution abatement technology at electric utilities. However, the estimated benefit-cost ratios are smaller than those from many other air pollution abatement policies and net benefits may be negative for technology that will operate for fewer than five years.

Potential Health Benefit of NO2 Abatement in China's Urban Areas: Inspirations for Source-specific Pollution Control Strategy

Potential Health Benefit of NO2 Abatement in China's Urban Areas: Inspirations for Source-specific Pollution Control Strategy

Spatiotemporal characteristics of PM2.5 and ozone concentrations in Chinese urban clusters

Despite China's public commitment to emphasise air pollution investigation and control, trends in PM2.5 and ozone concentrations in Chinese urban clusters remain unclear. This study quantifies the spatiotemporal variations in PM2.5 and surface ozone at the scale of Chinese urban clusters by using a long-term integrated dataset from 2015 to 2020. Nonlinear Granger causality testing was used to explore the spatial association patterns of PM2.5 and ozone pollution in five megacity cluster regions. The results show a significant downward trend in annual mean PM2.5 concentrations from 2015 to 2020, with a decline rate of 2.8 μg m-3 yr-1. By contrast, surface ozone concentrations increased at a rate of 2.1 μg m-3 yr-1 over the 6 years. The annual mean PM2.5 concentrations in urban clusters show significant spatial clustering characteristics, mainly in Beijing-Tianjin-Hebei (BTH), Fenwei Plain (FWP), Northern slope of Tianshan Mountains urban cluster (NSTM), Sichuan Basin urban cluster (SCB), and Yangtze River Delta (YRD). Surface ozone shows severe summertime pollution and distributional variability, with increased ozone pollution in major urban clusters. The highest increases were observed in BTH, Yangtze River midstream urban cluster (YRMR), YRD, and Pearl River Delta (PRD). Nonlinear Granger causality tests showed that PM2.5 was a nonlinear Granger cause of ozone, further supporting the literature's findings that PM2.5 reduction promoted photochemical reaction rates and stimulated ozone production. The nonlinear test statistic passed the significance test in magnitude and statistical significance. FWP was an exception, with no significant long-term nonlinear causal link between PM2.5 and ozone. This study highlights the challenges of compounded air pollution caused primarily by ozone and secondary PM2.5. These results have implications for the design of synergistic pollution abatement policies for coupled urban clusters.

Air Quality of Work, Residential, and Traffic Areas during the COVID-19 Lockdown with Insights to Improve Air Quality.

This study investigated the concentrations of air pollutants (NO, NO2, NOx, SO2, CO, O3, PM10, and PM2.5) at three sites with different traffic loads (work, residential, and traffic sites) before, during, and after the COVID-19 lockdown. The main objective of this study was to evaluate the effects and associated potential pollution control implications of the lockdown on the quality of ambient air at three selected sites in the urban area of Riyadh City. The average concentrations of NO, NO2, NOx, and CO decreased during the lockdown period by 73%, 44%, 53%, and 32% at the work site; 222%, 85%, 100%, and 60% at the residential site; and 133%, 60%, 101%, and 103% at the traffic site relative to the pre-lockdown period, respectively. The average concentration of O3 increased by 6% at the work site, whereas the concentration of SO2 increased by 27% at the residential site and decreased by 6.5% at the work site. The changes in PM10 and PM2.5 varied and did not exhibit a clear pattern. The air quality index (AQI) results indicated that the contribution to “undesired” air quality by O3 was 35.29% of the lockdown period at the work site while contributions to undesired air quality by PM10 and PM2.5 were 75.6% and 100% at the work site, 94.5% and 100% at the residential site, and 96.7% and 100% at the traffic site, respectively. The findings of this study are useful for devising effective urban pollution abatement policies. Applying control measures comparable to the lockdown measures over one week will result in a decrease of approximately 19% and 15% in CO mean concentration and 25% and 18% in NO2 mean concentration at residential and traffic sites, respectively.

The cost of inaction in air pollution abatement policies

Two alternative air quality policies are compared: one is the application of only mandatory abatement measures from 2020 to 2030. The second is the definition of a more active and locally-based policy that will lead to a better air quality at the end of the decade. Using an integrated modelling system, we demonstrate that the active policy is quite more convenient from the economic viewpoint, at least for the specific situation of the Lombardy region, considered in the study. Improving particulate matter concentrations may however produce worse ozone values. A full view of all pollutants is thus necessary when planning for air quality at regional level.

Hydroeconomic modeling for assessing water scarcity and agricultural pollution abatement policies in the Ebro River Basin, Spain

Water scarcity and water quality degradation are major problems in many basins across the world, especially in arid and semiarid regions. The severe pressures on basins are the consequence of the intensification of food production systems and the unrelenting growth of population and income. Agriculture is a major factor in the depletion and degradation of water resources, and contributes to the emissions of greenhouse gases (GHG). Our study analyzes water allocation and agricultural pollution into watercourses and the atmosphere, with the purpose of identifying cost-effective policies for sustainable water management in the Ebro River Basin (Spain). The study develops an hydroeconomic model that integrates hydrological, economic and water quality aspects, capturing the main spatial and sectoral interactions in the basin. The model is used to analyze water scarcity and agricultural pollution under normal and droughts conditions, providing information for evaluating mitigation and adaptation policies. Results indicate that drought events increase nitrate concentration by up to 63% and decrease water availability by 42% at the mouth of Ebro River, highlighting the tradeoffs between water quantity and quality. All mitigation and adaptation policies reduce the effects of climate change, improving water quality and reducing GHGs’ emissions, thus lowering environmental damages and enhancing social well-being. Manure fertilization and optimizing the use of synthetic fertilizers are important cost-effective policies increasing social benefits in a range between 50 and 160 million Euros. Results show that irrigation modernization increases the efficient use of nitrogen and water, augmenting social benefits by up to 90 million Euros, and enlarging stream flows at the river mouth. In contrast, manure treatment plants reduce private and social benefits even though they achieve the lowest nitrate concentrations. Our study provides insights on the synergies and tradeoffs between environmental and economic objectives. Another finding is that drought conditions decrease the effectiveness of policies, and increase the tradeoffs between water availability and nitrate pollution. The results contribute to the discussion of designing cost-effective policies for the abatement of agricultural polluting emissions into water and the atmosphere.

Quantifying the impact of ozone on crops in Sub-Saharan Africa demonstrates regional and local hotspots of production loss.

Tropospheric ozone can have a detrimental effect on vegetation, including reducing the quantity of crop yield. This study uses modelled ozone flux values (POD3IAM; phytotoxic ozone dose above 3 nmol m-2 s-1, parameterised for integrated assessment modelling) for 2015, together with species-specific flux-effect relationships, spatial data on production and growing season dates to quantify the impact of ozone on the production of common wheat (Triticum aestivum) and common beans (Phaseolus vulgaris) across Sub-Saharan Africa (SSA). A case study for South Africa was also done using detailed data per province. Results suggest that ozone pollution could decrease wheat yield by between 2 and 13%, with a total annual loss of 453,000 t across SSA. The impact on bean production depended on the season; however, estimated yield losses were up to 21% in some areas of SSA, with an annual loss of ~300,000 t for each of the two main growing seasons. Production losses tended to be greater in countries with the highest production, for example, Ethiopia (wheat) and Tanzania (beans). This study provides an indication of the location of areas at high risk of crop losses due to ozone. Results emphasise that efforts to reduce ozone precursors could contribute to reducing the yield gap in SSA. More stringent air pollution abatement policies are required to reduce crop losses to ozone in the future.

Assessing Multiple Inequalities and Air Pollution Abatement Policies

Addressing inequality is recognized a worldwide development objective. The literature has primarily focused on examining economic or social inequality, but rarely on environmental inequality. Since inequality is multidimensional, several facets may overlap imposing a disproportionate burden on vulnerable communities. This study investigates the magnitude of air-quality inequality in conjunction with economic and social inequalities in Bogota (Colombia). It explores where inequalities overlap and assesses alleviation measures by tackling air pollution. We develop a composite index to estimate performance in socioeconomic and air quality characteristics across the city and evaluate inequality with a variety of measures. Using an atmospheric-chemical transport model, we simulate the impact of three air pollution abatement policies: paving roads, industry fuel substitution, and diesel-vehicle renewal on fine particle concentrations, and compute their effect on inequality. Results show that allocation of air-quality across Bogota is highly unequal, exceeding economic or social inequality. Evidence indicates economic, social and air quality disparities intersect displaying southwest as the most vulnerable zone. Paving roads is the most progressive and cost-effective policy, reducing overall inequality between 19-84% with net benefits exceeding US$479 million. Our analysis also suggests that benefits of renewing diesel heavy- and light-duty vehicles do not compensate the costs.

Impact of the exclusive median bus lane system on air pollution concentrations in Seoul, Korea

Since many previous studies reported the health effect of air pollution and indicated traffic as a major pollution source, significant policy efforts have been made to control traffic to reduce air pollution. However, there have been few studies that evaluated such policy implementation. In Seoul, Korea, the exclusive median bus lane system was implemented in 2004, and the metropolitan government applied air pollution reduction policies such as conversion of diesel buses to compressed natural gas buses and installation of emission control devices. This paper aimed to investigate the impact of the exclusive median bus lane system on air pollution reduction. Using hourly concentrations of particulate matter (PM10) and nitrogen dioxide (NO2) measured at 131 regulatory monitoring sites in Seoul and Gyeonggi-do for 2001-2014, we calculated annual and daily average concentrations at each site. We assessed the impact of the policy using differences-in-differences analysis by annual and daily average models after adjusting for geographic and/or meteorological variables. This method divides population into treatment and control groups with and without policy application, and compares the difference between the two time periods before and after the policy implementation in the treatment group with the difference in the control group. We classified all monitoring sites into treatment and control groups using two definitions: 1) Seoul vs. Gyeonggi; 2) within vs. outside 300 meters from the median bus lane. Pre- and post-policy periods were defined as 2001-2005 and 2006-2014, and 2004 and 2014 in the annual and daily models, respectively. The decrease in PM10 concentrations between the two periods across monitoring sites in the treatment group was larger by 1.73-5.88 μg/m3 than in the control group. NO2 also showed the decrease without statistical significance. Our findings suggest that an efficient public transport policy combined with pollution abatement policies can contribute to reduction in air pollution.

How to design fully cooperative policies to abate transboundary air pollution between two highly asymmetric regions: An abnormal incrementalism analysis

Noncooperative policies for transboundary pollution abatement are inefficient and ineffective, but cooperative policies for pollution abatement are seldom successful in regions that have different development goals and conflicting interests. In this paper, by extracting the key components that lead to the success of pollution reduction policies between Hong Kong (HK) and Guangdong, we aim to construct a general framework for cooperative environmental management. The incentive for and the dynamic trajectory, core measures, and outcomes of cooperative pollution abatement policies to address transboundary air pollution were studied using incrementalism analysis. The context that drives the abnormal increment of cooperative policies between HK and Guangdong was analyzed to determine the factors that affect the full cooperation process. The political union between HK and China is the main driving force for fostering cooperative policies in these two regions that have highly asymmetric economic development levels and pollution emission intensities. The factors for successfully designing cooperative pollution reduction policies are revealed from trust building, political support, efficient governance, precise policies, a rational cost-sharing mechanism, and detailed management and implementation plans. Innovative multi-level and cross-department governance, and an unequal but rational cost-sharing scheme sustain long-term cooperation. A general framework is derived from these empirical key components and constructed as a systematic approach to provide a guide for designing cooperation in transboundary pollution reduction for the sustainable management of cross-border natural resources in different regions with conflicts of interest.

Multidecadal trend analysis of in situ aerosol radiative properties around the world

Abstract. In order to assess the evolution of aerosol parameters affecting climate change, a long-term trend analysis of aerosol optical properties was performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single scattering albedo, backscattering fraction, scattering and absorption Ångström exponents covered at least 10 years and up to 40 years for some stations. The non-parametric seasonal Mann–Kendall (MK) statistical test associated with several pre-whitening methods and with Sen's slope was used as the main trend analysis method. Comparisons with general least mean square associated with autoregressive bootstrap (GLS/ARB) and with standard least mean square analysis (LMS) enabled confirmation of the detected MK statistically significant trends and the assessment of advantages and limitations of each method. Currently, scattering and backscattering coefficient trends are mostly decreasing in Europe and North America and are not statistically significant in Asia, while polar stations exhibit a mix of increasing and decreasing trends. A few increasing trends are also found at some stations in North America and Australia. Absorption coefficient time series also exhibit primarily decreasing trends. For single scattering albedo, 52 % of the sites exhibit statistically significant positive trends, mostly in Asia, eastern/northern Europe and the Arctic, 22 % of sites exhibit statistically significant negative trends, mostly in central Europe and central North America, while the remaining 26 % of sites have trends which are not statistically significant. In addition to evaluating trends for the overall time series, the evolution of the trends in sequential 10-year segments was also analyzed. For scattering and backscattering, statistically significant increasing 10-year trends are primarily found for earlier periods (10-year trends ending in 2010–2015) for polar stations and Mauna Loa. For most of the stations, the present-day statistically significant decreasing 10-year trends of the single scattering albedo were preceded by not statistically significant and statistically significant increasing 10-year trends. The effect of air pollution abatement policies in continental North America is very obvious in the 10-year trends of the scattering coefficient – there is a shift to statistically significant negative trends in 2009–2012 for all stations in the eastern and central USA. This long-term trend analysis of aerosol radiative properties with a broad spatial coverage provides insight into potential aerosol effects on climate changes.

Assessment of real and perceived cost-effectiveness to inform agricultural diffuse pollution mitigation policies

Diffuse water pollution is a major problem in many agroecosystems, especially in irrigated areas linked to ecosystems of high ecological value. Pollution abatement policies imply the modification of agricultural measures and are usually rejected by farmers because of their impact on farm profitability. This paper aims to design an assessment procedure for an implementation programme of agricultural measures aimed at mitigating diffuse pollution, by combining relative effectiveness across measures with the perceived and real cost of the measures. Measures proposed by a law intended to mitigate diffuse pollution and thereby the degradation of the Mar Menor lagoon, a unique natural space in the southeast of Spain, have been used as a case study. The real cost was obtained from the market, and the perceived cost of the measures was obtained from a representative sample of the farmers involved. This work has allowed comparative real and perceived evaluations of the cost-effectiveness of the proposed measures to prioritise them and to reduce information bias, aimed to favours measures adoption. Results show that banning crops less than 100 m from the coast is the most cost-effective measure, followed by the adoption of a nitrate reduction system in desalinated effluent. Divergences between real and perceived cost-effectiveness indicates that good agricultural practices code adoption would require specific actions to reduce these subjective gap. Finally, increasing the acceptability of the policy would imply translating to the farmers information required to reduce the gap between real and perceived cost of the specific agricultural measures.

Pollution accumulation and abatement policies in two supply chains under vertical and horizontal competition and strategy types

This research investigates the impact of both horizontal and vertical competition, on the one hand, and strategy types (commitment-based versus contingent-based equilibrium strategies), on the other hand, on the pollution accumulated by two supply chains over time. We consider a two-stage game model where two manufacturers and two retailers are involved in a wholesale price contract, in order to supply the demand over a finite time horizon. In the first stage of the game, the manufacturers set their respective optimal transfer prices. During the second stage, polluting emissions are created over time in proportion with demand, which is controlled by the retailers’ respective consumer prices. In this stage, the manufacturers are involved in emissions abatement. In this setup, we seek to identify the combination of market structure and strategy type that leads the two supply chains to generate the lowest pollution intensity and the highest level of abatement intensity.

Pervasive Arctic lead pollution suggests substantial growth in medieval silver production modulated by plague, climate, and conflict

Lead pollution in Arctic ice reflects large-scale historical changes in midlatitude industrial activities such as ancient lead/silver production and recent fossil fuel burning. Here we used measurements in a broad array of 13 accurately dated ice cores from Greenland and Severnaya Zemlya to document spatial and temporal changes in Arctic lead pollution from 200 BCE to 2010 CE, with interpretation focused on 500 to 2010 CE. Atmospheric transport modeling indicates that Arctic lead pollution was primarily from European emissions before the 19th-century Industrial Revolution. Temporal variability was surprisingly similar across the large swath of the Arctic represented by the array, with 250- to 300-fold increases in lead pollution observed from the Early Middle Ages to the 1970s industrial peak. Superimposed on these exponential changes were pronounced, multiannual to multidecadal variations, marked by increases coincident with exploitation of new mining regions, improved technologies, and periods of economic prosperity; and decreases coincident with climate disruptions, famines, major wars, and plagues. Results suggest substantial overall growth in lead/silver mining and smelting emissions-and so silver production-from the Early through High Middle Ages, particularly in northern Europe, with lower growth during the Late Middle Ages into the Early Modern Period. Near the end of the second plague pandemic (1348 to ∼1700 CE), lead pollution increased sharply through the Industrial Revolution. North American and European pollution abatement policies have reduced Arctic lead pollution by >80% since the 1970s, but recent levels remain ∼60-fold higher than at the start of the Middle Ages.