The TOMPs ambient air monitoring network - Continuous data on UK air quality for over 20 years

A Decade of Global Atmospheric Monitoring Delivers Mixed Report Card on the Stockholm Convention

Time trends in atmospheric concentrations serve to evaluate how effective the Stockholm Convention is in reducing or eliminating environmental releases of persistent organic pollutants (POPs). Twelve years (2005-2016) of continuous monitoring with a global network of 20 sampling sites reveals that concentrations of the pesticide endosulfan began to drop coincident with its listing as POP in 2011. Concentrations of other POPs started to decrease prior to listing and during the sampling period declined very slowly or not at all. Concentrations of some unintentionally produced POPs (hexachlorobenzene, hexachlorobutadiene) increased to become the most abundant and most widely dispersed POPs in the global atmosphere. Their formation processes and release locations need to be identified to facilitate the Convention's goal of curbing releases from unintentional production.

Impacts of Proximity to Primary Source Areas on Concentrations of POPs at Global Sampling Stations Estimated from Land Cover Information

Given the considerable financial and logistical resources supporting long-term monitoring for air pollutants, and the use of these data for performance evaluation of mitigation measures, it is important to account for contributions from primary versus secondary sources. We demonstrate a simple approach for using open source Global land cover raster data from the National Mapping Organization from the Geospatial Information Authority of Japan to assess local source inputs for air measurements of legacy persistent organic pollutants (POPs)-polychlorinated biphenyls (PCBs) and organochlorine pesticides-reported under the Global atmospheric passive sampling (GAPS) Network at 119 locations for the time period 2005-2014. The land cover composition within a 10 km radius around the GAPS sites was identified to create source impact indicator (SII) vectors to quantify and rank the remoteness of the sites from human infrastructure. Using principal component analysis, three SII vectors were established to rank sites by impact of (i) general infrastructure/remoteness, (ii) urban infrastructure, and (iii) agricultural infrastructure. General infrastructure describes the combined effects of settlements and agricultural infrastructure. We found significant correlations (p < 0.05) between POP concentrations in air and specific SIIs. PCB levels in air had a statistically significant correlation to the SII ranking urban impacts around the sampling sites, while Endosulfan I, Endosulfan II, and Endosulfan sulfate had a statistically significant correlation with SII ranking agricultural impacts. The complete GAPS data set from 2004-2014 (1040 samples at 119 locations) was standardized based on the SII rankings to assess the global temporal trends of legacy POPs. SIIs were incorporated in the multiple regression analysis to determine global halving times. This includes short-term monitoring data from 79 locations that were previously excluded. Furthermore, the SII approach allows the integration of global monitoring data from different studies for broader global temporal trend analysis. This ability to link the results of independent and small-scale studies can enhance temporal trend analysis in support of the larger scale initiatives, such as inter alia, the Global Monitoring Plan and Effectiveness Evaluation of the Stockholm Convention in the case of POPs. This simple approach using open source data has a broad potential for application for other classes of air pollutants.

Spatial and Temporal Trends of Persistent Organic Pollutants across Europe after 15 Years of MONET Passive Air Sampling

The Global Monitoring Plan of the Stockholm Convention on Persistent Organic Pollutants (POPs) was established to generate long-term data necessary for evaluating the effectiveness of regulatory measures at a global scale. After 15 years of passive air monitoring (2003-2019), MONET is the first network to produce sufficient data for the analysis of continuous long-term temporal trends of POPs in air across the entire European continent. This study reports long-term concentrations of 20 POPs monitored at 32 sites in 27 European countries. As of January 1, 2019, the concentration ranges (pg/m3) were 1.1-52.8 (∑6PCB), 0.3-8.5 (∑12dl-PCB), 0.007-0.175 (∑17PCDD/F), 0.02-2.2 (∑9PBDE), 0.4-24.7 (BDE 209), 0.5-247 (∑6DDT), 1.7-818 (∑4HCH), 15.8-74.7 (HCB), and 5.9-21.5 (PeCB). Temporal trends indicate that concentrations of most POPs have declined significantly over the past 15 years, with median annual decreases ranging from -8.0 to -11.5% (halving times of 6-8 years) for ∑6PCB, ∑17PCDD/F, HCB, PeCB, and ∑9PBDE. Furthermore, no statistically significant differences were observed in either the trends or the concentrations of specific POPs at sites in Western Europe (WEOG) compared to sites in Central and Eastern Europe (CEE), which suggests relatively uniform compound-specific distribution and removal at the continental scale.

Polychlorinated biphenyls (PCB) and polychlorinated dibenzo-para-dioxins and dibenzofurans (PCDD/F) in ambient air and deposition in the German background

PCDD/Fs (17 congeners and Σ tetra -to octachloro homologues) and 209 PCBs were investigated in monthly samples of ambient air (gas + particle phase) and atmospheric deposition at two background monitoring sites in Germany in 2018/19. In atmospheric deposition samples, PCDD/F congeners as well as certain PCBs were frequently below the method quantification limits whereas values for PCDD/F homologue groups could be quantified more often. Annual deposition averages for individual PCDD/Fs were between <0.1 μg/m²d and 6.7 μg/m²d. Averages for Σ TeCDD/F to OCDD/F homologue totals in deposition were about 11 pg/m²d and 19 pg/m²d. Total PCB deposition rates were about 1900 pg/m²d and 1550 pg/m²d. PCDD/F + PCB-deposition rates were below 1 pg WHO₂₀₀₅-TEQ/m²d on average. In ambient air, both substance groups were frequently observed. Annual concentration averages for individual PCDD/F were between 0.1 fg/m³ and 50 fg/m³. Average values for Σ TeCDD/F to OCDD/F homologue totals in ambient air were 283 fg/m³ and 162 fg/m³. Total PCB concentrations were about 50 pg/m³ at both sites. PCDD/F + PCB-TEQ values were lower than 5 fg WHO₂₀₀₅-TEQ/m³ on average. Besides the frequently studied dioxin-like PCBs and six indicator PCBs, the analysis of the 209 PCBs (166 separated PCB-peaks) enabled the identification and evaluation of additional PCBs that might be of environmental concern. Of 166 PCBs or PCB-coelutions, up to 144 were quantified in air samples and up to 94 in atmospheric deposition samples. In ambient air, some of these PCBs were observed at levels similar to or exceeding those of the six indicator PCBs. Important additional PCBs in ambient air were PCB 5 + 8, PCB 11, PCB 17, PCB 18, PCB 20 + 33, PCB 31, PCB 43 + 49, PCB 44, PCB 47 + 48 + 65 + 75, PCB 93 + 95 + 98 + 102, PCB 139 + 149, and PCB 151. The presence of these PCBs in atmospheric samples implies that by analysing only selected PCBs potentially important contaminants are overlooked.

Environmental contamination and human exposure of polychlorinated biphenyls (PCBs) in China: A review

Polychlorinated biphenyls (PCBs), together with 11 other organic compounds, were initially listed as persistent organic pollutants (POPs) by the Stockholm Convention because of their potential threat to ecosystems and humans. In China, many monitoring studies have been undertaken to reveal the level of PCBs in environment since 2005 due to the introduced stricter environmental regulations. However, there are still significant gaps in understanding the overall spatial and temporal distributions of PCBs in China. This review systematically discusses the occurrence and distribution of PCBs in environmental matrices, organisms, and humans in China. Results showed that PCB contamination in northern and southern China was not significantly different, but the PCB levels in East China were commonly higher than those in West China, which might have been due to the widespread consumption of PCBs and intensive human activities in East China. Serious PCB contamination was found in e-waste disassembling areas (e.g., Taizhou of Zhejiang Province and Qingyuan and Guiyu of Guangdong Province). Higher PCB concentrations were also chronicled in megalopolises and industrial clusters. The unintentionally produced PCBs (UP-PCBs) formed during industrial thermal processes may play an increasingly significant role in PCB pollution in China. Low PCB levels were recorded in rural and underdeveloped districts, particularly in remote and high-altitude localities such as the Tibetan Plateau and the South China Sea. However, these data are limited. Human exposure to PCBs is closely related to the characteristics of environmental pollution. This review also discusses existing issues and future research prospects on PCBs in China. For instance, the accumulation characteristics and migration regularities of PCBs in food webs should be further studied. More investigations should be undertaken to assess the quantitative relationship between external and internal exposure to PCBs. For example, bioaccessibility and bioavailability studies should be supplemented to evaluate human health risks more accurately.

Application of land use regression modelling to describe atmospheric levels of semivolatile organic compounds on a national scale

Despite the success of passive sampler-based monitoring networks in capturing global atmospheric distributions of semivolatile organic compounds (SVOCs), their limited spatial resolution remains a challenge. Adequate spatial coverage is necessary to better characterize concentration gradients, identify point sources, estimate human exposure, and evaluate the effectiveness of chemical regulations such as the Stockholm Convention on Persistent Organic Pollutants. Land use regression (LUR) modelling can be used to integrate land use characteristics and other predictor variables (industrial emissions, traffic intensity, demographics, etc.) to describe or predict the distribution of air concentrations at unmeasured locations across a region or country. While LUR models are frequently applied to data-rich conventional air pollutants such as particulate matter, ozone, and nitrogen oxides, they are rarely applied to SVOCs. The MONET passive air sampling network (RECETOX, Masaryk University) continuously measures atmospheric SVOC levels across Czechia in monthly intervals. Using monitoring data from 29 MONET sites over a two-year period (2015-2017) and a variety of predictor variables, we developed LUR models to describe atmospheric levels and identify sources of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and DDT across the country. Strong and statistically significant (R² > 0.6; p < 0.05) models were derived for PAH and PCB levels on a national scale. The PAH model retained three predictor variables - heating emissions represented by domestic fuel consumption, industrial PAH point sources, and the hill:valley index, a measure of site topography. The PCB model retained two predictor variables - site elevation, and secondary sources of PCBs represented by soil concentrations. These models were then applied to Czechia as a whole, highlighting the spatial variability of atmospheric SVOC levels, and providing a tool that can be used for further optimization of sampling network design, as well as evaluating potential human and environmental chemical exposures.

Factors affecting multiple persistent organic pollutant concentrations in the air above Japan: A panel data analysis

Numerous reports have elucidated different statistical approaches to identify temporal trends in atmospheric persistent organic pollutant (POP) time series. However, the correlation of industrial activity with concentrations of atmospheric POPs in Japan has not yet been determined. Herein, a panel data analysis of a 16-year monitoring program (2003-2018) conducted by the Japanese Ministry of Environment was used to investigate a range of POPs in the atmosphere above Japan. This work focuses on polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCBz) collected each year at 53 sites across Japan. The panel analysis revealed that PCB, PCN, and PBDE concentrations were influenced by a combination of factors including year, industrial activity (municipal and industrial waste incinerators, cement kilns, steel industry, and secondary zinc production), population, temperature, and atmospheric boundary layer. However, HCB and PeCBz were not significantly affected by these factors. Industrial activity showed stronger positive correlations with all homologues of PCBs, PCNs, and PBDEs as compared to those demonstrated by population. Significant decreasing trends were identified for the atmospheric ∑PBDEs (half-life t_1/2 = 9.4 years), ∑PCNs (t_1/2 = 8.9 years), and ∑PCBs (t_1/2 = 13.5 years) concentrations, while HCB and PeCBz showed slightly increasing or steady levels. As a statistical tool, panel data analysis can contribute to the assessment of spatial and temporal trends of POPs at a national scale, while elucidating different behavioral responses to numerous environmental variables.

Tracking POPs in Global Air from the First 10 Years of the GAPS Network (2005 to 2014)

The Global Atmospheric Passive Sampling (GAPS) network, initiated in 2005 across 55 global sites, supports the global monitoring plan (GMP) of the Stockholm Convention on Persistent Organic Pollutants (POPs) by providing information on POP concentrations in air on a global scale. These data inform assessments of the long-range transport potential of POPs and the effectiveness evaluation of chemical regulation efforts, by observing changes in concentrations over time. Currently, measurements spanning 5-10 sampling years are available for 40 sites from the GAPS Network. This study was the first time that POP concentrations in air were reported on a global scale for an extended time period and the first to evaluate worldwide trends with an internally consistent sample set. For consistency between sampling years, site- and sample specific sampling rates were calculated with a new, public online model, which accounts for the effects of wind speed variability. Concentrations for legacy POPs in air between 2005 and 2014 show different trends for different organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The POPs discussed in this study were chosen due to being the most frequently detected, with detection at the majority of sites. PCB, endosulfan, and hexachlorocyclohexane (HCH) concentrations in air are decreasing at most sites. The global trends reflect global sources and recycling of HCH, ongoing emissions from old stockpiles for PCBs, and recent use restrictions for endosulfan. These chlorinated OCPs continue to present exposure threat to humans and ecosystems worldwide. Concentrations of other OCPs, such as chlordanes, heptachlor and dieldrin, are steady and/or declining slowly at the majority of sites, reflecting a transition from primary to secondary sources (i.e., re-emission from reservoirs where these POPs have accumulated historically) which now control ambient air burdens.

Persistent Organic Pollutants (POPs) and Related Chemicals in the Global Environment: Some Personal Reflections

Persistent organic pollutants (POPs) and related chemicals are fascinating because of their combination of physical-chemical properties and complex effects. Most are man-made, but some also have natural origins. They are persistent in the environment, but they can be broken down variously by biodegradation, atmospheric reactions, and abiotic transformations. They can exist in the gas or particle phases, or both, in the atmosphere and in the dissolved or particulate phases, or both, in water. These combinations mean that they may undergo long-range transport in the atmosphere or oceans, or they may stay close to sources. Hence, emissions from one country are frequently a source of contamination to another country. They are also usually lipophilic, so-combined with persistence-this means they can accumulate in organisms and biomagnify through food chains. We all have a baseline of POPs residues in our tissues, even the unborn fetus via placental transfer and the newly born baby via mother's milk. POPs in biological systems occur in mixtures, so confirming effects caused by POPs on humans and other top predators is never straightforward. Depending on which papers you read, POPs may be relatively benign, or they could be responsible for key subchronic and chronic effects on reproductive potential, on immune response, as carcinogens, and on a range of behavioral and cognitive end points. They could be a factor behind diseases and conditions which have been increasingly reported and studied in modern societies. In short, they are endlessly fascinating to scientists and a nightmare to regulators and policy makers.

Continuous nationwide atmospheric PCDD/F monitoring network in Taiwan (2006-2016): Variation in concentrations and apportionment of emission sources

Atmospheric polychlorinated-dibenzo-dioxins/dibenzo-furans (PCDD/Fs) remains an important environmental health concern. Although the total emission inventories of PCDD/Fs in Taiwan decreased from 320 to 52.1 g-I-TEQ/year during 2002-2016, the resulting concentrations of atmospheric PCDD/F and distributions in Taiwan are unknown. We, therefore, conducted a comprehensive investigation of spatial and seasonal variations and apportioned potential sources of ambient PCDD/F concentrations in Taiwan-based on 11-year observation data. A total of 1,008 atmospheric PCDD/F samples were collected from 25 air monitoring stations (from seven areas) and 1 background station for 2006-2016. Linear regression was used to model changes in PCDD/F concentrations. Principal component analysis (PCA) and positive matrix factorization (PMF) were used to identify potential contributors. PCDD/F concentrations in the ambient air gradually decreased during the study period, with a median concentration of 28.2 fg I-TEQ/m3 over 11 years. The highest median PCDD/F concentrations were found in the highly industrialized regions of western Taiwan (38.0-43.4 fg I-TEQ/m3). Lower concentrations were found in eastern Taiwan (∼10 fg I-TEQ/m3). Background stations reported the lowest concentrations of PCDD/Fs, with a median concentration of 1.47 fg I-TEQ/m3. Overall, the concentrations of atmospheric PCDD/Fs in Taiwan were higher in winter (13.4-86.7 fg I-TEQ/m3) than in summer (9.65-27.2 fg I-TEQ/m3). The PCA results indicated that PCDD/F profiles varied by both region (industrialized, urbanized, and background areas) and season. The PMF model for the overall data revealed that the major sources of PCDD/Fs were industrial activities (71.2%). However, in less industrialized areas, traffic activities, long-range transport, and open burning were dominant.

Evidence for Major Contributions of Unintentionally Produced PCBs in the Air of China: Implications for the National Source Inventory

Polychlorinated biphenyls (PCBs) were not widely manufactured or used in China before they became the subject of international bans on production. Recent work has shown that they have reached China associated with imported wastes and that there are considerable unintentional sources of PCBs that have only recently been identified. As such, it was hypothesized that the source inventory and profile of PCBs may be different or unique in China, compared to countries where they were widely used and which have been widely studied. For the first time in this study, we undertook a complete analysis of 209 PCB congeners and assessed the contribution of unintentionally produced PCBs (UP-PCBs) in the atmosphere of China, using polyurethane foam passive air samplers (PUF-PAS) deployed across a wide range of Chinese locations. ∑₂₀₉ PCBs ranged from 9 to 6856 pg/m³ (median: 95 pg/m³) during three deployments in 2016-2017. PCB 11 was one of the most detected congeners, contributing 33 ± 19% to ∑₂₀₉ PCBs. The main sources to airborne PCBs in China were estimated and ranked as pigment/painting (34%), metallurgical industry/combustion (31%), e-waste (23%), and petrochemical/plastic industry (6%). For typical Aroclor-PCBs, e-waste sources were dominated (>50%). Results from our study indicate that UP-PCBs have become the controlling source in the atmosphere of China, and an effective control strategy is urgently needed to mitigate emissions from multiple industrial sources.

Patterns of Personal Exposure to Urban Pollutants Using Personal Passive Samplers and GC × GC/ToF-MS

The performance of silicon wristband passive samplers (WB), combined with comprehensive two-dimensional gas-chromatography/time-of-flight mass-spectrometry (GC × GC/ToF-MS), for the analysis of urban derived pollutants in the personal environment was evaluated. Cumulative 5-day exposure samples from 27 individuals in areas with different geographical/socioeconomic characteristics within the Santiago Metropolitan Region (Chile) were collected during winter and summer (2016-2017). Samples were extracted without cleanup/fractionation and analyzed using targeted and nontargeted methods. The quantified semivolatile organic compounds (SVOCs, n = 33) (targeted analysis), and tentatively identified features ( n = 595-1011) (nontargeted analysis) were classified according to their use/source. Seasonal differences were observed in the targeted analysis, while seasonal and spatial differences were observed in the nontargeted analysis. Higher concentrations of combustion products were observed in winter, while higher concentrations of consumer products were found in summer. Spatial differences were observed in hierarchical clustering analysis of the nontargeted data, with distinct clusters corresponding to specific subregions of the urban area. Results from this study provide spatial and seasonal distributions of urban pollutants within an urban area and establish the utility of linking WB with nontargeted analysis as a tool to identify and prioritize new exposures to urban contaminants at the local/community level.

Assessment of POPs in air from Spain using passive sampling from 2008 to 2015. Part I: Spatial and temporal observations of PBDEs

The Stockholm Convention (SC) on Persistent Organic Pollutants (POPs) calls for the Parties' effectiveness evaluation of those measures taken to meet the reduction and eventual elimination of POPs from the environment. With that goal, air concentrations of different POP families have been measured uninterruptedly since 2008 under the Spanish Monitoring Program (SMP) by means of passive air sampling. This work focuses on data for polybrominated diphenyl ethers (PBDEs) determined in a total of 321 samples collected seasonally each year in 5 urban and 7 background sites. Neither significant temporal trends nor significant seasonal variations for total PBDE air burdens were detected. In contrast, significant variations were found among PBDE congeners. Those related to the octa-PBDE formulation significantly decreased in the study period. However, PBDEs related to the penta-formulation showed steady concentrations while PBDE-209, the congener found at the greatest levels, showed increasing or steady levels in most sampling sites. Seasonal variations were also markedly different among congeners. Concentrations of the lightest PBDEs (tri- to penta-substituted) were highly influenced by ambient temperature (T), showing maximum values in summer probably due to higher volatilization rates compared to those of heavier PBDEs. Contrarily, no clear seasonal trends were found for hexa- to deca-PBDEs, which were negatively related to precipitation; thereby, indicating an efficient atmospheric wash out by wet deposition episodes. Regarding spatial patterns, overall significant greater PBDE levels were found in cities compared to background areas, pointing out the role of highly populated areas as sources for these pollutants in Spain. Yet and especially in the case of PBDE-209, our results suggested the presence of significant unknown sources of PBDEs in some background sites. Further monitoring efforts are needed to assess potential unknown sources in the sampling network as well as to ensure temporal trends of these pollutants in Spain.

Self-organizing maps for indications of airborne polychlorinated biphenyl (PCBs) and organochlorine pesticide (OCPs) dependence on spatial and meteorological parameters

This paper investigates the relation of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in air samples with meteorological parameters (temperature, atmospheric pressure and relative humidity) using the Kohonen self-organizing map (SOM). Both gas- and particle-adsorbed phase of 20 PCB congeners and 7 OCPs including the three new ones (α-HCH, β-HCH, and γ-HCH) listed in the Stockholm Convention were collected during a one-year period at urban locations in Zagreb (Croatia). Moving beyond existing studies, the SOM analysis showed that the meteorological characteristics of transient seasons such as spring had no influence on the dissimilarities in the behavior of PCBs and OCPs. Towards the identification of pollutant spatial patterns, the SOM did not isolate a clear phenomenon probably due to the absence of local pollution sources contributing to the elevated concentrations of these compounds. Overall, our results have shown that the SOM method, by recognizing significant differences among PCB and OCP seasonality, could be recommended in the analysis of pollutant distribution depending on temperature and atmospheric pressure.

Predicting global scale exposure of humans to PCB 153 from historical emissions

Predicting human exposure to an environmental contaminant based on its emissions is one of the great challenges of environmental chemistry. It has been done successfully on a local or regional scale for some persistent organic pollutants. Here we assess whether it can be done at a global scale, using PCB 153 as a test chemical. The global multimedia fate model BETR Global and the human exposure model ACC-HUMAN were employed to predict the concentration of PCB 153 in human milk for 56 countries around the world from a global historical emissions scenario. The modeled concentrations were compared with measurements in pooled human milk samples from the UNEP/WHO Global Monitoring Plan. The modeled and measured concentrations were highly correlated (r = 0.76, p < 0.0001), and the concentrations were predicted within a factor of 4 for 49 of 78 observations. Modeled concentrations of PCB 153 in human milk were higher than measurements for some European countries, which may reflect weaknesses in the assumptions made for food sourcing and an underestimation of the rate of decrease of concentrations in air during the last decades. Conversely, modeled concentrations were lower than measurements in West African countries, and more work is needed to characterize exposure vectors in this region.

Higher atmospheric levels and contribution of black carbon in soil-air partitioning of organochlorines in Lesser Himalaya

Due to influence of wind patterns (monsoon and westerlies) and anthropogenic activities, lower stretch of Himalaya is at direct exposure to persistent organic pollutants (POPs). Current study was designed to monitor atmospheric concentrations of long lived organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) using polyurethane passive air sampling in the Lesser Himalayan Region (LHR) of Pakistan. Levels of ∑HCHs, ∑DDTs and ∑PCBs were observed in a range between 3 and 210 pg m^-3, 0.75-67.1 pg m^-3 and 8.49-458 pg m^-3, respectively. Though, air mass trajectories over LHR indicated long range transport as atmospheric source input which was further explained by Clausius-Clapeyron plots between ln P and inverse of temperature (1000/T; K) where all OCPs and most of the PCBs have shown insignificant relationship (r² = 5E-06-0.41; p-value = 0.06-0.995). However, local source emissions and valley transport may also implicate based on spatial distribution and altitudinal patterns. Additionally, soil-air partitioning of organochlorines was assessed using octanol-air partition (K_OA) and black carbon-air partition (K_BC) based models. Regression results indicated combined influence of both organic matter (r² = 0.298-0.85) and black carbon (r² = 0.31-0.86) via absorption and adsorption, respectively in soil-air partitioning of OCs in LHR. This paper sheds light on the atmospheric concentrations of OCs and help in better understanding of the processes involved in fate and transport of organic pollutants in Himalayan region. Further investigations are required to understand the role of carbon moieties in fate and transport of other groups of organic pollutants at higher altitudes of Himalayan region.

Emission Factors for Selected Semivolatile Organic Chemicals from Burning of Tropical Biomass Fuels and Estimation of Annual Australian Emissions

This study reveals that open-field biomass burning can be an important source of various semivolatile organic chemicals (SVOCs) to the atmosphere including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and a range of pesticides. Emission factors (EFs) for 39 individual SVOCs are determined from burning of various fuel types that are common in tropical Australia. Emissions of PAHs are found to be sensitive to differences in combustion efficiencies rather than fuel types, reflecting a de novo formation mechanism. In contrast, revolatilization may be important for other SVOCs such as PCBs. On the basis of the EFs determined in this work, estimates of the annual emissions of these SVOCs from Australian bushfires/wildfires are achieved, including, for example, ∑PAHs (160 (min)-1100 (max) Mg), ∑PCBs (14-300 kg), ∑PBDEs (8.8-590 kg), α-endosulfan (6.5-200 kg), and chlorpyrifos (up to 1400 kg), as well as dioxin toxic equivalents (TEQs) of ∑dioxin-like-PCBs (0.018-1.4 g). Emissions of SVOCs that are predominantly revolatilized appear to be related to their use history, with higher emissions estimated for chemicals that had a greater historical usage and were banned only recently or are still in use.