Particle Size Distribution of Halogenated Flame Retardants and Implications for Atmospheric Deposition and Transport

Abstract

This study investigates the distribution of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD) and a group of novel flame retardants (NFRs) on atmospheric aerosols. Two high volume cascade impactors were used to collect particulate fractions of ambient air over a one year period at urban and rural sites. The majority of FRs were found on the finest aerosols (<0.95 μm). Concentrations of HBCD were higher than those of ΣPBDEs. Moreover, we noted seasonality and spatial differences in particle size distributions, yet a large portion of the observed differences were due to differences in particulate matter (PM) itself. When normalized by PM, the size distributions of the FRs exhibited much greater heterogeneity. Differences existed between the FR distributions by molecular weight, with the higher molecular weight FRs (e.g., BDE-209, Dechlorane Plus) distributed more uniformly across all particulate size fractions. The seasonal, spatial, and compound-specific differences are of crucial importance when estimating dry and wet deposition of FRs as smaller aerosols have longer atmospheric residence times. Estimated wet and dry deposition of four representative FRs (BDE-47, BDE-209, HBCD, and Dechlorane Plus) using size-segregated aerosol data resulted in lower deposition estimates than when bulk aerosol data were used. This has implications for estimates of long-range atmospheric transport and atmospheric residence times, as it suggests that without size-specific distributions, these parameters could be underestimated for FRs.

Gas and particle size distributions of polychlorinated naphthalenes in the atmosphere of Beijing, China

“…The mass concentrations of PM determined in this study were almost at the same level as those measured in earlier studies in Beijing, China (Zhao et al, 2005), Guangzhou, China (Duan et al, 2007), and some Indian cities (Sharma and Maloo, 2005). However, the PM mass concentrations in this study were much higher than those reported in Shanghai, China , the Czech Republic (Okonski et al, 2014), Nagoya, Japan (Kadowaki and Naitoh, 2005), Western Europe and North America (Sharma and Maloo, 2005) and Illmitz, Austria (Barmpadimos et al, 2012).…”

“…The distribution patterns of organic pollutants in airborne particles (Ni and Zeng, 2013;Okonski et al, 2014) or dust (Cao et al, 2014;Wang et al, 2013a,b) have raised concern recently. However, to date, there has been no research on the size-specific distributions of PCNs in PM fractions in the atmosphere.…”

“…This information could also be used for PCN exposure assessments. To date, the particle size distributions of many contaminants have been studied extensively, including for PCDD/Fs (Chao et al, 2003;Chuang et al, 2015;Kaupp and McLachlan, 2000;Oh et al, 2002), PCBs , n-alkanes (Bi et al, 2005), polycyclic aromatic hydrocarbons (PAHs) (Bi et al, 2005;Duan et al, 2007;Hien et al, 2007), pesticides (Coscoll a et al, 2013), heavy metals (Zereini et al, 2005), halogenated flame retardants (Cao et al, 2014;Mandalakis et al, 2009;Okonski et al, 2014), hexabromocyclododecane (HBCD) (Ni and Zeng, 2013), tetrabromobisphenol A (TBBPA) (Ni and Zeng, 2013) and some other components (ions, organic matter and mineral matter) (S anchez-Sober on et al, 2015). Previous studies of PCNs in the atmosphere have mainly focused on the gas phase (Hogarh et al, 2012b;Li et al, 2012) and there have been few studies of particle-bound PCNs or their size distributions.…”

Non-polar organic compounds in autumn and winter aerosols in a typical city of eastern China: size distribution and impact of gas–particle partitioning on PM&lt;sub&gt;2.5&lt;/sub&gt; source apportionment

“…Additionally, another crucial factor affecting particle-bound concentrations of NPOCs is their aerodynamic diameter ). The size-specific distributions of compounds are dependent on their physical-chemical properties, gasparticle partitioning and photodegradation (Okonski et al, 2014;X. Chen et al, 2016).…”

New insight into the levels, distribution and health risk diagnosis of indoor and outdoor dust-bound FRs in colder, rural and industrial zones of Pakistan

“…Because their semi-volatile nature is considered to be a good repository of their explicit large surface area (Cao et al, 2014). These semi-volatile FRs have the potential to be partitioned between gas and particulate phases in the air being important for their environmental fate (Okonski et al, 2014). Moreover, the coarse and fine particles are the main contributor to the deposition (wet and dry) processes of the particle-bounds FRs.…”