Acute respiratory symptoms and evacuation-related behavior after exposure to chlorine gas leakage

Acute chlorine poisoning caused by an accident at a swimming pool

Chlorine is an irritant gas that is widely used in water purification. Several previous reports had reported accidents of inhalation injuries at swimming pools. However, there have been limited data on the detection of on-site chlorine concentration. This study aims to report a chlorine leakage accident at a swimming pool caused by improper disinfection operations. Calculation using the gas diffusion simulation software showed that the on-site chlorine concentration was 221.45 ppm. When the accident occurred, there were 92 individuals at the swimming pool and the gym, among which 61 were referred to the emergency department of five different hospitals for feeling ill. Among them, 22 patients underwent chest high-resolution computed tomography scans in our hospital. According to the findings, 4 (18.2%) patients had peribronchitis, 3 (13.6%) had tracheobronchitis, 4 (18.2%) had pneumonia, 4 (18.2%) had interstitial pulmonary edema, and 3 (13.6%) had alveolar pulmonary edema. The symptoms of 22 patients who visited our hospital significantly improved after comprehensive treatment. Three months after the accident, 8 of 17 patients presented obstructive ventilation defects or small airway dysfunction. The accidental exposure to chlorine may induce acute poisoning with various respiratory injuries and prolonged lung dysfunction.

Removal of gaseous elemental mercury by hydrogen chloride non-thermal plasma modified biochar

Hydrogen chloride (HCl) non-thermal plasma was applied to introduce Cl active sites on biochar prepared from sorghum straw in this study. Surface modified biochar was then placed in flue gas with typical components to investigate its elemental mercury (Hg⁰) capture ability. To elucidate the adsorption mechanism & binding properties, samples were characterized by N₂ adsorption, scanning electron microscopy with energy dispersive spectrometer (SEM-EDS) and X-ray absorption near edge structure (XANES) analysis of Hg L_III-edge, Cl K-edge and S K-edge. Experimental results showed that HCl plasma modification successfully increased Cl active sites on biochar and greatly increased its mercury removal efficiency. Both HCl treatments (w/without plasma involvement) altered biochar's surface structure and layered structure generated. XANES spectra revealed that adsorbed-Hg on HCl-treated biochars mainly in the form of Hg⁺. Gaseous Hg⁰ was believed to heterogeneously react with chlorinated sites through electron-transfer and formed Hg₂Cl₂ compounds. With the presence of NO or SO₂ in the system, adsorbed mercury existed on biochar mainly as Hg⁺. SO₂ competed and inhibited the adsorption of Hg⁰; while NO promoted Hg⁰ removal capacity by increasing the active sites and enhancing the adsorption kinetics of adjacent Cl-containing sites.