Elevated levels of chloramines and chlorine detected near an indoor sports complex.

Chloramines (NH ₂ Cl, NHCl ₂ , and NCl ₃ ) are toxic compounds that can be created during the use of bleach-based disinfectants that contain hypochlorous acid (HOCl) and the hypochlorite ion (OCl ^- ) as their active ingredients. Chloramines can then readily transfer from the aqueous-phase to the gas-phase. Atmospheric chemical ionization mass spectrometry using iodide adduct chemistry (I-CIMS) made observations across two periods (2014 and 2016) at an urban background site on the University of Leicester campus (Leicester, UK). Both monochloramine (NH ₂ Cl) and molecular chlorine (Cl ₂ ) were detected and positively identified from calibrated mass spectra during both sampling periods and to our knowledge, this is the first detection of NH ₂ Cl outdoors. Mixing ratios of NH ₂ Cl reached up to 2.2 and 4.0 parts per billion by volume (ppbv), with median mixing ratios of 30 and 120 parts per trillion by volume (pptv) during the 2014 and 2016 sampling periods, respectively. Levels of Cl ₂ were observed to reach up to 220 and 320 pptv. Analysis of the NH ₂ Cl and Cl ₂ data pointed to the same local source, a nearby indoor sports complex with a swimming pool and a cleaning product storage shed. No appreciable levels of NHCl ₂ and NCl ₃ were observed outdoors, suggesting the indoor pool was not likely to be the primary source of the observed ambient chloramines, as prior measurements made in indoor pool atmospheres indicate that NCl ₃ would be expected to dominate. Instead, these observations point to indoor cleaning and/or cleaning product emissions as the probable source of NH ₂ Cl and Cl ₂ where the measured levels provide indirect evidence for substantial amounts transported from indoors to outdoors. Our upper estimate for total NH ₂ Cl emissions from the University of Leicester indoor sports complexes scaled for similar sports complexes across the UK is 3.4 × 10 ⁵ ± 1.1 × 10 ⁵ μg h ^-1 and 0.0017 ± 0.00034 Gg yr ^-1 , respectively. The Cl-equivalent emissions in HCl are only an order of magnitude less to those from hazardous waste incineration and iron and steel sinter production in the UK National Atmospheric Emissions Inventory (NAEI).