Influence of biomass burning plumes on HONO chemistry in eastern China

Abstract

Abstract. Nitrous acid (HONO) plays a key role in atmospheric chemistry by influencing the budget of hydroxyl radical (OH). In this study, a two-month measurement of HONO and related quantities were analyzed during a biomass burning season in 2012 at a suburban site in the western Yangtze River delta, eastern China. An overall high HONO concentration with the mean value of 0.76 ppbv (0.01 ppbv to 5.95 ppbv) was observed. During biomass burning (BB) periods, both HONO concentration and HONO/NO 2 ratio were enhanced significantly (more than a factor of 2, p<0.01) compared with non-biomass burning (non-BB) periods. A correlation analysis showed that the HONO in BB plumes was more correlated with nitrogen dioxide (NO 2 ) than that with potassium (a tracer of BB). Estimation by the method of potassium tracing suggests a maximum contribution of 17 ± 12 % from BB emission to the observed HONO concentrations, and the other over 80 % of the observed nighttime HONO concentrations during BB periods were secondarily produced by the heterogeneous conversion of NO 2 . The NO 2 -to-HONO conversion rate (C HONO ) in BB plumes was almost twice as that in non-BB plumes (0.0062 hr −1 vs. 0.0032 hr −1 ). Given that the residence time of the BB air masses was lower than that of non-BB air masses, these results suggest BB aerosols have higher NO 2 conversion potentials to form HONO than non-BB aerosols. A further analysis based on comparing the surface area at similar particle mass levels and HONO/NO 2 ratios at similar surface area levels suggested larger specific surface areas and higher NO 2 conversion efficiencies of BB aerosols. A mixed plume of BB and anthropogenic fossil fuel (FF) emissions was observed on 10 June with even higher HONO concentrations and HONO/NO 2 ratios. The strong HONO production potential (high HONO/NO 2 to PM 2.5 ratio) was accompanied with a high sulfate concentration in this plume, suggesting a promotion of mixed aerosols to the HONO formation. In summary, our study suggests an important role of BB in atmospheric chemistry by affecting the HONO budget. This can be especially important in eastern China, where agricultural burning plumes are inevitably mixed with urban and industrial pollution.

Aerosol size distribution and new particle formation in the western Yangtze River Delta of China: 2 years of measurements at the SORPES station

“…2d). Here, we defined BB events as potassium concentration K + > 2 µg cm −3 and K + / PM 2.5 ratio > 0.02 (K + was measured using MARGA; Nie et al, 2015). The average NC of accumulation-mode particles during BB events in June was 31 700 cm −3 , which is almost 6 times higher than the corresponding NC in non-BB event days (5300 cm −3 ).…”

“…Relatively large (> 100 nm) particles are emitted directly from BB (Reid et al, 2005;Li et al, 2007), or formed rapidly after emissions by the combination of NPF and various particle growth processes (Hennigan et al, 2012;Vakkari et al, 2014). Such particles are able to promote atmospheric heterogeneous chemistry by providing a large surface area (Nie et al, 2015), influence the global climate by enhancing the cloud condensation nuclei capacity (Hennigan et al, 2012), and even change the everyday weather (Ding et al, 2013b). …”

Persistent sulfate formation from London Fog to Chinese haze

“…The sampling site in Beijing (from 21 January to 4 February 2015) was located on the campus of Peking University in northwestern Beijing (21). Gaseous species and PM properties were monitored by a suite of instrumentations and methods (54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64). Laboratory experiments were performed to evaluate SO 2 oxidation by NO 2 on bulk solutions and aerosols under dark conditions (see also SI Appendix).…”

Ambient Particles (PM10, PM2.5 and PM1.0) and PM2.5 Chemical Components in Western Yangtze River Delta (YRD): An Overview of Data from 1-year Online Continuous Monitoring at Nanjing

“…MARGA is also capable in measurements of some gases like NH 3 , SO 2 , HCl, HNO 3 and HONO. More details about the instrument setup and detection limits can be found in some previous publications (Cowen et al 2011;Xie et al 2015;Nie et al 2015). Briefly, the system included a wet rotating denuder for gases and a steam Jet aerosol collector for particle.…”